Evaluation Report No. E0576D
Printed: October, 1977
Tested at: Humboldt
ISSN 0383-3445
Evaluation Report
28
Belarus Niva SK-5 Self-Propelled Combine
A Co-operative Program Between
ALBERTA
FARM
MACHINERY
RESEARCH
CENTRE
PAMI
PRAIRIE AGRICULTURAL MACHINERY INSTITUTE
BELARUS NIVA SK-5 SELF-PROPELLED
COMBINE
MANUFACTURER:
Tractoroexport
Rostselmash
Rostov-on-Don, U.S.S.R.
RETAIL PRICE:
$27,926.24 (July, 1977, f.o.b. Regina with 4420 mm (14.5 ft) table,
3200 mm (126 in) Melroe pickup, grain loss monitor, automatic
feed control, six-bat pickup reel, cutter bar, metric tools and spare
parts kit.
DISTRIBUTOR:
Belarus Equipment of Canada Ltd.
1739 Victoria East
Regina, Saskatchewan
S4P 0P9
FIGURE 1. Schematic View of the Belarus Niva SK-5.
SUMMARY AND CONCLUSIONS
Functional performance of the Belarus Niva SK-5 selfpropelled combine, was very good in dry grain and oilseed crops.
Functional performance was very good to good in tough and
damp crops.
The MOG feedrate (straw and chaff feedrate) at 3% total
grain loss varied from 8.95 t/h (329 lb/min) in 2.76 t/ha (41 bu/ac)
Neepawa wheat to 7.3 t/h (268 lb/min) in 3.48 t/ha (65 bu/ac)
Bonanza Barley. The capacity of the Niva SK-5 was greater than
the capacity of the PAMI reference combine for a similar total
loss. Straw walker loss limited the capacity of the NIVA SK-5 in
most crops. A reduction in grain loss over the straw walkers would
have permitted higher combining rates. Cylinder and shoe losses
usually were insignificant.
The engine had ample power for normal crops but operated
near its limit when combining heavy, damp crops in soft, hilly
fields. It would probably be underpowered if using a straw chopper
in heavy damp crops. Fuel consumption varied from 14 to 18 L/h
(3 to 4 Imp. gal/h).
Air entrainment problems with the fuel system occurred
intermittently during the test resulting in poor starting, occasional
loss of power and rough idling. The radiator screen did not
effectively prevent radiator plugging while the engine air intake
pre-cleaner was ineffective leading to rapid plugging of the filter
elements. At temperatures below +5° C, ether was needed to
start the cold engine.
After modifications, performance of the automatic feed control
was very good in uniformly varying windrows and the control
effectively maintained losses near a desired level. The automatic
feed control could not be used in bunchy windrows and had to be
switched to manual mode. The factory installed grain loss monitor
was very easy to set and was reasonably accurate.
The steering system and individual wheel brakes were
unsatisfactory since it was impossible to turn most corners in a
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windrowed field without stopping and reversing to negotiate the
turn. Instrument and control lever layout at the operator’s station
was poor. Many controls were irresponsive and inconveniently
placed. The cab was very dusty due to ineffective pressurization.
Sound level at the operator’s ear was about 90 decibels (A
scale).
Header visibility was good during the daytime, but was poor
at night because of poor long range lighting and reflections from
the windshield louvers. Grain tank visibility was very good.
Road transport was tedious due to difficult handling and a
low maximum speed of 20.1 km/h (12.4 mph). Right visibility was
severely restricted by the grain tank requiring extra caution at
road intersections.
Grain tank capacity of 2.1 t (77 bu) was too small and did not
match the threshing and separating capacity at the NIVA SK-5.
The unloading auger clutch was unsuitable for unloading on-thego.
The NIVA SK-5 was easy to adjust for specific field conditions.
Ease of adjustment would have been improved if return tailings
could have been inspected. Ease of servicing was good.
The cylinder, table auger and feeder all were positive and
aggressive. Plugging was infrequent, even in damp conditions.
If plugging occurred, unplugging was relatively easy and
convenient.
The stone trap was not completely effective and permitted
a number of stones to enter the cylinder. The stone trap was
inconvenient to clean.
Once properly adjusted, the pickup had excellent feeding
characteristics, delivering the crop beneath the table auger. The
pickup drive was unsatisfactory as delivered. After modification,
performance of the pickup drive was good in dry crops and fair in
damp crops.
No serious safety hazards were encountered when operated
according to the manufacturer’s recommended procedures.
Although the operator’s manuals provided much information,
including a parts list, they were very wordy and difficult to
understand and did not include some necessary information.
A considerable number of minor but aggravating durability
problems occurred and several field modifications had to be
performed resulting in many hours of down time. Most problems
stemmed from improper pre-delivery by the local distributor.
In addition, distributor service personnel were unfamiliar with
combine maintenance, servicing and adjustment and were unable
to correct some problems.
RECOMMENDATIONS
It is recommended that the manufacturer consider:
1. Modifying the steering and individual wheel brakes to allow
non stop picking of windrows around 90° corners.
2. Increasing the grain tank capacity to match threshing and
separating capacity.
3. Modifying the grain tank unloading clutch to permit unloading
on-the-go.
4. Increasing header lift speed and maximum header lift height.
5. Providing a safe and easy method for sampling return railings,
preferably from the operator’s seat.
6. Modifying the variable speed traction drive belt tightener
assembly or modifying the belt tightening instructions in the
operator’s manual to prevent pivot clevis deformation when
tightening the traction drive belts.
7. Checking assembly procedures to ensure proper main
hydraulic pump clutch adjustment and assembly.
8. Modifying procedures to prevent entrance of foreign material
into the hydraulic system during factory assembly as well as
flushing of hydraulic systems, on combines already in stock,
before delivery.
9. Improving the quality of the clean grain sieve to ensure
uniform closing of all louvers.
10. Providing a straw chopper and a straw spreader as available
options.
11. Modifying the actuating cable on the automatic feed control to
make the control operational and, in addition, initiating proper
pre-delivery procedures on the control system and instructing
distributor service personnel on its correct operation and
adjustment.
12. Supplying an elevated cyclone pre-cleaner for the engine air
intake as standard equipment.
13. Modifying the radiator air intake screen to improve radiator
cooling efficiency.
14. Providing a lock on the seat backrest to improve operator
safety.
15. Modifying the windshield louvers so they can readily be
swung out of the way for night operation and for windshield
cleaning.
16. Modifying the lighting system to provide better long range
lighting in front of the combine for night operation.
17. Modifying the cab pressurization system to reduce dust
accumulation in the cab.
18. Installing the main power switch in the operator’s cab.
19. Modifying the speedometer to eliminate its erratic and
intermittent performance.
20. Modifying the hydraulic control lever assemblies for header
lift and pickup speed to reduce rapid linkage wear and to
increase ease of operation.
21. Repositioning the ground speed and header lift control
levers to one side of the steering column to increase ease of
operation.
22. Modifications to eliminate air entrainment problems in
the engine fuel system and instructing distributor service
personnel on proper fuel system servicing procedures.
23. Modifications to prevent premature header drive belt failure.
24. Modifying the pickup drive assembly to eliminate belt slippage
and to eliminate creeping of the pickup speed control. In
addition, improving procedures at the distributor level to
ensure that the pickup is properly assembled and supplied
with the proper drive sprockets at delivery.
25. Modifying the stone trap to increase its effectiveness and to
improve ease of stone removal.
26. Improving the ease of removal of the chaffer and clean grain
sieves and including removal instructions in the operator’s
manual.
27. Providing an extension on the grease fitting for the inboard
upper tailings cross auger bearing to improve ease and safety
of lubrication.
