04/10 MN04020001Z-EN
Electrical Installation
53
Insulation testing 
The frequency inverter of the M-Max
TM
 series are tested, delivered 
and require no additional testing.
If insulation testing is required in the power circuit of the PDS, you 
must consider the following measures.
Testing the motor cable insulation
Disconnect the motor cable from the connection terminals U/T1,
V/T2 and W/T3 of the frequency inverter and from the motor (U, V, 
W). Measure the insulation resistance of the motor cable between 
the individual phase conductors and between the phase conductor 
and the protective conductor.
The insulation resistance must be greater than 1 MO.
Testing the mains cable insulation
Disconnect the power cable from the mains supply network and 
from the connection terminals L1, L2/N and L3 of the frequency 
inverter. Measure the insulation resistance of the mains cable 
between the individual phase conductors and between each phase 
conductor and the protective conductor.
The insulation resistance must be greater than 1 MO.
Testing the motor insulation
Disconnect the motor cable from the motor (U, V, W) and open the 
bridge circuits (star or delta) in the motor terminal box. Measure 
the insulation resistance of the individual motor windings. The 
measurement voltage must at least match the rated voltage of the 
motor but is not to exceed 1000 V.
The insulation resistance must be greater than 1 MO.
i
Warning!
On the control signal and the connection terminals of the 
frequency inverter, no leakage resistance tests are to be 
performed with an insulation tester.
j
Warning!
Wait at least 5 minutes after switching the supply voltage 
off before you disconnect a connection on the connection 
terminals (L1, L2/N, L3, U/T1, V/T2, W/T3, R+, R-) of the 
frequency inverter.
h
Consider the information from the motor manufacturer in 
testing the insulation resistance.