Flooded type water cooled screw chiller (PCB Control) MCAC-CTSM-2012-11
45
e.g. at nominal voltage 3N~, AC380V, 50Hz, the measured UAB=376V, UAC=379V, UBC=385V.
Average voltage = (376+379+385) 3= 380V
Determined deviation from average voltage:
△UAB=380-376=4V, △UAC=380-379=1V, △UBC=385-380=5V,
Maximum deviation: 5V
5/380=1.3%, the maximum phase voltage unbalance is 1.3%.
4) Inspect whether the supply circuit is the compressor is firmly and properly connected, and
tighten it if there is any looseness. The screws might be loose due to the factors such as
long-distance transport and hoisting of the master compressor. Or, the electrical elements (e.g.
air switch, AC contactor, etc.) in the control cabinet of the master compressor and the
compressor might be damaged.
5) Carefully inspect all the electrical lines with a multimeter, and whether the connections are
properly installed. Carry out measurement in mega ohm and ensure that there is no short circuit
at the shell. Inspect whether the earth wire is properly installed, and whether the insulation
resistance to ground exceeds 2MΩ. And inspect whether the supply line meets the requirement
of capacity.
6) Inspect whether disconnection switch is installed to the supply line of the supply unit.
7) Carry out complete inspect for all connections of the main circuit in the control cabinet and all
external connections of the control circuit before power connection (e.g. oil heater, compressor
electronic protection, circulatory water temperature sensor, target-type flow switch connection,
water pump linked control, communication line connection, etc.); inspect the bolts of the wiring
terminal for looseness. Inspect whether various electric meters and appliances are properly
installed, complete and available. Inspect the interior and exterior of the electrical cabinet,
especially various wiring ports, for cleanness. If the communication lines of the PCB and control
screen are damaged, refer to the diagram below.
8) After the inspection for all the above items is complete, connect the control cabinet and the
supply indication lamp will light up, indicating that the oil heater is working. Observe whether
the phase loss protection is in normal condition, if it is (green light on), close the single-pole
switch in the control cabinet, then the control circuit begins working, and the touch screen and
PCB control are put into operation.
9) Before start up the machine, inspect whether the external system of the unit meets the
conditions for start-up (e.g. whether the water cooling pump of the system is externally
controlled or interlocked with the master compressor, and that the water pump must be started
before starting up the master compressor via external control).
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