Delta v. Wye and Equipment wear

[dedshort]

I have a 40hp motor that I plan to operate on 480v.
The name plate calls for a delta connection. My service options are 277/480 Y,. or 480 Delta (B phase grounded)

1. Will operating the motor using the 3 hots of the Y system have any adverse effects on the motor? (this will allow for lighting to run on 277 and eliminate the need for a step down xfmr.)

 

[davidbeach]

Three wires out of a black box and there is no way of telling whether the source is delta or wye. Your motor would join millions of motors connected delta to wye systems.

 

[waross]

Davidbeach said it. Use 480/277 V and 277 volt lighting.
respectfully

 

[isquaredr]

If connected in y would that not effect the available torque produced by the motor compared to being connected in delta.

 

[ScottyUK]

The motor requires 480V. It doesn't know or care whether the source of the supply is star or delta: the supply is still 480V across the lines. You are confusing the characteristics of the supply with the connection of the motor windings.


----------------------------------

Sometimes I only open my mouth to swap feet...

 

[isquaredr]

ScottyUk
I will read the question correctly next time before jumping in.
I guess it was beacause 480 delta is not an option here in the UK so I assumed dedshort was talking about the motor connection.

 

[dedshort]

Thanks for the responses... found out what I want thru some other searches.

My concern was in regards to losing a leg and weather I would loose power to the entire motor v. a weakend voltage.

 

[JBinCA]

ScottyUK was correct, a delta motor will operate fine on a system.

Phase loss is a concern for motors, but is one that is typically ignored due to economics for motors in the 40 Hp range.

Regards,

JB

 

[alehman]

The motor will have equally limited capacity (very close to 0) with one phase out, whether the source is wye or delta.

 

[JBinCA]

When one phase of supply is lost to a delta motor, opens the circuit for two of the three internal phases, and onl leaves one powered.

That remaining phase cannot develop a rotating magnetic field, only a pulsating one. I believe that rotation can be maintained if the motor is very lightly loaded when the phase loss happens, but can not be started.

At any rate, the motor will draw significant current in the circuit of the intact phase and produce little to no usefull work in this condition.

Regards,

JB

 

[alehman]

An induction motor with one phase out will drive (not start) significant load for a time, but it will overheat in short order if there is any significant load.

 

[controlsdude]

I thought you would always get single phasing in a wye connection or the motor would overload. But in a delta connection you would lose square root of 3 of the power??