Unit Options. Trane CDHF 1500, CVHE 500, Series S CVHS 300, CenTraVac CVHF 1470 103 Pages

Unit Options. Trane CDHF 1500, CVHE 500, Series S CVHS 300, CenTraVac CVHF 1470
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Below you will find brief product information for CenTraVac CVHF 1470, Series S CVHS 300, CVHE 500, CDHF 1500. These water-cooled liquid chillers offer a range of capacities, from 120 to 3,950 tons, and are designed for high efficiency and reliability. The Trane CenTraVac™ chiller has only one primary moving part—a single rotating shaft supported by two aircraft-turbine-rated bearings. This design minimizes the chance of failure and reduces wear and drag on parts, resulting in more sustainable, reliable, and efficient operation.

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Unit Options

Trane Starters and Drives

A Wide Array of Low- and Medium-Voltage Starters

Trane starters can be applied to low- or medium-voltage applications. The current draw of the compressor motor determines the size of the starter. The starter size must be greater than, or equal to, the compressor motor current draw.

Table 2.

Trane CenTraVac™ chiller starter and drive choices

Low Voltage (208–600 V)

Remote-Mounted Unit-Mounted

Wye-Delta

• Up to 1,700 amps

Solid-State

• Up to 1,120 amps with disconnect or circuit breaker required

Wye-Delta

• Up to 1,316 amps

• Up to 1,120 amps with disconnect/circuit breaker option

Solid-State

• Up to 1,120 amps with disconnect or circuit breaker required

Adaptive Frequency™

Drive

• 460/480/575/600 V

• Up to 1,360 amps

(460/480 V)

• Up to 1,120 amps

(575/600 V)

Adaptive Frequency

Drive

• Up to 1,210 amps

• Circuit breaker standard

460–480 V

Adaptive Frequency

Drive AFD

3

• Up to 636 amps

• Circuit breaker standard

575–600 V

Medium Voltage (2,300–6,600 V)

Remote-Mounted

Across-the-Line

• Up to 360 amps

• Isolation switch, power fuses standard

Unit-Mounted

Across-the-Line

• Up to 288 amps

• Isolation switch, power fuses standard

Medium Voltage

(10,000–13,800 V)

Remote-Mounted

Across-the-Line

• Up to 94 amps

• Isolation switch, power fuses standard

Primary Reactor

• Up to 360 amps

• Isolation switch, power fuses standard

Autotransformer

• Up to 360 amps

• Isolation switch, power fuses standard

Primary Reactor

• Up to 205 amps

• Isolation switch, power fuses standard

Autotransformer

• Up to 205 amps

• Isolation switch, power fuses standard

Primary Reactor

• Up to 94 amps

• Isolation switch, power fuses standard

Autotransformer

• Up to 94 amps

• Isolation switch, power fuses standard

Adaptive Frequency

Drive

• Up to 250 amps

• Isolation switch, power fuses standard

Overview, Standard and Optional Features

All factory-installed or remote-mounted starters provided by Trane offer the following standard features for safe, efficient application and ease of installation:

Standard Features

NEMA 1 starter enclosure.

Starter enclosures capable of being padlocked (unit-mounted wye-delta and solid-state starters).

120 volt, 60 hertz, 1-phase fused pilot and safety circuits.

Control power transformer (4 kVA) producing 120 volt, 50 or 60 hertz, single-phase. This provides auxiliary power for all chiller-mounted devices

1

.

Three-phase incoming line terminals.

Six output load terminals (three for medium-voltage) factory-connected to the motor.

Automatic closed-transition transfer from wye to delta on any two-step starter

(unit-mounted).

One pilot relay to initiate start sequence from CenTraVac™ chiller control circuit signal.

CTV-PRC007L-EN

1

Exception: Remote-mounted medium-voltage AFDs.

17

Unit Options

Standard and Optional Features on Trane Starters

Optional Features

Ground fault protection.

Digital metering devices.

Surge protector/lighting arrestor.

Standard, high interrupt, and higher interrupt circuit breakers that are mechanically interlocked to disconnect line power when the starter door is open.

Special NEMA enclosures.

Analog ammeters and voltmeters.

Special function pilot lights.

Under/over voltage.

Factory-Installed Starters

Enhances electrical system reliability.

Factory-tested chiller/starter combination.

Optimizes control of the CenTraVac™ chiller motor/compressor start and protection subsystem.

Factory quality control of the starter-to-chiller electrical connections.

Eliminates field-installed disconnect switch (when optional circuit breaker is used).

Reduces the number of field electrical connections.

Eliminates chiller-to-starter field wiring.

Reduces starter installation costs 20 percent to 35 percent.

Complete package available with UL, UL/EEV, or UL/California code agency approval.

Eliminates starter mounting-pad and required equipment room floor space.

Eliminates starter-to-disconnect switch field wiring (when optimal circuit breaker is used).

Reduces system design time-starter components and interconnecting wiring are preengineered and selected.

