RST FRC-F Series, Manual

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9.581.140-6
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2.13 Mains feedback
Three-phase commutation reactors (NEDs) must be provided between the mains and the frequency
converter to reduce the low-frequency mains effects.
2.14 Energy recovery
Motor protection switches on principle do not suit a VVVF-controlled elevator drive and should
therefore not be applied.
To optimize any potential mains feedback, in particular if group drives are used, we recommend the
use of three-phase commutation reactors. These are available at RST Elektronik upon request.
2.15 Reactive current compensation
If capacitors compensating reactive current were connected directly to the motor connectors, they
would destroy the VVVF controller, as due to the high switching frequency of the transistors a would-
be short circuit would be created.
Reactive current compensation, if at all, is to be executed at the mains connection of the building, but
never in the machine room.
3 Warranty
As for warranty please refer to our General Conditions. Demands going beyond these conditions are
subject to a special agreement.