HP | Generating Set | User's Manual | HP Generating Set User's Manual

GENERATING SET
INSTALLATION
MANUAL
FOREWORD
This installation manual will guide you to the factors to be considered in the
installation of your diesel generator system. It discusses location and mounting
of the generating set; size of room; ventilation and air flow; engine cooling water
supply or radiator location; exhaust outlet; fuel tank and fuel transfer system.
By following the suggestions in this installation manual, you will be able to plan
an economical, efficient generating set installation with operating characteristics
suitable to each particular application.
You can make you work easier by enlisting the aid of an FG Wilson Distributor
when planning your generating set installation. Getting his advice early may save
cost and avoid problems. He knows engines, electrical equipment, local laws and
insurance regulations. With his help, you can be sure your generating set
installation will fulfil your needs without unnecessary cost.
ii
TABLE OF CONTENTS
PAGE
1.
INSTALLATION FACTORS
1
2.
MOVING THE GENERATING SET
1
3.
GENERATING SET LOCATION
1
4.
GENERATING SET MOUNTING
2
5.
VENTILATION
3
6.
ENGINE EXHAUST
6
7.
EXHAUST SILENCING
9
8.
SOUND ATTENUATION
10
9.
ENGINE COOLING
10
10. FUEL SUPPLY
13
11. SELECTING FUELS FOR STANDBY DEPENDABILITY
18
12. TABLES AND FORMULAS FOR ENGINEERING STANDBY
GENERATING SETS:
19
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
Table 10
Table 11
Table 12
Table 13
Length Equivalents
Area Equivalents
Mass Equivalents
Volume and Capacity Equivalents
Conversions for Units of Speed
Conversions of Units of Power
Conversions for Measurements of Water
Barometric Pressures and Boiling Points of Water at Various Altitudes
Conversions of Units of Flow
Conversions of Units of Pressure and Head
Approximate Weights of Various Liquids
Electrical Formulae
kVA/kW Amperage at Various Voltages
Conversions of Centigrade and Fahrenheit
Fuel Consumption Formulas
Electrical Motor Horsepower
Piston Travel
Break Mean Effective Pressure
13. GLOSSARY OF TERMS
 Copyright 1997 by FG Wilson (Engineering) Ltd
All rights reserved. No part of the contents of this manual may be reproduced, photocopied or transmitted
in any form without the express prior written permission of FG Wilson (Engineering) Ltd.
19
19
19
20
20
20
21
21
22
22
22
23
24
25
25
25
25
25
26
Never lift the generating set by attaching to the
engine or alternator lifting lugs!
1. INSTALLATION FACTORS
Once the size of the generating set and the required
associated control panel and switchgear have been
established, plans for installation can be prepared.
Proper attention to mechanical and electrical
engineering details will assure a satisfactory power
system installation.
For lifting the generating set, lift points are
provided on the baseframe. Shackles and chains of
suitable length and lifting capacity must be used
and a spreader bar is required to prevent damaging
the set. See figure 2.1. An optional "single point
lifting bale" is available if the generating set will be
regularly moved by lifting.
Factors to be considered in the installation of a
generator are:
3. GENERATING SET
LOCATION
Access and maintenance location.
Floor loading.
Vibration transmitted to building and equipment.
Ventilation of room.
Engine exhaust piping and insulation.
Noise reduction.
Method of engine cooling.
Size and location of fuel tank.
Local, national or insurance regulations.
Smoke and emissions requirements.
The set may be located in the basement or on
another floor of the building, on a balcony, in a
penthouse on the roof or even in a separate
building. Usually it is located in the basement for
economics and for convenience of operating
personnel. The generator room should be large
enough to provide adequate air circulation and
plenty of working space around the engine and
alternator.
2. MOVING THE GENERATING
SET
If it is necessary to locate the generating set
outside the building, it can be furnished enclosed in
a housing and mounted on a skid or trailer. This
type of assembly is also useful, whether located
inside or outside the building, if the installation is
temporary. For outside installation the housing is
normally "weatherproof". This is necessary to
prevent water from entering the alternator
compartment if the generating set is to be exposed
to rain accompanied by high winds.
The generating set baseframe is specifically
designed for ease of moving the set. Improper
handling can seriously damage the generator and
components.
Using a forklift,the generating set can be lifted or
pushed/pulled by the baseframe. An optional "Oil
Field Skid" provides fork lift pockets if the set will
be regularly moved.
FIG 2.1. PROPER LIFTING ARRANGEMENT
1
4. GENERATING SET
MOUNTING
discharge duct, conduit for control and power
cables and other externally connected support
systems.
The generating set will be shipped assembled on a
rigid base that precisely aligns the alternator and
engine and needs merely to be set in place (on
vibration isolation pads for larger sets) and levelled.
See figure 4.1
4.2 Floor Loading
Floor loading depends on the total generating set
weight (including fuel and water) and the number
and size of isolator pads. With the baseframe
mounted directly on the floor, the floor loading is:
4.1 Vibration Isolation
Floor Loading =
It is recommended that the generating set be
mounted on vibration isolation pads to prevent the
set from receiving or transmitting injurious or
objectionable vibrations. Rubber isolation pads are
used when small amounts of vibration transmission
is acceptable. Steel springs in combination with
rubber pads are used to combat both light and
heavy vibrations. On smaller generating sets, these
isolation pads should be located between the
coupled engine/alternator feet and the baseframe.
The baseframe is then securely attached to the
floor. On larger sets the coupled engine/alternator
should be rigidly connected to the baseframe with
vibration isolation between the baseframe and floor.
Other effects of engine vibration can be minimised
by providing flexible connections between the
engine and fuel lines, exhaust system, radiator air
Total Generating Set Weight
Area of Skids
With vibration isolation between the baseframe and
the floor, if the load is equally distributed over all
isolators, the floor loading is:
Floor Loading =
Total Generating Set Weight
Pad Area x Number of Pads
Thus, floor loading can be reduced by increasing
the number of isolation pads.
If load is not equally distributed, the maximum floor
pressure occurs under the pad supporting the
greatest proportion of load (assuming all pads are
the same size):
Load on Heaviest Loaded Pad
Max Floor Pressure =
Pad Area
FIG 4.1 REDUCING VIBRATION TRANSMISSION
2
In providing ventilation, the objective is to maintain
the room air at a comfortable temperature that is
cool enough for efficient operation and full
available power, but it should not be so cold in
winter that the room is uncomfortable or engine
starting is difficult. Though providing adequate
ventilation seldom poses serious problems, each
installation should be analysed by both the
distributor and the customer to make sure the
ventilation provisions are satisfactory.
5. VENTILATION
Any internal combustion engine requires a liberal
supply of cool, clean air for combustion. If the air
entering the engine intake is too warm or too thin,
the engine may not produce its rated power.
Operation of the engine and alternator radiates heat
into the room and raises the temperature of the
room air. Therefore, ventilation of the generator
room is necessary to limit room temperature rise and
to make clean, cool intake air available to the
engine.
5.1 Circulation
Good ventilation requires adequate flow into and
out of the room and free circulation within the room.
Thus, the room should be of sufficient size to allow
free circulation of air, so that temperatures are
equalised and there are no pockets of stagnant air.
See figure 5.1. The generating set should be
located so that the engine intake draws air from the
cooler part of the room. If there are two or more
generating sets, avoid locating them so that air
heated by the radiator of one set flows toward the
engine intake or radiator fan of an adjacent set. See
figure 5.2.
When the engine is cooled by a set mounted
radiator, the radiator fan must move large quantities
of air through the radiator core. There must be
enough temperature difference between the air and
the water in the radiator to cool the water
sufficiently before it re-circulates through the
engine. The air temperature at the radiator inlet
depends on the temperature rise of air flowing
through the room from the room inlet ventilator. By
drawing air into the room and expelling it outdoors
through a discharge duct, the radiator fan helps to
maintain room temperature in the desirable range.
FIG 5.1 TYPICAL ARRANGEMENT FOR ADEQUATE AIR CIRCULATION AND VENTILATION
3
Both the inlet and exit ventilators should have
louvres for weather protection. These may be fixed
but preferably should be movable in cold climates.
For automatic starting generating sets, if the
louvres are movable, they should be automatically
operated and should be programmed to open
immediately upon starting the engine.
