Service manual

4. Troubleshooting

4-11

［C］ Measurement of Insulation Resistance of Generator Winding Wires

Measurement is performed with a 500V megger. The situation is considered to be satisfactory if the

measurement produces a result of 1M or more, while a result of less than that value indicates

failure.

Voltage selection switch position 480/277V

6-17-1

(1) Generator armature winding wires

● (Procedure)(Megger tester required)

1. Remove the load side cable from the output

terminal board.

2. Remove the cable between the terminal "N" and

terminal "Ground" which are connected on the

back of the output terminal plate.

3. Remove the AVR connector inside the generator

control panel.

4. Switch ON the three-phase breaker, and then

measure each insulation resistance between the

terminals L1, L2, L3 terminal and bonnet.

5. Insulation resistance when measured with a

500V megger tester must be above 1 MΩ.

6. After finishing the measurement of insulation

resistance, re-connect the cable between the

terminal "N" and terminal "Ground".

 After making sure that the insulation resistance of

the generator is higher than 1 MΩ, be sure to

re-connect the cable between the terminal "N" and

terminal "Ground" just as it was originally

connected. If it is left disconnected, the grounding

becomes imperfect so that it could cause electric

shock.

A040180-1

A040179

SDG45S/65S-6A6

Bonnet

VR Connector