I have a 15 horsepower motor hooked up to 3 phase 480 and it's supposed to be drawing 16 to 17 amps it's drawing 29 and its overheating its controled by relays and goes through a contactor and is on a 30 amp breaker and I don't know what is causing it.do I need to put it on a VFD? Its for a blower in a car wash and it never had anything else before on the motor

 

Is it a dual voltage motor? do you have it wired for 480V?

 

Was this motor replaced because the existing motor failed?

 

I'm almost certain that you have it wired for low voltage when it should be wired for high voltage...Re-do the connections at once for High Voltage! You may have a dual voltage starter, ie: Low Voltage Start...High Voltage Run.

Cheers, DPW [Everything has limitations...and I hate limitations.]

 

I'm almost certain that you have it wired for low voltage when it should be wired for high voltage..

Me too, but I have the uncanny power of changing root cause by expressing absolute certainty. So I don't.

 

it is dual voltage 208 & 460 its got 12 different leads for different combinations of hookups for delta run or delta start wye start to Delta run. I'm a state certified journeymen electrician an inside wireman with the International Brotherhood of Electrical Workers I'm confident in my abilities to know that its hooked up correctly(not said in athe one who replaced was doing the exact same thing and tripping the breaker

 

Have you tried running it unloaded?

 

Ok lets have the pictures of it then and a model number..

 

Havent tried to run it unloaded but its only a mechanical blower and I can spin it with my hand but I will take pictures soon as I get back to that site thank you all for your help

 

Perhaps you somehow lost a phase. Have you checked the current in all three phases?

 

it is dual voltage 208 & 460 its got 12 different leads for different combinations of hookups for delta run or delta start wye start to Delta run. I'm a state certified journeymen electrician an inside wireman with the International Brotherhood of Electrical Workers I'm confident in my abilities to know that its hooked up correctly...

So, how is the motor started, across the line?

 

Have any shrounds, etc. been removed from the blower and not replaced. An increase in the intake size of a blower can cause higher loads on the motor. Listen to the motor on a vacuum cleaner when you restrict the air flow. Motor unloads and speeds up.

 

no shrouds have been removed from it the old motor was doing the exact same thing figured and decided to replace it

 

no shrouds have been removed from it the old motor was doing the exact same thing figured and decided to replace i

Now it sounds like the motor was undersized for the job in the first place.. Any more information?

 

no shrouds have been removed from it the old motor was doing the exact same thing figured and decided to replace i

Now it sounds like the motor was undersized for the job in the first place.. Any more information?

Not yet, the tread is only two pages. To early to spill all the beans.