Voltage Imbalance - Trane SCIH Installation Operation & Maintenance

Installation

Voltage Imbalance

Live Electrical Components!
During installation, testing, servicing and troubleshooting of this product, it may be necessary
to work with live electrical components. Have a qualified licensed electrician or other individual
who has been properly trained in handling live electrical components perform these tasks.
Failure to follow all electrical safety precautions when exposed to live electrical components
could result in death or serious injury.
Voltage imbalance on three-phase systems can cause motor overheating and premature failure.
Maximum allowable imbalance is 2.0%, and the readings used to determine it must be measured
at the compressor terminals.
Voltage imbalance is defined as 100 times the sum of the division of the three voltages from the
average voltage. If, for example, the three measured voltages are 221, 230, 227, the average would
be:
(221+230+227)/3 = 226 volts
The percentage of voltage imbalance is then:
100*(226-221)/226 = 2.2%
In this example, 2.2 percent imbalance of more than 2.0 percent exists, be sure to check the voltage
at the unit disconnect and terminal block switch. If an imbalance at the unit disconnect switch does
not exceed 2.0 percent, the imbalance is caused by faulty wiring within the unit. Be sure to conduct
a thorough inspection of the unit electrical wiring connections to locate the fault, and make any
repairs necessary.
Table 6.
Unit Size
Notes:
1. Voltage range: nominal voltage: 208-230V, acceptable range: 187 - 253V, nominal voltage: 380V, acceptable range: 342 -
2. Ampacity = (1.25 x compressor RLA) + the sum of the second compressor RLA (if used) and all other motor FLAs
3. MFS = (2.25 x compressor RLA) + the sum of the second compressor RLA (if used) and all other motor FLAs
18
WARNING
Integral air-cooled standard motor electrical data
Voltage RLA
5 208-230/60/3 22.9
460/60/3 10.7
575/60/3 8.5
7.5 208-230/60/3 25.0
460/60/3 12.0
575/60/3 9.8
10 208-230/60/3 19.3
460/60/3 8.2
575/60/3 6.6
15 208-230/60/3 25.0
460/60/3 12.0
575/60/3 9.8
416V, nominal voltage: 460V, acceptable range: 414 - 506V, nominal voltage: 575V,
electrical requirements and installation procedure
Condenser Evaporator
Compressor Fan Motor
LRA Hp
155.0 1.0
75.0
54.0
179.0 2.0
101.0
74.0
135.0 2.0
61.8
49.4
179.0 5.0
101.0
74.0
Fan Motor
FLA Hp FLA
3.15 1.0 3.15
1.42 1.42
1.14 1.14
5.81 1.5 4.42
2.63 2.00
2.10 1.60
5.81 2.0 5.81
2.63 2.63
2.10 2.10
13.70 3.0 8.32
6.18 3.76
4.94 3.01
acceptable range: 518 - 633V
SXIH-SVX01C-EN
MCA MFS
34.9 50
16.2 25
12.9 20
41.5 60
19.6 30
16.0 25
55.0 70
23.7 30
19.1 25
78.3 100
36.9 45
30.0 35