28. Improving overall pre-delivery servicing and adjustment of the
combine.
29. Revising the operator’s manual to improve clarity, and to
include missing information such as loss monitor adjustment
procedure, a complete lubrication schedule, instructions for
removing the chaffer and sieve and instructions for properly
adjusting the variable speed traction drive belts.
Chief Engineer E.O. Nyborg
Senior Engineer - L.G. Smith
Project Engineer- P.D. Wrubleski
THE MANUFACTURER STATES THAT
With regard to recommendation number:
1. Rear tread width has been increased and steering geometry
modified to allow sharper turns.
2. A 4.5 m³ (150 bu) capacity grain tank will be installed on the
new model NIVA SK-5.
3. The existing clutch is designed to permit unloading on-the-go.
No problems have been encountered to date.
4. The header lift is designed to travel from ground level to full
height in 4 seconds. Low lift rata on the model tested may have
been caused by problems outlined in RECOMMENDATION 8.
Modification to header lift height is under consideration.
5. Providing for sampling of return tailings from the operator’s
platform would require major design changes in the combine.
The operator is warned of overloading by light and by horn.
6. A hydraulic cylinder automatically controls belt tension and
the tightener frame has been strengthened on the new model
NIVA SK-5.
7. No problems of this nature have been experienced with other
models of the NIVA SK-5. The shifter fork may have been
improperly engaged. A decal will be added to advise of proper
operating procedure.
8. A magnetic method of cleaning the hydraulic pipes and
flushing the hydraulic system has been incorporated at the
factory.
9. This recommendation is being considered.
10. A straw chopper is now available as an option for the Niva
SK-5.
11. A modified automatic feedrate control has been incorporated
in the new model NIVA SK-5.
12. A pre-cleaner bag, normally supplied as standard equipment
should have been supplied and installed on the NIVA SK-5.
13. A new design of radiator air intake is used on the current
model NIVA SK-5.
14. A more comfortable operator’s seat with locking back rest will
be installed on the new model NIVA SK-5.
15. New louvers with wider spacing permit better visibility for night
operation and improved access for windshield cleaning.
16. The lighting system will be modified on the new model NIVA
SK-5. Additional lights are presently available as an option.
17. A new design of cab with better pressurization system will be
installed on the new model NIVA SK-5.
18. The main power switch will be installed in the operator’s cab.
19. Lubrication of the speedometer drive has been incorporated
into pre-delivery servicing to eliminate this problem.
20. Modified hydraulic control lever assemblies for all controls will
be installed on new model NIVA SK-5.
21. The ground speed and header lift control levers will be
repositioned on the new model NIVA SK-5.
22. This problem is under investigation.
23. It is recommended that the drive be engaged only at low engine
speed. Provision of higher quality belts is being investigated.
24. The pickup and drive assembly was supplied by Melroe
Division, Clark Equipment. A factory built pickup drive
assembly which eliminates belt slippage is now available. The
creeping of the pickup speed control was probably due to a
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damaged O-ring in the piston.
25. The stone trap will be modified on new model Niva SK-5.
26. The straw buncher feed finger assembly will be removed
from combines sold in Western Canada and replaced with a
deflector shield over the rear axle. In addition, instructions on
removal of sieves will be more explicit.
27. The inboard bearing on the cross auger has been replaced
with a sealed bearing. In addition, all other bearings on the
combine with the exception of the two main cylinder bearings
are sealed units.
28. Pre-delivery instructions at the branch level will be more
explicit with complete running-in of all units before delivery.
29. New instruction manuals will be supplied complete with
a lubrication chart and information on all necessary
adjustments.
RESULTS AND DISCUSSION
EASE OF OPERATION
Operator Location: The Niva SK-5 was equipped with an
operator’s cab as standard equipment. The cab was positioned left
of the grain tank giving good visibility to the rear, left, and front.
Visibility to the right was completely obstructed by the grain tank,
requiring extra care during highway transport or when manoeuvring
in confined areas. The grain level could be viewed through a small
window but grain and return tailings could not be sampled from the
operator’s seat.
The operator’s seat was fairly comfortable and had an ample
range of adjustment, however, seat adjustments were inconvenient.
The folding backrest was hazardous. Most operators, when stepping
down into the cab, would lean on the backrest for support and would
fall forward as the backrest folded (FIGURE 2). The cab was high
enough to permit standing operation.
GENERAL DESCRIPTION
The Belarus Niva SK-5 (FIGURE 1) is self-propelled and
powered with a 82 kW (110 hp) turbocharged four cylinder Diesel
engine. The traction drive is through a three speed transmission
with a single plate dry clutch and variable speed belt. The Niva SK-5
is equipped with hydraulic wheel brakes, power steering, a louvered
cab, an automatic feed controller and a loss monitor. A spare parts
kit and a set of metric tools are included.
The Niva SK-5 has a 4420 mm (14.5 ft) floating header and
is supplied with a 3200 mm (126 in) Melroe 351 pickup. Neither a
straw spreader nor a straw chopper are available.
The separator drive is lever controlled through a single-plate
dry clutch, while the header drive is lever controlled through an overcentre belt tightener. The grain tank unloading auger is engaged
through a dog clutch and can be operated only when the separator
is running.
Hydraulic levers control the ground speed, header height,
pickup or reel speed, reel height, grain tank vibrator for tough grain,
and the radiator chaff deflector. Both concave clearance and cylinder
speed can be adjusted on-the-go from the operator’s platform. Fan
speed is adjusted by a hand wheel controlling a variable speed belt
drive, while the chaffer and Sieve are adjusted with hand wheels on
the side of the combine. There is no provision to safely and quickly
sample the return tailings.
Complete specifications are given in APPENDIX I.
FIGURE 2. Folding Seat Backrest.
SCOPE OF TEST
The Belarus Niva SK-5 was operated in a variety of
Saskatchewan and Alberta crops (TABLES 1 AND 2) for 169 hours
while harvesting about 354 ha (873 ac). It was evaluated for ease of
operation, ease of adjustment, rate of work, grain loss characteristics,
operator safety, and suitability of the operator’s manual. Throughout
the test, comparisons were made to the PAMI reference combine.
TABLE 1. Operating Conditions
Average Yield
Swath Width
Field Area
Crop
Variety
t/ha
bu/ac
m
ft
Hours
ha
ac
Wheat
Barley
Barley
Oats
Flax
Rapeseed
Neepawa
Betzes
Bonanza
Harmon
Linott
Midas
2.8
2.5
2.4
3.4
1.3
1.2
41
47
45
88
20
21
4.9-6.1
4.9-5.5
4.6-7.3
4.6-6.1
4.9
4.6-4.9
16-20
16-18
15-24
15-20
16
15-16
75.0
12.0
38.5
13.0
10.5
20.0
164
17
73
19
30
51
404
42
180
47
74
126
169
354
873
Total
TABLE 2. Operation in Stony Fields
Field Area
Field Conditions
Hours
ha
ac
Stone Free
Occasional Stones
Moderately Stony
Very Stony
45
63
34
27
83
138
70
63
204
341
172
156
Total
169
354
873
All windows were shaded with external metal louvers. The
louvers appreciably reduced cab temperature by preventing direct
sunlight from entering. Although visibility was good for normal
combining, the louvers severely restricted upward visibility for
passing under telephone or power lines. Night visibility was poor due
to inadequate long range front lighting and louver reflections on the
windshield. Cleaning windows under the louvers was very difficult
as they were bolted in place and could not be swung outward.
When the louvers were removed, night visibility was good, but
the cab became extremely hot and uncomfortable during sunny
days. It is recommended that the manufacturer consider hinged
louvers that can easily be swung out of the way for night operation
and for window cleaning.
