20.4 PART WINDING
This algorithm allows to reduce the start-up current when using hermetic or semi-hermetic compressors or medium – big screw
compressors.
Each compressor needs two relay outputs:
• One is the PW motor coil 1 of the compressor;
• One is the PW motor coil 2 of the compressor
The time delay between the two outputs is determined by CO11 expressed in decimal of second.
The maximum number of relay outputs is 4 this means 2 compressors with Part Winding start-up.
First is turned on the PW motor coil 1 of the compressor 1 (relay K1 of fig2), after the CO11 delay it is turned on the second motor coil of
the same compressor (relay K2 of fig2).
To turn off the compressor the two relay outputs are both turned off at the same time.
Fig 2
20.5 PART WINDING START- UP OF COMPRESSORS OR CAPACITY COMPRESSORS
If one or more capacity compressors are configured and the thermoregulation requires the full load start-up: the controller turns the
solenoid valve on, after 1 second the first motor part of the 1
st
compressor (relay K1 of Fig. 2) and then the complete control with the
contactor K2. Durning the CO12 time delay the step valve is forced on: minimum power. When the C012 is expired if the
thermoregulation requires more power the valve will be switched off (maximum power).
21 CAPACITY CONTROL
Only the compressor 1 can be configured with 3 capacity step.
CO06 capacity control operative mode.
The relay configured as capacity control are managed by the thermoregulation as shown in the graph and into the tables here below.
Par CO06 = 0 ON/OFF step
0= Step control. Depending on the thermoregulation requests and the output polarity a power step can be enabled or disabled. The step
is activated only after the previous is turned off.
Eg: 1 capacity compressor with 3 partializations: 4 Power steps.
Capacity 25% 50% 75% 100%
Compr. Compressor ON Compressor ON Compressor ON Compressor ON
Out relay Step P 1 ON Step P 1 OFF Step P 1 OFF Step P 1 OFF
Out relay Step P 2 OFF Step P 2 ON Step P 2 OFF Step P 2 OFF
Out relay Step P 3 OFF Step P 3 OFF Step P 3 ON Step P 3 OFF
Step control process
Compressor Part 1 Part 2 Part 3 Power involved
0 %
25 %
50 %
75 %
100 %
Par CO06 = 1 direct action with sequential step
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