Commissioning
7.1 Measures before commissioning
Standard motors SH 63 ... 355
78
Operating Instructions, 12/2018, A5E38483075A
7.1.4
Testing the insulation resistance and polarization index
WARNING
Hazardous voltage at the terminals
During and immediately after measuring the insulation resistance or the polarization index
(PI) of the stator winding, hazardous voltages may be present at some of the terminals.
Contact with these can result in death, serious injury or material damage.
•
If any power cables are connected, check to make sure line supply voltage cannot be
delivered.
•
Discharge the winding after measurement until the risk is eliminated, e.g. using the
following measures:
–
Connect the terminals with the ground potential until the recharge voltage drops to a
non-hazardous level
–
Attach the connection cable.
Measure the insulation resistance
1.
Before you begin measuring the insulation resistance, please read the operating manual
for the insulation resistance meter you are going to use.
2.
Short-circuit the ends of the temperature sensor cables before applying the test voltage. If
the test voltage is connected to only one temperature sensor terminal, the temperature
sensor will be destroyed.
3.
Make sure that no power cables are connected.
4.
Measure the winding temperature and the insulation resistance of the winding in relation
to the machine enclosure. The winding temperature should not exceed 40° C during the
measurement. Convert the measured insulation resistances in accordance with the
formula to the reference temperature of 40° C. This thereby ensures that the minimum
values specified can be compared.
5.
Read out the insulation resistance one minute after applying the measuring voltage.
