Help With Reassembling Basic 110 VAC Motor

[budm]

Re: Help With Reassembling Basic 110 VAC Motor

According to OP, it is 2-prong AC plug.

[Used_Cars]

Re: Help With Reassembling Basic 110 VAC Motor

I've been traveling all day and my brain is fried. I read all the posts and will get into the details of them all tomorrow.

Usually wet/dry shop vacs use a 3-wire cord, and that outlet looks like a standard NEMA 5-15 - which is usually paired with a 15-amp fuse or breaker.

Looking at the photo closer, oh nice, it's an even "newer" tamper resistant outlet ... not sure about the design tradeoffs they made to make these tamper resistant outlets...

I don't think it's "tamper proof". I've seen those and I hate them. I assume the type you are talking about have some kind of plastic shield that slides out of the way when you plug something in. If so, this outlet is not one of those. I've never had any trouble with this outlet before.

If the "It's the outlet" people are correct, then the vacuum should work just fine on another outlet. If they're wrong, I might scorch another outlet.

As mentioned previously, the scorched outlet works for a low-watt light bulb. I'll find the highest draw appliance I can and see what happens.

Is this a 2 wire cord or a 3 wire cord?

It's two-wire, which I think is odd but that's how it was made.

CONFESSION TIME

So the way this motor is constructed, the brushes are held against the rotor by some kind of flexible tape springs. Several times I have pulled the rotor from the stator and the two opposing brushes have slammed together and they are now somewhat chipped, instead of the regularly curved end from being worn against the rotor.

Could chipped brushes be causing this?

I purchased some brushes this summer for a starter on a small gas engine and the new brushes perfectly square against the curved surface of the rotor (on the starter). So it seems to me that the curved shape where it makes contact with the rotor is not necessary to make it work, either in the case of the Starter, or in the case of the motor for this Shop-Vac.

But they're chipped.

Could debris or some foreign material be causing this? What if (for example) the motor ingested some metal somehow, maybe shorting the windings? Could the windings have overheated and fused together? If "shorted windings" happened, would that cause symptoms like this?

[Sparkey55]

Re: Help With Reassembling Basic 110 VAC Motor

CONFESSION TIME

So the way this motor is constructed, the brushes are held against the rotor by some kind of flexible tape springs. Several times I have pulled the rotor from the stator and the two opposing brushes have slammed together and they are now somewhat chipped, instead of the regularly curved end from being worn against the rotor.

Could chipped brushes be causing this?

I purchased some brushes this summer for a starter on a small gas engine and the new brushes perfectly square against the curved surface of the rotor (on the starter). So it seems to me that the curved shape where it makes contact with the rotor is not necessary to make it work, either in the case of the Starter, or in the case of the motor for this Shop-Vac.

But they're chipped.

Could debris or some foreign material be causing this? What if (for example) the motor ingested some metal somehow, maybe shorting the windings? Could the windings have overheated and fused together? If "shorted windings" happened, would that cause symptoms like this?


The soft carbon alloy brushes are spring loaded against the COMMUTATOR segments which are a part of the rotor. As the brushes ware down they acquire the curved shape to match the commutator.
The motor should be sealed in such a way as to prevent anything but air to flow past it.

The rotor has a fan attached that blows air onto the coils to prevent over heating.

The only thing that the rotor winding could short out to would be the steel core lamination of the rotor but this insulated via the plastic bearings cup.

Remember this whole thing is a SERIES wired circuit. Break connection anywhere in the circuit and the motor is dead.

Even if the field coils were shorted to the metal frame no other part makes contact with them electrically.

[eccerr0r]

Re: Help With Reassembling Basic 110 VAC Motor

I don't think it's "tamper proof". I've seen those and I hate them. I assume the type you are talking about have some kind of plastic shield that slides out of the way when you plug something in. If so, this outlet is not one of those. I've never had any trouble with this outlet before.

Strange, with nothing plugged in, it looks like the blade slots are blocked and there's an imprint of the two letters "TR" faintly visible - for Tamper Resistant? This is the "new" kind that the government mandated to prevent little kids sticking screwdrivers into the blade slots. I think you need to press in both slots in order to open it and contact power. Trying to press in one or the other blade will simply not push in and not contact AC.

If the "It's the outlet" people are correct, then the vacuum should work just fine on another outlet. If they're wrong, I might scorch another outlet.

As mentioned previously, the scorched outlet works for a low-watt light bulb. I'll find the highest draw appliance I can and see what happens.

Yes the outlet won't fail unless you have a high current load, typically people get this to happen to their outlets and power strips when they plug in AC units, space heaters, etc.. Is the outlet loose in the least bit when you plug something in, how easy is it to pull out? If it's easy to pull out (note: the tamper resistant covers probably drag against the blades so these will give you a false sense of security) then it's time to replace that outlet.

I have a power strip that all of its outlets easily pull out. I dare not use this power strip for high current devices because of this problem.

It's two-wire, which I think is odd but that's how it was made.

This is highly odd. Normally I'd imagine things that work with water to be grounded for safety.

Could chipped brushes be causing this?

You probably lost some life from the brushes but it shouldn't cause a short, unless the dust is spreading everywhere. Eventually they should wear back mostly flat again but make sure you remove any brush dust...

[Sparkey55]

Re: Help With Reassembling Basic 110 VAC Motor

Quote:
It's two-wire, which I think is odd but that's how it was made.
This is highly odd. Normally I'd imagine things that work with water to be grounded for safety


This is what is called Double Insulated. No ground wire is used here. the reason why is because if the ground wire lost connection to earth ground or became shorted to any exposed metal then if you touched the metal you could be electrocuted when you complete the circuit to earth ground. Very old power tools used to have metal housings and caused many deaths when a wire frayed its insulation and came into contact with the housing.

