Rockwell Automation 7763 Medium Voltage OneGear SMC Flex Motor Controller (10-15 kV) - Manual (Page 51)

Rockwell Automation Publication 7760-UM001D-EN-P - October 2014 51
Commissioning Procedure Chapter 2
Insulation may be tested from phase to phase and phase to ground. The
recommended level for AC HI-POT testing is (2 X VLL) Volts, where VLL is the
rated line-to-line voltage of the power system. The leakage current may be
recorded for future comparison testing, and must be less than 40 mA.
If a Megger is used, it should indicate 50 k megohms or greater if it is isolated as
explained in the next paragraph. If the motor is connected, the Megger should
indicate 5k megohms or greater.
It is recommended that the Main and Bypass switches be in the open position,
and that the input and output cables be disconnected for each phase. If an
earthing switch is provided, it must be open. This will ensure the unit is isolated
from the line, earth and the motor. The line and the motor may be tested
separately to locate problem areas.
After completing the test, remove all semiconductor jumpers and test the devices
with a multimeter to ensure no damage has occurred from the insulation test.
Reconnect the system as it existed prior to this section. Perform the power supply
and resistance checks in the following sections.
ATTENTION: Solid-state devices can be destroyed by high voltage. Use jumper
wires between line and load terminals above the power poles to short out the
SCRs before applying high test voltages to the power circuit. Disconnect ground
wires from the voltage sensing board and remove the plug connector. If voltage
transformers are present, remove one primary fuse from each device.
ATTENTION: Use caution when performing the HI-POT or Megger Test. High
voltage testing is potentially hazardous and may cause severe burns, injury or
death. Where appropriate, the case of the test equipment should be connected
to ground.
ATTENTION: Failure to reconnect all wires and cables correctly may result in
equipment damage, personal injury or death.