198 Rockwell Automation Publication 7000-UM202D-EN-P - May 2018
Appendix E Insulation Resistance Test
4. Test the drive.
All three phases on the line and machine sides of the drive connect
through the DC Link and snubber network. Therefore a test from any
one of the input or output terminals to ground will provide all the
sufficient testing required for the drive.
a. Connect the insulation resistance tester to the drive, following the
specific instructions for that model.
b. If the test has a lower voltage setting (normally 500V or 1000V),
apply that voltage for 5 seconds as a precursor for the higher voltage
rating. This may limit the damage if you forgot to remove any
grounds. If the reading is very high, apply 5kV from any drive input or
output terminal to ground.
c. Perform an insulation resistance test at 5 kV for 1 minute and record
the result.
The test should produce a reading greater than the minimum values
listed below. If the test results produced a value lower than these
values start segmenting the drive system down into smaller
components and repeat the test on each segment to identify the
source of the ground fault. This implies isolating the line side of the
drive from the machine side by removing the appropriate cables on
the DC Link reactor.
You may need to completely isolate the DC Link reactor from the drive,
at which point you must disconnect all four power cables. You must
ensure that you have electrically isolated all electrical components to be
tested from ground.
Items that may produce lower than expected readings are surge
capacitors at the motor terminals, motor filter capacitors at the output
of the drive. The testing procedure must follow a systematic
segmentation of electrical components to isolate and locate a ground
fault.
IMPORTANT Verify the drive and any connected equipment is clear of personnel and tools
prior to commencing the insulation resistance test. Barricade off any open or
exposed conductors. Conduct a walk-around inspection before commencing
the test
ATTENTION: Discharge the insulation resistance tester prior to
disconnecting it from the equipment.
Type of Drive Minimum Insulation Resistance Value
Liquid-cooled drive 200 M Ω
Air-cooled drive 1k M Ω
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