For a winding temperature of approx. 25° C, the minimum insulation resistances are 20 MΩ
(U ≤ 1000 V) or 300 MΩ (U > 1000 V). The values apply for the complete winding to ground.
Twice the minimum values apply to the measurement of individual assemblies.
● Dry, new windings have an insulation resistance of between 100 and 2000 MΩ, or possibly
even higher values. An insulation resistance value close to the minimum value could be
due to moisture and/or dirt accumulation. The size of the winding, the rated voltage and
other characteristics affect the insulation resistance and may need to be taken into account
when determining measures.
● Over its operating lifetime, the motor winding insulation resistance can drop due to ambient
and operational influences. Calculate the critical insulation resistance value depending on
the rated voltage by multiplying the rated voltage (kV) by the specific critical resistance
value. Convert the value for the current winding temperature at the time of measurement,
see above table.
Measuring the polarization index
1. To determine the polarization index, measure the insulation resistances after one minute
and ten minutes.
2. Express the measured values as a ratio:
PI = R
insul 10 min
/ R
insul 1 min
Many measuring devices display these values automatically following the measurement.
For insulation resistances > 5000 MΩ, the measurement of the PI is no longer meaningful and
consequently not included in the assessment.
R
(10 min)
/ R
(1 min)
Assessment
≥ 2
Insulation in good condition
< 2
Dependent on the complete diagnosis of the insulation
NOTICE
Damage to insulation
If the critical insulation resistance is reached or undershot, this can damage the insulation
and cause voltage flashovers.
● Contact the Service Center (Page 137).
● If the measured value is close to the critical value, you must subsequently check the
insulation resistance at shorter intervals.
Limit values of the anti-condensation heating insulation resistance
The insulation resistance of the anti-condensation heating with respect to the machine housing
should not be lower than 1 MΩ when measured at 500 V DC.
Assembling
5.1 Preparations for installation
SIMOTICS DC 1GG6
38
Operating Instructions 02/2016
Summary of Contents for SIMOTICS DC 1GG6
Page 2: ...08 02 2016 10 27 V4 00 ...
Page 12: ...Table of contents SIMOTICS DC 1GG6 12 Operating Instructions 02 2016 ...
Page 14: ...Introduction 1 1 About these instructions SIMOTICS DC 1GG6 14 Operating Instructions 02 2016 ...
Page 70: ...Commissioning 7 8 Switch off SIMOTICS DC 1GG6 70 Operating Instructions 02 2016 ...
Page 82: ...Operation 8 9 Faults SIMOTICS DC 1GG6 82 Operating Instructions 02 2016 ...
Page 104: ...Maintenance 9 2 Repair SIMOTICS DC 1GG6 104 Operating Instructions 02 2016 ...
Page 138: ...Service and Support SIMOTICS DC 1GG6 138 Operating Instructions 02 2016 ...
Page 142: ...Quality documents SIMOTICS DC 1GG6 142 Operating Instructions 02 2016 ...
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