The cab was very dusty. It was pressurized with two fans but
they were ineffective in keeping dust out of the cab. The foam filter
on the fan outlet severely restricted airflow. An additional propeller
fan was provided for air circulation within the cab or windshield
defrosting. Although this fan could be used for cooling the operator’s
face, the dust moved by the fan caused eye irritation.
Total noise at operator ear level was 90 decibels (A scale)
with all doors and windows closed while operating at rated capacity
in wheat. This noise level equals current operator exposure
recommendations1 for eight hours per day. It is recommended that
the operator wear suitable ear protection if operating for more than
eight hours per day.
Controls: The control arrangement for the Niva SK-5 is shown
in FIGURE 3. The hydraulic control levers for header height, reel
1
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4
”Occupational Safety and Health Standards “, Fed. Regist. 36(105), Pt. II (May 29, 1971)
height, pickup or reel speed, radiator chaff deflector and grain
tank vibrator were located in a cluster to the right of the operator.
Arrangement of these controls was confusing, the controls were
quite irresponsive and the mechanical linkages wore rapidly during
use. The header lift was slow, especially with warm hydraulic fluid,
often necessitating stopping when crossing gullies or washouts, to
prevent the header from striking the ground.
set the feed control at the desired feedrate. The desired feedrate
was determined by referring to the loss monitor output. Once the
control was properly set, it very effectively held the combine below
a desired loss level by automatically varying the forward speed to
maintain a uniform feedrate. Feedrate control was very good in
uniformly varying windrows. The automatic feed control could not
be used in very bunchy windrows and also had to be set to manual
before turning corners. In very bunchy windrows, the automatic feed
control could not respond fast enough.
FIGURE 3. Control Layout on the Niva SK-5.
The variable speed traction drive control was located to the left
of the operator. Since the traction drive and header height controls
were on opposite sides of the cab, the operator constantly had to
change hands on the steering wheel when combining bunchy nonuniform windrows. It is recommended that the ground speed and
header height controls be repositioned together, close to the steering
wheel on the same side of the steering column.
Although the concave adjusting lever and separator drive
lever were conveniently positioned, when the concave was closed
interference occurred among the concave lever, separator drive
lever and header height control lever (FIGURE 4).
FIGURE 5. Automatic Feed Control on Niva SK-5.
FIGURE 4. Interference Among Control Levers.
The Niva SK-5 was equipped with an automatic feed control
(FIGURE 5) and a loss monitor as standard equipment. The
feed control sensed the amount of straw entering the feeder and
automatically adjusted the forward speed according to the amount
of straw in the feeder. Two levers, to the left of the operator were
used to set the feed control. A two position lever set the combine in
either the manual or automatic feeding mode, while the second lever
Steering: Steering and maneuverability of the Niva SK-5 were
unsatisfactory. Although it was equipped with power steering, the
steering was hard and irresponsive. The turning radius was 6910 mm
(23 ft) to the right and 9800 mm (32 ft) to the left. It was impossible
to pick windrows around 90 degree corners (FIGURE 6) without
stopping and backing up during the turn. Gears were difficult to shift
and the combine had to come to a complete stop for shifting. The
individual wheel brakes had to be pumped each time they were used
and were ineffective in reducing the turning radius. The steering and
braking system must be modified before the Niva SK-5 is acceptable
for Western Canadian conditions.
Instruments: The instrument console (FIGURE 7) included
gauges for engine oil pressure, battery charging rate, coolant
temperature, ground speed, and cylinder speed. Indicator lights
were provided for engine oil temperature, grain tank level return and
clean grain elevator slip clutches, turn signals, parking brake, and for
the main power switch. The main power switch was inconveniently
located outside the cab on the side of the combine and could only
be conveniently reached from the ground. The main power switch
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had to be turned off whenever the engine was not running to prevent
battery discharge. The electrical system circuit breaker was also
inconveniently located inside the battery box.
FIGURE 6. Schematic Illustration of Manoeuvring Required to Pick a Windrow Around a
90° Corner.
FIGURE 7. Instrument Console on Niva SK-5.
The speedometer was driven from the transmission input
shaft and had a scale for each gear. Its operation was erratic and
intermittent throughout the test.
The grain loss monitor dial was conveniently located on the
steering column. The monitor was easy to calibrate and adjust. It
sampled the amount of clean grain passing through the shoe as well
as walker and shoe losses and gave a readout in percent loss. The
percent-loss-readout was more meaningful than the non-calibrated
readouts on some loss monitors, giving the operator a better
appreciation of combine performance in varying crop conditions.
Lights: The Niva SK-5 had adequate lighting for the grain tank,
the unloading auger, and the rear of the combine. Lighting at the
header was very good but long range lighting in front of the combine
was poor.
Engine: The engine had ample power reserve for normal
combining but operated near its power limit when combining damp
crops on soft, hilly fields. The engine had sufficient power reserve
for the addition of a straw chopper in normal dry crops but probably
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would be underpowered with a straw chopper in heavy damp crops.
Average fuel consumption varied from 14 to 18 L/h (3 to 4 gal/h).
The engine was very easy to service and was accessible from all
sides.
The engine radiator screen plugged quickly when combining
dusty crops. The hydraulic diverters for chaff removal usually had
to be operated several times for each hopper of grain. Although
the engine temperature warning light signalled the operator that
cleaning was necessary, a rotating inlet screen for automatic chaff
removal, as is commonly used on most combines, would be more
convenient. The radiator screen also was ineffective in preventing
radiator plugging and occasional cleaning, especially between the
radiator and oil cooler, was required.
The engine air intake used a screen pre-cleaner and two dry
filters. The filters were very effective in keeping dust out of the
engine but the outer filter plugged quickly in dusty conditions and
needed daily cleaning. A centrifugal bowl pre-cleaner in place of the
screen pre-cleaner is recommended to increase filter life and reduce
filter servicing.
The engine was equipped with a 24V electric starter. It had a
decompression lever, hand primer pump and a starter button on the
engine for cold starting, as well as a starter button on the instrument
console for normal use. If night temperature dropped below +5°C,
ether was needed to start the cold engine. As the engine was not
equipped with an automatic ether starting aid, ether had to be hand
fed through the engine air intake. At higher ambient temperatures,
the cold engine started easily using the hand primer pump and
decompression lever.
During the last part of the test, the engine fuel system was
plagued with problems of air entrainment resulting in loss of power,
poor starting and rough idling. Although the problem appeared to be
of minor nature, caused by fuel line air leaks, probably at the hand
primer pump, local manufacturer service personnel were unable to
correct the problem.
Engine oil consumption was about 0.9 L (1 quart) every
10 hours when new. Oil consumption gradually decreased during
the test as the engine wore in.
Stability: The Niva SK-5 was very stable, even with a full
grain tank. The centre of gravity with a three-quarters full grain tank
was 1580 mm (62 in) above ground, 450 mm (18 in) behind the
drive wheels and 30 mm (1 in) to the left of the combine centre
line. Normal care had to be used when turning corners on steep
hillsides.
Grain Tank: The grain tank held 2.1 t (77 bu) of wheat.
Unloading a full hopper of dry wheat took 75 seconds. The grain
tank was covered, with access through a small door on top. A level
indicator light signalled the operator when the grain tank was full
and a flashing light and horn on the elevator slip clutch signalled
the operator if overfilling was attempted. The grain tank was much
too small. To match the threshing and separating capacity of the
Niva SK-5, the grain tank should hold at least 4 t (150 bu). The
grain tank cover made tank access and sample inspection difficult
and prevented the possibility of attaching extensions to increase
tank capacity. The grain tank cover was removed and special tank
extensions were fabricated in an attempt to increase tank capacity.
