Eliminated from:
8400 StateLine, HighLine and TopLine: FW version >= 13.00.00.00
Response of the new version?
The brake chopper threshold is adapted to the setting of the mains voltage in C173.
Which products are affected?
Inverter Drives 8400 StateLine, HighLine, and TopLine up to the firmware version 12.01.00.00
Only 400V devices: E84AVxxxxxx4
What happens?
The brake chopper is not switched on at the expected DC-bus voltage-threshold, but is always fixed at 725VDC, irrespective of the setting in C173.
If the AC-voltage is above 513V, the brake chopper may be activated permanently. The temperature contact of the brake resistor is triggered.
When does the problem occur?
In the case of 400V inverters with a motor that works in generator mode and a connected brake resistor. In addition, an offset of the default brake chopper threshold of 725V must be set in C173. For the operation on AC systems higher than 400V, the nominal mains voltage is set in C173. Now an automatic increase of the brake chopper threshold is expected, which, however, does not occur.
Diagnostics options?
Diagnostics of the DC-bus voltage when the brake chopper is active and the brake chopper threshold is changed via C173.
Short-term measures/recommendations?
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Evaluation:
If the inverter is actuated on a 500V system, the internal brake chopper cannot be reasonably used, since, from 2.6% of the positive mains tolerance, the brake chopper would be activated permanently.
With recommended wiring, overheating of the brake resistor should be prevented by opening the mains contactor through the temperature contact at the brake resistor.
