QES
Senior Member
- Location
- California
can you use a part-winding motor starter for a wye start delta run motor?
Part-winding motor starter
- Thread starter QES
- Start date
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- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
QES said:
Contactors are contactors, so if you do enough rewiring the answer could be yes. Of course you would need to check the rating of each contactor.
From what I remember, a part winding starter uses (1) 4-pole and (1) 2-pole contactor. but, an open-transition wye-delta would use (2) 3-pole and (1) 2-pole contactor. I know there are other possible wiring diagrams available.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
No, a Part Winding motor starter is specifically for a motor configured for Part Winding (PW) start. Literally, the winding is split in two, so to start it you are connecting only a portion of it, then to run you connect the rest by just adding it in; no transition. There are two contactors, one for each part, and a simple timer.
For a Wye Delta start, you need 3 contactors and a special timer and/or control circuit that changes the wiring pattern of the leads in an open transition (meaning for a moment, the contactors must be open). Plus the motor configuration and wiring is totally different.
There are however, motors with multiple leads brought out to the pecker head that can be configured in the field for either Part Winding or Wye Delta start. The starters are still completely different though.
For a Wye Delta start, you need 3 contactors and a special timer and/or control circuit that changes the wiring pattern of the leads in an open transition (meaning for a moment, the contactors must be open). Plus the motor configuration and wiring is totally different.
There are however, motors with multiple leads brought out to the pecker head that can be configured in the field for either Part Winding or Wye Delta start. The starters are still completely different though.
broadgage
Senior Member
- Location
- London, England
For some reason part winding start is much more popular on large A/C chillers than on other motors, at least in the UK.
All the ones that I have seen have have six leads, connected to two identical 3 phase windings (connected internally in delta or Y )
This arrangement limits the starting current by first connecting one set of windings to the supply, and then after a short delay also connecting the other set.
Such motors appear vulnerable to insulation failure between the two sets of windings, rather than to earth.
All the ones that I have seen have have six leads, connected to two identical 3 phase windings (connected internally in delta or Y )
This arrangement limits the starting current by first connecting one set of windings to the supply, and then after a short delay also connecting the other set.
Such motors appear vulnerable to insulation failure between the two sets of windings, rather than to earth.
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Reeves431 said:
Huh, strange. I answered this a while ago and it didn't show up...
Yes, you can use a soft starter. Just run all 6 leads to the soft starter and connect the two windings in parallel. Make sure the soft starter is big enough, i.e. don't go by the size of the contactors because each one is only carrying a portion of the load. Use the motor nameplate FLA to size the soft starter.
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