5.2 Ventilators
To bring in fresh air, there should be an inlet
ventilator opening to the outside or at least an
opening to another part of the building through
which the required amount of air can enter. In
smaller rooms, ducting may be used to bring air to
the room or directly to the engine's air intake. In
addition, an exit ventilator opening should be
located on the opposite outside wall to exhaust
warm air. See Figure 5.3.
FIG 5.2 TYPICAL ARRANGEMENT FOR PROPER VENTILATION WITH MULTIPLE GENERATING SETS
4
and silencer so that heat radiation from this source
may be neglected in calculating air flow required for
room cooling.
5.3 Inlet Ventilator Size
Before calculating the inlet ventilator size, it is
necessary to take into account the radiator cooling
air flow requirements and the fan static pressure
available when the generating set is operating at its
rated load. In standard room installations, the
radiated heat is already taken into account in the
radiator air flow.
After determining the required air flow into the
room, calculate the size of inlet ventilator opening
to be installed in the outside wall. The inlet
ventilator must be large enough so that the
negative flow restriction will not exceed a maximum
of
10 mm (0.4 in) H2O. Restriction values of air filters,
screens and louvres should be obtained from
manufacturers of these items.
For generator room installation with remote
radiators, the room cooling airflow is calculated
using the total heat radiation to the ambient air of
the engine and alternator and any part of the
exhaust system.
5.4 Exit Ventilator Size
Engine and alternator cooling air requirements for
FG Wilson generating sets when operating at rated
power are shown on specification sheets. Exhaust
system radiation depends on the length of pipe
within the room, the type of insulation used and
whether the silencer is located within the room or
outside. It it usual to insulate the exhaust piping
Where the engine and room are cooled by a set
mounted radiator, the exit ventilator must be large
enough to exhaust all of the air flowing through the
room, except the relatively small amount that enters
the engine intake.
FIG 5.3 INLET AND EXIT VENTILATORS
5
It is not normally recommended that the engine
exhaust share a flue with a furnace or other
equipment since there is danger that back pressure
caused by one will adversely affect operation of the
others. Such multiple use of a flue should be
attempted only if it is not detrimental to
performance of the engine or any other equipment
sharing the common flue.
6. ENGINE EXHAUST
Engine exhaust must be directed to the outside
through a properly designed exhaust system that
does not create excessive back pressure on the
engine. A suitable exhaust silencer should be
connected into the exhaust piping. Exhaust system
components located within the engine room should
be insulated to reduce heat radiation. The outer
end of the pipe should be equipped with a rain cap
or cut at 60° to the horizontal to prevent rain or
snow from entering the exhaust system. If the
building is equipped with a smoke detection
system, the exhaust outlet should be positioned so
it cannot set off the smoke detection alarm.
The exhaust can be directed into a special stack that
also serves as the outlet for radiator discharge air
and may be sound-insulated. The radiator
discharge air enters below the exhaust gas inlet so
that the rising radiator air mixes with the exhaust
gas. See figures 6.2 and 6.3. The silencer may be
located within the stack or in the room with its tail
pipe extending through the stack and then outward.
Air guide vanes should be installed in the stack to
turn radiator discharge air flow upward and to
reduce radiator fan air flow restriction, or the sound
insulation lining may have a curved contour to
direct air flow upward. For a generating set
enclosed in a penthouse on the roof or in a separate
outdoor enclosure or trailer, the exhaust and
radiator discharges can flow together above the
enclosure without a stack. Sometimes for this
purpose the radiator is mounted horizontally and
the fan is driven by an electric motor to discharge
air vertically.
6.1 Exhaust Piping
For both installation economy and operating
efficiency, engine location should make the exhaust
piping as short as possible with minimum bends
and restrictions. Usually the exhaust pipe extends
through an outside wall of the building and
continues up the outside of the wall to the roof.
There should be a sleeve in the wall opening to
absorb vibration and an expansion joint in the pipe
to compensate for lengthways thermal expansion or
contraction. See figure 6.1.
WALL SLEEVE
AND EXPANSION
JOINT
RAIN CAP
SILENCER/PIPEWORK
SUPPORTS
EXHAUST
SILENCER
FIG 6.1 TYPICAL EXHAUST SYSTEM INSTALLATION
6
and silencer and retained by a stainless steel or
aluminium sheath may substantially reduce heat
radiation to the room from the exhaust system.
6.2 Exhaust Pipe Flexible Section
A flexible connection between the manifold and the
exhaust piping system should be used to prevent
transmitting engine vibration to the piping and the
building, and to isolate the engine and piping from
forces due to thermal expansion, motion or weight
of piping. A well designed flex section will permit
operation with ± 13 mm (0.5 in) permanent
displacement in any direction of either end of the
section without damage. Not only must the section
have the flexibility to compensate for a nominal
amount of permanent mismatch between piping and
manifold, but it must also yield readily to
intermittent motion of the Generating Set on its
vibration isolators in response to load changes.
The flexible connector should be specified with the
Generating Set.
An additional benefit of the insulation is that it
provides sound attenuation to reduce noise in the
room.
6.4 Minimising Exhaust Flow
Restriction
Free flow of exhaust gases through the pipe is
essential to minimise exhaust back pressure.
Excessive exhaust back pressure seriously affects
engine horsepower output, durability and fuel
consumption. Restricting the discharge of gases
from the cylinder causes poor combustion and
higher operating temperatures. The major design
factors that may cause high back pressure are:
6.3 Exhaust Pipe Insulation
•
•
•
•
•
No exposed parts of the exhaust system should be
near wood or other inflammable material. Exhaust
piping inside the building (and the silencer if
mounted inside) should be covered with suitable
insulation materials to protect personnel and to
reduce room temperature. A sufficient layer of
suitable insulating material surrounding the piping
FIG 6.2
HORIZONTALLY MOUNTED EXHAUST SILENCER
WITH EXHAUST PIPE AND RADIATOR AIR
UTILISING COMMON STACK
7
Exhaust pipe diameter too small
Exhaust pipe too long
Too many sharp bends in exhaust system
Exhaust silencer restriction too high
At certain critical lengths, standing pressure
waves may cause high back pressure
FIG 6.3
RADIATOR AIR DISCHARGING INTO
SOUND-INSULATED STACK CONTAINING
EXHAUST SILENCER
Excessive restriction in the exhaust system can be
avoided by proper design and construction. To
make sure you will avoid problems related to
excessive restriction, ask The FG Wilson distributor
to review your design.
Flexible Sections:
Length (ft): 0.167 x Diameter (inches)
The following formula is used to calculate the back
pressure of an exhaust system:
The effect of pipe diameter, length and the
restriction of any bends in the system can be
calculated to make sure your exhaust system is
adequate without excessive back pressure. The
longer the pipe, and the more bends it contains, the
larger the diameter required to avoid excessive flow
restriction and back pressure. The back pressure
should be calculated during the installation stage to
make certain it will be within the recommended limits
for the engine.
P =
CLRQ
5
D
2
where:
P = back pressure in inches of mercury
C = .00059 for engine combustion airflow of 100 to 400 cfm
= .00056 for engine combustion airflow of 400 to 700 cfm
= .00049 for engine combustion airflow of 700 to 2000 cfm
= .00044 for engine combustion airflow of 2000 to
5400 cfm
L = length of exhaust pipe in feet
R = exhaust density in pounds per cubic foot
Measure the exhaust pipe length from your
installation layout. See figure 6.4. Take exhaust
flow data and back pressure limits from the
generating set engine specification sheet. Allowing
for restrictions of the exhaust silencer and any
elbows in the pipe, calculate the minimum pipe
diameter so that the total system restriction will not
exceed the recommended exhaust back pressure
limit. Allowance should be made for deterioration
and scale accumulation that may increase restriction
over a period of time.
R=
41.1
o
o
Exhaust temperature F * + 460 F
Q = exhaust gas flow in cubic feet per minute*
D = inside diameter of exhaust pipe in inches
* Available from engine specification sheet
These formulae assume that the exhaust pipe is
clean commercial steel or wrought iron. The back
pressure is dependent on the surface finish of the
piping and an increase in the pipe roughness will
increase the back pressure. The constant 41.1 is
based on the weight of combustion air and fuel
burned at rated load and SAE conditions. See
engine specification sheet for exhaust gas
temperature and air flow. Conversion tables to other
units are provided in Section 12.
