Bad dust collector motor?

Bad dust collector motor? · 08-10-2009, 04:19 PM

Hi all,

My 5 year old 1 1/2 hp 110v ShopFox dust collector has gone on strike. I went to shut it off yesterday - flipped the switch - and it stayed on. This has happened before so I assumed the switch had gone bad. I had a new replacement switch in the shop so I took out the old one and put in the new. Nada, nothing, zero, zilch. Unfortunately I am quite electro-phobic and replacing a switch exhausts my knowledge of motor mechanics. A friend came over with a machine (ohmmeter?) and checked the old and new switches - both are fine. We took out the starter capacitor and it checked out fine too. The impeller is moving freely. I guess that leaves the motor as the source of the problem. ShopFox wants $150 plus shipping for a new one. I think I'd rather take the motor to an electric motor shop and see if they can fix it. Before I do...... does anyone know of anything else that could be causing this problem?

Thanks,
Ernie

Mike Davis · 08-10-2009, 05:03 PM

I never heard of one staying on being the problem.

I really don't see how a motor can run with the power turned off.

How did you turn it off to work on it?

ErnieM · 08-10-2009, 05:30 PM

Mike - that's just it - the switch wouldn't turn the power off. I unplugged the machine to work on it.

Ernie

froglips · 08-10-2009, 05:31 PM

Since the motor still runs with the switch off sounds like maybe some sort of grounding or short (or that other thing I can't remember).

I'd be worried there is a wire between the switch and the motor that is conducting electricity when it shouldn't be. A nice loose wire doing something weird. If the motor is working, which it sounds like it is, I'd guess the problem is in the wiring between the switch and the motor.

You'd want to be careful with that, as there could be live current in places you really don't want it.

Tracing that could be a bit of fun, but something doable by an electric motor repair place or a local auto mechanic.

I mention this, as a new motor might not fix it if there is a loose wire elsewhere. It doesn't sound like your motor is shot so thats $150 spent that might not fix it.

Hope this helps, it always fun when electricity is involved!

Jim

ErnieM · 08-10-2009, 05:36 PM

Since the motor still runs with the switch off sounds like maybe some sort of grounding or short (or that other thing I can't remember).

Jim - Actually, the motor is not running. After replacing the switch, it wouldn't run at all. Before replacing the switch I could turn it on/off by plugging/unplugging it. I've tried two different switches that both check out ok but the motor will not start at all.

Ernie

froglips · 08-10-2009, 05:45 PM

Sounds like you need to build a treadle dust collector then :-p

Have you checked with your friends meter if power is getting to the motor?

I'm new to learning how to use my meter, so I'm always walking around testing things (if I am not on the board for a few weeks, you can guess what happened).

Jim

Glennbear · 08-10-2009, 08:55 PM

I am by no means an electric motor expert however at one time I rejuvenated a similar motor by an ample blasting of compressed air followed by a dosing of electronic contact cleaner (Radio Shack or NAPA). Being mounted on a dust collector the motor has had ample opportunity to accumulate gunk on the centrifigual switch. The procedure I used was of course done with POWER UNPLUGGED and time allotted for solvent flash off before repowering.

McRabbet · 08-10-2009, 09:54 PM

With the unit clearly unplugged, I would check the wiring in detail. It could easily be a bad wire coming out of the switch or in the motor. If the motor has brushes, check them, too. Glenn's suggestions are good as well.

ErnieM · 08-11-2009, 12:11 AM

Thanks to all for your suggestions. I realize even more than I did before that I'm in way over my head. After a call to ShopFox tech tomorrow, I'm going to take the motor to a pro and have it checked out. ShopFox wants $180 including shipping for a new motor but Amazon sells the entire machine for $280. It may be decision time.

Ernie

scsmith42 · 08-11-2009, 09:53 AM

Ernie, troubleshooting you problem should not be that big of a deal for anyone with a good grasp of electrical principles.

Based upon your original problem, it does not sound like you need a new motor. What you probably have is a wiring problem somewhere between the motor, the switch and the plug.

I wish that we were closer; I'd stop by with a volt-ohm meter and help you figure it out.

If I had to guess, you have a defective neutral wire and your motor was using the ground to complete the circuit, and keep on running. I'd also guess that the original switch, rather than being wired in the hot line was wired in the neutral circuit, which is why the unit would not shut off. This is purely a SWAG though.

Have someone verify the circuitry between the switch and the motor, and the switch and the plug before dropping the coin on a new motor (unless you're really just looking for an excuse to upgrade!)

Do we have any NCWoodworkers near Ernie that understand basic electricity and have a volt ohm meter?

Scott

ErnieM · 08-11-2009, 11:39 AM

If I had to guess, you have a defective neutral wire and your motor was using the ground to complete the circuit, and keep on running. I'd also guess that the original switch, rather than being wired in the hot line was wired in the neutral circuit, which is why the unit would not shut off. This is purely a SWAG though.

Have someone verify the circuitry between the switch and the motor, and the switch and the plug before dropping the coin on a new motor (unless you're really just looking for an excuse to upgrade!)

Do we have any NCWoodworkers near Ernie that understand basic electricity and have a volt ohm meter?

Scott - Thanks for your reply. What you say makes sense - even to an electrophobe like me. I've e-mailed my local woodworkers club to see if anyone near me can help with the diagnosis.

Ernie