Maintenance
9.2 Inspection and maintenance
9.2.9
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 64)
9.2.10
Servicing the external fan
Injury caused by rotating parts or live (under voltage) parts
Live electrical parts are dangerous. Contact with them can cause death, serious injury or
material damage.
● Before carrying out any maintenance work on the external fan, disconnect it from the
● Make sure that the device cannot be switched back on.
Servicing the external fan
However, dirt and dust deposits on the impeller and the motor, particularly in the gap between
the impeller and the inlet nozzle can impair its function.
● Remove the dirt and dust deposits regularly; the intervals depend on how dirty the
surrounding area is.
● Make sure that the impeller is cleaned evenly, as irregular deposits can lead to an
imbalance.
● The full air flow can only be achieved when air can freely flow through the impeller.
88
WARNING
mains, particularly before opening the terminal box.
1PC134, 1PC136 crane motors SH 132 ... 315
Operating Instructions, 02/2019, A5E43212221A