What a Starter Does. Trane Drives, CVHG, Starters, CVHF, Electrical Components, CVHE, CDHG, CDHF 82 Pages
What a Starter Does. Trane Drives, CVHG, Starters, CVHF, Electrical Components, CVHE, CDHG, CDHF
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CTV-PRB004.book Page 7 Sunday, December 18, 2011 6:39 PM
About Starters
What a Starter Does
Electric, centrifugal, water-cooled chillers use relatively large induction motors to drive the compressors.These motors use a control device to connect to and disconnect from the electrical power source.These control devices are referred to as combination controllers or, most commonly, as motor starters. Variable-frequency drives or Adaptive Frequency™ Drives (AFDs) also serve as motor starters, but their capabilities extend beyond starting and stopping the motor.
There are three main functions of the motor starter.The first function is to serve as the link between the chiller’s motor and the electrical distribution system. It is used during the starting and stopping sequence.
Starting an induction motor from standstill causes a large electrical current draw for a few seconds.
The extra current is used to develop the required torque to get the compressor motor running at full speed. The initial rush of current decreases as the compressor motor ramps up to full speed, and is commonly referred to as inrush current.
The second function of the starter is to keep the initial current inrush below a specified level.Third, the starter communicates with the unit controller to coordinate motor protection.
Starters can be as simple or as complex as necessary to meet various engineering specifications and/or customer needs. A variable-speed drive can provide starter functions, among other things
(see “Low Voltage—Unit-Mounted Adaptive Frequency Drive,” p. 25 and “Medium Voltage—
Remote-Mounted Adaptive Frequency Drive,” p. 42 ). It will be classified as a starter type for the purposes of this document.
Several voltage classes and starter types are available as indicated on the chart below. Each one is described in greater detail in this document.
Table 1.
Trane CenTraVac chiller starter choices
Medium Voltage
(10–13.8 kV)
Remote-Mounted
Across-the-Line
Up to 94 amps
Isolation switch, power fuses standard
Low Voltage (208–600 V)
Remote-Mounted Unit-Mounted
Medium Voltage (2,300–6,600 V)
Remote-Mounted Unit-Mounted
Wye-Delta
Up to 1,700 amps
Wye-Delta
Up to 1,316 amps
(Up to 1,120 amps with disconnect/circuit breaker option)
Across-the-Line
Up to 360 amps
Isolation switch, power fuses standard
Solid-State
(Up to 1,120 amps with disconnect or circuit breaker required)
Solid-State
(Up to 1,120 amps with disconnect or circuit breaker required)
Primary Reactor
Up to 360 amps
Isolation switch, power fuses standard
Adaptive Frequency
Drive
V
Up to
amps
1,120
Adaptive Frequency
Drive
Up to 1,210 amps
Circuit breaker standard
460–480 V
Autotransformer
Up to 360 amps
Isolation switch, power fuses standard
Adaptive Frequency
Drive
amps
Isolation switch, power fuses standard
Across-the-Line
Up to 288 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
CTV-PRB004-EN 7
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