Electrical installation
48
Checking the insulation of the assembly
Drive
Do not make any voltage tolerance or insulation resistance tests (e.g. hi-pot or
megger) on any part of the drive as testing can damage the drive. Every drive has
been tested for insulation between the main circuit and the chassis at the factory.
Also, there are voltage-limiting circuits inside the drive which cut down the testing
voltage automatically.
Supply cable
Check the insulation of the supply (input) cable according to local regulations before
connecting to the drive.
Motor and motor cable
Check the insulation of the motor and motor cable as follows:
1. Check that the motor cable is connected to the motor, and disconnected from the
drive output terminals U2, V2 and W2.
2. Measure the insulation resistance between each phase conductor and the
Protective Earth conductor using a measuring voltage of 500 V DC. The
insulation resistance of an ABB motor must exceed 10 Mohm (reference value at
25 °C or 77 °F). For the insulation resistance of other motors, please consult the
manufacturer’s instructions. Note: Moisture inside the motor casing will reduce
the insulation resistance. If moisture is suspected, dry the motor and repeat the
measurement.
Braking resistor assembly
Check the insulation of the braking resistor assembly (if present) as follows:
1. Check that the resistor cable is connected to the resistor, and disconnected from
the drive output terminals R+ and R-.
2. At the drive end, connect the R+ and R- conductors of the resistor cable together.
Measure the insulation resistance between the combined conductors and the PE
conductor by using a measuring voltage of 1 kV DC. The insulation resistance
must be higher than 1 Mohm.
ohm
M
3~
U1
V1
W1
PE
ohm
R-
R+
PE
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