Hoover Convertible Motor Troubleshooting

[MPN]

Well, ummmmmmmmm ? ? ?

"@hoovercelebrity: If I were to use a lathe, as MPN suggested, I would imagine I could easily use commutator stones, am I wrong?"

NO! use the lathe's cutting tool bit, because you want to remove as little material as possible to achieve "Concentricity". Using a hand-held stone will only follow the "Eccentricity" of the OUT OF ROUND commutator MAKING MATTERS WORSE!

1.Turn the commutator on a lathe until concentric. 2.Finish dress with a fine Scotch-Bright Pad.

 

[vacuumlover]

Yep. 220 is what I use.

 

[hoovercelebrity]

Well, for those of us who aren't able to go to the lathe store and pick up a lathe, the stones work just fine. I've rebuilt hundreds of vacuum cleaner motors over the years, the majority of those being Hoover Convertibles, and have never once had a problem using them. I still maintain that you should put new carbon brushes in, anytime you rebuild the motor.

 

[vacuumlover]

@hooveru4089 (reply #20)

Sorry but I just realised that I've skipped out the part of the bearings. They do look a little rough and IMHO I would just replace both.

 

[hooveru4089]

I am just trying to put 2-and-2 together since each of you seem to have different opinions. Based on your suggestions, I think I will replace the upper bearing and brushes. I searched the web for commutator stones, as HooverCelebrity advised, but they all seem to be at least $50 (perhaps you know if I can get them any cheaper).

@MPN: I am aware that there are several types of Scotch Brite pads (i.e. scouring, scrubbing, stripping, etc.), obviously for different purposes. Which do you use to clean the commutator shafts of these motors?

@hoovercelebrity: I am just curious, since you stated that it is difficult to stick a commutator stone into a running Hoover Convertible motor, if it would be easier to put the commutator on a rotating lathe.

 

[MPN]

Point well taken, but . . .

"Well, for those of us who aren't able to go to the lathe store and pick up a lathe, the stones work just fine."

I offered my comment regarding truing the commutator on a lathe as he'd already disassembled the vacuum, his noise complaint, brush wear, and the photos indicating lack of lubrication discoloring the armature shaft.

My uncle owned an electric motor rebuild shop for 45-years, retiring the end of last year. I worked in his shop many summers, and learned a few things along the way. The main thing I learned was "Commutator Concentricity" is essential to ensure the longevity of a motor rebuild, ESPECIALLY in situations similar to this one where these kind of are noises are involved.

We used ROTARY stones mounted in a Dremel-type motor fitted to the lathe's tool holder to "Finish Dress" commutators, once they were cut and trued. Your complaint is centered around a "sputtering noise" common with arcing as result of brush float likely created by worn brushes, thus weakening brush spring tension. Here's the paradox: A machine shop will likely charge you $10-$15 to chuck your armature up in their lathe. Is your old vacuum worth $10-$15?

 

[hoovercelebrity]

Thanks for the clarification and the advice. I'll have to look into finding a local motor rebuild shop that will do that if I ever find an armature that has too much of a wear groove in it (usually I have spares, and just swap the part for a new one). I certainly didn't mean to question your knowledge; it must have been nice to have machines such as lathes available to you whenever you needed them. It's certainly becoming a thing of the past; I'm surprised when I google it in Minneapolis, that a few still pop up!

I personally don't think that the armature looks all that bad, although the picture isn't crystal clear. I've certainly seen worse! A bit of very fine sandpaper might even do the trick for you to get the initial layer of "gunk" off.

I did find the commutator stones online - SteelCityVac.com; they're a vacuum parts supplier. They have the brown stones (2pk for $28), and the white diamond stones (4pk for $15). Yes, perhaps likely pricier than $10-15 that getting the commutator re-cut may cost, but if you rebuild machines with any regularity, these will come in handy!

 

[hooveru4089]

@MPN: I do have a Dremel tool if you think that could be useful. If so, could you explain that technique again because I was not quite understanding it.

As I am reading each of your comments, I also thought about running the commutator in a lathe and holding up a strip of sandpaper just enough to remove the gunk evenly while truing the shape. Again I am simply trying to put 2-and-2 together but I would like to hear what you think of that idea, if it makes sense.

 

[MPN]

http://www.vacuumland.org/TD/JPEG/BASKET/2016/20160322/hoovercelebrity-2016032213164905005_1.jpg

OK, now you have almost $30.00 tied up in stones ALONE, that could have the whole job done by a PROFESSIONAL on a lathe for around HALF of that. YOU DO THE MATH ! ! !

 

[hoovercelebrity]

Those stones will last for years - many, many, many rebuilds. I've been on the same set of stones for at least the past 5 years. 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.

-Gas to drive it there
-They probably couldn't do it while I wait
-Gas to drive back home
-Gas to drive and pick it up
-Gas to drive it back home
-likely a multi-day process

Usually I just want to get my motor rebuilt so I can get the cleaner back together and go about using it.

 

[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.