Measuring the insulation resistance

Notice

Damage to the variable frequency drive due to dielectric strength or insulation resistance tests

Dielectric strength or insulation tests at variable frequency drive can destroy internal components or protective components. Induced voltages can cause insulation breakdowns, partial discharges or latent damage leading to malfunctions, fire or electric shock risks.

Do not carry out any dielectric strength or insulation tests on variable frequency drive
When measuring the insulation resistance of the servomotor, disconnect the motor cable from the output terminals of the Economy variable frequency drive

	For variable frequency drive, the insulation between the main circuit and the housing was tested at the factory. The variable frequency drive is equipped with voltage-limiting circuits that automatically limit the test voltage.

Insulation resistance measurement of the motor and motor cable

Check the insulation of the mains cable before connecting it to the variable frequency drive. Follow the local regulations. The following points must be observed when measuring the motor and motor cable:

►Check that the motor cable is connected to the motor and disconnected from the output terminals U, V and W of the economy variable frequency drive.

►Test the insulation resistance between each phase conductor and the protective earth (PE) with a voltage of 1000 V DC.

The insulation resistance of a motor must be more than 100 MOhm (at 25 °C / 77 °F).
Moisture in the motor housing reduces the insulation resistance.

►If the motor is damp, dry it and then measure it again.