Hoover Convertible Motor Troubleshooting

[hoovercelebrity]

I don't think you need to put the motor in a drill; you could, just be careful not to bend or strip any of the threading which the fan nut screws onto. Also be careful not to damage the upper part of the armature, the part which fits into the upper bearing.

See the following two pictures - Taken directly from the Hoover Service manual, sanding by hand is acceptable.

 

[MPN]

maybe so . . .

"Consider all of the time and money I'd have spent if I took every armature into a motor shop every time I serviced a machine."

We used to growl, short-test, and machine armatures for janitorial and restaurant equipment companies, appliance repair shops, and appliance stores. They'd send bin boxes of complete motors, armatures, and field windings with their corresponding work order numbers marked on tags. Needless to say volume pricing was in effect.

I remember a guy coming in with an armature from a commercial dough mixer, that was between a rock and a hard place as hundreds of pounds of fermenting dough was spoiling as time passed. My cousin threw it on the growler, short-tested it, cut and dressed the commutator on the lathe, and handed it off to him. When the guy asked what he owed, my uncle knowing his dilemma, told him to "Beat it!" You might get lucky as well . . .

The ONLY REASON I recommended truing the commutator on a lathe is due to YOUR NOISE COMPLAINT and that's it!!!

 

[hooveru4089]

Here's the commutator after sanding w/ 220-grit wet/dry sandpaper. How does it look?

 

[vacuumlover]

Looks much better IMHO. Belooks of it there's copper drag and bar burning. This is due to the commy over heating multiple times. Not sure how one fixes that though. If at all.

 

[MPN]

You look at it and tell me . . .

"Here's the commutator after sanding w/ 220-grit wet/dry sandpaper. How does it look?"

Well, whatta YOU think ? ? ?

Are the commutator segments linear & flat longitudinally to provide full brush contact ? ? ?

 

[hooveru4089]

"Are the commutator segments linear & flat longitudinally to provide full brush contact ? ? ?"
@MPN: Looks like it to me! I just thought I would keep all of you updated on my progress. Like I said before, I have very little experience servicing electric motors; I imagine those of you who have been providing input have considerably more experience (or at least HooverCelebrity does, LOL!).

@vacuumlover: MPN mentioned earlier in the thread that the overheating could be the result of lack of lubrication due to the buildup on the upper bearing shaft of the armature. I still have not gotten to that yet; I ran out of Scotch Brite pads. Would a soft wire brush also work for removing this buildup, BTW?

 

[vacuumlover]

Yep. Steel wool works too. You've just got to make sure that there is no wire left. Vacuum and wipe it a lot afterwards.

 

[hooveru4089]

I could try steel wool. Not sure what you mean by "[y]ou've just got to make sure that there is no wire left."

 

[MPN]

"@MPN: Looks like it to me!"

It doesn't to me from what I'm seeing in your photo. I should be seeing CONSISTANTLY FRESH, CLEAN, and SMOOTH COPPER COMMUTATOR SEGMENTS!

Did you lay a straight edge along each commutator segment, and hold the armature up to the light to see if there's a gap between the copper and ruler?

"I ran out of Scotch Brite pads. Would a soft wire brush also work for removing this buildup, BTW?"

NO! You need the cutting-action of the powdered industrial diamonds in Scotch-Bright pads.

As far as the Oilite-Bronze bearings are concerned, the BLUE discoloring on the motor shaft pretty much indicates they've been overheated to the point of the lubricant permeated into 'em at the factory being long since vaporized away!

You're now at the point of asking yourself: Is all this really worth it??? The ONLY REASON I went as far as I did with my vacuum is that it was a brand-new Royal Metal Upright that was about $400.00 new in the original box with ONLY ONE PART robbed from it, given to me for free! I now have a NEW commercial-grade vacuum cleaner for a few bucks and an hour or so of my time.

 

[hooveru4089]

After reading all of your suggestions…

…I am inclined to think that a little more sanding of the commutator, a cleanup of the shaft, a new upper bearing and a new set of carbon brushes should do the trick. If anyone thinks that there's more to it, I would certainly appreciate further advice. Considering that this vacuum cleaner is in excellent cosmetic condition overall with all of its original parts, I would think it's worth repairing.

 

[MPN]

Whatever floats yer boat . . .

"…I am inclined to think that a little more sanding of the commutator, a cleanup of the shaft, a new upper bearing and a new set of carbon brushes should do the trick. If anyone thinks that there's more to it, I would certainly appreciate further advice. Considering that this vacuum cleaner is in excellent cosmetic condition overall with all of its original parts, I would think it's worth repairing."

The bottom line is that it's your vacuum cleaner, to do with as YOU please.

You kept going on and on for suggestions, so I assumed (I hate that word) that you were really out to do the job RIGHT THE FIRST TIME! I repair & restore exotic cars for a living, so when I repair ANYTHING, I repair it so it DOESN'T COME BACK. I MAKE MORE MONEY and stay outta court that way.

Now that I know your real prerogative, just throw it back together and don't waste anymore time ! ! !

 

[vacuumlover]

@HooveU4089 (reply #40)

When using steel wool, there's little bits of wire that come off of the wire pad that fall on the armature.

 

[MPN]

"When using steel wool, there's little bits of wire that come off of the wire pad that fall on the armature."

THE FASTEST WAY TO KILL an electric motor ! ! !

 

[vacuumlover]

That's why I said to make sure you vacuum it and "dust" it to make sure there is no remaining wire.

 

[MPN]

Ummmmmmmmmmmmm . . . NOPE ! ! !

"That's why I said to make sure you vacuum it and "dust" it to make sure there is no remaining wire."

The problem here is, PULVORIZED DANDRUFF from steel wool (or "WIRE WOOL" as you Brits call it) gets imbedded in the phenolic micas that insulate each commutator segment from each other, partially shorting them out with each other until the commutator gets hot enough to melt and sling solder from the neck connections.

To put things in plain English for you: You're striking matches on a dynamite keg ! ! !

 

[vacuumlover]

I don't know if you're purposely trying to add fuel to my fire or not, but trust me, I've done it enough times before and my motors have (and still are) turned out perfectly fine.

Yes, it's best to use wet and dry sand paper, but as a last resort (if one doesn't have or can't get wet and dry sand paper) then steel wool is a last resort.

Oh and there's no need to say "To put things in plain English for you."

I am quite capable of understating what you have said without you needing to patronize me.

 

[hoovercelebrity]

I think that armature looks great. Add some new carbon brushes to the mix, and hopefully a new upper motor bearing, and you will be Hoovering again in no-time. I do love the model 719 - it was the first Convertible of that style that I ever had; was given to me by an elderly couple when I was 11 years old.

At this point, you could also run the armature through the dishwasher to make sure it's clean as can be - I do this with all of my motors as part of the restoration process - a trick I picked up from Tom Gasko many years ago. I just keep an eye on it and don't let it go through the dry cycle. I then let it dry overnight with a fan running to keep air circulating around the parts that are washed.

 

[hooveru4089]

I used an air compressor and blow gun after I sanded the commutator and cleaned the shaft. That appeared to clean it up well. I also have a small ultrasonic cleaner if any of you would still suspect that there could be fine pieces of steel wool.

Thanks for all the tips; I think I have a good handle now on how to finish this job. I think my other convertible of the same vintage could use a little TLC as well. If possible, I'll try to give an update after I buy the parts.

 

[vacuumlover]

An air compressor should of gotten rid of all the wire.

 

[kenkart]

Re dishwaher cleaning of motor parts.

Clay Floyd came up with that idea many years ago, he used to run everything thru the DW except the carbon brushes, when he got thru you had a practically new machine.