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#193952 - 04/30/10 10:03 PM Wye Delta Start Closed Transition
DYNAMITE Offline
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Registered: 12/22/03
Posts: 36
Loc: Winkler, MB, Canada
Would anyone know how to size the resistors on a Wye start/delta run closed transition starter? Say for a 50 Hp 230V motor?
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#194021 - 05/05/10 01:48 AM Re: Wye Delta Start Closed Transition [Re: DYNAMITE]
Scott35 Offline

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Registered: 10/19/00
Posts: 2707
Loc: Anaheim, CA. USA
I believe the Resistors would be sized ("size" = Resistance value - in Ohms), so as to allow the same level of Current that the "Wye" configuration does.

Example:
Motor's FLA = 130 Amps
Starting (Wye Connection) Ampere = +/- 75 Amps
Resistors are sized to allow +/- 75 Amps at rated Voltage.

I am not 100% sure on this, so let me find some references, then reply back.

Scott
_________________________
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
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#194026 - 05/05/10 08:54 AM Re: Wye Delta Start Closed Transition [Re: Scott35]
DYNAMITE Offline
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Registered: 12/22/03
Posts: 36
Loc: Winkler, MB, Canada
That makes sense to me. The smaller you make them the closer to normal current you have. The next question is Watt ratings. The resistors are only in the circuit for a split second in the transition between wye and delta so would you need full power ratings(Peak I^2 R) on them?
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