Electrical data, connections and wiring
Compressor model
Overheating
protection
Over current
protection
Locked rotor
protection
Phase reversal protection
WSH 090 - 105 - 120 - 140- 161 - 184
Internal motor protection
Internal reverse vent
Motor protection
Compressor models WSH090-105-120-140-
161 -184 have been provided with an internal
overload motor protection to prevent against
excessive current and temperature caused by
overloading, low refrigerant flow or phase loss.
The cutout current is the MCC value listed in
section “Three phase electrical characteristics”.
The protector is located in the star point of the
motor and, should it be activated, will cut out all
three phases. It will be reset automatically.
While not compulsory, an additional external
overload is still advisable for either alarm or
manual reset.
Then it must be set below MCC value (at max
operating current:
• when the motor temperature is too high, then
the internal protector will trip
• when the current is too high the external
overload protection will trip before the internal
protection therefore offering possibility of
manual reset.
Use a phase meter to establish the phase
orders and connect line phases L1, L2 and L3
to terminals T1, T2 and T3, respectively. The
compressor will only operate properly in a single
direction, and the motor is wound so that if the
connections are correct, the rotation will also be
correct.
Phase sequence and
reverse rotation
protection
Compressor models WSH090-105-120-140-
161-184 incorporates an internal reverse vent
valve which will react when the compressor
is run in reverse and will allow refrigerant to
circulate through a by-pass from the suction
to the discharge. Although reverse rotation is
not destructive for these models, it should be
corrected as soon as possible. Repeated reverse
rotation longer than 24hours may have negative
impact on the bearings. Reverse rotation will be
obvious to the user as soon as power is turned
on: the compressor will not build up pressure, the
sound level will be abnormally high and power
consumption will be minimal. If reverse rotation
symptoms occur, shut the compressor down and
connect the phases to their proper terminals. If
reverse rotation is not halted, the compressor will
cycle off-on the motor protection.
Vavg = Mean voltage of phases 1, 2, 3.
V1-2 = Voltage between phases 1 and 2.
V1-3 = Voltage between phases 1 and 3.
V2-3 = Voltage between phases 2 and 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
15
FRCC.PC.028.A5.02
Application Guidelines
