Need Electrical help

[10es&]

I know almost nothing about electricity and have an electrical problem any help would be much appreciated!

Here is the problem, the fan motor for my shop heater is getting HOT and tripping the breaker but the gas burner keeps going.
After it trips the breaker I can reset the switch and the fan will work for an hour or so, enough to cool down the heater (thank God).

The heater is pretty old and was here when I bought the house so I don?t know the age or history?But I have put many hours on it since purchasing the house and never had an issue until yesterday.

So do I just purchase a new motor or is there a possibility that there is a bigger issue???????

Thanks Brett

[Doug Lester]

I think that this is a place to call in an electrician because the answere to you question is, yes the heater's fan motor could be shot or there could be more going on. Whatever it is, you have a problem. Circut breakers should not be getting thrown on a regular basis.

Doug Lester

[reefera4m]

First and foremost - Do not continue to run a motor that gets hot and trips the circuit breaker. Eventually it will short out and possibly start an electrical fire.


Motor overheating and a circuit breaker that trips are an indication of excessive amp draw by the motor. In my experience there are several things that can cause your problem, the most common being dirt/dust build-up in the fan or motor. Dust and dirt can cause the fan and/or motor to drag, increasing the amp draw on the motor and causing the breaker to trip. Another common problem is dry, dirty or warn bearings with will also cause a drag on the motor, increasing the amp draw and tripping the breaker.

The first step I would take is to isolate the problem ? is it a sticky/dragging fan or is it the motor. Turn the electricity off and disconnect the fan from the motor , and turn the fan by hand (if the design permits). If the fan turns freely and easily, check the motor. Even if you can?t disconnect the fan, turning it by hand with the motor and electricity off should give you a good idea indication if is dragging. Next, if you can disconnect the fan from the motor, briefly turn on the motor and see if it runs freely without the fan.

If you can?t disconnect the fan then I would still treat it first ? if the motor is bad it won?t make a difference but if the fan is the problem fixing it will protect the motor.

I will assume that since you've put many hours on the problem you've already cleaned the fan and motor. If not that would be my first step ? continued operation of a fan that?s dragging will eventually burn up the motor. I use a vacuum first then compressed air to blow out and dust and dirt from the fan and motor. Dust/dirt that blocks the air circulation, which cools the motor, will cause it to overheat and trip the breaker. It will soon shorten the life of the motor.

Next I would try lubing the fan and motor bearings if possible. If the fan and/or motor have lube ports (usually small tubes with colored caps), then I would apply some good machine oil or compressor oil in the bearings. Even if they don't have lube ports you might try dripping a little oil on the bearings, both fan and motor.

On some fans and motors it is possible to replace the bearings, most likely are they won?t be replaceable. And it is not cost effective to re-build small electric motors these days so you may have to replace the motor or fan/motor unit.

Again, Do Not continue to run a motor that gets hot and trips the circuit breaker.

[Crex]

Most all small fan motors like that aren't worth rebuilding as the bearings are bronze sleeved. Usually the winding insulation is beginning to break down from age. Easiest and best thing is to do is replace it.
Grainger's probably has a match in stock. You might have the motor amp draw tested and the breaker checked out as well. Continual tripping wears on it and it will start tripping at a lower ampeage.

Reefer's last piece of advice is dead on.

[10es&]

Guys, thanks for the information!!! I really appreciate you taking time to help me out!

The motor is completely enclosed there are no air vents at all so I could not ?blow it out?. The motor is a direct drive to the fan and spins very freely. I did not separate the two since the initial hand spinning was good.

There were two ports to oil the bearings and I have not oiled them in the last year so I did do that today?.

The total number of times the breaker tripped is three times but since the motor is getting so hot I am pretty sure it is the motor and not a wiring issue.

Since there is no real way to service this sealed motor I now think it is probably best to just replace it. It can?t be more than $50 -$100 and nothing last forever?

Thanks again for the help if there are any more ideas I?m all ears.

[ARCustomKnives]

Are you running the fan on an extension cord? Try plugging directly into an outlet if so. Sometimes a long extension cord will cause what ever is plugged into it to draw too many amps and trip breakers or over heat while under load. The same concepts apply if it's hardwired. Make sure the conductors are of proper gauge, and not excessively long.

Also, if you can, double check the electrical connections of the power cord to the motor (while unplugged, or with the breaker off of course) and make sure they are solid. Check that the prongs on the plug are tight in the outlet as well if it's not hardwired. Some times loose wires/connections can also generate heat or draw excessive current.

Hope this helps.