Cable And Motor Insulation Checks - Honeywell SmartVFD HVAC MR4 User Manual

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4.4.3

Cable and motor insulation checks

1. Motor cable insulation checks
Disconnect the motor cable from terminals U, V and W of the drive and from the motor.
Measure the insulation resistance of the motor cable between each phase conductor as
well as between each phase conductor and the protective ground conductor. The insula-
tion resistance must be >1MΩ at ambient temperature of 68°F.
2. Mains cable insulation checks
Disconnect the mains cable from terminals L1, L2 and L3 of the drive and from the mains.
Measure the insulation resistance of the mains cable between each phase conductor as
well as between each phase conductor and the protective ground conductor. The insula-
tion resistance must be >1MΩ at ambient temperature of 68°F.
3. Motor insulation checks
Disconnect the motor cable from the motor and open the bridging connections in the
motor connection box. Measure the insulation resistance of each motor winding. The
measurement voltage must equal at least the motor nominal voltage but not exceed 1000
V. The insulation resistance must be >1MΩ at ambient temperature of 68°F.
Figure 40.
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OWER CABLING