The grain elevator, however, did not have enough capacity to fill the
tank beyond its original level, except in oats. If the separator drive
was stopped with a full hopper of flax, flax ran down the clean grain
elevator, completely plugging it, requiring hand cleaning before the
separator could be started.
The unloading auger drive was through a jaw clutch and
operated only when the separator drive was engaged. Since the
clutch was positive, it subjected the auger drive to excessive impact
loads unless engine speed was reduced before engaging the auger.
Although auger height and reach were ample for easy unloading
on-the-go, the auger clutch made on-the-go unloading impractical.
The hydraulic vibrator on the grain tank floor was very effective
in emptying the tank when combining damp grain, however, the
unloading auger occasionally would not start when the tank was
filled with tough barley. The unloading auger folded manually
for transport. One man could easily fold the auger in less than a
minute.
The grain tank, grain elevator and unloading auger drive all
require modification before the Niva SK-5 is suitable for Western
Canadian conditions.
Plugging: The table auger and feeder were very aggressive.
When properly adjusted, table auger plugging seldom occurred,
even in damp crops. Occasional plugging of the table auger occurred
in tough bunchy Midas rapeseed and in damp heavy windrows of
Bonanza and Betzes barley. Table auger unplugging was made
easy by using the supplied bar and rocking hub on the upper feeder
shaft. The feeder conveyor never plugged during the test.
The cylinder was very aggressive and positive. Plugging and
backfeeding seldom occurred, even in damp and wet windrows.
If the cylinder plugged, it could usually be unplugged from the
operator’s seat, by lowering the concave. Cylinder access was
convenient and there was ample room to use a breaker bar through
the cylinder bars, if severe plugging should occur. It was important
to keep the thresher clutch and all drive belts in proper adjustment
when combining tough crops.
A
s with most combines, dust and chaff collected inside the
cylinder rasp bars, causing cylinder imbalance. The inside of the rasp
bars occasionally had to be cleaned to prevent cylinder vibration.
Stone Trap: The Niva SK-5 was equipped with a stone trap
in front of the cylinder. Although the trap caught many stones, roots
or stones could occasionally be heard passing through the cylinder
and one stone bent the front concave bar and broke one of the front
concave hanger bolts. As with most combines, if a large stone was
inadvertently picked, it could damage the table auger or feeder
before being stopped by the stone trap.
Cleaning the stone trap was inconvenient. The header had to
be raised and an access door under the cylinder removed by hand.
Stones could be removed through three 102 by 248 mm (4 by 9.8 in)
openings (FIGURE 8). Larger stones, which could not pass through
these openings, had to be maneuvered into the feeder housing and
removed by turning the feeder backward.
FIGURE 8. Stone Trap Access on the Niva SK-5.
Pickup: The Niva SK-5 was equipped with a 3200 mm
(126 in) Melroe model 351 pickup. The pickup was installed by the
local distributor before combine delivery. Several problems resulted
with the pickup due to improper installation. Improper drive sprockets
were supplied, the windguard was improperly assembled and severe
drive belt slippage occurred. The pickup was powered from the reel
drive (FIGURE 9). The reel drive was not designed for the type of
load imposed by a pickup. As a result, the reel pivot pipe flexed
causing the drive belt to loosen and slip under load. In addition, the
variable speed reel drive, which was also used as a pickup drive,
constantly crept to slow-speed position during operation because
the control ram worked loose in its support clamp.
The reel support pipe was braced to eliminate flexing, different
drive sprockets were installed to obtain proper pickup speed and the
windguard was removed and properly assembled. This corrected
most of the drive problems, however, creeping of the variable
speed drive sheave to slow-position, accompanied by variable
speed belt slippage occurred frequently during the test although the
support clamp was repeatedly tightened. The pickup drive requires
modification before it is suitable.
In spite of drive problems, the pickup had excellent feeding
characteristics, delivering the crop beneath the table auger in all
conditions. In bunchy Midas rapeseed, the windguard had to be
removed to eliminate plugging between the windguard and pickup
draper. Some plugging occurred between the rear pickup roller and
the front draper roller in damp Bonanza and Betzes barley.
FIGURE 9. Drive Assembly for the Melroe Pickup on the Niva SK-5.
Machine Cleaning: When operating in tough or damp crops,
the grain pan steps occasionally built up with an accumulation of dirt.
The grain pan steps could be cleaned through side access doors
with a cleaning poker supplied with the combine.
As with most combines, completely cleaning the Niva SK-5,
for combining seed grain was a laborious, time-consuming job.
The chaffer and sieve were very difficult to remove. Removal
and replacement for cleaning took about two hours. The grain
tank was difficult to clean due to the small access port and many
obstructions.
Lubrication: The Niva SK-5 had 109 pressure grease fittings.
The lubrication schedule outlined in the operator’s manual was
confusing. Thirty-three fittings were not included in the lubrication
chart. Of the remainder, two required greasing every 10 hours,
21 required greasing every 60 hours and 35 required greasing every
240 hours. Three fittings were difficult to reach; the remainder were
quite accessible.
Engine and hydraulic oil levels required daily checking while
the common transfer case for the transmission, differential and final
drives should be checked every 60 hours. The engine was equipped
with a spinning disk mechanical oil filter. It had to be removed and
cleaned every 240 hours when the engine oil was changed.
EASE OF ADJUSTMENT
Field Adjustments: The Niva SK-5 was easy to adjust and
could be quickly set for a crop by one person. Since return tailings
could not be inspected, the operator did not have a complete feel
of the effect of settings on performance. Both cylinder speed and
concave clearance could be adjusted from the operator’s seat,
however, if return tailings could have been inspected, the need for
changing settings during the day would have been easier to detect.
Concave Adjustment: The Niva SK-5 had a two section
concave (FIGURE 10). Both sections were reversible, permitting the
concave to be turned around when worn. The concave was easily
levelled and inspected through three inspection holes on each side
of the combine. A set of feeler gauges for levelling was supplied.
In closed position, the manufacturer recommended clearances of
2 mm (0.08 in) at the rear, 14 mm (0.55 in) at the centre and 18 mm
(0.71 in) at the front. This minimum setting was suitable for all crops
except flax. In flax, a minimum setting of 1 mm (0.04 in) rear, 13 mm
(0.51 in) centre and 17 mm (0.67 in) front was found suitable. The
concave adjusting lever, on the operator’s platform, was convenient
to use and had an ample range for all crops. In wide open position,
Page
7
clearances were 42 mm (1.65 in) rear, 46 mm (1.81 in) centre and
48 mm (1.89 in) front. Suitable concave settings were 4 mm (0.16 in)
rear, 16 mm (0.63 in) centre and 20 mm (0.79 in) front in dry wheat.
In rapeseed suitable settings were 22 mm (0.87 in) rear, 33 mm
(1.30 in) centre and 36 mm (1.42 in) front.
FIGURE 10. Concave on the Niva SK-5.
Filler bars were not required in any crop. When properly
adjusted, average dockage from bolls, white caps, and chaff was
about 0.5% in wheat and 0.75% in flax.
Shoe Adjustments: The chaffer, clean grain sieve and fan
were convenient to adjust with calibrated handwheels at the rear of
the combine (FIGURE 11).
Chaffer extension opening and slope had to be adjusted from
the rear through a sliding gate at the end of the shoe. This adjustment
was inconvenient due to shielding by the straw rake pan. Care had
to be taken to ensure that the rear. gate was properly adjusted to
prevent loss of cleaning air.