Elbow restriction is most conveniently handled by
calculating an equivalent length of straight pipe for
each elbow and adding it to the total length of pipe.
For elbows and flexible sections, the equivalent
length of straight pipe is calculated as follows:
45° Elbow:
Length (ft) = 0.75 x Diameter (inches)
90° Elbow:
Length (ft) = 1.33 x Diameter (inches)
FIG 6.4 MEASURING EXHAUST PIPE LENGTH TO DETERMINE EXHAUST BACK PRESSURE
8
Silencers normally are available in two
configurations - (a) end inlet, end outlet, or (b) side
inlet, end outlet. Having the choice of these two
configurations provides flexibility of installation,
such as horizontal or vertical, above engine, on
outside wall, etc. The side-inlet type permits 90°
change of direction without using an elbow. Both
silencer configurations should contain drain fittings
in locations that assure draining the silencer in
whatever attitude it is installed.
7. EXHAUST SILENCING
Excessive noise is objectionable in most locations.
Since a large part of the generating set noise is
produced in the engine's pulsating exhaust, this
noise can be reduced to an acceptable level by
using an exhaust silencer. The required degree of
silencing depends on the location and may be
regulated by law. For example, the noise of an
engine is objectionable in a hospital area but
generally is not as objectionable in an isolated
pumping station.
7.1
The silencer may be located close to the engine,
with exhaust piping leading from the silencer to the
outside; or it may be located outdoors on the wall
or roof. Locating the silencer close to the engine
affords best overall noise attenuation because of
minimum piping to the silencer. Servicing and
draining of the silencer is likely to be more
convenient with the silencer indoors.
Exhaust Silencer Selection
The silencer reduces noise in the exhaust system by
dissipating energy in chambers and baffle tubes
and by eliminating wave reflection that causes
resonance. The silencer is selected according to
the degree of attenuation required by the site
conditions and regulations. The size of silencer and
exhaust piping should hold exhaust back pressure
within limits recommended by the engine
manufacturer.
However, mounting the silencer outside has the
advantage that the silencer need not be insulated
(though it should be surrounded by a protective
screen). The job of insulating piping within the
room is simpler when the silencer is outside, and the
insulation then can aid noise attenuation.
Silencers are rated according to their degree of
silencing by such terms as "low degree" or
"industrial", "moderate" or "residential" and "high
degree" or "critical".
•
Low-Degree or Industrial Silencing - Suitable
for industrial areas where background noise
level is relatively high or for remote areas
where partly muffled noise is permissible.
•
Moderate-Degree or Residential Silencing Reduces exhaust noise to an acceptable level
in localities where moderately effective
silencing is required - such as semiresidential areas where a moderate
background noise is always present.
•
Since silencers are large and heavy, consider their
dimensions and weight when you are planning the
exhaust system. The silencer must be adequately
supported so its weight is not applied to the
engine's exhaust manifold or turbocharger. The
silencer must fit into the space available without
requiring extra bends in the exhaust piping, which
would cause high exhaust back pressure. A sideinlet silencer may be installed horizontally above
the engine without requiring a great amount of
headroom.
Silencers or exhaust piping within reach of
personnel should be protected by guards or
insulation. Indoors, it is preferable to insulate the
silencer and piping because the insulation not only
protects personnel, but it reduces heat radiation to
the room and further reduces exhaust system noise.
Silencers mounted horizontally should be set at a
slight angle away from the engine outlet with a
drain fitting at the lowest point to allow the disposal
of any accumulated moisture.
High-Degree or Critical Silencing - Provides
maximum silencing for residential, hospital,
school, hotel, store, apartment building and
other areas where background noise level is
low and generating set noise must be kept to a
minimum.
9
8. SOUND ATTENUATION
If noise level must be limited, it should be specified
in terms of a sound pressure level at a given
distance from the generator enclosure. Then the
enclosure must be designed to attenuate the noise
generated inside the enclosure to produce the
required level outside. Don't attempt to make this
noise level unnecessarily low, because the means of
achieving it may be costly.
Use of resilient mounts for the generating set plus
normal techniques for controlling exhaust, intake
and radiator fan noise should reduce generating set
noise to an acceptable level for many installations.
If the remaining noise level is still too high, acoustic
treatment of either the room or the generating set is
necessary. Sound barriers can be erected around
the generating set, or the walls of the generator
room can be sound insulated, or the generating set
can be enclosed in a specially developed sound
insulated enclosure. See figure 8.1.
In most cases it is necessary that the air intake and
air discharge openings will have to be fitted with
sound attenuators. If it is desired to protect
operating personnel from direct exposure to
generating set noise, the instruments and control
station may be located in a separate soundinsulated control room.
9. ENGINE COOLING
Some diesel engines are air cooled but the majority
are cooled by circulating a liquid coolant through
the oil cooler if one is fitted and through passages
in the engine block and head. Hot coolant emerging
from the engine is cooled and recirculated through
the engine. Cooling devices are commonly coolantto-air (radiator) or coolant-to-raw water (heat
exchanger) types.
In the most common generating set installation, the
engine coolant is cooled in a set-mounted radiator
with air blown through the radiator core by an
engine driven fan. Some installations use a remotely
mounted radiator, cooled by an electric motordriven fan. Where there is a continuously available
supply of clean, cool raw water, a heat exchanger
may be used instead of a radiator; the engine
coolant circulates through the heat exchanger and
is cooled by the raw water supply.
An important advantage of a radiator cooling
system is that it is self-contained. If a storm or
accident disrupted the utility power source, it might
also disrupt the water supply and disable any
generating set whose supply of raw water
depended upon a utility.
Whether the radiator is mounted on the generating
set or mounted remotely, accessibility for servicing
the cooling system is important. For proper
maintenance, the radiator fill cap, the cooling
system drain cocks, the fan belt tension adjustment
must all be accessible to the operator.
9.1 Set Mounted Radiator
A set-mounted radiator is mounted on the
generating set base in front of the engine. See
figure 9.1. An engine-driven fan blows air through
the radiator core, cooling the liquid engine coolant
flowing through the radiator.
FIG 8.1 TYPICAL SOUND ATTENUATED INSTALLATION
10
FIG 9.1 SET MOUNTED RADIATOR DISCHARGING THROUGH OUTSIDE WALL
Set mounted radiators are of two types. One type is
used with the cooling fan mounted on the engine.
The fan is belt-driven by the crankshaft pulley in a
two-point drive. The fan support bracket, fan
spindle and drive pulley are adjustable with respect
to the crankshaft pulley in order to maintain proper
belt tension. The fan blades project into the
radiator shroud, which has sufficient tip clearance
for belt tension adjustment.
be relatively clean to avoid clogging the radiator
core. Adequate filtration of air flowing into the
room should assure relatively clean air. However if
the air at the site normally contains a high
concentration of dirt, lint, sawdust, or other matter,
the use of a remote radiator, located in a cleaner
environment, may alleviate a core clogging problem.
It is recommended that a set-mounted radiator's
discharge air should flow directly outdoors through
a duct that connects the radiator to an opening in
an outside wall. The engine should be located as
close to the outside wall as possible to keep the
ducting short. If the ducting is too long, it may be
more economical to use a remote radiator. The air
flow restriction of the discharge and the inlets duct
should not exceed the allowable fan static pressure.
The other type of set mounted radiator consists of
an assembly of radiator, fan, drive pulley and
adjustable idler pulley to maintain belt tension. The
fan is mounted with its centre fixed in a venturi
shroud with very close tip clearance for highefficiency performance. The fan drive pulley, idler
pulley and engine crankshaft pulley are precisely
aligned and connected in a three-point drive by the
belts. This second type of set-mounted radiator
usually uses an airfoil-bladed fan with the closefitting shroud.
When the set-mounted radiator is to be connected
to a discharge duct, a duct adapter should be
specified for the radiator. A length of flexible duct
material (rubber or suitable fabric) between the
radiator and the fixed discharge duct is required to
isolate vibration and provide freedom of motion
between the generating set and the fixed duct.
