Wye -Start Delta- Run Motor

[gregorsc]

We have fire pump motor that can be wired wye-start delta run or delta start delta run. Who should determine which way to wire the motor?

 

[coulter]

We have fire pump motor that can be wired wye-start delta run or delta start delta run. Who should determine which way to wire the motor?

Someone who understands the electrical system including the service and the limitations. I am likely considered biased. I would pick your knowledgable engineer and give them all the one-lines.

Y-D start/run motors are usually pretty big for the power system. An example would be a 400hp motor on 480V. It's tough to start. Full load current is up in the 500a range and LRA is in the 2500A range. Y-D is used as a reduced voltage starting method to limit LRA. The few I have seen worked fine.

The decision will be based on the stiffness of the utility and the ability of the plant to stnad the voltage sags caused by the starting current.

With the limited information you have given, no way to give any recomendation other than: If it's available, the motor is probably big enough to need it.

I'm also partial to AB SMC 150 soft starts.

carl

 

[frenchelectrican]

speaking of Fire pumps you may want to check with the local inspectors to see how they want it set up and also you may have to sized the OCPD to the locking rotor current not the running amps.

most fire pumps useally are DOL starting and they useally are ahead of the main breaker of the building electrical system and i think there is pretty strcit issuse how to termatited or use per NFPA code so IMO this is very tricky situation to deal with the starting system.

Merci , Marc

 

[brian john]

Normally (in my expierence) a motor that is to be wye/delta started comes with the starter they are ordered as a package.