The shoe was easily adjusted and performed well in most
crops, after some modifications. The clean grain sieve, as delivered,
did not close uniformly (FIGURE 12) making it difficult to set the
sieve. The sieve was removed and the individual louvers were
bent so that the sieve opened and closed uniformly. After sieve
modifications, the shoe performed well in all crops and was fairly
easy to set. The shoe would have been much easier to set if return
tailings could have been inspected. Total dockage in the grain tank,
including cracks, whitecaps, and chaff, usually varied from 1 to 3%
when properly adjusted.
As is common with most combines, the shoe was difficult to
set in non-uniform crops of some varieties of rapeseed due to the
large variation in seed size and amount of shoe load between heavy
and light windrows. It was found best to set the shoe for optimum
performance in the heavy windrow sections and to increase feedrate
in light windrow sections to maintain a fairly uniform shoe load. The
automatic, feed control was very useful in reducing shoe loss in
one non-uniform field of Midas rapeseed by maintaining a relatively
uniform shoe load.
In normal conditions, shoe plugging never occurred. In late
fall combining in extremely wet conditions, the chaffer and sieve
plugged with wet material and combining could not take place
unless the temperature was well below freezing.
As is common with most combines, the windrow should be
centered on the feeder housing. Feeding to one side caused nonuniform shoe loading with increased shoe losses. Similarly, as with
most combines, shoe loss increased noticeably when combining on
side slopes greater than 3°, due to non-uniform shoe loading.
Adjusting the Automatic Feed Control: When the combine
was received, the automatic feed control (FIGURE 5) was not
operational. The sensor fingers were loose and out of adjustment,
several pivot points lacked lubrication and were “seized” with paint,
while, the control cable was faulty. Local distributor personnel
were unable to correct these problems. Although a new control
cable was supplied, it was also faulty. A modified control cable
was fabricated by PAMI and the control was modified and adjusted
to make it operational. Once it had been modified and properly
serviced, the feed control performed well. Adjustments were simple.
The feed control was set from the operator’s seat by referring to
the loss monitor output. It is recommended that the manufacturer
properly pre-deliver and service the combine so that the automatic
feed control is operational at time of delivery. Distributor service
personnel should be trained in its proper operation.
FIGURE 11. Shoe Adjustments on Niva SK-5.
Cylinder Adjustment: The cylinder was equipped with a
variable speed drive, adjustable from the operator’s seat, and
a tachometer. The cylinder was also driven through a two-speed
gearbox. This gave cylinder speeds from 325 to 600 rpm in low gear
and 750 to 1360 rpm in high gear. Suitable cylinder speeds were
about 800 rpm in flax, 900 rpm in dry wheat, 350 rpm in rapeseed,
and 750 rpm in dry barley. Cylinder speeds from 600 to 750 rpm
were not available. These speeds were not required during the
test, however, they may be required for certain crops. Typical grain
crackage varied from 0.5 to 1.5% when properly adjusted. The
cylinder rasp bars were in good condition at the end of the test,
showing negligible wear. The cylinder stripper consisted of 3 mm
(0.125 in) thick belting attached to a metal plate. Although the belting
was worn requiring replacement at the end of the test, backfeeding
never was a problem.
Page
8
FIGURE 12. Uneven Closing of Louvers on Clean Grain Sieve.
Adjusting the Loss Monitor: The loss monitor was adjusted
with a knob on the control box in the operator’s cab. To set the
monitor, the combine was operated at the maximum speed which
gave negligible losses and the knob adjusted until the loss needle
read zero. It was necessary to inspect losses on the ground behind
the combine to determine the zero loss setting. The loss monitor had
to be readjusted for every field. Once the operator became familiar
with combine characteristics in various crops, adjusting the loss
monitor was quite simple. When properly adjusted, any increase
in losses above the selected zero loss level, was indicated on the
meter as percent of total grain being harvested. Instructions for loss
monitor adjustment were not included in the operator’s manual.
Header Adjustments: The Niva SK-5 was equipped with
a floating header. The floating mechanism allowed the header to
follow ground contours, on skid shoes, independent of the combine
wheels, and was designed for straight combining. The header
floating mechanism was not evaluated since the combine was used
only with a windrow pickup. When using a pickup the float linkage is
locked.
The table could be removed from the feeder. Removal and
installation took three men about 1.5 hours. The table and feeder
housing could also be removed from the combine as a unit. Removal
and replacement took two men about one-half hour.
RATE OF WORK
Average Workrates: TABLE 3 presents the average workrates
for the Niva SK-5, at acceptable loss levels, in all crops harvested
during the test. Average workrates are affected by crop conditions
in a specific year and should not be used for comparing combines
tested in different years. In some crops, workrates were reduced
by bunchy and sunken windrows, muddy or rough ground, irregular
shaped fields with many corners and driving the combine empty to
unload grain at a central location. During the 1976 harvest, average
workrates varied from 6.1 t/h (225 bu/h) in 2.8 t/ha (41 bu/ac)
Neepawa Wheat to 3.0 t/h (132 bu/h) in 1.2 t/ha (21 bu/ac) Midas
rapeseed.
TABLE 3. Average Workrates for the Niva SK-5
Average
Yield
Crop
Wheat
Barley
Barley
Oats
Flax
Rapeseed
Average
Speed
Average Workrate
Variety
t/ha
bu/ac
km/h
mph
ha/h
ac/h
t/h
bu/h
Neepawa
Betzes
Bonanza
Harmon
Linott
Midas
2.8
2.5
2.4
3.4
1.3
1.2
41
47
45
88
20
21
6.2
4.5
5.1
4.3
8.0
6.6
3.3
2.8
3.2
2.7
5.0
4.1
2.2
1.3
1.9
1.4
2.9
2.5
5.5
3.4
4.7
3.4
7.0
6.1
6.1
3.3
4.7
4.7
3.8
3.0
225
159
215
304
140
132
Maximum Feedrate: The workrates given in TABLE 3 represent
average workrates at acceptable loss levels. The engine had ample
power to achieve much higher workrates in nearly all crops. In most
crops the maximum acceptable feedrate was limited by grain loss,
while in light crops the maximum feedrate was limited by pickup
performance. Maximum feedrate was limited by engine power only
when combining wet heavy windrows in soft or hilly fields.
Capacity: Combine capacity is the maximum rate at which a
combine can harvest a certain crop, at a specified total loss level,
when adjusted for optimum performance. Many crop variables affect
combine capacity. Crop type and variety, grain and straw moisture
content, grain and straw yield and local climatic conditions during
the growing season all affect the threshing and separating ability of
a combine.
MOG Feedrate, MOG/G Ratio and Percent Loss: When
determining combine capacity, combine performance and crop
conditions must be expressed in a meaningful way. The loss
characteristics of a combine in a certain crop depend mainly on two
factors, the quantity of straw and chaff being processed and the
quantity of grain being processed.
The weight of straw and chaff passing through a combine per
unit time is called the MOG Feedrate. MOG is an abbreviation for
“material-other-than-grain” and represents the weight of all plant
material passing through the combine except for the grain or seed.
The weight of grain or seed passing through a combine per
unit time is called the Grain Feedrate. The ratio of MOG Feedrate to
Grain Feedrate, which is abbreviated as MOG/G gives an indication
of how difficult a certain crop is to separate. For example, if a certain
combine is used in two wheat fields of identical grain yield but one
with long straw and one with short straw, the combine will have
better separation ability in the short crop and will be able to operate
faster. This crop variable is expressed with the MOG/G ratio when
determining combine capacity. MOG/G ratios for prairie wheat crops
vary from about 0.5 to 2.25.
Grain losses from a combine are of two main types, unthreshed
grain still in the head and threshed grain or seed, which is discharged
with the straw or chaff. Unthreshed grain is called cylinder loss.
Free grain in the straw and chaff are called separator losses and
consist of shoe loss and straw walker loss. Shoe and straw walker
losses are very dependent upon MOG Feedrate and MOG/G ratio.
