Siemens 1MB115 Installation And Maintenance Manual page 83

damage parts mounted by customers, such as cables manufactured out of
materials that are not heat resistant.
• Temperature-sensitive parts must not come in contact with or be attached
to components mounted on the machine.
• Only use heat-resistant mounting parts. The connecting cables and cable
entries must be suitable for the particular application.
3.1.2 Check
3.1.2.1 Testing the insulation resistance and polarization index
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 ºC during the measurement. Convert the measured
insulation resistances in accordance with the formula to the reference
temperature of 40 ºC. This thereby ensures that the minimum values
specified can be compared.
!
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.
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