The proper radiator and fan combinations will be
provided by FG Wilson and furnished with the
generating set. Air requirements for cooling a
particular FG Wilson generator are given in the
specification sheet. The radiator cooling air must
11
FIG 9.2
REMOTE RADIATOR CONNECTED DIRECTLY
TO ENGINE COOLING SYSTEM
9.2 Remote Radiator
A remote radiator with electric motor-driven can be
installed in any convenient location away from the
generating set. See figure 9.2. A well-designed
remote radiator has many useful features and
advantages that provide greater flexibility of
generating set installations in buildings.
FIG 9.3
REMOTE RADIATOR ISOLATED FROM
ENGINE COOLING SYSTEM BY HEAT
EXCHANGER
A separate pump circulates radiator coolant
between the remote radiator and the heat exchanger
tank.
Heat exchangers also are used for cooling the
engine without a radiator, as described in the
following section.
9.4 Heat Exchanger Cooling
More efficient venturi shroud and fan provide a
substantial reduction in horsepower required for
engine cooling. The fan may be driven by a
thermostatically controlled motor, which will only
draw power from the generating set when required
to cool the engine. A remote radiator can be
located outdoors where there is less air flow
restriction and air is usually cooler than engine
room air, resulting in higher efficiency and smaller
size radiator; and fan noise is removed from the
building.
Remote radiators must be connected to the engine
cooling system by coolant piping, including flexible
sections between engine and piping.
9.3 Remote Radiator/Heat Exchanger
System
Another type of remote radiator system employs a
heat exchanger at the engine . See figure 9.3 and 9.4.
In this application, the heat exchanger functions as
an intermediate heat exchanger to isolate the engine
coolant system from the high static head of the
remote radiator coolant. The engine pump
circulates engine coolant through the engine and
the element of the heat exchanger.
A heat exchanger may be used where there is a
continuously available supply of clean, cool raw
water. Areas where excessive foreign material in the
air might cause constant radiator clogging - such as
in saw mill installations - may be logical sites for
heat exchanger cooling. A heat exchanger cools the
engine by transferring engine coolant heat through
passages in the elements to cool raw water. Engine
coolant and raw cooling water flows are separated
completely in closed systems, each with its own
pump, and never intermix.
A heat exchanger totally replaces the radiator and
fan. See figure 9.5. It usually is furnished as part of
the generating set assembly, mounted on the
engine, although it can be located remotely. Since
the engine does not have to drive a radiator fan,
there is more reserve power available.
The raw water side of the heat exchanger requires a
dependable and economical supply of cool water.
Soft water is desired to keep the heat exchanger in
good operating condition. For standby service, a
well, lake or cooling tower is preferred over city
water since the latter may fail at the same time that
normal electric power fails, making the generator
useless.
12
AUXILIARY PUMP
HEAT
EXCHANGER
FIG 9.4 TYPICAL HEAT EXCHANGER INSTALLATION
FIG 9.5 HEAT EXCHANGER COOLING SYSTEM
9.5 Antifreeze Protection
10. FUEL SUPPLY
If the engine is to be exposed to low temperatures,
the cooling water in the engine must be protected
from freezing. In radiator-cooled installations,
antifreeze may be added to the water to prevent
freezing. Ethylene glycol permanent antifreeze is
recommended for diesel engines. It includes its
own corrosion inhibitor, which eventually may have
to be replenished. Only a non-chromate inhibitor
should be used with ethylene glycol.
A dependable fuel supply system must assure
instant availability of fuel to facilitate starting and
to keep the engine operating. This requires, at a
minimum, a small day tank (usually incorporated
into the generating set baseframe - called a
basetank) located close to the set. With generally
only a capacity of 8 hours operation, this day tank
is often backed up by an auxiliary remote fuel
system including a bulk storage tank and the
associated pumps and plumbing. Extended
capacity basetanks are also generally available for
longer operation prior to refuelling. Especially for
standby generating sets it not advisable to depend
on regular delivery of fuel. The emergency that
requires use of the standby set may also interrupt
the delivery of fuel.
The proportion of ethylene glycol required is
dictated primarily by the need for protection against
freezing in the lowest ambient air temperature that
will be encountered. The concentration of ethylene
glycol must be at least 30% to afford adequate
corrosion protection. The concentration must not
exceed 67% to maintain adequate heat transfer
capability.
10.1 Fuel Tank Location
For heat exchanger cooling, antifreeze does only
half the job since it can only be used in the engine
water side of the heat exchanger. There must be
assurance that the raw water source will not freeze.
The day tank should be located as close to the
generating set as possible. Normally it is safe to
store diesel fuel in the same room with the
generating set because there is less danger of fire or
fumes with diesel than with petrol (gasoline). Thus,
if building codes and fire regulations permit, the day
tank should be located in the base of the generating
set, along side the set, or in an adjacent room.
9.6 Water Conditioning
Soft water should always be used in the engine
whether cooling is by radiator or by heat exchanger
Adding a commercial softener is the easiest and
most economical method of water softening. Your
FG Wilson Distributor can recommend suitable
softeners. Manufacturers instructions should be
carefully followed.
Where an remote fuel system is to be installed with
a bulk storage tank, the bulk tank may be located
outside the building where it will be convenient for
refilling, cleaning and inspection. It should not,
however, be exposed to freezing weather because
fuel flow will be restricted as viscosity increases
with cold temperature. The tank may be located
either above or below ground level.
13
10.2 Remote Fuel Systems
Three types of remote fuel systems are
recommended by the manufacturer:
Fuel System 1: Installations where the bulk fuel
tank is lower than the day tank.
Fuel System 2: Installations where the bulk fuel
tank is higher than the day tank.
Fuel System 4: Installations where fuel must be
pumped from a free standing bulk fuel tank to
the day tank.
Fuel System 1: The bulk fuel tank is lower than the
day tank. With this system the fuel must be pumped
up from the bulk tank to the day tank which is
integrated into the baseframe. See figure 10.1.
fuel level gauges on the basetank and no manual fill
facility All other connections on top of the tank
must be sealed to prevent leakage. Fuel System 1 is
not compatible with the polyethylene fuel tanks
standard on smaller generator sets. The optional
metal tank is required. A 2001 Series control system
(or above) is required.
The position of the bulk fuel tank should take into
account that the maximum suction lift of the fuel
transfer pump is approximately 3 metres and that the
maximum restriction caused by the friction losses in
the return fuel line should not exceed 2 psi.
Fuel System 2: The bulk tank is located higher
than the basetank. With this system the fuel is
gravity fed from the bulk tank to the basetank. See
figure 10.2.
Figure 10.2:Typical Layout with Fuel System 2
Figure 10.1: Typical Layout with Fuel System1
The key components are the bulk fuel tank (item 1),
which is lower than the basetank, remote fuel
system controls (item 2) located in the generator set
control panel, an AC powered electric fuel pump
(item 3), fuel level switches in the basetank (item 4),
an extended vent on the basetank (item 5), the fuel
supply line (item 6), the fuel return line (item 7), and
a fuel strainer (item 8) on the inlet side of the pump.
When set to automatic, the system operates as
follows: low fuel level in the basetank is sensed by
the fuel level sensor. The pump begins to pump
fuel from the bulk tank to the basetank through the
fuel supply line. To help ensure that clean fuel
reaches the engine, fuel from the bulk tank is
strained just prior to the electric fuel pump. When
the basetank is full, as sensed by the fuel level
sensor, the pump stops. If there should be any
overflow of fuel in the basetank, the excess will
drain back into the bulk tank via the return line.
With this system, the basetank must include the
overflow (via the return line), a 1.4 metre extended
vent to prevent overflow through the vent, sealed
The key components are the bulk fuel tank (item 1),
which is higher than the basetank, remote fuel
system controls (item 2) located in the generator set
control panel, a DC motorised fuel valve (item 3),
fuel level switches in the basetank (item 4), an
extended vent/return line (continuous rise) on the
basetank (item 5), the fuel supply line (item 6), a
fuel strainer (item 7) and an isolating valve at the
bulk tank (item 8).
When set to automatic, the system operates as
follows: low fuel level in the basetank is sensed by
the fuel level sensor. The DC motorised valve is
opened and fuel is allowed to flow from the high
level bulk tank to the basetank by the force of
gravity. To help ensure that clean fuel reaches the
engine, fuel from the bulk tank is strained just prior
to the motorised valve. When the basetank is full,
as sensed by the fuel level sensor, the motorised
valve is closed.