Losses are expressed as a percent of total grain passing through
the combine. Combine capacity is expressed as the maximum MOG
Feedrate at which total grain loss (cylinder loss plus separator loss)
is 3% of the total grain yield.
Capacity of the Niva SK-5: TABLE 4 presents capacity results
for the Niva SK-5 in four different crops. MOG Feedrates for a 3%
total grain loss varied from 9.7 t/h (357 lb/min) in a field of Neepawa
wheat to 7.3 t/h (268 lb/min) in a field of Bonanza barley. In flax, the
total loss level was only 1% at the maximum feedrate of 9.2 t/h (338
lb/min). In this crop, capacity was limited by pickup performance at
higher speeds.
GRAIN LOSS CHARACTERISTICS
The grain loss characteristics for the Niva SK-5, in the four
crops described in TABLE 4, are presented in FIGURES 13 to 16.
Walker Loss: As is common with most combines, walker
loss was the most significant factor limiting capacity in all grain
crops. Cylinder loss and shoe losses usually were insignificant in
comparison to walker loss. A reduction in free grain loss over the
straw walkers would have enabled much higher combining rates
especially in difficult-to-separate crops such as barley.
Shoe Loss: Shoe loss rarely limited combine capacity although
adjustment was critical in rapeseed and flax and high losses could
occur with improper settings.
Cylinder Loss: Cylinder loss was low in all dry and well
matured crops. Although loss increased slightly in tough and damp
crops, it was always very acceptable. The good performance of
the cylinder in damp crops was attributed to the large wrap of the
concave (146°), which gave a large threshing area. A comparison
of FIGURES 13 AND 14 illustrates the effect of improper cylinder
adjustment. Both figures give results from 2.7 t/ha (40 bu/ac) fields
of relatively hard-to-thresh Neepawa wheat. In FIGURE 13, the
straw was tough and the grain moisture content was 14.7%. With
proper adjustment, cylinder loss was about 0.5%. FIGURE 14 gives
results for dry straw with grain moisture of 12.0% and the cylinder
running too slow. In this case, cylinder loss varied from 0.5% to
2.5%. Increasing the cylinder speed slightly would probably have
reduced cylinder loss to 0.5% in this crop.
Body Loss: Slight grain leakage occurred from the bottom
and top inspection doors of the return elevator, and from several
other locations, but was insignificant. Total grain leakage from the
combine body, measured in a 1.3 t/ha (20 bu/ac) crop of Linott flax,
was only 0.11% of yield.
FIGURE 13. Grain Loss for the Niva SK-5 in Neepawa Wheat at 14.7% Grain Moisture
Content.
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9
TABLE 4. Capacity of the Niva SK-5 at a Total Grain Loss of 3% of Yield*
Crop Conditions
Width of Cut
Crop Yield
Crop
Variety
m
ft
t/ha
bu/ac
Straw
Condition
Wheat
Wheat
Barley
Flax
Neepawa
Neepawa
Bonanza
Linott
5.5
5.5
7.3
4.6
18
18
24
15
2.76
2.72
3.48
1.44
41
40
65
23
dry to tough
dry
dry to tough
very dry
Capacity Results
Grain Moist.ure
%
MOG/
G
14.7
12.0
14.6
8.7
1.31
1.52
0.96
1.47
MOG Feedrate
Grain Feedrate
Ground Speed
t/h
lb/min
t/h
bu/h
km/h
mph
Loss Curve
8.95
9.70
7.30
9.20
329
357
268
338
6.83
6.38
7.45
6.30
251
235
342
246
4.5
4.3
2.9
12.7
2.8
2.7
1.8
7.9
Fig. 13
Fig. 14 & 17
Fig. 15 & 18
Fig. 16 & 19
*In flax, maximum total loss was only 1% of yield.
the prairie provinces and is described in PAMI Evaluation Report
E0576C.
FIGURES 17 to 19 compare the total grain losses of the
Niva SK-5 and the PAMI reference combine in three of the crops
described in TABLE 4. The shaded areas on the figures are the 95%
confidence belts. If the shaded areas (confidence belts) overlap,
the loss characteristic of the two combines are not significantly
different whereas if the shaded areas do not overlap, the losses are
significantly different. The capacity of the Niva SK-5 was greater
than the capacity of the reference combine and the Niva SK-5
usually had lower grain losses than the reference combine when
operating at the same feedrate.
FIGURE 14. Grain Loss for the Niva SK-5 in Neepawa Wheat at 12.0% Grain Moisture
Content.
FIGURE 17. Total Grain Losses for the Niva SK-5 and the PAMI Reference Combine in
Neepawa Wheat at 12.0% Grain Moisture Content.
FIGURE 15. Grain Loss for the Niva SK-5 in Bonanza Barley.
FIGURE 18. Total Grain Losses for the Niva SK-5 and the PAMI Reference Combine in
Bonanza Barley.
FIGURE 16. Grain Loss for the Niva SK-5 in Linott Flax.
Comparison to Reference Combine: Comparing the
capacities of two combines is complex because crop and growing
conditions influence combine performance with the result that
slightly different capacity characteristics can be expected every
year. As an aid in determining relative combine capacities, PAMI
uses a reference combine. This combine is operated alongside
test combines whenever capacity measurements are made. This
permits the comparison of loss characteristics of every test combine
to those of the reference combine, independent of crop conditions.
The reference combine used by PAMI is commonly accepted in
Page
10
OPERATOR SAFETY
Comprehensive safety sections were included in both the
combine and engine operator’s manuals. The Niva SK-5 had
adequate warning decals, but was not equipped with a Slow Moving
Vehicle sign. Since a sign is required for transport on public roads
in most Canadian provinces, the distributor should install an SMV
sign before delivery to the dealer. The Niva SK-5 was not equipped
with warning lights or rear view mirrors. The manufacturer should
consider adding both to improve safety in road transport due to
limited visibility on the right of the combine.
Shielding on the Niva SK-5 was excellent, and gave good
protection from all moving parts. Most shields were hinged and
easily opened for servicing, thereby discouraging the practice of
permanent shield removal.
The Niva SK-5 was equipped with a header lock and its proper
use was emphasized in the operator’s manual. The header lock must
be used when working beneath the header, such as when cleaning
the stone trap.
FIGURE 19. Total Grain Losses for the Niva SK-5 and the PAMI Reference Combine in
Linott Flax.
The ladder for cab and engine access was safe, convenient
and equipped with adequate railings.
Care must be taken when servicing the engine, to avoid slipping
and falling from the combine.
Care must be taken to remove the rocking wrench from the
feeder shaft hub if it has been used for unplugging the table auger.
Serious injury could result if the wrench is not removed.
The grain tank must not be entered when the engine is running.
Entering the grain tank for cleaning was both difficult and hazardous
due to the small size of the access port.
The flexible seat backrest (FIGURE 2) was hazardous. The
operator would often lean upon the backrest for support when
stepping down into the cab and would fall forward as the backrest
pivoted. It is recommended that a lock be provided on the seat
backrest.
If recommended safety procedures were followed, all
adjustments could be safely made. Since the Niva SK-5 was
designed for a factory installed straw and chaff buncher, it was
equipped with rotating straw buncher feed fingers and feed pan
(FIGURE 20) directly behind the shoe. Extreme care had to be taken
when hand sampling shoe losses while the combine was running to
avoid contact with the feed fingers. The straw buncher feed fingers
were not required in dry crops, however, they were required in
damp barley and in green crops to prevent chaff build-up behind the
shoe.
FIGURE 20. Straw Buncher Feed Finger Assembly.
The grease fitting on the inboard bearing of the upper railings
cross auger, was hazardous to service.