Standard Motor Protection

Three precision current transformers monitor phase current. Contactor position and various voltage signals provide extensive interlocking between the starter and the chiller controller. All logic and subsequent instruction originate in the chiller controller. Protection against the following starter detections is provided:

Loss of phase

Distribution fault

Excessive accelerating time

Incomplete starting sequence

Phase reversal

Improper starter circuitry

Phase amperage unbalance

High motor current (starting and running)

18 CTV-PRC007L-EN

Figure 6.

Typical equipment room layout: unit-mounted Wye-Delta starter

Line-Side Power Conduit

(Field-Provided)

Unit-Mounted Starter with Circuit Breaker Control Circuit Wire

(Factory-Wired)

Control Panel

Unit Options

CTV-PRC007L-EN

Figure 7.

Typical equipment room layout: conventional remote Wye-Delta starter

Line-Side Power Conduit

Disconnect Switch

Concrete Pad

Wye-Delta

Closed

Transition

Starter

Load-Side Power Conduit

Control Wire

Conduit

Motor Junction Box

Control Panel

19

Unit Options

Unit-Mounted Low-Voltage Wye (Star)-Delta Starters

One of the most common starters in the industry is the wye (star)-delta. It is an electromechanical starter initially set up in a “wye” or “star” configuration, then it transitions to a “delta” configuration during the starting sequence. This starter type can selected as a unit- or remote-

mounted option as shown in Figure 6, p. 19

and

Figure 7, p. 19

; also refer to Figure 8

for a typical view of the wye-delta starter. When starting and during acceleration, the motor is connected in its wye configuration. Because of this arrangement, the voltage applied to the motor windings is reduced to the inverse of the square root of three or 0.58 times line voltage. This reduction in winding voltage results in a reduction in inrush current. The inrush current is 0.33 times the fullvoltage locked rotor current rating of the motor. The accelerating torque of the motor is also reduced to 33 percent the full-voltage torque rating, which is sufficient to fully accelerate the compressor motor. The chiller controller monitors the motor current during operation via current transformers located in the starter enclosure. During acceleration, when the line current drops to approximately 0.85 times rated load current, transition is initiated. The closed transition feature provides for a continuous motor current flow during transition by placing resistors in the circuit momentarily. This prevents the motor from losing phase to the line current during this period. With the completion of transition, the motor windings are connected in the delta configuration with full line voltage.

Additional electrical information is available in CTV-PRB004-EN (Engineering Bulletin: Starters and

Electrical Components for CenTraVac™ Chillers).

Figure 8.

5

1.

Top entry power only

2. 4 kVA Control power transformer

3. Circuit breaker (optional)

4. Transition resistors

5. Power factor correction capacitors (optional)

2 1

3

4

20 CTV-PRC007L-EN

Unit Options

Unit-Mounted Low-Voltage Solid-State Starters

A solid-state starter controls the starting characteristics of a motor by controlling the voltage to the motor. It does so through the use of SCRs (Silicon Controlled Rectifiers), which are solid-state switching devices, and an integral bypass contactor for power control.

Silicon Controlled Rectifiers (SCR)

An SCR will conduct current in one direction only when a control signal (gate signal) is applied.

Because the solid-state starter is for use on AC (alternating current), two SCRs per phase are connected in parallel, opposing each other so that current may flow in both directions. For threephase loads, a full six-SCR configuration is used.

During starting, control of current or acceleration time is achieved by gating the SCR on at different times within the half-cycle. The gate pulses are originally applied late in the half-cycle and then gradually applied sooner in the half-cycle. If the gate pulse is applied late in the cycle, only a

small increment of the wave form is passed through, and the output is low.

If the gate pulse is applied sooner in the cycle, a greater increment of the wave form is passed through, and the output is increased. So, by controlling the SCRs output voltage, the motor’s acceleration characteristic and current inrush can be controlled.

Integral Bypass Contactors

When the SCRs are fully “phased on,” the integral bypass contactors are energized. The current flow is transferred from the power pole to the contactors. This reduces the energy loss associated with the power pole, which otherwise is about one watt per amp per phase.

When the starter is given the stop command, the bypass contactors are de-energized, which transfers the current flow from the contactors back to the power poles. The SCRs are then turned off, and the current flow stops.

Because the SCRs are turned off during normal operation, the design can be air-cooled and harmonic currents are not an issue.

Additional electrical information is available in CTV-PRB004-EN (Engineering Bulletin: Starters and

Electrical Components for CenTraVac™ Chillers).

Figure 9.

1.

Top entry power only

2. 4 kVA Control power transformer

3. Circuit breaker

4. Intelligent technology (IT) controller

5. Starter control board

6. Potential transformers

3

1

4

2

5

6

CTV-PRC007L-EN 21

Unit Options

Unit-Mounted Low-Voltage Adaptive Frequency Drive

The Trane Adaptive Frequency™ Drive AFD is a refrigerant-cooled, microprocessor controlled design. The AFD is used in lieu of a constant-speed starter and is currently available for use with

460/480 volts 60 Hz or 380-415 volts 50 Hz line power only. Adaptive Frequency is a trademarked term for the Trane variable-speed drive, using proprietary control logic and made to Trane specifications.

