Danfoss VZH052 Manual page 15

Electrical data, connections and wiring
Soft-start control
Phase sequence and
reverse rotation
protection
The CDS303 frequency converter generates by
design a compressor soft start with an default
initial ramp up of 7.5s to 50 rps.
Current inrush will not exceed the frequency
converter maximum current.
The compressor will only operate properly
in a single direction. If electrical connections
are done correctly between the drive and the
compressor terminals (compressor T1/T2/T3 and
drive terminals U, V & W matching), the drive will
provide correct phase supply to the compressor,
and reverse rotation will be not possible:
• CDS terminal U (96) to VZH terminal T1
• CDS terminal V (97) to VZH terminal T2
• CDS terminal W (98) to VZH terminal T3
If compressor T1/T2/T3 and drive U, V & W
terminals are not matching, the compressor
Basically seen from the mains, the inrush peak
reach a level which is only a few percent more
than the rated nominal current.
can operate in a reverse rotation. This results in
excessive noise, no pressure differential between
suction and discharge, and suction line warming
rather than immediate cooling. The compressor
can be rapidly damaged in these conditions.
If reverse rotation symptoms occur, shut the
compressor down and connect the phases to
their proper terminals.
Mains connection to the CDS frequency
converter order has no influence on the output
phase sequence which is managed by the
frequency converter.
AB237586440343en-000601
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