Preconditions For Correct Alignment And Secure Attachment - Siemens SIMOTICS M-1PH8 Operating Instructions & Installation Instructions

Assembling

5.3 Preconditions for correct alignment and secure attachment

Note the following:
● When measuring at winding temperatures other than 40 °C, the measured value must be
● Dry, new windings have an insulation resistance of between 100 ... 2000 MΩ, or even higher
● Over its operating lifetime, the motor winding insulation resistance can drop due to ambient
Example calculation
Critical resistance for a rated voltage (V
3,3 kV x 1,8 MΩ / kV = 6 MΩ at 40° C.
A winding temperature of T = 25°C during the measurement, results in a critical insulation
resistance of 16.5 MΩ.
CAUTION
Critical insulation resistance reached or undershot
If the critical insulation resistance is reached or undershot, this can damage the insulation
and cause voltage flashovers.
● Contact your Siemens Service Center.
● If the measured value is close to the critical value, you must subsequently check the
5.3 Preconditions for correct alignment and secure attachment
Detailed specialist knowledge of the following measures is required in order to correctly align
and securely fit the equipment.
● Preparing the foundation
● Selecting and mounting the coupling
● Measuring the concentricity and axial eccentricity tolerances
● Positioning the machine
48
converted to the reference temperature of 40 °C. The value is calculated using the formula
specified in the table from IEEE 43‑2000. In this case, doubling or halving the insulation
resistance at a temperature change of 10 K is used as the basis.
– The insulation resistance halves every time the temperature rises by 10 K.
– The resistance doubles every time the temperature falls by 10 K.
values, if required. Insulation resistance close to the minimum value could be due to
humidity and/or dirt accumulation. However, 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.
and operational influences. Depending on the rated voltage, the critical insulation resistance
value is to be calculated by multiplying the rated voltage (kV) by the specific critical
resistance value and then converted to the current winding temperature at the time of the
measurement, see previous table.
insulation resistance at shorter intervals.
) of 3.3 kV:
N
Operating Instructions 05/2012 A5E03986435A AA
SIMOTICS M-1PH8