About the Trane AFD

The AFD is unit-mounted and ships completely assembled, wired, and tested from the factory. The

AFD controller is designed to interface with the chiller controller. It adapts to the operating ranges and specific characteristics of the chiller. The optimum chiller efficiency is created by coordinating the compressor-motor speed with the compressor inlet guide vanes. The chiller controller and the

AFD controller work together to maintain the chilled-water setpoint and avoid instability regions like low level surge. If low level surge is detected, the chiller controller's surge-avoidance logic in the chiller controller makes the proper adjustments to move the operating point away from surge.

The reason it is desirable to operate safely near the instability region is because this is where efficiency is maximized.

How it Works

The frequency drive regulates output voltage in proportion to output frequency to maintain ideal motor flux and constant torque-producing capability. Or put simply, a variable-speed drive controls load-side frequency and voltage to adjust the compressor motor speed. The AFD is a voltage source, pulse-width modulated (PWM) design. It consists of three primary power sections as shown in

Figure 10

: the active rectifier, the DC bus, and the inverter.

Figure 10. AFD power sections

22

Rectifier (active).

The rectifier (active) takes incoming AC power, filters it with an LCL filter (not shown), and then converts it to a fixed DC voltage. The insulated-gate bipolar transistor (IGBT) active rectifier significantly reduces the amount of line-side harmonic levels and the amount of ripple on the DC bus. No additional line side filters are required to meet IEEE harmonic requirements. This also simplifies the installation and avoids the optional filter efficiency losses.

The active rectifier also has some traditional post-generation filtering capabilities to further smooth out remaining line-side harmonics.

DC bus.

Capacitors store the DC power provided by the rectifier until it is needed by the inverter.

Inverter.

Converts the DC voltage into a synthesized AC output voltage. This synthesized output controls both the voltage and the frequency. The synthesized output waveform consists of a series of pulses, hence the “pulse” in PWM.

CTV-PRC007L-EN

CTV-PRC007L-EN

Unit Options

Unit-Mounted Low-Voltage Adaptive Frequency Drive

Starting Sequence

Trane AFDs are programmed to start the compressor motor using low frequency and low voltage, thereby minimizing the inrush current. The motor is then brought up to speed by gradually increasing both frequency and voltage at the same time. Thus, current and torque are much lower during startup and motor acceleration than the high current, high torque associated with acrossthe-line or even reduced-voltage starters.

Patented Adaptive Control

A fourth element of AFD design is the microprocessor control logic which is the intelligence for the power section. It also includes all feedback sensors required for stability in the system and any required shutdown due to a fault.

The combination of speed control and inlet guide-vane (IGV) position is optimized mathematically and controlled simultaneously. The microprocessor performance allows the chiller to operate longer at higher efficiencies and with greater stability.

Features

The standard design features for the AFD include:

• NEMA 1, ventilated enclosure with a hinged door, tested to a short circuit current rating (SCCR) of 65,000 amps.

• Padlock-able, door-mounted circuit breaker/shunt trip with an Ampere Interrupting Rating (AIC) rating of 65,000 amps.

• UL/CUL listed as a package.

• Simple, modular construction.

• 460/480/60/3 or 380-415/60/50 Hz input power ±10 percent, with drive overload capability of

100 percent continuous to 150 percent for five seconds.

• Active input rectifier will regulate to a displacement power factor of 0.98 or better at full load and a value of 0.96 at part loads.

• Full motor voltage is applied regardless of the input voltage.

• Motor thermal overload protection 102 percent continuous, 108 percent for 60 seconds,

140 percent for 1.5 seconds.

• Minimum efficiency of 97 percent at rated load and 60 hertz.

• Soft-start, controlled acceleration, coast-to-stop.

• Adjustable frequency from 38 to 60 hertz.

• Control circuit voltages physically and electrically isolated from power circuit voltage.

• 150 percent instantaneous torque available for improved surge control.

• Output line-to-line and line-to-ground short-circuit protection.

• Ground fault protection (UL-listed).

Option

AFD enclosure short circuit current rating SCCR and AIC rating of 100,000 amps available.

23

1

2

4

Unit Options

Unit-Mounted Low-Voltage Adaptive Frequency Drive

Figure 11. Trane AFD

5

3

1.

Pre-charge contactor

2. Inductor (behind the panel)

3. Adjustable-speed drive

(inverter)

4. Circuit breaker (standard)

5. Active rectifier

6. 3 kVA control-power transformer

6

24

Environmental Specification

• 32°F to 104°F (0°C to 40°C) operating ambient temperature

• Altitude to 3,300 feet (1,000 m), amperage derate of 1 percent per every 300 feet above

3,300 feet

• Humidity, 95 percent non-condensing

Digital Data Display

The following points are digitally displayed at the chiller controller:

• Output speed in hertz

• Output speed in rpm

• Input frequency

• Input/output line voltage

• Input/output kW

• Input/output current

• Average output current in percent RLA

• Load-side power factor

• AFD transistor temperature

• Fault

Harmonic attenuation

Harmonic attenuation is standard on the unit-mounted refrigerant-cooled AFDs and includes:

• Integrated active rectification control of the building AC power assures low line-generated harmonics back to the user’s power grid. This results in less than 5 percent total demand distortion (TDD) as measured at the AFD. This is based on an electrical system with voltage distortion less than 1.5 percent.