Any overflow into the basetank or overpressure in
the basetank will flow back to the bulk tank via the
extended vent.
14
With this system, the basetank must include an
overflow via the return line, sealed fuel level gauges
and no manual fill facility. All other connections on
top of the tank must be sealed to prevent leakage.
Fuel System 2 is not compatible with the
polyethylene fuel tanks standard on smaller
generator sets. The optional metal tank is required.
A 2001 Series control system (or above) is required.
top of the tank must be sealed to prevent leakage.
Fuel System 4 is not compatible with the
polyethylene fuel tanks standard on smalle
generator sets. The optional metal tank is required.
A 2001 Series control system (or above) is required.
Distance ‘A’ on Figure 10.4 is limited to 1400mm for
all generator sets with metal basetanks. Note that
the maximum restriction caused by friction losses
and height of the return line should not exceed 2
psi.
Distance ‘A’ in Figure 10.2 is limited to 1400mm for
all generator sets with metal basetanks.
Fuel System 4: Some installations may require a
system where fuel is pumped from a free standing
bulk tank (see Figure 10.4). This pumped system
would only be used if gravity feed is not possible
from the bulk tank to the basetank.
10.3 Tank Construction
Fuel tanks are usually made of welded sheet steel or
reinforced plastic. If an old fuel tank is used, be
sure it is made of a proper material. It should be
cleaned thoroughly to remove all rust, scale and
foreign deposits.
Connections for fuel suction and return lines must
be separated as much as possible to prevent recirculation of hot fuel and to allow separation of
any gases entrained in the fuel. Fuel suction lines
should extend below the minimum fuel level in the
tank. Where practical, a low point in the tank
should be equipped with a drain valve or plug, in an
accessible location, to allow periodic removal of
water condensation and sediment. Or a hose may
be inserted through the tank's filter neck when
necessary to suck out water and sediment.
Figure 10.4:Typical Layout with Fuel System 4
The key components are the above ground bulk
fuel tank (item 1), remote fuel system controls (item
2) located in the generator set control panel, an AC
Fuel Pump (item 3), a DC motorised fuel valve (item
4), fuel level switches in the basetank (item 5), the
fuel supply line (item 6), an extended vent/return
line (continuous rise) on the basetank (item 7), a
fuel strainer (item 8) and an isolating valve at the
bulk tank (item 9).
The filler neck of the bulk fuel tank should be
located in a clean accessible location. A removable
wire screen of approximately 1.6 mm (1/16 inch)
mesh should be placed in the filler neck to prevent
foreign material from
entering the tank. The filler neck cap or the highest
point in the tank should be vented to maintain
atmospheric pressure on the fuel and to provide
pressure relief in case a temperature rise causes the
fuel to expand. It will also prevent a vacuum as fuel
is consumed. The tank may be equipped with a fuel
level gauge - either a sight gauge or a remote
electrical gauge.
When set to automatic, the system operates as
follows: low fuel level in the basetank is sensed by
the fuel level sensor. The DC motorised valve is
opened and the pump begins to pump fuel from the
bulk tank to the basetank through the supply line.
To help ensure that clean fuel reaches the engine,
fuel from the bulk tank is strained just prior to the
motorised valve. When the basetank is full, as
sensed by the fuel level sensor, the pump stops
and the motorised valve is closed. Any overflow
into the basetank or overpressure in the basetank
will flow back to the bulk tank via the extended
vent.
With this system, the basetank must include an
overflow via the return line, sealed fuel level gauges
and no manual fill facility. All other connections on
10.4 Fuel Lines
The fuel lines can be of any fuel compatible material
such as steel pipe or flexible hoses that will tolerate
environmental conditions.
Fuel delivery and return lines should be at least as
large as the fitting sizes on the engine, and overflow
piping should be one size larger. For longer runs of
piping or low ambient temperatures the size of these
lines should be increased to ensure adequate flow.
15
Flexible piping should be used to connect to the
engine to avoid damage or leaks caused by engine
vibration.
The fuel delivery line should pick up fuel from a
point no lower than 50 mm (2”) from the bottom of
tank at the high end, away from the drain plug.
10.5 Day Tank Capacity
The capacity of the day tank is based on the fuel
consumption and the expected number of hours of
operation that is requested between refills.
Particularly with standby generators, the availability
of fuel delivery service will determine the number of
operating hours that must be provided for. Don't
depend on quick service the very day your set
starts to operate. A power outage may hamper your
supplier's operation also.
In addition, the size of the day tank should be large
enough to keep fuel temperatures down, since some
engines return hot fuel used to cool the injectors.
Model
P910-P1100E
P1250-P1650E
P1700-P2200E
Extra Capacity
With Fuel
Without Fuel
Coolers
Coolers
1500 litres
3000 litres
2250 litres
4500 litres
3000 litres
6000 litres
16
11. SELECTING FUELS
FOR STANDBY
DEPENDABILITY
Reliable operation of diesel engines may vary from
one fuel to another, depending on many factors,
including fuel characteristics and engine operating
conditions.
The types of fuels available for diesel engines, vary
from highly volatile jet fuels and kerosene to the
heavier fuel oils. Most diesel engines are capable
of burning a wide range of fuels within these
extremes. The following information will assist you
in selecting the type of fuel that will afford the best
overall performance and reliability of your
Generating Set.
The fuels commonly known as high-grade fuels
seldom contribute to the formation of harmful
engine deposits and corrosion. On the other hand,
while refining improves the fuel, it also lowers the
B.T.U. or heat value of the fuel. As a result, the
higher grade fuels develop slightly less power than
the same quantity of low grade fuel. This is
usually more than offset by the advantages of high
grade fuels such as quicker starts and less frequent
overhauls. Before using low-grade fuels, therefore,
some understanding of the problems and extra
costs that may be encountered is necessary.
11.1 Types Of Fuel Oil
The quality of fuel oil can be a dominant factor in
satisfactory engine life and performance. A large
variety of fuel oils are marketed for diesel engine
use. Their properties depend upon the refining
practices employed and the nature of the crude oils
from which they are produced. For example, fuel
oils may be produced within the boiling range of
148 to 371°C (300 to 700°F), having many possible
combinations of other properties.
Fuels with high sulphur content cause corrosion,
wear and deposits in the engine. Fuels that are not
volatile enough or don't ignite rapidly may leave
harmful deposits in the engine and may cause poor
starting or running under adverse operating
conditions. The use of low grade fuels may require
the use of high priced, higher detergent lubricating
oils and more frequent oil changes.
The additional contaminants present in low grade
fuels may result in darker exhaust and more
pronounced odour. This may be objectionable in
hospitals, offices commercial and urban locations.
Thus, location, application and environmental
conditions should be considered when selecting
fuel.
11.2 Fuel Selection Guide
Specify fuel properties according to the following
chart.
The Generating Set owner may elect to use a low
grade fuel because high-grade fuels are not readily
available in his area or because he can realise a net
saving with low grade fuels despite higher engine
maintenance costs. In that case, frequent
examination of lubrication oil should be made to
determine sludge formation and the extent of lube
oil contamination.
Winter
Summer
Final
Boiling
Point
290°C (550ºF)
315°C (600ºF)
Cetane
Number
(Min)
45
40
Sulphur
Number
(Max)
0.5 %
0.5 %
Selecting a fuel that keeps within these
specifications will tend to reduce the possibility of
harmful deposits and corrosion in the engine, both
of which could result in more frequent overhauls
and greater maintenance expense. Specify exact
fuel properties to your local fuel supplier.
Aside from the various grades of fuel oil commonly
used in diesel engines, aircraft jet fuels also are
sometimes used, especially in circumstances where
the jet fuels are more readily available than
conventional fuels. Jet fuels are lower in B.T.U.
content and lubrication quality than conventional
fuels. As a result, some diesel fuel systems must
undergo major modifications to accommodate this
type of fuel. For use of jet fuel please consult FG
Wilson.
11.3 Maintaining Fresh Fuel
Most fuels deteriorate if they stand unused for a
period of many months. With standby generators it
is preferable to store only enough fuel to support a
few days or even only eight hours of continuous
running of the Generating Set so that normal engine
testing will turn over a tank full within a year and a
half.
