Insulation Resistance; Insulation Resistance And Polarization Index; Checking The Insulation Resistance And Polarization Index Of The Winding - Siemens SIMOTICS SD 1LE5 Operating Instructions Manual

5.2.2

Insulation resistance

5.2.2.1

Insulation resistance and polarization index

Measuring the insulation resistance and polarization index (PI) provides information on the
condition of the machine. It is therefore important to check the insulation resistance and the
polarization index at the following times:
• Before starting up a machine for the first time
• After an extended period in storage or downtime
• Within the scope of maintenance work
The following information is provided regarding the state of the winding insulation:
• Is the winding head insulation conductively contaminated?
• Has the winding insulation absorbed moisture?
As such, you can determine whether the machine needs commissioning or any necessary
measures such as cleaning and/or drying the winding:
• Can the machine be put into operation?
• Must the windings be cleaned or dried?
Detailed information on testing and the limit values can be found here:
"Testing the insulation resistance and polarization index" (Page 47)
5.2.2.2

Checking the insulation resistance and polarization index of the winding

Hazardous voltage at the terminals
Hazardous voltages are sometimes present at the terminals during and immediately after
measurement of the insulation resistance or polarization index of the winding. Contact with
these can result in death, serious injury or material damage.
• If power cables are connected, ensure that a line voltage cannot be applied.
• Discharge the winding after measurement until the risk is eliminated, e.g. using the
Measure the insulation resistance
1. Follow the instructions in the Operating Manual of the insulation measuring instrument
used.
2. Ground other windings, integrated winding temperature sensors and, if applicable, other
mounted and installed components.
1LE5, 1PC4 shaft height 315/355
Operating Instructions, 10/2020, A5E41454666A
WARNING
following measures:
– Ground the terminals until the recharge voltage drops to a non-hazardous level.
– Attach the connection cable.
Assembly
5.2 Preparing for installation
47