Separate Supply Of The Field-Current Bridge At A High Motor Field Voltage - Lenze 4800 Manual

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Installation
4.3.2 Separate supply of the field-current bridge at a high motor
field voltage
Stop!
Ensure correct phase connection of the separate field supply.
Incorrect connection leads to blown fuses.
The phase shift of the voltages from the power stage to the control electronics must
be smaller than 2 °(electrically).
To reduce the mains feedback, separate mains chokes are required for the field
supply (chapter 13.2.2).
The fuses F''4 and F''5 are cable protection fuses. They must be matched to the
cross section of the cables used and dimensioned for at least I .
Frated
In weak mains supplier, field-current fluctuations may occur and thus the torque
can be reduced. For rated field voltages V > 210V, we recommend a separate
Frated
supply for the field bridge.
The armature current control circuit and the field current control circuit are
electrically decoupled by an external supply for the field controller with voltage
pick-off before the mains choke.
Remove the wire bridges BR1 and BR2 of the controllers 4902 to 4907 (4902LP,
4903LP or 4905LP) when no voltage is applied. The bridges can be easily
accessed:
1. Open the controller cover (4 mounting screws)
2. Unbolt the 2 mounting screws for the cover of the control electronics
3. Open the cover.
48XX/49XXSHB0399
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