10KV Delta Power Supply vs Star Connected Motor

[macmckim]

Have a plant with a incoming 10KV Delta power supply. The motor has a Wye winding connection.The difference between Delta and Wye is in the voltage between the phases and neutral. It was my understanding that if the plant provided a 10 KV Delta feed and the motor was wired for a Wye feed, that the motor would actually see a different voltage than 10 KVA. Wye also has a neutral wire while Delta does not. Any explanation of what the connection types might mean to the motor?

 

[RRaghunath]

macmckim,

Don't worry, whether the source is star or delta connected. If the motor is 3-phase and is receiveing 3-phase power supply, it is going to work fine.

The motor may be delta connected or star connected depending on its rating. The star point in motor winding is not connected to earth.

 

[ScottyUK]

You might want to check how, or if, the delta supply is grounded.


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

One day my ship will come in.
But with my luck, I'll be at the airport!

 

[aolalde]

macmckim:

Electric motors are wound to operate on watever way the substation transformers are connected. There are no such a thing as motors winded for wye or delta transformers.

The only matching required is the voltage line to line and the frequency of the system.

Some motors of large size have the neutral terminals out to allow the connection of differential protection. Normally the user must specify that requirement to the motor manufacturer. The other type of six leads construction is for dual voltage possibilities ( use the connection that matches your power supply) or for wye start--delta run application.

 

[macmckim]

thankyou for your comments gentlemen. You confirmed my thoughts on the matter. I am dealing with a mainland China group that has been going around in circles on this issue and communiation at the best of times is difficult with them.

 

[jraef]

Any 3 phase motor can be designed with the internal connections to be Y or Delta, depending on what the designer's criteria were. Usually, permanent Y connections inside of the motor are used for dual voltage motors when the voltage difference is 1.732:1, for instance 4000/2300V. The same windings are connected in Y for the higher voltage, Delta in the lower voltage. Maybe yours was originally designed for a Part Winding start, because otherwise I'm not sure why a 10kV motor would require a Y connection (I've never heard of 5800V), but then again I'm not a motor designer. Some others in this forum are, maybe they can enlighten us.

As rraghunath said though, it has nothing to do with how the line power source is derived. That is a separate issue that is irrelevant to the motor.

"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more." Nikola Tesla
Read the Eng-Tips Site Policies at faq731-376
Member, [blue]P³[/blue]