CTV-PRB004-EN
55
Electrical System—Design Guidelines
•
Additional (non-chiller) loads on the power circuit
When evaluating a power system for a chiller-compressor motor with a specified starter type,
calculations must be done in order to size or “correct” the power circuit properly in order to
successfully start the motor and keep the motor-starter combination online during operation.
Table 9
and
Table 10, p. 55
show specific starter characteristics and minimum power requirements.
Note:
The maximum allowable under/overvoltage during normal operation is ±10 percent.
Table 9.
Sizing requirements
Starter Type
Voltage Range
Inrush
Current
% LRA
Chiller Controller
Maximum Acceleration
Time Setpoint (sec)
(a)
(a) The Chiller Controller Maximum Acceleration Time Setpoint is the maximum allowable acceleration time;
if the chiller has not started within this time, a diagnostic will be set.
Percent
Rated
Torque
Wye-Delta
208–600 V
33
27
33
Solid-State
208–600 V
~45
27
33
X-Line
2.3–13.8 kV
100
6
100
Primary Reactor
2.3–13.8 kV
65
16
42
Autotransformer
2.3–13.8 kV
45
16
42
AFD
460–600 V
<13
12
Varies
Table 10. Motor starter operational voltage range—during a start
Starter Size
Starter Description
Maximum
Line-to-Line
RMS Voltage Sag
Maximum
Line-to-Line
RMS Voltage Swell
155–606 amps
Unit- and Remote-Mounted
Wye-Delta
25%
15%
607–1,316 amps
Unit-Mounted
Wye-Delta
25%
15%
607–1,856 amps
Remote-Mounted
Wye-Delta
20%
15%
185–1,120 amps
Unit- and Remote-Mounted
Solid-State
25%
15%
180–960 amps
Remote-Mounted,
High-Fault Solid-State
25%
15%
961–1,600 amps
Remote-Mounted,
High-Fault Wye-Delta
25%
15%
155–1530 amps
Unit- and Remote-Mounted
Low Voltage AFD
(460–600
V)
25%
10%
94, 187, 205/288 amps
(205 reduced voltage, 288
full voltage)
Unit-Mounted
Medium Voltage
(2.3–6.6 kV)
25%
(20% w/additional
protection)
15%
94, 187, 360 amps
Remote-Mounted
Medium Voltage
(2.3–6.6 kV)
25%
(20% w/additional
protection)
15%
94 amps
Remote-Mounted
Medium Voltage
(10–13.8 kV)
25%
(20% w/additional
protection)
15%
61–250 amps @ 4,160
V
Remote Medium-Voltage AFD
25%
10%
CTV-PRB004.book Page 55 Sunday, December 18, 2011 6:39 PM