17
Other solutions are to add inhibitors to the fuel or
to obtain greater turnover by using the fuel for
other purposes. A gum inhibitor added to diesel
fuel will keep it in good condition up to two years.
If the building furnace has an oil burner, it is
possible to burn diesel fuel in the furnace,
connecting both the engine and the furnace to the
same tank. In this way, a large supply of diesel fuel
is available for emergency use by the Generating
Set, and the fuel supply is continuously turned over
since it is being burned in the furnace. Thus, there
is no long term storage problem.
11.4 Self Contained Dependability
In some areas, where natural gas is cheap, natural
gas spark ignition engines are used in Generating
Sets that are intended for continuous service. For
standby service, however, this is not recommended.
The natural gas supply and regulation system adds
substantially to the complexity of the installation,
and there is little to be gained in terms of fuel cost
over a period of time. More important, it makes the
emergency power less dependable. Not only is
such an engine less dependable than a diesel, but
often the same storm or accident that disrupts the
normal electric power also cuts off gas service.
Thus, a natural gas engine would be disabled at the
very time it is needed. By contrast, a diesel engine,
with its fuel in a nearby tank, is a self contained
system that does not depend on outside services.
It is more dependable and affords greater standby
protection than systems which depend on a public
utility for fuel.
18
12. TABLES AND FORMULAS FOR ENGINEERING STANDBY GENERATING
SETS
Table 1. Length Equivalents
Unit
Microns
Meters
Kilometres
Inches
Feet
Yards
Miles
1 Micron
1
1,000,000
-25,400
----
0.000001
1
1000
0.0254
0.3048
0.9144
1609
--1
---1.609
0.00003937
39.37
39,370
1
12
36
63,360
-3.281
3281
0.0833
1
3
5280
-1.0936
1093.6
0.0278
0.3333
1
1760
--0.621
---1
1 Meter
1 Kilometre
1 Inch
1 Foot
1 Yard
1 Mile
One unit in the left-hand column equals the value of units under the top heading.
Table 2. Area Equivalents
Unit
1 In 2
1 Ft 2
1 Acre
1 Mile 2
1 M2
1 Hectare
1 Km 2
In 2
Ft2
Acre
Mile 2
M2
Hectare
Km 2
1
144
--1550
---
0.006944
1
43,560
27,878,400
10.764
107,639
10,763,867
--1
640
-2.471
247.1
--0.0015625
1
-0.003861
0.3861
0.00064516
0.0929
4,047
2,589,998
1
10,000
1,000,000
--0.4047
258.99
-1
100
--0.004047
2.5899
-0.01
1
One unit in the left-hand column equals the value of units under the top heading.
Table 3. Mass Equivalents
Unit
1 Ounce
1 Pound
1 Kilogram
1 Short Ton
1 Long Ton
1 Metric Ton
Ounces
Pounds
Kilograms
Short
Tons
Long
Metric
1
16
35.27
32000
35840
35274
0.0625
1
2.205
2000
2240
2205
0.02835
0.4536
1
907.2
1016
1000
---1
1.12
1.102
---0.8929
1
0.9842
---0.9072
1.016
1
One unit in the left-hand column equals the value of units under the top heading.
19
Table 4. Volume and Capacity Equivalents
Unit
Inches 3
Feet3
Yards 3
1 Inch 3
1
1728
46656
61023
231
0.000579
1
27
35.31
0.1337
0.0000214
0.03704
1
1.308
0.00495
0.0000164
0.0283
0.765
1
0.003785
277.42
61.02
0.16
0.03531
0.00594
0.001308
0.004546
0.001
1 Ft.3
1 Yd.3
1 M3
1
U.S.Liq.Gal
1 Imp. Gal.
1 Litre
Meters 3
US Liquid
Gallons
Imperial
Gallons
Litres
0.004329
7.481
202
264.2
1
0.00359
6.23
168.35
220.2
0.833
0.0164
28.32
764.6
1000
3.785
1.2
0.2642
1
0.22
4.546
1
One unit in the left-hand column equals the value of units under the top heading.
Table 5. Conversions for Units of Speed
Unit
1 Foot/Sec
1 Foot/Min
Feet/Secon
d
1
1 Meter/Min
0.0167
1.467
3.281
0.05468
1 Km/Hr
--
1 Mile/Hr
1 Meter/Sec
Feet/Min
Miles/Hr
Meters/Sec
Meters/Mi
n
Km/Hr
60.0
1
88
196.848
---
0.6818
0.1136
1
-0.03728
0.6214
0.3048
0.00508
18.288
-26.822
-1
--
--1.6093
--1
1
-0.2778
One unit in the left-hand column equals the value of units under the top heading.
Table 6. Conversions For Units Of Power
Unit
Horsepower
Foot-lb/Minute
Kilowatts
Metric
Horsepower
Btu/Minute
1 Horsepower
1
--
33,000
1
0.746
--
1.014
--
42.4
0.001285
1.341
0.986
44,260
32,544
1
0.736
1.360
1
56.88
41.8
0.0236
777.6
0.0176
0.0239
1
1 Footlb/Minute
1 Kilowatt
1 Metric
Horsepower
1 Btu. /Minute
One unit in the left-hand column equals the value of units under the top heading.
Mechanical power and ratings of motors and engines are expressed in horsepower.
Electrical power is expressed in watts or kilowatts.
20
Table 7. Conversions for Measurements of Water
Unit
Feet3
Pounds
Gal
(U.S
)
Gal
Litres
(IMP)
Head
(Ft)
lb/in²
Ton/Ft²
Head
(Meters
)
Ft³/Min
Gal.(U.S)
/Hr
Feet3
1
0.01602
--
62.42
1
8.34
-0.12
1
-0.10
--
-0.4536
--
----
----
---
----
----
---
--
10.0
--
1
--
--
--
--
--
---
2.2046
--
---
---
1
--
-1
-4.335
---
----
----
----
----
----
2.3070
35.92
--
1
-1.4221
0.02784
1
--
0.7039
-1
---
---
---
---
---
---
---
---
---
Pounds
Gal
(U.S)
Gal
(IMP)
Litres
Head
(Ft)
lb/in²
Ton/Ft²
Head
(Meters)
Ft³/Min
Gal.
(U.S)/Hr
1
0.002227
One unit in the left-hand column equals the value of units under the top heading.
Table 8. Barometric Pressures and Boiling Points of Water at Various Altitudes
Barometric Pressure
(Ft)
Inches of
Mercury
lb/in 2
Feet Water
Sea Level
1000
2000
3000
4000
5000
6000
7000
8000
9000
10,000
11,000
12,000
13,000
14,000
15,000
29.92
28.86
27.82
26.81
25.84
24.89
23.98
23.09
22.22
21.38
20.58
19.75
19.03
18.29
17.57
16.88
14.69
14.16
13.66
13.16
12.68
12.22
11.77
11.33
10.91
10.50
10.10
9.71
9.34
8.97
8.62
8.28
33.95
32.60
31.42
30.28
29.20
28.10
27.08
26.08
25.10
24.15
23.25
22.30
21.48
20.65
19.84
18.07
One unit in the left-hand column equals the value of units under the top heading.
21
Water Boiling
Point
ºF
ºC
212.0
210.1
208.3
206.5
204.6
202.8
201.0
199.3
197.4
195.7
194.0
192.0
190.5
188.8
187.1
185.4
100
99
98
97
95.9
94.9
94.1
93
91.9
91
90
88.9
88
87.1
86.2
85.2
448.92
1
Table 9. Conversions of Units of Flow
Unit
U.S
Gallons/Minute
Million U.S
Gallons/Day
Feet3 /Second
Meters 3 /Hour
Litres/Second
1 U.S
Gallon/Minute
1 Million U.S
Gallons/Day
1 Foot3 /Second
1
0.001440
0.00223
0.2271
0.0630
694.4
1
1.547
157.73
43.8
448.86
4.403
15.85
0.646
0.00634
0.0228
1
0.00981
0.0353
101.9
1
3.60
28.32
0.2778
1
1 Meter3 /Hour
1 Litre/Second
One unit in the left-hand column equals the value of units under the top heading.
Table 10. Conversions of Units of Pressure and Head
Unit
mm Hg
in. Hg
in H2 O
ft H2 O
lb/in²
kg/cm²
Atmos
kPa
1mm
Hg
1 in.
