7.2.1
Inspection work
7.2.1.1
Checking the ground conductor
1.
Measure the resistance between ground conductor and ground.
The resistance must be lower than 1
Ω.
2.
Replace any damaged components by original spare parts.
DANGER
Defective ground conductor
Electric shock!
▷
Never switch on a pump set with a defective ground conductor.
7.2.1.2
Measuring the insulation resistance
Measure the insulation resistance of the motor winding during annual maintenance
work.
✓
The pump set has been disconnected in the control cabinet.
✓
Use an insulation resistance measuring device.
✓
The maximum measuring voltage is 500 V (maximum permissible voltage
1000 V).
1.
Measure the winding against ground.
To do so, connect all winding ends together.
2.
Measure the winding temperature sensor against ground.
To do so, connect all core ends of the winding temperature sensors together
and connect all winding ends to ground.
⇨
The insulation resistance of the core ends against ground must not be lower than
1 M
Ω.
If the resistance measured is lower, power cable and motor resistance must be
measured separately. Disconnect the power cable from the motor for this
purpose.
NOTE
If the insulation resistance of one of the power cables is lower than 1 M
Ω
, the
power cable is defective and must be replaced.
NOTE
If the insulation resistance values measured on the motor are too low, the winding
insulation is defective. The pump set must not be returned to service in this case.
7.2.1.3
Checking the sensors
CAUTION
Excessive test voltage
Damage to the sensors!
▷
Use a commercially available ohmmeter to measure the resistance.
The tests described below measure the resistance at the core ends of the control
cable. The actual sensor function is not tested.
Table 7: Resistance measurement
Measurement between terminals ...
Resistance
10 and 11
200 Ω - 1000 Ω
Temperature sensors in
the motor winding
7 Servicing/Maintenance
32 of 68
Amacan P