CTV-PRC007L-EN

CTV-PRC007L-EN

Unit Options

Unit-Mounted Low-Voltage Adaptive Frequency Drive

• Active input rectifier will regulate to a displacement power factor of 0.98 or better at full load and a value of 0.96 at part load.

• Full motor voltage is applied regardless of the input voltage.

Note: TDD is a direct affect of variable frequency drives and is a larger and more critical value than the amount of total harmonic distortion (THD). As measured at the AFD, the amount of THD will be less than the TDD.

IEEE 519

It is important to recognize that IEEE 519 as a guideline relates to the entire system, not specifically to any one load or product. IEEE 519 establishes requirements at the point of common coupling

(PCC) where the building connects to the utility system. The standard contains no specific requirements for the internal electrical loads. Even though Trane AFD-equipped chillers will attenuate their own harmonics, other nonlinear loads on the same system could still create harmonic problems. In buildings where harmonics might be a concern, Trane recommends conducting a power-distribution system analysis to determine if there is a need to further attenuate harmonics at the system level.

Application of Drives on Chillers

Certain system characteristics favor installation of an AFD because of energy cost savings and shorter payback. These systems include:

• Condenser water temperature relief (colder than design temperatures)

• Chilled-water reset

• Utilities with high kWh and low kW demand rates

Condenser Water Temperature Relief or Chilled-Water Reset

Compressor lift reduction is required for a AFD chiller application, both to provide stable chiller operation and to achieve greater energy savings. Lift said another way is called relief and assumes colder condenser inlet temperatures over the design entering temperature. Intelligent control to reduce condenser water temperature, or chilled-water reset strategies, are key to AFD savings in chiller system applications. Many believe that AFDs offer better efficiency at part load. The reason this belief exists is because when people review part load data it typically has been run with condenser relief. An AFD can incrementally improve efficiency over a constant speed chiller at any load if you have substantial hours reduced entering condenser temperatures.

High Operating Hours with Relief

Figure 12, p. 26 is based on a 800-ton chiller at 42°F/55°F in the evaporator, and 85°F entering

condenser water temperature, and 2.5 gpm/ton of flow. Three lines are plotted (ECWT at 85°F, 75°F, and 65°F); the y-axis is kW/ton and the x-axis is chiller percent load.

First, note the unloading curve with the 85°F entering condenser water—this would be considered unloading with no relief. Then compare this curve with next two curves showing unloading with relief at 75°F and 65°F, respectively. Note that efficiency improves significantly independent of the chiller load. This is why AFDs are applied when there are significant hours of operation during which the condensing temperature is reduced.

25

Unit Options

Unit-Mounted Low-Voltage Adaptive Frequency Drive

Figure 12. Unloading curves with AFD chiller and 85°F, 75°F, 65°F ECWT temps

800 Ton Centrifugal Water-Cooled Chiller

1.200

ECWT 85°F

1.100

1.000

0.900

0.800

0.700

0.600

ECWT 75°F

ECWT 65°F

0.500

0.400

0.300

0.200

10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Load

High kW Demand Charges

Electric utility bills normally include both peak-based and consumption-based energy components. The demand or distribution charges are still significant portions of the energy bill, even in deregulated markets. These charges are established by usage during utility peak hours, by individual peak usage, or a combination of peak and individual usage. This portion may or may not be influenced by installation of an AFD, because an AFD-equipped chiller draws more power at full load. If the peak chiller load coincides with utility peak hours, then the peak-based portion of the energy bill will increase. The energy or kWh portion will almost certainly be reduced because of the improved efficiency of the chiller plant during part-load and part-lift conditions throughout the year.

The greater the kWh charge, and the smaller demand or distribution charges, the shorter the payback.

Unit-Mounted Adaptive Frequency Drive (AFD

3

)

The Trane AFD

3

is a refrigerant-cooled, microprocessor controlled design. The AFD

3

is used in lieu of a constant-speed starter and is currently available for use with 460 or 480 V on the CVHS chiller and 575 or 600 V on the CTV chiller.

The AFD

3

is a voltage-source, pulse-width modulated (PWM) design. It consists of three primary power sections as shown in

Figure 13

: the diode rectifier, the DC bus, and the inverter.

Rectifier.

Takes incoming AC power and then converts it to a fixed DC voltage using diodes.

DC bus.

Capacitors store the DC power provided by the rectifier until it is needed by the inverter.

Inverter.

Converts the DC voltage into a synthesized AC output voltage. This synthesized output controls both the voltage and the frequency. The synthesized output waveform consists of a series of pulses, hence the “pulse” in PWM.

24-Pulse Transformer.

A true 24-pulse transformer is used to mitigate the harmonic currents.

