Siemens 1PL618 Series, Руководство по эксплуатации

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Start-up
4.1 Preparations
A5E00215731A AD
40
Siemens AG Operating Instructions 2.02 1PL618
● When measuring, wait until the final resistance value is reached; this takes approximately
one minute.
Stator winding insulation resistance limit values
The following table shows the measuring circuit voltage and the limit values for the minimum
insulation resistance and the critical insulation resistance for the stator winding.
Table 4-1 Stator winding insulation resistance at 25 °C
Rated voltage U
N
< 2 kV
Measuring circuit voltage 500 V (min. 100 V)
Minimum insulation resistance with new, cleaned or
repaired windings
10 MΩ
Critical specific insulation resistance after a long operating
time
2.5 MΩ/kV
Note the following:
●
Dry, new windings have insulation resistance of between 100 and 2000 MΩ, or possibly
values that are even higher.
If the insulation resistance is close to the minimum value, then the cause could be
humidity and/or fouling.
● 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
Critical insulation resistance is reached or insufficient
If the critical insulation resistance is reached or is insufficient, damage to the insulation and
flashover voltages can result.
Dry the windings or clean and dry them thoroughly, having first removed the rotor.
If the clean windings have not cooled to 25°C, then lower insulation resistance will be
measured. The insulation resistance can only be properly assessed after conversion to the
reference temperature of 25°C. Allow the windings to cool to 25°C or convert the insulation
resistance using 25°C as the reference temperature.
If the measured value is close to the critical value, you must check the insulation resistance
at appropriately frequent intervals subsequently.
[ID: 344.01]