Troubleshooting and fault elimination
Operating instructions SVCD(S)
73
123456278
-
419A58
Elektrotechnische Anlagen GmbH
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7
Troubleshooting and fault elimination
The five LEDs in the cover of the power feedback unit display the operating condition.
For easier visibility during service and first powering up similar LED's are placed on the
control board.
Stop!
If the power feedback unit trips during retardation, it must not be reset until the end of the re-
tardation and until the DC-bus voltage has fallen to normal values.
To avoid any kind of problems you can block the impulse-release of the inverter by connecting
the collective-error-relay-contact of the power-feedback-unit with the corresponding connec-
tion of the frequency inverter.
U
CE
-tripping:
The power feedback unit trips by the U
CE
-protective-circuitry, if the specific maximum
current of the device is exceeded. The principle of this protective-circuitry implies that
for a short time (less than one millisecond) the IGBT is stressed over its specification for
normal operation. For an single case this means no problem for the power feedback unit.
However, if the over current cut off arises often or even periodically, the high power
semiconductors will age very rapidly and fail premature.
The cause of periodical U
CE
cut offs may be over load, under voltage in the network, a
defective or oscillating controller, an oscillating reference input or a wrong design of the
plant.
STOP