26 CTV-PRC007L-EN

Unit Options

Unit-Mounted Adaptive Frequency Drive (AFD

3

)

Starting sequence

The Trane AFD

3

is programmed to start the compressor motor using low frequency and low voltage, thereby minimizing the inrush current. The motor is then brought up to speed by gradually increasing both frequency and voltage at the same time. Thus, current and torque are much lower during startup and motor acceleration than the high current, high torque associated with acrossthe-line or even reduced-voltage starters.

• The AFD

3

is rated by output current and is limited to a maximum of 100-percent continuous RLA

(rated-load amps) by the Trane chiller unit controller.

A 100 percent output current capability results in 100 percent torque generated by the motor.

Figure 13. AFD

3

power sections

24 Pulse

Transformer

Rectifier

Section

Figure 14. Trane AFD

3

—CTV 575/600 Volt

1

2

3

DC Bus

Inverter

Section

1.

Control power transformer

2. AFD

3

rectifier and inverter

3. Circuit breaker

4. True 24-pulse harmonic filter

4 4

CTV-PRC007L-EN

Features

The standard design features for the AFD

3

include:

• NEMA 1, ventilated enclosure with a hinged door, tested to a short-circuit current rating of

65,000 amps.

• Padlock-able, door-mounted circuit breaker/shunt trip with an AIC rating of 65,000 amps.

• SCCR/AIC rating of 100,000 amps available as a design special; contact your local Trane representative.

• UL/CUL listed as a package.

27

Unit Options

Unit-Mounted Adaptive Frequency Drive (AFD

3

)

• Simple, modular construction.

• 460-480/60/3 ±10 percent, with drive overload capability of 100 percent continuous to

150 percent for five seconds (CVHS chillers).

• 575-600/60/3 input power ±10 percent, with drive overload capability of 100 percent continuous to 150 percent for five seconds.

• Motor thermal overload protection 102 percent continuous, 108 percent for 60 seconds,

140 percent for 1.5 seconds.

• Minimum efficiency of 97 percent at rated load and 60 hertz.

• Film-type DC bus capacitors for reliable, extended life.

• Soft-start, controlled acceleration, coast-to-stop.

• Adjustable frequency from 38 to 60 hertz.

• Control circuit voltages physically and electrically isolated from power circuit voltage.

• 150 percent instantaneous torque available for improved surge control.

• Designed for individual component replacements.

• Output line-to-line and line-to-ground short-circuit protection.

• Shore power (external 115V) connection to facilitate start-up commissioning and diagnostic assessments.

• Ground fault protection (UL listed).

Environmental specification

• 32°F to 104°F (0°C to 40°C) operating ambient temperature.

• Altitude to 3,300 feet (1,000 m), amperage derate of 1 percent per 300 feet above 3,300 feet.

• Humidity, 95 percent non-condensing.

Dimensions

Typical dimensions for the unit-mounted AFD

3

are shown in

Figure 15 and

Figure 16 . Always

consult the submittal drawings for as-built dimensions.

Figure 15. AFD

3

dimensions—CTV 575/600 Volt (318 max RLA design)

67.00

71.00

21.00 without doors and covers

24.10 with doors and covers

Note:

Fan enclosures at base of unit add 5.25 inches to height.

28 CTV-PRC007L-EN

CTV-PRC007L-EN

Unit Options

Unit-Mounted Adaptive Frequency Drive (AFD

3

)

Figure 16. AFD

3

dimensions—CTV 575/600 Volt (530 and 636 max RLA design)

71.00

80.00

23.00 without doors and covers

26.10 with doors and covers

Note:

Fan enclosures at base of unit add 5.25 inches to height.

Figure 17. AFD

3

dimensions—CVHS

29

Unit Options

Unit-Mounted Adaptive Frequency Drive (AFD

3

)

Motor-AFD mutual protection

The chiller unit-controller capabilities allow the control/configuration interface to, and the retrieval/ display of AFD

3

-related data. AFD

3

standard design features controlled through the Tracer

AdaptiView™ include:

• Current limited to 100 percent.

• Motor overload protection.

• Motor over-temperature protection.

• Phase loss, phase reversal, and phase imbalance protection.

• Undervoltage and overvoltage protection.

• Output speed reference via IPC3 communication bus from the chiller controller to the AFD

3

.

Digital data display

The following points are digitally displayed at the chiller controller:

• Output speed Hertz

• Output speed rpm

• Input frequency

• Average input voltage

• Output voltage

• Average input current

• Output current

• Output current % RLA

• Input/output kw

• Load side power factor

• AFD

3

transistor temperature

Harmonic attenuation

Harmonic attenuation is standard on the unit-mounted refrigerant-cooled AFD

3

and includes:

• True 24-pulse transformer to ensure minimal line-side harmonic currents. This results in less than 5 percent current total demand distortion (TDD) as measured at the AFD

3

. This is based on an electrical system with voltage distortion less than 1.5 percent.

• Active input rectifier will regulate to a displacement power factor of 0.98 or better at full load and a value of 0.96 at part load.

Note: TDD is a direct affect of variable frequency drives and is a larger and more critical value than the amount of total harmonic distortion (THD). As measured at the AFD

3

, the amount of THD will be less than the TDD.