Hg
1 in
H2 O
1 ft
H2 O
1 lb/ in²
1
kg/cm²
Atmos.
kPa
1
0.0394
0.5352
0.0447
0.01934
0.00136
0.0013
--
25.4
1
13.5951
1.1330
0.49115
0.03453
0.0334
3.386
1.86827
0.0736
1
0.0833
0.03613
0.00254
0.0025
0.249
22.4192
0.8827
12
1
0.43352
0.030479
0.0295
2.989
51.7149
735.559
2.0360
28.959
27.6807
393.7117
2.3067
32.8093
1
14.2233
0.07031
1
0.0681
0.9678
6.895
98.07
760.456
7.50064
29.92
0.2953
406.5
4.0146
33.898
0.3346
14.70
0.14504
1.033
0.0102
1
0.0099
101.3
1
One unit in the left-hand column equals the value of units under the top heading.
Table 11. Approximate Weights of Various Liquids
Diesel Fuel
Ethylene Glycol
Furnace Oil
Gasoline
Kerosene
Lube. Oil (Medium)
Water
Pounds per U.S
Gallon
Specific Gravity
6.88 - 7.46
9.3 - 9.6
6.7 - 7.9
5.6 - 6.3
6.25 - 7.1
7.5 - 7.7
8.34
0.825 - 0.895
1.12 - 1.15
0.80 - 0.95
0.67 - 0.75
0.75 - 85
0.90 - 0.92
1.00
22
Table 12. Electrical formulae
Desired Data
Kilowatts (kW)
Kilovolt-Amperes
kVA
Electric Motor
Horsepower
Output (HP)
Amperes (I)
When Horsepower
is known
Single Phase
Three-Phase
Direct Current
I x V x PF
3 x I x V x PF
IxV
1000
1000
1000
IxV
3 xVxE
1000
1000
I x V x Eff . x PF
3 x I x V x Eff . x PF
746
746
HP x 746
V x Eff . x PF
HP x 746
3 x V x Eff . x PF
I x V x Eff .
746
HP x 746
V x Eff
Amperes (I)
When Kilowatts
are known
kW x 1000
kW x 1000
kW x 1000
V x PF
3 x V x PF
V
Amperes (I)
When kVA is
known
kVA x 1000
kVA x 1000
V
3 xV
Where:
V = Volts
I = Amperes
Eff = Percentage Efficiency
Watts
PF = Power Factor=
IxV
23
TABLE 13. kVA/kW AMPERAGE AT VARIOUS VOLTAGES
(0.8 Power Factor)
kVA
6.3
9.4
12.5
18.7
25
31.3
37.5
50
62.5
75
93.8
100
125
156
187
219
250
312
375
438
500
625
750
875
100
0
112
5
125
0
156
3
187
5
218
8
250
0
281
2
312
5
375
0
437
5
500
0
kW
208V
220V
400V
440V
460V
480V
600V
5
7.5
10
15
20
25
30
40
50
60
75
80
100
125
150
175
200
250
300
350
400
500
600
700
800
17.5
26.1
34.7
52
69.5
87
104
139
173
208
261
278
347
433
520
608
694
866
1040
1220
1390
1735
2080
2430
2780
16.5
24.7
33
49.5
66
82.5
99
132
165
198
247
264
330
413
495
577
660
825
990
1155
1320
1650
1980
2310
2640
240V
15.2
22.6
30.1
45
60.2
75.5
90.3
120
152
181
226
240
301
375
450
527
601
751
903
1053
1203
1504
1803
2104
2405
380V
9.6
14.3
19.2
28.8
38.4
48
57.6
77
96
115
143
154
192
240
288
335
384
480
576
672
770
960
1150
1344
1540
9.1
13.6
18.2
27.3
36.4
45.5
54.6
73
91
109
136
146
182
228
273
318
364
455
546
637
730
910
1090
1274
1460
8.3
12.3
16.6
24.9
33.2
41.5
49.8
66.5
83
99.6
123
133
166
208
249
289
332
415
498
581
665
830
996
1162
1330
8.1
12
16.2
24.4
32.4
40.5
48.7
65
81
97.5
120
130
162
204
244
283
324
405
487
568
650
810
975
1136
1300
7.6
11.3
15.1
22.5
30.1
37.8
45.2
60
76
91
113
120
150
188
225
264
301
376
451
527
602
752
902
1052
1203
6.1
9.1
12
18
24
30
36
48
61
72
90
96
120
150
180
211
241
300
361
422
481
602
721
842
962
6
7.5
9.1
12.1
15.1
18.1
22.6
24.1
30
38
45
53
60
75
90
105
120
150
180
210
241
4.4
5.5
6.6
8.8
10.9
13.1
16.4
17.6
21.8
27.3
33
38
44
55
66
77
88
109
131
153
176
3.5
4.4
5.2
7
8.7
10.5
13
13.9
17.5
22
26
31
35
43
52
61
69
87
104
121
139
900
3120
2970
2709
1730
1640
1495
1460
1354
1082
271
197
156
1000
3470
3300
3009
1920
1820
1660
1620
1504
1202
301
218
174
1250
4350
4130
3765
2400
2280
2080
2040
1885
1503
376
273
218
1500
5205
4950
4520
2880
2730
2490
2440
2260
1805
452
327
261
1750
5280
3350
3180
2890
2830
2640
2106
528
380
304
2000
6020
3840
3640
3320
3240
3015
2405
602
436
348
2250
6780
4320
4095
3735
3645
3400
2710
678
491
392
2500
7520
4800
4560
4160
4080
3765
3005
752
546
435
3000
9040
5760
5460
4980
4880
4525
3610
904
654
522
3500
10550
6700
6360
5780
5660
5285
4220
1055
760
610
4000
12040
7680
7280
6640
6480
6035
4810
1204
872
695
24
2400V
33000V
4160V
Conversions of Centigrade and Fahrenheit
Water freezes at
0 ºC (32ºF)
Water boils at
100 ºC (212ºF)
ºF= ( 1.8 x ºC ) + 32
ºC = 0.5555 ( ºF - 32 )
Fuel Consumption Formulas
Fuel Consumption(lb / hr) = Specific FuelCons.( lb / BHP / hr) xBHP
Fuel Consumption(US gal / hr ) =
Spec. Fuel Cons. (lb / BHP / hr) x BHP
FuelSpecific Weight(lb / US gal )
FuelSpec.Weight( lb / US gal) = FuelSpecific Gravity x8.34 lb
Specific FuelConsumption(lb / BHP / hr ) =
FuelCons.( US gal / hr) x FuelSpec. Wt (lb / US gal)
Specific Fuel Consumption( kg / BHP / hr) =
BHP
Spec.Fuel Cons.(lb / BHP / hr)
BHP
Electrical Motor Horsepower
Electrical Motor Horsepower =
kW Input x Motor Efficiency
0.746 x Generator Efficiency
kW Output Required
Engine Horsepower Required =
0.746 x Generator Efficiency
Piston Travel
Feet Per Minute ( FPM) = 2 x L x N
Where L = Length of Stroke in Feet
N = Rotational Speed of Crankshaft in RPM
BREAK MEAN EFFECTIVE PRESSURE (BMEP) (4 Cycle)
BMEP =
792 , 000 x BHP
Total Displacement x RPM
25
13. GLOSSARY OF TERMS
ALTERNATING CURRENT (AC) - A current which periodically reverses in direction and changes its magnitude
as it flows through a conductor or electrical circuit. The magnitude of an alternating current rises from zero to
maximum value in one direction, returns to zero, and then follows the same variation in the opposite direction.
One complete alternation is one cycle or 360 electrical degrees. In the case of 50 cycle alternating current the
cycle is completed 50 times per second.
AMBIENT TEMPERATURE - The air temperature of the surroundings in which the generating system operates.
This may be expressed in degrees Celsius or Fahrenheit.
AMPERE (A) - The unit of measurement of electric flow. One ampere of current will flow when one volt is applied
across a resistance of one ohm.
APPARENT POWER (kVA, VA)- A term used when the current and voltage are not in phase i.e. voltage and
current do not reach corresponding values at the same instant. The resultant product of current and voltage is
the apparent power and is expressed in kVA.
