Siemens SIMOTICS XP Operating Instructions Manual page 58

Assembly
5.2 Preparations for installation
Note
Comment to IEEE 43
According to IEEE 43, also for winding temperatures < 40 °C, R
reference temperature of 40 °C.
As the minimum values for R
winding temperatures below 40 °C.
Measuring the polarization index
1. To determine the polarization index, measure the insulation resistances after 1 and
10 minutes.
2. Express the measured values as a ratio:
Polarization index = R
Many measuring devices display these values automatically following the measurement.
Measuring the polarization index is not helpful for insulation resistances > 5000 MΩ, and is
therefore not included in the assessment.
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 143).
• If the measured value is close to the critical value, you must subsequently check the
See also
Insulation resistance and polarization index (Page 53)
Limit values of the anti-condensation heating insulation resistance
It is not permissible that the insulation resistance of the anti-condensation heating with
respect to the machine enclosure falls below 1 MΩ when measured at 500 V DC.
56
i 10 min
R / R
i 10 min i 1 min
≥ 2
< 2
insulation resistance at shorter intervals.
apply at 40 °C, the required R
i
/ R
i 1 min
Insulation in good condition
Dependent on the complete diagnosis of the insulation
must be converted over to the
i
values are somewhat higher for
i
Assessment
1MB..5/6 shaft height 71 ... 355
Operating Instructions, 10/2021, A5E41926185A