30 CTV-PRC007L-EN

Unit Options

Unit-Mounted AMPGARD Medium-Voltage Starters

The AMPGARD

®

medium-voltage starter family by Eaton Cutler-Hammer

®

, built to Trane specifications, is available as a factory-installed option for use with CenTraVac™ chillers. Trane mounts, wires, and tests 2,300–6,600 volt starters at the factory, so you don’t have to. This reduces, or eliminates altogether, the time, expense, and any added risk associated with having the starter installed and wired at the job site.

AMPGARD reduces starter size to nearly half

Medium-voltage starters have traditionally been freestanding due to their large size and weight.

Not until recent advances in contactor technology and component layout have medium-voltage starters been small enough to make unit-mounting feasible. This way, the starter becomes an integral part of the chiller, saving on equipment floor space.

Across-the-Line (Full Voltage)

An across-the-line starter is the smallest medium-voltage starter option. These starters draw the highest inrush current at startup (100 percent of LRA), and have the shortest acceleration time (3–

5 seconds).

Primary Reactor

Primary reactor type starters have an inrush current draw of 65 percent of LRA at startup. Their acceleration time (3–8 seconds) is slightly higher than an across-the-line starter.

Autotransformer

Autotransformer starters have the lowest inrush current draw of 45 percent of LRA at startup. They have an acceleration time of 3–8 seconds.

Standard Features

UL approved

Factory installed (unit-mounted only)

Non-load-break isolation switch and current limiting fuses

NEMA Class E2 fused interrupting ratings

– 200 MVA @3000 V

– 400 MVA @4600 V

– 750 MVA @6600 V

Voltage range of 2,300–6,600 volts

Types: Across-the-line (full voltage), primary reactor, autotransformer

Phase voltage sensors for kW, volts/phase protection, under/overvoltage

Eaton Cutler-Hammer

®

AMPGARD

®

, designed and built to Trane specifications

Optional Features

IQ150 and IQDP 4130 electrical metering packages

Ground fault protection

Factory-installed power factor correction capacitors sized specific to the motor, factory-wired and mounted inside the starter

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Unit Options

Unit-Mounted AMPGARD Medium-Voltage Starters

Figure 18. Unit-mounted medium-voltage primary reactor or autotransformer

Figure 19. Reduced-voltage section of a unit-mounted starter

Starter by Others

If CenTraVac™ chiller starting equipment is provided by others, the starter must be designed in accordance with the current Trane standard engineering specification “Water-Cooled CenTraVac

Starter Specification.” It is also recommended that two copies of the interconnecting and control circuit wiring diagrams be forwarded to Trane for review. This service is provided at no charge, and is intended to help minimize the possibility that Trane CenTraVac chillers will be applied in improper starting and control systems. However, the responsibility for providing proper starting and control systems remains with the system designer and the installer.

32 CTV-PRC007L-EN

Unit Options

Unit-Mounted AMPGARD Medium-Voltage Starters

Integrated Rapid Restart

A loss of cooling capacity can be costly, which is why Series L™ chillers are designed to integrate seamlessly with uninterruptible power supplies (UPS) and have the shortest restart times in the industry.

In the event of a power interruption, the chiller defaults to its rapid restart mode, optimizing electrical and mechanical variables, including guide vane position. This not only helps the chiller get back online faster, but it also provides the least amount of load on your building’s electrical infrastructure — which can make a big difference if your building has a backup generator.

Even under extreme conditions, CenTraVac™ chiller restart times have been verified at as few as

43 seconds, as shown in Figure 20 . Thanks to fast restart times like these, you can substantially

minimize the risks of financially devastating damage to assets caused by overheating due to power outages. Of course, the truest test of a chiller’s restart capabilities is the amount of time it takes to resume full-load cooling—and this is where the Series L chiller really shines. An 80 percent cooling load can be achieved in less than three minutes after power restoration: your assurance that the cooling capacity your equipment depends on is just a few minutes away.

Figure 20. CTV AdaptiView Simplex restart time after power loss (with UPS)

(a) (b) (c) (d)

Compressor Start

Chiller loading time

180 sec

(d)

Confirm cond flow 6 sec

Close inlet guide vanes

20–43 sec

(b)

Confirm evap flow 6 sec

Confirm oil flow 10 sec

(c)

Power loss timer 15 sec

Time to Restart (sec)

0 43 223

(a) Assumes chiller starter power restored within 120 seconds

(b) Function of chiller load

(c) Oil pump on UPS

(d) Estimated time to 80% load

Optimization for Elevated Chilled-Water Temperature Applications

Trane Series L™ CenTraVac™ chiller (model CVHL) is a direct result of Trane commitment to provide the right technology for the right application at the right time.

Understanding that industrial processes and data center equipment have unique cooling requirements, Trane developed the Series L CenTraVac chiller. Designed to meet the specific needs of elevated chilled-water temperature applications, the Series L chiller’s compressor technology is optimized to deliver water cooled to 60°F–70°F with up to 35 percent better efficiency at full-load and off-design conditions.

Providing efficient, reliable elevated-temperature cooling you need and can count on.