AUTOMATIC SYNCHRONIZER - This device in its simplest form is a magnetic type control relay which will
automatically close the generator switch when the conditions for paralleling are satisfied.
BREAK MEAN EFFECTIVE PRESSURE (BMEP) - This is the theoretical average pressure on the piston of an
engine during the power stroke when the engine is producing a given number of horsepower. It is usually
expressed in pounds/inch2. The value is strictly a calculation as it cannot be measured, since the actual cylinder
pressure is constantly changing. The mean or average pressure is used to compare engines on assumption that
the lower the BMEP, the greater the expected engine life and reliability. In practice, it is not a reliable indicator of
engine performance for the following reasons.:
The formula favours older design engines with relatively low power output per cubic inch of displacement in
comparison with more modern designs. Modern engines do operate with higher average cylinder pressures, but
bearings and other engine parts are designed to withstand these higher pressures and to still provide equal or
greater life and reliability than the older designs. The formula also implies greater reliability when the same engine
produces the same power at a higher speed. Other things being equal, it is unlikely that a 60 Hz generating set
operating at 1800 RPM is more reliable than a comparable 50 Hz generating set operating at 1500 RPM. Also it is
doubtful that a generator operating at 3000 RPM will be more reliable than one operating at 1500 RPM even if the
latter engine has a significantly higher BMEP. The BMEP for any given generating set will vary with the rating
which changes depending on fuel, altitude and temperature. The BMEP is also affected by generator efficiency
which varies with voltage and load.
CAPACITANCE (C)- If a voltage is applied to two conductors separated by an insulator, the insulator will take
an electrical charge. Expressed in micro-farads (µf).
CIRCUIT BREAKER - A protective switching device capable of interrupting current flow at a pre-determined
value.
CONTINUOUS LOAD - Any load up to and including full rated load that the generating set is capable of
delivering for an indefinitely long period, except for shut down for normal preventive maintenance.
CONTINUOUS RATING - The load rating of an electric generating system which is capable of supplying
without exceeding its specified maximum temperature rise limits.
26
CURRENT (I) - The rate of flow of electricity. DC flows from negative to positive. AC alternates in direction. The
current flow theory is used conventionally in power and the current direction is positive to negative.
CYCLE - One complete reversal of an alternating current or voltage from zero to a positive maximum to zero to a
negative maximum back to zero. The number of cycles per second is the frequency, expressed in Hertz (Hz).
DECIBEL (dB) - Unit used to define noise level.
DELTA CONNECTION - A three phase connection in which the start of each phase is connected to the end of
the next phase, forming the Greek letter Delta (D). The load lines are connected to the corners of the delta. In
some cases a centre tap is provided on each phase, but more often only on one leg, thus supplying a four wire
output.
DIRECT CURRENT - An electric current which flows in one direction only for a given voltage and electrical
resistance. A direct current is usually constant in magnitude for a given load.
EFFICIENCY - The efficiency of a generating set shall be defined as the ratio of its useful power output to its
total power input expressed as a percentage.
FREQUENCY - The number of complete cycles of an alternating voltage or current per unit of time, usually per
second. The unit for measurement is the Hertz (Hz) equivalent to 1 cycle per second (CPS).
FREQUENCY BAND - The permissible variation from a mean value under steady state conditions.
FREQUENCY DRIFT - Frequency drift is a gradual deviation of the mean governed frequency above or below
the desired frequency under constant load.
FREQUENCY DROOP - The change in frequency between steady state no load and
steady state full load which is a function of the engine and governing systems.
FULL LOAD CURRENT - The full load current of a machine or apparatus is the value of current in RMS or DC
amperes which it carries when delivering its rate output under its rated conditions. Normally, the full load current
is the "rated" current.
GENERATOR - A general name for a device for converting mechanical energy into electrical energy. The
electrical energy may be direct current (DC) or alternating current (AC). An AC generator may be called an
alternator.
HERTZ (Hz) - SEE FREQUENCY.
INDUCTANCE (L) - Any device with iron in the magnetic structure has what amounts to magnetic inertia. This
inertia opposes any change in current. The characteristic of a circuit which causes this magnetic inertia is know
as self inductance; it is measured in Henries and the symbol is "L".
INTERRUPTABLE SERVICE - A plan where by an electric utility, elects to interrupt service to a specific
customer at any time. Special rates are often available to customers under such agreements.
kVA - 1,000 Volt amperes (Apparent power). Equal to kW divided by the power factor.
27
kW - 1,000 Watts (Real power). Equal to KVA multiplied by the power factor.
POWER - Rate of performing work, or energy per unit of time. Mechanical power is often measured in
horsepower, electrical power in kilowatts.
POWER FACTOR - In AC circuits, the inductances and capacitances may cause the point at which the voltage
wave passes through zero to differ from the point at which the current wave passes through zero. When the
current wave precedes the voltage wave, a leading power factor results, as in the case of a capacitive load or
over excited synchronous motors. When the voltage wave precedes the current wave, a lagging power factor
results. This is generally the case. The power factor expresses the extent to which voltage zero differs from the
current zero. Considering one full cycle to be 360 degrees, the difference between the zero point can then be
expressed as an angle q. Power factor is calculated as the cosine of the q between zero points and is expressed as
a decimal fraction (0.8) or as a percentage (80%). It can also be shown to be the ratio of kW, divided by kVA. In
other words, kW= kVA x P.F.
PRIME POWER - That source of supply of electrical energy utilised by the user which is normally available
continuously day and night, usually supplied by an electric utility company but sometimes by owner generation.
RATED CURRENT - The rated continuous current of a machine or apparatus is the
value of current in RMS or DC amperes which it can carry continuously in normal service without exceeding the
allowable temperature rises.
RATED POWER - The stated or guaranteed net electric output which is obtainable continuously from a
generating set when it is functioning at rated conditions. If the set is equipped with additional power producing
devices, then the stated or guaranteed net electric power must take into consideration that the auxiliaries are
delivering their respective stated or guaranteed net output simultaneously, unless otherwise agreed to.
RATED SPEED - Revolutions per minute at which the set is designed to operate.
RATED VOLTAGE - The rated voltage of an engine generating set is the voltage at which it is designed to
operate.
REACTANCE - The out of phase component of impedance that occurs in circuits containing inductance and/or
capacitance.
REAL POWER - A term used to describe the product of current , voltage and power factor, expressed in kW.
RECTIFIER - A device that converts AC to DC.
ROOT MEAN SQUARE (RMS) - The conventional measurement of alternating current and voltage and
represents a proportional value of the true sine wave.
SINGLE PHASE - An AC load or source of power normally having only two input terminals if a load, or two
output terminals if a source.
STANDBY POWER - An independent reserve source of electrical energy which upon failure or outage of the
normal source, provides electric power of acceptable quality and quantity so that the user's facilities may
continue in satisfactory operation.
STAR CONNECTION - A method of interconnecting the phases of a three phase system to form a
configuration resembling a star ( or the letter Y). A fourth or neutral wire can be connected to the centre point.
28
TELEPHONE INFLUENCE FACTOR (TIF) - The telephone influence factor of a synchronous generator is a
measure of the possible effect of harmonics in the generator voltage wave on telephone circuits. TIF is measured
at the generator terminals on open circuit at rated voltage and frequency.
THREE PHASE - Three complete voltage/current sine waves, each of 360 electrical degrees in length, occurring
120 degrees apart. A three phase system may be either 3 wire or 4 wire ( 3 wires and a neutral).
UNINTERRUPTABLE POWER SUPPLY (UPS) - A system designed to provide power
without delay or transients, during any period when the normal power supply is incapable of performing
acceptably.
UNITY POWER FACTOR - A load whose power factor is 1.0 has no reactance's causing the voltage wave to lag
or lead the current wave.
WATT - Unit of electrical power. In DC, it equals the volts times amperes. In AC, it equals the effective volts
times the effective amps times power factor times a constant dependent on the number of phases.
29
GROUP HEADQUARTERS
Old Glenarm Road
Larne, Co. Antrim BT40 1EJ
Northern Ireland, United Kingdom
Telephone: (44) 028 2826 1000
Fax: (44) 028 2826 1111
276-851
INSTALL.DOC/0601
Download PDF

advertising