KEB COMBIVERT F5 Applications Manual page 15

Error/Message Alt.
(NUM)
Error Over EOP
Voltage (1)
(continued)
Error Under EUP
Voltage (2)
/ Description
The DC bus
voltage drops
below the
permissible value.
For 460V drives,
the under voltage
level is 240VDC
and for 230V
drives, the under
voltage level is
216VDC.
The under
voltage
level cannot be
adjusted.
Cause/Solution/Troubleshoot
Measure DC bus directly and verify against DC bus
voltage read from the CP32. The DC bus should be
approximately 1.41xAC Input phase to phase
If there is an issue due to high frequency noise:
Verify proper mains grounding.
Causes for under voltage include:
Input voltage too low or unstable.
Verify input voltage and wiring. The DC bus should
measure approximately 1.41 x AC Input phase to
phase and should match the DC bus measurement
by the drive in CP32
One phase of the line input is missing.
Line input phases are imbalanced. The phase-to-phase
voltage measurement should not exceed 2%.
Isolation transformer undersized or wired incorrectly.
If there is an issue with the DC bus voltage measurement
circuit:
Measure DC bus directly and verify against DC bus
voltage read from the Diagnostics screen. The DC
bus should be approximately 1.41xAC phase to
phase.
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