CTV-PRC007L-EN 33

Unit Options

Enhanced Electrical Protection Package Options

Customers who purchase the Enhanced Electrical Protection Package have additional electrical options. These options can be applied to remote-mounted medium-voltage starters, both from

Trane and other starter manufacturers.

CPTR, Control Power Transformer (Enhanced Electrical Protection Package option) on Low- and Medium-Voltage Starters

Unit-mounted, factory-wired, separate enclosure mounted next to the control panel with:

Flanged disconnect

Secondary fuse status indictor (blown or not-blown)

Fused primary and secondary power

UL 508 Type 12 construction

4 kVA control power transformer (480 to 115 volts)

SMP, Supplemental Motor Protection (Enhanced Electrical Protection Package option) on Medium-Voltage Staters Only

Unit-mounted, factory-wired, separate enclosure mounted to the motor with:

Surge capacitors

Field-accessible terminal block for trouble-shooting via panel

Lightning arrestors

Zero-sequence ground fault

UL 347 tested Type 12 construction

DMP, Differential Motor Protection (SMP option) on Medium-Voltage Staters

Only

DMP replaces the zero-sequence ground fault protection. Instead, it uses a flux-summation selfcompensating differential protection scheme for more quickly and more precisely removing line power during a fault.

Note: DMP is available only for 1062 kW and larger motor sizes up to 5000 volts.

CVAC, Customer-Supplied Vacuum Circuit Breaker on Medium-Voltage Staters

Only

Three-pole disconnect

Relays for vacuum circuit-breaker starter type

Industrial terminal block

Secondary 120 to 30 volt PTs (for medium-voltage units)

34 CTV-PRC007L-EN

Unit Options

Free Cooling Allows Reduced Operating Costs

Consider a CenTraVac™ chiller option that can provide up to 45 percent of the nominal chiller capacity—without operating the compressor. Think of the significant energy and cost savings possible in many applications. This option is available on most Trane chillers, factory-installed.

Free cooling operation is based on the principle that refrigerant migrates to the area of lowest temperature. When condenser water is available at temperatures lower than the required leaving chilled-water temperature, typically 50°F to 55°F (10°C to 12.8°C), the unit control panel starts the free cooling cycle automatically.

Figure 21. Free cooling schematic

CTV-PRC007L-EN

When the free cooling cycle can no longer provide sufficient capacity to meet cooling requirements, mechanical cooling is restarted automatically by the unit control panel.

For example, a building with a high internal cooling load is located in a climate with cold winters.

It is possible to cool the building exclusively with free cooling three to six months of the year! Free cooling payback can easily be less than a year.

Free cooling is factory installed and requires no additional floor space or piping than the standard

CenTraVac chiller (unlike plate-frame heat exchangers).

Benefits

The Trane patented free cooling accessory for Trane CenTraVac™ chillers adapts the basic chiller so it may function as a simple heat exchanger using refrigerant as the working fluid. When condenser water is available at temperatures lower than the desired chilled liquid temperature, free cooling can provide up to 45 percent of nominal chiller capacity without operation of the compressor. This feature may result in substantial energy cost savings on many installations.

Reliability

Two simple valves are the only moving parts.

Single-Source Responsibility

Free cooling is Trane-engineered, -manufactured, and -installed.

Ease of Operation

Changeover on free cooling by single switch control.

35

Unit Options

Free Cooling Allows Reduced Operating Costs

36

Ease of Installation

Completely factory-installed and leak-tested components. All valve operators and controls are factory wired.

Application

Modern buildings often require some form of year-round cooling to handle interior zones, solar loads, or computer loads. As the outside air temperature decreases below the inside air design temperature, it is often possible to use an outside air economizer to satisfy the cooling requirements. There are a number of instances, however, where CenTraVac™ chiller free cooling offers a number of advantages over the use of an outside air economizer. It is possible for the free cooling chiller to satisfy the cooling load for many hours, days, or months during the fall, winter, or spring seasons without operation of the compressor motor. This method of satisfying the cooling requirement can result in significant total energy savings over other types of systems. The savings available are most easily determined through the use of a computer energy analysis and economic program, such as TRACE™ (Trane Air Conditioning and Economics).

The suitability of free cooling for any particular installation depends upon a number of factors. The availability of low temperature condensing water, the quality of the outside air, the type of airside system, the temperature and humidity control requirements, and the cost of electricity all have a direct impact on the decision to use a free cooling chiller.

The use of CenTraVac chiller free cooling depends on the availability of cold condenser water from a cooling tower, river, lake, or pond. As a general rule of thumb, locations which have a substantial number of days with ambient temperatures below 45°F (7.2°C) wet bulb or more than 4000 degreedays per year are well suited to free cooling operation. A cooling tower must be winterized for offseason operation and the minimum sump temperature is limited by some cooling tower manufacturers. Cooling tower manufacturers should be consulted for recommendations on low temperature operation. With river, lake, or pond supply, condenser water temperatures down to freezing levels are possible. Areas which have fouled air may be more conducive to free cooling operation than the use of an outside air economizer.

Airside systems which both heat and cool the air can often effectively use a free cooling chiller.

