Application guidelines
14
FRCC.PC.021.A5.22
Electrical data, connections and wiring
Motor voltage
Voltage unbalance
Electrical data
LRA (Locked Rotor Amp)
MCC (Maximum Continuous
Current)
Max. operating current
The operating voltage limits are shown in the
table section “Motor voltage”. The voltage applied
to the motor terminals must lie within these
table limits during both start-up and normal
operations. The maximum allowable voltage
unbalance is 2%. Voltage unbalance causes high
amperage over one or several phases, which in
turn leads to overheating and possible motor
damage. Voltage unbalance is given by the
formula:
Vavg = Mean voltage of phases 1, 2, 3.
V1-2 = Voltage between phases 1 & 2.
V1-3 = Voltage between phases 1 & 3.
V2-3 = Voltage between phases 2 & 3.
Locked Rotor Amp value is the highest average
current as measured on mechanically blocked
compressor tested under nominal voltage. The
LRA value can be used as rough estimation for
the starting current. However in most cases, the
real starting current will be lower. A soft starter
can be applied to reduce starting current.
The MCC is the current at which the motor
protection trips under maximum load and
low voltage conditions. This MCC value is the
maximum at which the compressor can be
operated in transient conditions and out of the
application envelope. Above this value, the OCS
will cut-out the compressor to protect the motor.
The max. operating current is the current when
the compressors operates at maximum load
conditions and 10% below nominal voltage
(59°F evaporating temperature and 154.4°F
condensing temperature). Max. operating current
can be used to select cables and contactors.
In normal operation, the compressor current
consumption is always less than the Max
operating A. value.
| Vavg - V1-2 | + | Vavg - V1-3 | + | Vavg - V2-3 |
% voltage unbalance= _______________________________________________ x100
2 x Vavg
Motor voltage code
Code 4
Code 9
50Hz
Nominal voltage
380-415V~3
-
Voltage range
357-440V~3
-
60Hz
Nominal voltage
460V~3
380V~3
Voltage range
414-506V~3
342-418V~3
Compressor models
LRA
MCC
Maximum
Operating Current
Winding
resistance
A
A
A
Ω
Motor code 4
PSH051
211
60
50
0.57
PSH064
248
72
64
0.48
PSH077
319
83
78
0.39
Motor code 9
PSH051
273
66
61
0.38
PSH064
315
90
79
0.33
PSH077
399
98
91
0.27
