Electric wiring of GRH3 air compressor

 1. Cabling of GRH3 air compressor

The lead-in cabling to the compressor should be executed by an competent engineer. Any poor wiring may cause electic shock or other electric fault. Do not alter control parts or electric circuits attached to the electric box. The compressor may be damaged due to malfunction of protection. When opening the electric box door for routine maintenance or repairs, the main power should be turned off to avoid any electric shock accident.

2.Wiring of GRH3 air compressor

The compressor is already wired internally. If opening the front door, you may find a hole for lead-in power cable on the bottom of the right side. Insert a wire into the hole for connection.
If open the front door, there is TB1. Please connect the power to it.
In case of wiring to the electric box, use the rubber bushing to protect the cable shearth and wire it to avoid of the shearth.
3.Power cable specifications
Use the EV or CV cable for 600V. For the thickness refer to page 24.
Rated current of main motor

                                          *The rated current may vary depending on a motor type
4. Grounding
Grounding in accodance with the KSC rules. The grounding terminal inside the compressor’s electric box is located as presented in the below figure.

Attach a circuit breaker for wiring on the primary power supply of the compressor. For the capacity of the breaker, refer to page 24. When repairing or maintaining the compressor, make sure to turn if off first.

Example of circuit-breaker wiring.

5. Routine checkpoints

Connecting to TBI of the compressor’s electric box.

If any impurities or dust is found inside when visually inspecting it, turn it off and clean it up with compressed air.

Black cable is power cable and the red/white/blue insulation tubes are inserted at the end of it. If the colors of insulation tubes are discolored to black, check the tightness of screws.

If screws are loosely tightened, it may generate heat, deteriorating cables and probably leading to a fire, so they should be maintained once a month.

Cable checkpoints.

6. Check motor insulation resistance

Take the following steps if insulation resistance is to be checked, for instance, operation of circuitbreaker. 1) Turn off the power of the compressor. 2) Set the voltage range of insulation resistance tester lower than 500V. 3) How to check the resistance; Loosen the bolt with (motor’s cable) and separate the cable from the terminal.

If it displays 10MΩ and over as the above, it is norma

Power Facilities of GRH3 air compressor.
1.Cable thickness.
Since the compressor may not work properly depending on the power facility capacity and the thickness/length of the power cable and it may stop due to voltage dropping of control circuit or defective acceleration of the main motor, make sure to supply the power with the voltage dropping set within 5% of the rated power.
 For the cable thickness of the lead-in cable, refer to the following table.

It is recommended that the cable length between a transformer/distribution board and the compressor is 100m and shorter; if longer than the length, the thickness may need reselecting.
2.Grounding specifications.
 Grounding specifications are as follows.

3.Thickness of grounding cable (Bề dầy của dây nối đất)

4. Circus breaker capacity.
The main power supply essentially needs a circuit breaker to avoid electric shock and protect the motor.
When selecting a breaker, refer to the following table.

 4.1. Electric wiring

The lead-in cabling to the compressor should be executed by an competent
engineer. Any poor wiring may cause electic shock or other electric fault.
Do not alter control parts or electric circuits attached to the electric box. The
compressor may be damaged due to malfunction of protection.
When opening the electric box door for routine maintenance or repairs, the main
power should be turned off to avoid any electric shock accident.

4.2.Wiring

The compressor is already wired internally. If opening the front door, you may find a hole for lead-in power cable on the bottom of the right side. Insert a wire into the hole for connection.
If open the front door, there is TB1. Please connect the power to it.
In case of wiring to the electric box, use the rubber bushing to protect the cable shearth and wire it to avoid of the shearth.
4.3.Power cable specifications
Use the EV or CV cable for 600V. For the thickness refer to page 24.

Rated current of main motor

                                          *The rated current may vary depending on a motor type
4. Grounding
Grounding in accodance with the KSC rules. The grounding terminal inside the compressor’s electric box is located as presented in the below figure.

Attach a circuit breaker for wiring on the primary power supply of the compressor. For the capacity of the breaker, refer to page 24. When repairing or maintaining the compressor, make sure to turn if off first.

Example of circuit-breaker wiring.

5. Routine checkpoints

Connecting to TBI of the compressor’s electric box.

If any impurities or dust is found inside when visually inspecting it, turn it off and clean it up with compressed air.

Black cable is power cable and the red/white/blue insulation tubes are inserted at the end of it. If the colors of insulation tubes are discolored to black, check the tightness of screws.

If screws are loosely tightened, it may generate heat, deteriorating cables and probably leading to a fire, so they should be maintained once a month.

Cable checkpoints.

6. Check motor insulation resistance

Take the following steps if insulation resistance is to be checked, for instance, operation of circuitbreaker. 1) Turn off the power of the compressor. 2) Set the voltage range of insulation resistance tester lower than 500V. 3) How to check the resistance; Loosen the bolt with (motor’s cable) and separate the cable from the terminal.

If it displays 10MΩ and over as the above, it is norma

Power Facilities of GRH3 air compressor

1.Cable thickness.
Since the compressor may not work properly depending on the power facility capacity and the thickness/length of the power cable and it may stop due to voltage dropping of control circuit or defective acceleration of the main motor, make sure to supply the power with the voltage dropping set within 5% of the rated power.

 For the cable thickness of the lead-in cable, refer to the following table.

It is recommended that the cable length between a transformer/distribution board and the compressor is 100m and shorter; if longer than the length, the thickness may need reselecting.

2.Grounding specifications.

 Grounding specifications are as follows.

3.Thickness of grounding cable (Bề dầy của dây nối đất)

4. Circus breaker capacity.

The main power supply essentially needs a circuit breaker to avoid electric shock and protect the motor.
When selecting a breaker, refer to the following table.

Minh Phu provides maintenance and repair services for air compressors, in addition Minh Phu also provides spare parts for air compressors with high quality at reasonable prices. For further information, please contact (+84)919 23 28 26. Sincerely thank you for your interest and your trust of our service.