Measures To Be Performed Prior To Commissioning - Siemens AH 180 Operating Instructions Manual

Startup

4.2 Measures to be performed prior to commissioning

When making the measurement, you must wait until the final insulation resistance value is
reached (approx. 1 minute).
Limit values
The table below specifies the measuring circuit voltage and the limit values for the minimum
insulation resistance and the critical insulation resistance:
Measuring circuit voltage
Minimum insulation resistance with new, cleaned or
repaired windings
Critical specific insulation resistance after a long operating
time
Note the following points:
• Dry, new windings have insulation resistances of between 100 and 2000 MΩ, or possibly
[ID: 344]
4.2 Measures to be performed prior to commissioning
Overview
4-2
even higher values.
If the insulation resistance is close to the minimum value, then the cause could either be
humidity and/or dirt accumulation.
Over its operating lifetime, the motor winding insulation resistance can drop due to
ambient and operational influences. The critical insulation resistance at a winding
temperature of 25°C is 2.5 MΩ
Notice
If the critical insulation resistance is less than or equal to this value, the windings must be
dried or, if the fan is removed, cleaned thoroughly and dried.
Please note that the insulation resistance of dried, clean windings is lower than that of
warm windings. The insulation resistance can only be evaluated accurately when
measured on a winding that has been cooled down to room temperature (approx. 20 to
30°C).
Notice
If the measured value is close to the critical value, the insulation resistance should be
subsequently checked at appropriately frequent intervals.
Rated voltage U
500 V (min. 100 V)
10 MΩ
2.5 MΩ/kV
SIEMENS AG A5E00215729A, 1PH718
Operating Instructions - Three-phase induction motor - AH 180
< 2 kV
N
V 2.0