Dual-duct, multizone, and reheat systems fall into this general category. As the outside temperature begins to fall, the cool outside air satisfies the cooling requirements (through an outside air economizer). As the outdoor air temperature becomes very low, the outdoor air may need to be heated in order to maintain the design supply air temperature when it is mixed with return air. This “heating penalty” can be eliminated by using CenTraVac chiller free cooling. Warm chilled-water temperatures provided by the free cooling chiller would allow a warmer air temperature off the chilled-water coils, eliminating the heating energy required by using only an outside air economizer. With high cost electricity in most areas of the country, this heating penalty can be very significant.

Temperature and humidity control requirements are important considerations when evaluating the use of CenTraVac chiller free cooling. Low temperature outside air (from the outside air economizer) often requires a large amount of energy for humidification purposes. Free cooling operation helps to reduce these humidification costs on many applications.

It is important to note that those applications which require extremely precise humidity control typically cannot tolerate warmer than design chilled-water temperatures. Therefore, since free cooling chillers normally deliver warmer than design chilled water temperatures, free cooling operation is usually not applicable with systems which require precise humidity control.

Free cooling is not used in conjunction with heat recovery systems, since mechanical cooling must be used to recover heat that will be used elsewhere in the building for simultaneous heating.

Operation

Free cooling operates on the principle that refrigerant flows to the area of lowest temperature in the system. The Tracer™ system/Chiller Plant Manager (CPM) can be used for automatic free cooling control. When condenser water is available at a temperature lower than the required

CTV-PRC007L-EN

CTV-PRC007L-EN

Unit Options

Free Cooling Allows Reduced Operating Costs

leaving chilled-water temperature, the CPM starts the free cooling cycle. If the load cannot be satisfied with free cooling, the CPM or a customer-supplied system can automatically switch to the powered cooling mode. If desired, the chiller can be manually switched to the free cooling mode at the unit control panel. Upon changeover to free cooling, the shutoff valves in the liquid and gas lines are opened and a lockout circuit prevents compressor energization. Liquid refrigerant drains from the storage tank into the evaporator, flooding the tube bundle. Since the refrigerant temperature and pressure are higher in the evaporator than in the condenser, due to the water temperature difference, the refrigerant gas boiled off in the evaporator will flow to the condenser.

The gas then condenses and flows by gravity back to the evaporator. This automatic refrigeration cycle is sustained as long as a temperature difference exists between the condenser water and evaporator water.

The difference in temperature between the condenser and evaporator determines the rate of refrigerant flow between the two shells and hence the free cooling capacity.

If the system load becomes greater than the free cooling capacity either the operator manually stops free cooling, a binary input from a customer-supplied system disables free cooling, or the

CPM can automatically perform this function. The gas and liquid valves close and the compressor starts. Refrigerant gas is drawn out of the evaporator by the compressor, compressed, and introduced into the condenser. Most of the condensed liquid first takes the path of least resistance by flowing into the storage tank which is vented to the high pressure economizer sump by a small bleed line. When the storage tank is filled, liquid refrigerant must flow through the bleed line restriction. The pressure drop through the bleed line is greater than that associated with the orifice flow control device, hence liquid refrigerant flows normally from the condenser through the orifice system and into the economizer.

The free cooling option consists of the following factory-installed or supplied components:

Additional refrigerant charge required for the free cooling cycle

Manual free cooling controls on the unit control panel

A refrigerant gas line, including an electrically actuated shutoff valve, installed between the evaporator and condenser

A liquid-refrigerant storage vessel adjacent to the economizer

A valved-liquid return line, including an electrically activated shutoff valve, between the condenser sump and evaporator

For specific information on free cooling applications, contact your local Trane sales office.

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Unit Options

Free Cooling Allows Reduced Operating Costs

Figure 22. Compressor operation schematic

1

2

2

3

1.

Condenser

2. Economizer

3. Refrigerant Storage Tank

4. Compressor

5. Evaporator

5

4

Figure 23. Free cooling operation schematic

1

2

2

3

1.

Condenser

2. Economizer

3. Refrigerant Storage Tank

4. Compressor

5. Evaporator

5

4

38 CTV-PRC007L-EN

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Key Features

  • High efficiency
  • Low emissions
  • Direct-drive design
  • Leak-tight warranty
  • Multiple-stage compression
  • Variable-speed drive
  • Free cooling
  • Heat recovery
  • Ice storage

Frequently Answers and Questions

What are the tonnage ranges for the CenTraVac chillers?
The CenTraVac chillers are available in tonnage ranges from 120 to 3,950 tons.
What is the key to the highest energy efficiency and lowest leak rate?
The key is the use of the low-pressure refrigerant R-123.
What kind of warranty does the CenTraVac chiller have?
The CenTraVac chiller has a 5-year 0.0% Leak-Tight Warranty.
What are some of the optional features available for the CenTraVac chiller?
Optional features include free cooling, heat recovery, auxiliary condenser, variable-speed drives, and medium-voltage compressor motors.
What kind of control strategies are used in the CenTraVac chiller?
The CenTraVac chiller uses Tracer™ chiller control strategies.

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