Coleman fan humming no spin

[Lothlorian]

The AC fan is humming and not moving when I turn it on. If I spin the cage and turn on the fan it works great. The shaft of the motor spins freely. Again when the cage is stopped the fan just humms. When I spin the cage which moves freely and turn on the fan it works great. Does the fan have its own capacitor? could that be the problem?

Brian

[SeeMore]

Most likely the brushes in the motor are worn. Replacing the motor is not too difficult. Here's a YouTube how-to for a Coleman. It may not be a match for your unit but the process is the same:

https://www.youtube.com/embed/doJ_oD18lZs

[Lothlorian]

Thanks for the info

[damonbeals]

Check your start and run capacitor. The motor won't start or run if it's bad.

Damon

[HiHoAgRV]

The fan in my AC does have a start cap, that sounds like what is wrong with yours. I just bought a new compressor start/run cap at my local electrical parts house for $15, it solved my problem.

Cool...

[68 TWind]

I think Vernon is correct. It sounds exactly like a bad capacitor to me. The cap gives the fan motor an extra surge of current during the start mode. By spinning the fan you are getting it going. The fact that it runs fine after you spin it to get it going it indicates to me that most likely it is a bad capacitor. I had a table saw that did the same thing recently and a new cap fixed it. CAUTION: Capacitors can hold a big charge so short between the terminals with an insulated screw driver to discharge any stored charge before you try and it out. Do make sure you replace it with the correct one, the voltage and microfarad numbers should match. Older Armstrong AC's like the one on my 68 have a separate capacitor for the fan motor and the compressor, yours may have a combination cap that serves both.
I'd check for a local HVAC supply house as they will have a large selection. Take the old one with you. Most likely be cheaper than getting it from a camper supply place.

[Lothlorian]

Thanks a bunch. I a will get on it tomorrow.

Brian

[Lothlorian]

OK here is what I know. All my capacitors are OK had them checked by AC technician. I put oil in the oil port on the motor. The shaft of the motor moves freely. With all that this is how it works. The blower will not run unless I help it with a twirl with my hand. After I do that the blower works. It runs great, but when I try to turn it on cool the Motor stops and the breaker switch kicks out. The AC technician thinks it is my blower motor that needs to be replaced. The other technician told me to run the fan for hours because some times it works itself out.

Does anybody have any ideas

[jdalrymple]

Sounds the entire unit is shot.

The fan motor probably has a bad start winding. Some motors have two separate copper wire windings. One is a start winding; it is the circuit the capacitor adds power to to help the motor start without overloading the breaker. The motor also has a run winding that stays powered on to spin the motor.

With your description the start winding is bad, so when you spin the motor it takes off and runs but can't start on it's own.

If the breaker trips when you try and start the compressor, it sounds as though the compressor is locked up.

A wild a$#ed guess is that the fan motor failed and the compressor ran until the coils froze up. Then, the overload protection didn't stop the compressor before it ran overpressure and locked up.

But, that is just a guess.

Good Luck.

Regards,

JD



Regards,

JD

[perryg114]

Make sure the compressor is working and the coils are getting cold. If it is working then get a new fan motor. They are not cheap $150. My old Coleman could have been fixed but by the time I fixed all the broke stuff I would be a long way toward a new unit and that is what I got.

Perry

[HiHoAgRV]

Pull the leads to the fan motor and see if the compressor will start. If it does, DONT run it for very long! The head pressure on the compressor will quickly build and bad things start to happen. If it does start, I would give it one last chance by looking for a cheap used fan motor.

That's what I'd do but then again I like trying to save stuff from the bone yard.

[jdalrymple]

HIHO,

I like your theory too.

It could be the fan motor is shot and running over current.

Then the added load of the the compressor trying to start puts total draw over the limit of the breaker.


Regards,

JD

[Lothlorian]

I borrowed a generator with a 30 amp plug. Everything works fine except the fan needs a twirl and when I turn it on and everything works. Capacitors are all good because I had them checked. It is the motor, but it does have oil ports and I oiled them. No go with the motor starting without help... I read that the motors with oil ports can be rebuilt, but I called four places and they said nope we don't to those types. I guess I have to buy a new motor and it will have to be with three brackets on it.

The best deal I found is a FASCO from Canada. I will call them see what it will come to. $168 from my local RV place. I would like to get it cheaper.
Thanks folks for your help

[NavyCorpsman]

If the caps are good, the motor is probably finished.

[garry]

I would buy a new start/run capacitor and try it first. Least expensive option.

The capacitor provides a phase shift that last only a fraction of a second to kick start the motor and can test good (not shorted or open) depending on what device it is tested with.

If you decide to do this take your old one with you for an exact match.