A fire extinguisher should be carried on the combine at all
times.
OPERATOR’S MANUAL
Operator’s manuals in both English and Russian were supplied
with the Niva SK-5 for the combine, the engine and the automatic
feed control. No operator’s manual was supplied for the factory
installed loss monitor. The English operator’s manuals were a direct
translation of the Russian manuals. They were very wordy and quite
difficult to understand mainly due to inadequate translation.
The manuals contained three dimensional cut away views of
most combine components. These aided in repair and adjustment
in many cases but were inadequate in other cases. For example,
although a lengthy description was provided on the shoe, instructions
for removing and replacing the sieves were not included.
The procedure outlined in the operator’s manual for adjusting
the variable speed traction drive was incomplete and resulted in
deformation of the pivot clevis and drive belt misalignment if followed
in detail.
The lubrication section in the operator’s manual was confusing
and incomplete. Thirty-three grease fittings were not included in the
lubrication chart.
No suggested combine settings for various crops were provided
in the operator’s manuals, although suggested settings for several
crops, as well as many operating instructions, were included on
decals attached to various parts of the combine.
Some of the controls and components described in the
operator’s manual did not correspond to those on the combine. It
is recommended that the operator’s manual for the Niva SK-5 be
revised, corrected and updated.
DURABILITY RESULTS
TABLE 5 outlines the mechanical history of the Belarus Niva
SK-5 combine during 169 hours of operation while combining about
354 ha (873 ac). The intent of the test was evaluation of functional
performance. The following failures occurred during functional
testing, An extended durability evaluation was not conducted.
TABLE 5. Mechanical History
Item
Hydraulic System
-The hydraulic system was flushed and the oil replaced to remove
sludge, paint and metal cuttings at
-The main hydraulic pump shifter clutch began jumping out of gear
under load, The shifter fork and clutch jaws were modified to eliminate
the problem at
-The header hydraulic control lever wore out at the pivot shaft attaching
point and was rebuilt at
-The header hydraulic control lever wore out again. Both the lever and
pivot shaft were replaced at
-Oil began leaking from the header lift spool valve at
-The main hydraulic line burst at the relief valve coupling and was
replaced at
Drives
-The unloading auger final drive chain jumped off due to sprocket
misalignment. The drive was aligned and the chain replaced at
-The unloading auger final drive chain broke due to sprocket
misalignment. The drive shaft was shimmed to prevent misalignment
and the chain repaired at
-The variable speed traction drive pivot clevis bent, while tightening the
traction drive belt and was straightened at
-The header drive chain broke and was repaired at
-The header drive belt cracked requiring replacement at
This recurred at
-The lower left tailings elevator bearing failed damaging the auger shaft,
bearing retainer and seal. All were replaced at
-One grain unloading auger pivot junction drive cog broke when folding
the auger into working position at
Engine
-Intermittent problems with air entrainment in the fuel system began
occurring at
-Oil began leaking from the turbocharger at
-The oil leak became severe requiring turbocharger replacement at
Cylinder and Concave
-The left front concave adjusting bolt broke and was rewelded, and two
bars on the front concave segment bent and two feeder slats bent when
a stone entered the cylinder at
Miscellaneous
-The lower tailings inspection door hinge broke and was repaired at
-The batteries required replacement at
Field Area
Operating
Hours
ha
(ac)
20
41
(101)
20
41
(101)
75
176
(435)
101
111
236
266
(583)
(657)
150
324
(801)
2
4
(10)
72
169
(418)
13
33
70
95
24
76
163
222
(59)
(188)
(403)
(549)
74
174
(430)
138
312
(771)
85
111
124
196
266
292
(484)
(657)
(722 )
85
196
(484)
164
343
(848)
End of Test
Page
11
DISCUSSION OF MECHANICAL PROBLEMS
VARIABLE SPEED TRACTION DRIVE
The variable speed traction drive performed well, however,
during initial adjustment (needed due to belt stretching), the pivot
clevis (FIGURE 21) bent when following adjusting procedures
outlined in the operator’s manual. To maintain belt alignment
during adjustment it was necessary to wedge the left side of the
inner adjusting clevis to prevent clevis deformation from the belt
load. Modifying the pivot clevis assembly to prevent bending
during adjustment or modifying the belt tightening procedure in the
operator’s manual are required.
HYDRAULIC PUMP CLUTCH
The main hydraulic pump was equipped with a jaw-clutch to
facilitate cold weather starting. The clutch began disengaging under
load. The pump was removed and it was found that the jaw-clutch
had never been properly adjusted at the factory and was engaging
only on the corners of the jaws, which had become worn. The jaw
faces were reground, and the shifter fork assembly was bent to
provide full jaw engagement. No further problems occurred.
FIGURE 21. Traction Drive Adjustment.
ENGINE TURBOCHARGER
The turbocharger began leaking oil out the discharge air port.
The subsequent chaff build up caused a fire which was extinguished
before it had damaged any components. Leakage could possibly
have been initiated by restricted air filters. The turbocharger was
removed and disassembled, and the oil slingers were found to be
worn excessively. Since no replacement parts were available, a new
turbocharger was installed. The primary and secondary air filters
were replaced, and a centrifugal pre-cleaner was installed since the
original pre-cleaner had a coarse screen resulting in quick plugging
of the primary air filter. No further problems occurred.
ENGINE FUEL SYSTEM
An aggravating problem throughout the last half of the test was
intermittent air entrainment in the fuel system causing loss of power,
rough idling and poor starting. Complete bleeding and repriming of
the fuel system would result in normal operation for a limited time.
By the end of the test all connections had been checked and all
filters and the hand priming pump had been replaced. Although
replacement of the hand priming pump reduced the problem, air
entrainment still occasionally occurred apparently at the hand
priming pump. Local distributor service personnel were unable to
correct the problem.
HEADER DRIVE BELT
The header drive belt failed twice. Both belts cracked on the
inside edge, possibly due to the severe reverse bend over the drive
tightener. A shorter drive belt may increase belt life by reducing the
reverse bend.
TAILINGS ELEVATOR
Failure of the left lower bearing on the tailings elevator
Page
12
damaged the tailings auger shaft, bearing housing, and inboard
bearing seal. Only the bearing was included in the spare parts
kit. Most bearings on the Niva SK-5 are of a unique design, not
compatible with North American bearings, requiring special tools
for removal and mounting. The special tools are supplied with the
combine and function adequately.
COMBINE PRE-DELIVERY
Many minor problems occurred initially with the Niva SK-5.
Most of these were due to improper combine pre-delivery, poor
instruction manuals and distributor service personnel unfamiliar with
the combine. Most of these problems could be eliminated by proper
procedures at the distributor level.
APPENDIX I
SPECIFICATIONS
MAKE:
MODEL:
SERIAL NUMBER:
MANUFACTURER:
WINDROW PICKUP:
-- make and model
-- serial number
-- type
-- pickup width
-- number of belts
-- teeth per belt
-- type of teeth
-- number of rollers
-- apron
-- draper
-- height control
-- speed control (combine)
-- apron speed range
-- draper speed range
HEADER:
-- type
-- width
-- auger diameter
-- feeder conveyor
-- conveyor speed
-- range of pickup height
-- number of lift cylinders
-- raising time
-- lowering time
FEEDER BEATER:
-- type
-- diameter
-- speed
Belarus Niva Self-propelled Combine
SK-5
Header N235,
Combine body N-3-8351,
Engine 75438214
Tractoroexport
Rostselmash
Rostov-on-Don, U.S.S.R.
