Vacuum Experts?

Hello all!I'm wondering if there is anyone on the forums who knows a little about vacuums/electric motors. I've got a Hoover Runabout that stopped working a while ago. Just went into the repair shop and got a new switch for it (they tested the old one and confirmed that it wasn't working). I installed the new switch, and the vacuum is still not working right.When I turn it on, it will sometimes run for about a second before kicking back off, and then refusing to start at all again. I've tried tinkering with the magnets (I think that's what they are) and cleaning out the motor, and still no luck. Occasionally after tinkering with it the thing will 'work' againrun for a second then kick offbut nothing solid so far. I really cannot afford a new vacuum, and would hate to have to now go buy a used one, since the switch was $10, and I could have bought a used vacuum for that price. If anyone has any suggestions, they'd be appreciated!Thanks,
Jon

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Sounds like a possible short.
I am not a vacuum cleaner tech, but usually episodic performance means a short circut. That could pose some difficulty in tracking down in a motor as it could occur internally in the windings.Another possible is sometimes large electric motors have a Start capacitor. If that goes bad it may not start. But tracking a cap down plus shipping can get pricey.Scrap it and buy another used one till it dies.
Or run the risk of electrocution and or buying pricey parts only to end up in the same boat.

Thanks for the reply!What gets me is how the old switch could have gone out as well. The switch pretty much controls the power flow into the motor, so I would be a little surprised to find that a short inside the motor could damage the switch, but maybe that's how these things work... JonABE:I just found out that I can kick it into running by spinning the shaft manually while the switch is in the on position. It then will run for a second and kick off (along with creating a light show). I cannot smell anything burning near the motor when I do this.Edited by Jon, : ABE

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Everything has a wear cycle. Somethings just get used up and need to be replaced. I am all for saving money so I usually attempt to repair. Sometimes Im lucky and fix the problem with ease and little investment. Others I find myself spending for pricey parts and to no avail. Its a crap shoot.But do know if a switch goes bad all other components under load are due for failure too. It may be as simple as time for a new motor.
I can guess its a short, or cold solder joint gone bad somewhere.
Cant hurt to poke around. Just ground out any CAPs and use a pencil when doing the probing.

As far as I can tell there's nothing fancy in the motor. It's just a bunch of copper wires running around a shaft.

If you can find a large cylinder looking thing somewhere in the motor, that may be a start capacitor gone bad. BE VERY CAREFUL if you find one because it stores lots of amperage and can zap the shit out of you. You must discharge the cap. Google how.If it is bulged or distorted it may be bad. Look at the stuff written on it. may have something like 110v 35mfd or something like that. If you find a large Start cap buy a replacement and replace.
Caps cost about 5 to 8 bucks. Find local for no shipping or your out another 8 bucks. See how fast this shit adds up.

Hi , it is more than likely the brushes, or rather where they make contact is wore out, not much you can do about that. If the motor isn't that old then it probably a short in a winding, most motors do not use permanent magnets. I cant think of any vacuum size motors that use a starter cap. I often have to deal with motors on pumps...ect. Sorry I cant be anymore help Where these copper wires attach to shaft is where brushes make contact., if you look close you might see where a grove has been made by the brushes, they are pieces of carbon, not brush-like. Edited by fearandloathing, : No reason given.

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"I hate to advocate the use of drugs, alcohol, violence, or insanity to anyone, but they always worked for me." - Hunter S. ThompsonAd astra per aspera

Do single-phase AC motors have brushes?I don't think he has a short; I think a bearing has seized and the motor is drawing so much current it's tripping some kind of GFCI.

Yes, you would need permanent magnets to have a brush-less motor.If a bearing was seized you wouldn't be able to turn it easily, I don't know how easy it is to turn by hand.Throwing sparks is usually brushes, or rather where they make contact.Edited by fearandloathing, : No reason given.

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"I hate to advocate the use of drugs, alcohol, violence, or insanity to anyone, but they always worked for me." - Hunter S. ThompsonAd astra per aspera

Thanks, fearandloathing; I did a little research, and the things I thought were 'magnets' are actually the brushes you're talking about.I checked them some more, and they don't actually make full contact with the shaft; and you are right, the shaft is worn where they are supposed to contact. Shouldn't there be a way, though, to adjust them so that what is left of them can contact the shaft? It seems a waste to have to replace them when they still have so much material left on them if only they could be moved closer to the shaft.Jon

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Induction motors don't have brushes or permanent magnets because the rotor is energized directly by EM induction. Clever design; Tesla invented it, natch.Most AC motors are induction motors, but I don't know if you can have a single-phase AC induction motor. Oh, now that I look it up, you can - shaded-pole induction motors are one such type.

Induction motors do not have brushes. AC/DC motors do have brushes. The vacuum cleaners that I have examined use AC/DC motors. The "light show" that Jon mentioned suggests brushes.

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I don't know if you can move where the brushes make contact? I am by no means an expert. I only know how to trouble shoot what I deal with in plumbing. I know of induction motors an brush-less ac motors that use perm. mags, but I don't think I have ever had to work on or replace one.My previous post were not exactly accurate, I only answered based on my limited knowledge of what I encounter without having researched it.Edited by fearandloathing, : No reason given.Edited by fearandloathing, : No reason given.

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"I hate to advocate the use of drugs, alcohol, violence, or insanity to anyone, but they always worked for me." - Hunter S. ThompsonAd astra per aspera

NMR schooled us both - I'd never heard of an AC/DC motor.A replacement brush set isn't expensive. If they've worn down so that the little springs no longer push them all the way onto the commutator then there's nothing to salvage. They're just little carbon rods anyway. Your vacuum guy can do it, if you still trust him.

Actually, everything you told me was great information! I looked up the brushes on Wikipedia, and the picture they have shows the same thing I thought were magnets (with a few minor differences).

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