# 15 hp motor high amp readings



## garfield (Jul 30, 2009)

I have a carwash blower motor that is puzzling me. It's a 15 hp motor 208-230/460 that runs for 1 minute at a time every 5-6 minutes when busy. On 214 volts it's running a little over 60 amps on each leg. This seemed out of line and the overloads didn't like it either. I was wondering if the motor wasn't producing the torque it needed to get up to full speed at this voltage. I then got a transformer and hooked it up to 492 volts, retapped the motor and it was 16 amps per line which is fla for the motor. I thought... well I figured that one out. Then I check the other 2 motors and they are running 26 amps per leg on 214 volts. These are used blowers that have just been installed at this location.


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## hhb480 (May 16, 2015)

Agree amps is too high when tapped at low voltage should be somewhere around 45 amps fla 
But the amps are where it should be at 480 volts. We're the terminations correct when it was tapped for low voltage? Or possibly a bad connection. I would have megged it to test windings maybe motors no good


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## garfield (Jul 30, 2009)

It megged infinity at 1000 volts. It was tapped properly.


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## Cow (Jan 16, 2008)

Are the blower fans direct drive or do they use pulleys/belt? Are they sized properly?

Is EVERYTHING exactly the same across all three blower setups? 

If you've got good solid voltage tested right at the motor connections, I'd be inclined to tell them to get another motor.


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## JRaef (Mar 23, 2009)

Assuming these are EXACTLY the same motors and blowers.
On the one that is running high, is there possibly a blown out duct seam? Or was there supposed to be a guide vane on the inlet that didn't get hooked up right or is missing? Blowers like those used in car washes are centrifugal, which means load increases with flow. If the blower was DESIGNED to provide a specific amount of flow, and restrictive devices like vanes are part of the original design, then removing them or having them not work can result in TOO MUCH flow from the blower, which increase the load on the motor and it overloads. The same holds for a blown out duct seam. I've seen that in car washes, because the duct corrodes and the seams split, so more air flows, the motor overloads.


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## hhb480 (May 16, 2015)

I do electrical in the oilfields of South texas at each facility they have flares which burn the h2s gas coming from the well at the bottom of the flare there is a blower which just blows straight up the stacks on the blower there's always a flute where you can restrict the air flow into the blower have found out if flute is wide open the motor is high on current and trips overloads we usually set them half open and motor runs correct point being not sure if you if there is any thing where you restrict air flow or allow more air in might just need to reduce some air flow going into blower


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## hhb480 (May 16, 2015)

Sorry for my lack of punctuation/writing, hope it made sense.


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## garfield (Jul 30, 2009)

I'll look and see if there are veins but I don't think so. What would explain the higher voltage bringing the amps back to normal? I guess I could try tapping the transformer down to put out just double the 214 so 428 volts and see if the amps stayed high relative to the voltage. I also thought about hooking it to a drive and seeing if it faulted out. The amps are like 61 63 64 and any time I've seen a bad motor they aren't even close. To my untrained eye the blower wheels and housings look identical. The motor has two leads that have the metal tags on them and are a different color making me think it's been rewound at some point.


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## micromind (Aug 11, 2007)

Since the only change appears to be the addition of a transformer and re-connection of the motor, I doubt if the issue is mechanical. 

A 15HP motor is commonly wound either ∆ or Y. Assuming 9 leads, the high voltage connection for both types is the same, but different for low voltage. It's possible that the motor was re-wound and the nameplate connection is no longer correct for low voltage, but is correct for high. 

Since this is a new installation, miswiring certainly is a possibility. 

The way to find out is to ohm the windings and determine if it's Y or ∆ and connect accordingly.


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## garfield (Jul 30, 2009)

Cow said:


> Are the blower fans direct drive or do they use pulleys/belt? Are they sized properly?
> 
> Is EVERYTHING exactly the same across all three blower setups?
> 
> If you've got good solid voltage tested right at the motor connections, I'd be inclined to tell them to get another motor.


Blower fans are mounted to the shaft of the motors. They are oem motors and I think they are all the same.


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## garfield (Jul 30, 2009)

Well after ohming out the motor two of the leads were labeled wrong and all was normal. Thanks everyone for the help. I thought micromind had it pegged when i left the shop this morning. At least we didn't already get a new motor.


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