Melroe 351-12
MB 8148
alumimum apron with rubber draper
3200 mm (126 in)
7
40
spring steel
2
2
support chains
variable pitch sheaves hydraulically
controlled
150 to 320 rpm
185 to 400 rpm
centre feed, full floating
4420 mm (14.5 ft)
508 mm (20 in)
3 roller chains, undershot slatted conveyor
2.9 m/s (573 ft/min)
-100 to 730 mm (-4 to 29 in)
2
6s
3s
four wing drum
195 mm (7.69 in)
700 rpm
CYLINDER:
-- type
-- number of bars
-- diameter
-- width
-- drive
-- speed range
-- low gear
-- high gear
-- stripper
325 to 600 rpm
750 to 1360 rpm
3 mm (0.13 in)bar fabric belting
CYLINDER BEATER:
-- type
-- speed
four wing box
845 rpm
CONCAVE:
-- type
-- number of bars
-- front segment
-- rear segment
-- configuration
-- area
-- transition grate area
-- wrap
-- grain delivery to shoe
rasp bar
8
600 mm (23.63 in)
1185 mm (46.63 in)
crank controlled variable pitch belt
bar and wire grate, two segment
7
12
18 intervals with 5 mm (0.19 in) wires and
12 mm (0.47 in) spaces
1.01 m² (1567 in²)
0.27 m² (426 in²)
146 degrees
grain pan
STRAW WALKERS:
-- type
-- number
-- length
-- total width
-- separating area
-- throw
-- speed
-- grain delivery to shoe
rotary, fin and wire
4
3618 mm (142 in)
1177 mm (46.38 in)
4.26 m² (6600 in²)
100 mm (4 in)
205 rpm
closed bottom walkers
SHOE:
-- type
-- throw
-- speed
-- chaffer sieve
-- clean grain sieve
opposed action
55 mm (2.17 in)
260 rpm
adjustable lip, 1.16 m² (1800 in²)
adjustable lip, 0.97 m² (1509 in²)
CLEANING FAN:
-- type
-- diameter
-- width
-- drive
-- speed range
5 blade undershot
570 mm (22.44 in)
888 mm (35 in)
crank controlled variable pitch belt
460 to 700 rpm
ELEVATORS:
-- type
-- clean grain (bottom drive)
-- tailings (bottom drive)
roller chain with rubber flights and
bottom delivery
130 x 225 mm (5.13 x 8.88 in)
130 x 225 mm (5.13 x 8.88 in)
GRAIN TANK:
-- volume
-- unloading time
2.8 m³ (77 bu)
75 s
ENGINE:
-- make
-- model
-- type
-- number of cylinders
-- governed speed (full throttle)
-- SAE rating @ 1900 rpm
-- fuel tank capacity
Tractoroexport
SMD-17K
4 stroke turbocharged diesel
4 displacement 6.33 L (386 in³)
2040 rpm
82 kW (110 hp)
190 L (42 Imp. gal)
CLUTCHES:
-- header
-- separator
-- unloading auger
-- traction drive
V-belt
dry friction disk
dog clutch with friction disk assist
dry friction disk
NUMBER OF CHAIN DRIVES:
8
NUMBER OF BELT DRIVES:
14
LUBRICATION POINTS:
-- 10 h lubrication
-- 60 h lubrication
-- 240 h lubrication
-- unspecified lubrication time
2
21
35
33
TIRES:
-- front
-- rear
2, 530 x 610 (20.9 x 24), 10-ply
2, 310 x 406 (12.2 x 16), 8-ply
TRACTION DRIVE:
-- type
-- speed ranges with 530 x 610 tires
-- 1st gear
-- 2nd gear
-- 3rd gear
-- reverse
1.4 to 3.0 km/h (0.9 to 1.9 mph)
3.8 to 7.7 km/h (2.4 to 4.8 mph)
9.5 to 20.0 km/h (5.9 to 12.4 mph)
3.7 to 8.1 km/h (2.3 to 5.0 mph)
OVERALL DIMENSIONS:
-- wheel tread (front)
-- wheel tread (rear)
-- wheel base
-- transport height
-- transport length
-- transport width
-- field height
-- field length
-- field width
-- unloader discharge height
-- unloader clearance height
-- unloader reach
-- turning radius
-- left
-- right
-- clearance radius
-- left
-- right
WEIGHT: (with empty grain tank)
-- right front wheel
-- left front wheel
-- right rear wheel
-- left rear wheel
TOTAL
hydraulically controlled variable pitch belt
2420 mm (95 in)
1215 mm (48 in)
3540 mm (139 in)
4020 mm (158 in)
8980 mm (354 in)
4390 mm (173 in)
4020 mm (158 in)
8890 mm (350 in)
6850 mm (270 in)
2870 mm (113 in)
2900 mm (114 in)
2560 mm (101 in)
9800 mm (386 in)
6910 mm (272 in)
11,600 mm (457 in)
9960 mm (392 in)
2750 kg (6060 lb)
3430 kg (7650 lb)
625 kg (1380 lb)
610 kg (1350 lb)
7415 kg (16,350 lb)
OPTIONAL EQUIPMENT:
-- straw and chaff collector
Page
13
APPENDIX II
STATISTICAL SIGNIFICANCE OF CAPACITY RESULTS
The following data are presented to illustrate the statistical significance of the capacity
results shown in FIGURES 13 to 16. This information is intended for use by those who
may wish to check results in greater detail. Sufficient information is presented to permit
calculation of confidence belts.
In the following table for the Belarus Niva SK-5 combine, C = cylinder loss in percent of
yield, S = shoe loss in percent of yield, W = straw walker loss in percent of yield, F = the
MOG feedrate in t/h, while ln is the natural logarithm, Sample size refers to the number
of loss collections. Limits of the regressions may be obtained from FIGURES 13 to 16
while crop conditions are presented in TABLE 4.
APPENDIX III
MACHINE RATINGS
The following rating scale is used in PAMI Evaluation Reports:
(a) excellent
(d) fair
(b) very good
(e) poor
(c) good
(f) unsatisfactory
APPENDIX IV
METRIC UNITS
In keeping with the Canadian metric conversion program, this report has been prepared
in SI units. For comparative purposes, the following conversions may be used:
1 kilometre/hour (km/h)
= 0.62 miles/hour (mph)
1 hectare (ha)
= 2.47 acres (ac)
1 kilogram (kg)
= 2.2 pounds (lb)
1 tonne (t)
= 2204.6 pounds (lb)
1 tonne/hectare (t/ha)
= 0.45 ton/acre (ton/ac)
1 tonne/hour (t/h)
= 36.75 pounds/minute (lb/min)
1000 millimetres (mm) = 1 metre (m) = 39.37 inches (in)
1 kilowatt (kW)
= 1.34 horsepower (hp)
1 litre/hour (L/h)
= 0.22 Imperial gallons/hour (gal/h)
Prairie Agricultural Machinery Institute
Head Office: P.O. Box 1900, Humboldt, Saskatchewan, Canada S0K 2A0
Telephone: (306) 682-2555
3000 College Drive South
Lethbridge, Alberta, Canada T1K 1L6
Telephone: (403) 329-1212
FAX: (403) 329-5562
http://www.agric.gov.ab.ca/navigation/engineering/
afmrc/index.html
Test Stations:
P.O. Box 1060
Portage la Prairie, Manitoba, Canada R1N 3C5
Telephone: (204) 239-5445
Fax: (204) 239-7124
P.O. Box 1150
Humboldt, Saskatchewan, Canada S0K 2A0
Telephone: (306) 682-5033
Fax: (306) 682-5080
This report is published under the authority of the minister of Agriculture for the Provinces of Alberta, Saskatchewan and Manitoba and may not be reproduced in whole or in part without the prior
approval of the Alberta Farm Machinery Research Centre or The Prairie Agricultural Machinery Institute.