21
FRCC.PC.007.B8.02
Application guidelines
Compressor models SH090-105-120-140-161-184
have no internal reverse rotation protection. If
reverse rotation occurs it will be obvious as soon
as power is turned on. The compressor will not
build-up any pressure, the sound level will be
abnormally high and power consumption will be
minimal. In such case, shut down the compressor
immediately and connect the phases to their
proper terminals. Prolonged reverse rotation will
damage the compressor.
Phase sequence detector is strongly
recommended.
Electrical data, connections and wiring
The lockout may be cancelled by resetting the
power mains (disconnect L-N) for approximately
5 seconds.
Compressor models SH 240 to 485 are delivered
with an electronic module which provides
protection against phase reversal and phase
loss at start-up. Apply the recommended wiring
diagrams from section "Suggested wiring
diagram logic". The circuit should be thoroughly
checked in order to determine the cause of the
phase problem before re energizing the control
circuit.
The phase sequencing and phase loss monitoring
functions are active during a 5-sec window 1
second after compressor start-up (power on
L1-L2-L3).
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.
| Vavg - V1-2 | + | Vavg - V1-3 | + | Vavg - V2-3 |
2 x Vavg
% voltage
imbalance
=
x 100
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
imbalance is 2%. Voltage imbalance causes high
amperage over one or several phases, which in
turn leads to overheating and possible motor
damage. Voltage imbalance is given by the
formula:
Voltage imbalance
Compressor model SH180 incorporates an
internal reverse vent valve which will react in
the presence of reverse rotation and will allow
refrigerant to circulate through a by-pass from
the suction to the discharge. Although reverse
rotation is not destructive for the SH180, even
over long periods of time, it should be corrected
as soon as possible. If reverse rotation is not
halted, the SH180 will cycle off on the motor
protection.
Compressor
start
Phase monitoring
0 1 s 6 s
Phase sequence module logic
Should one of these parameters be incorrect, the
relay would lock out (contact M1-M2 open). The
red led on the module will show the following
blink code:
In case of phase reverse error:
Appr. 1 second
In case of phase loss error:
Appr. 1 second