[Sparkey55]

Re: Help With Reassembling Basic 110 VAC Motor

If used cars made a mistake in wiring it back and created a dead short it would have tripped the breaker in just a few milliseconds not 3 seconds as stated. I say it is the outlet or connected wiring at fault, a very dangerous situation here.

[Sparkey55]

Re: Help With Reassembling Basic 110 VAC Motor

The wiring in this house is completely f*****. Before we moved in, there was a house fire and this is the area of the house that burned. Afterwards, some kind of professional "flipping" company did the repairs and they did horrible terrible things with everything, such as painting over charred wood, and other things with the wiring too terrible to even mention. So defective wiring is on the list for possible suspects in every outlet in the entire house.

PLEASE tell us about the "too terrible to even mention" wiring.

[eccerr0r]

Re: Help With Reassembling Basic 110 VAC Motor

This is what is called Double Insulated. No ground wire is used here. the reason why is because if the ground wire lost connection to earth ground or became shorted to any exposed metal then if you touched the metal you could be electrocuted when you complete the circuit to earth ground. Very old power tools used to have metal housings and caused many deaths when a wire frayed its insulation and came into contact with the housing.

Right, double insulation IS an option, but I would have thought that ground pin would help against water ingress, at least it's another path to GND.

My wet/dry 1.5HP shop vac does have a ground pin for whatever reason (and it's pretty much all plastic as well)...

I suspect a GFCI would be better in any case.

[budm]

Re: Help With Reassembling Basic 110 VAC Motor

So OP, is there follow-up as to what you find?

[Used_Cars]

Re: Help With Reassembling Basic 110 VAC Motor

PLEASE tell us about the "too terrible to even mention" wiring.

I'm resurrecting this old thread because I think that the house wiring is to blame.

After a while I got tired of messing with the vacuum, so I bought a brand-new one. It sat in the garage for about 6 weeks until I had time to mess with it.

Put it together, plugged it in, turned it on and it worked normally for a few minutes. I ran it along the toe-kick in front of the kitchen cabinets, picking up loose hair and cobwebs. Got about 20 linear feet done and the brand-new vacuum started smelling like electronics, the motor speed dropped to almost nothing. Turned it off. Turned it back on about 1 minute later and the motor was still acting wrong.

Total Run Time: Less than 5 minutes.

I'm not turning it back on again until I get some reason to believe the house wiring won't permanently kill the motor, if it's not already dead.

Choice A is that a brand new motor is bad from the factory, of the exact same model as a vacuum that performed reliably under very harsh construction condition for years.

Choice B is that the house wiring killed an both vacuums.


I think it's "B".

What is it about house wiring that can kill a motor. Everything else in the house seems to work fine. No circuit breaker tripped. Could a bad circuit breaker cause this? The circuit that the 1st vacuum cleaner was on when it died could also be the same circuit that the 2nd vacuum was on (common wall, different outlet).

Can the electricity be tested, besides measuring for voltage? Could there be a problem that would only present if the circuit was under load (meaning good voltage when no amperage draw, but voltage drops under load)?


I have a cheap multimeter with all functions (voltage, resistance, etc...) and some theoretical knowledge.

What's the next step?

[goontron]

Re: Help With Reassembling Basic 110 VAC Motor

Could there be a problem that would only present if the circuit was under load (meaning good voltage when no amperage draw, but voltage drops under load)?

No, but the voltage could RISE under load. And if it does, its throw all the breakers, call an electrician, and call the utility company time.

Do any of the lights get brighter in your house when a big load is switched on? (the fridge, A/C, coffee pot, etc)

[redwire]

Re: Help With Reassembling Basic 110 VAC Motor

I think you're just seeing the results of cheap chinese motors in appliances.

If anything, your house wiring might be so good the motor gets full line voltage which makes it run hotter. I'd measure voltage at the outlet and see.

In a vacuum cleaner, lower voltage gives lower motor speed but the blower also requires less torque as it is spinning slower.
So I don't think the motor will overheat.

Many product recalls and problems on built-in vacs smoking out the chinese motors. A few brands had to replace the motors to stop them from burning up. The old motors were fine, but the off-shore replacements cheaper with little steel and copper, but lots of heat.

[Used_Cars]

Re: Help With Reassembling Basic 110 VAC Motor

Do any of the lights get brighter in your house when a big load is switched on? (the fridge, A/C, coffee pot, etc)

No, everything works perfectly except for this. The only exception is last summer the ancient AC went out (15+ yo) and took a 220 VAC circuit breaker with it. Both the AC and the circuit breaker were replaced and the AC has been working perfectly ever since.

The 1st vacuum was plugged into an exterior outlet that has so much rotten siding around it that rain fall directly into the utility box (whatever it's called). I'll post a pic tomorrow to show how horrific it is. I intend to cut this box out of the circuit, screw the wiring together and cover the hole in the exterior wall.

The 2nd vacuum was plugged into an outlet on the same wall, but on the interior, and I suspect that they share the same circuit. I'll test them tomorrow to confirm this is true (or not).

After I posted this, I plugged the 2nd (new) vacuum into an outlet completely unrelated to the other two (on the kitchen circuit) and it operated normally for about 5 minutes, so it's not permanently damaged. I wonder if the wiring has corroded (due to water), is overheating/arcing and that's the cause of the problems? Visual inspection tomorrow.

[budm]

Re: Help With Reassembling Basic 110 VAC Motor

https://www.badcaps.net/forum/attach...0&d=1521680044
So what happen to this outlet?
"The 1st vacuum was plugged into an exterior outlet that has so much rotten siding around it that rain fall directly into the utility box (whatever it's called)." The same one?