Midea LSBLG320/MZ - Compressor Thermal Relay Value; Main Base Controller DIP Setting; Digital Switch Factory Default Status; S3 Digital Switch Instruction

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)
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5).Compressor thermal relay value:
The calculation of compressor overload value (transformation ratio of current mutual inductor is A/B) is
as follows:
(Maximum running current of compressor/current mutual inductor A) x B = Thermal relay value of
compressor. For example, if the maximum running current of compressor is 250 A, and the
transformation ratio of current mutual inductor is 300/5, Thermal relay value = (250/300) x 5 = 4.17
Note: Use a value that is smaller than the calculated one. For example, in the preceding calculation, the
calculated value is 4.17; in practice, set the value to 4.15.
Unit Type
Maximum Running
Current of Compressor
Transformation Ratio of
Current Transformer
Thermal Relay
Value of
Compressor
255
126
200/5
3.2
320
150
200/5
3.8
400
200
300/5
3.4
485
232
300/5
3.9
630
295
400/5
3.7
860
400
500/5
4.1
970
464
300/5
3.9
1060
497
300/400
39/3.4
1260
589
400/5
3.7
1490
695
500/5 and 400/5
3.7/4.1
6) Main base controller DIP setting
Digital switch factory default status
There are adjustable digital switch on PCB.
S3 digital switch instruction:
Digital switch 1：for single compressor unit, dial to ON; for dual compressors, dial to OFF.
Digital switch 2：for no lubricating oil temperature sensor unit ,dial to ON; for lubricating oil
temperature sensor unit ,dial to OFF.
Note：Compressor overload relay, only apply to 3UA series of Siemens brand
DIPs S1, S2, and S3
Digital switch S3