Flooded Type Water Cooled Screw Chiller Technical M
anual
28
Sectional area of Earth Line
Sectional area of phase wire for device “S”(mm2)
Earth line (mm2)
S
≤
16
S
16
＜
S
≤
35
16
35
＜
S
≤
400
S/2
400
＜
S
≤
800
200
S
＞
800
S/4
5 Commissioning of Unit
5.1 Preparation before Commissioning
Step 1:
Check wiring of power supply and electrical system
Before initial startup, check if distribution capacity complies with power of the unit and if
diameter of power cable can stand max working current of main unit.
Check is power system complies with the unit; power system of the unit: three-phase five-line
system (
L1, L2, L3, N, PE
,
380V 3N~/50Hz
), check if phase sequence is correct.
Check power supply line of compressor and retighten if it is loose. Otherwise, A/C contactor or
even the compressor will be damaged.
Measure with megohmmeter the insulation resistance of earth line at phase line end of power
supply, and measure the insulation resistance of earth line for motor winding; resistance
shouldn’t be less than 10M
Ω
; if the insulation resistance of earth line at compressor winding
end is more than 2M
Ω
, check if earth line is correctly and reliably installed;
Check if power cord meets capacity requirement.
Check if circuit breaker is installed on power cord of supply unit.
Check external wiring (wiring of target flow switch, interlocking control of water pump)
according to wiring diagram and check if inside and outside, especially each wiring joint, of
electrical cabinet are clean without sundries.
Before starting, check if external system of unit meets condition of startup. As for water pump
controlled externally, it’s necessary to firstly open water pump before starting main unit.
Conduct trial operation when main loop disconnects and check if electrical components act
normally.
