Hoover Convertible Motor Troubleshooting

[vacuumlover]

The brushes look like they have a slight chattering problem IMHO and they also look like they have over heated. The commy looks like it has slight threading and bar burning which would back up the statement of the brushes.

Also I on just seen your other comment. When there's q slight dust build up I just wipe the brushes and commy with a soft cloth.

And, if it's not too much of a problem, would it be possible to ser the brushes'"face" (that's what I nickname the part that touches the commy.)

If it has a slight line through it, that would also back up my statement of dust build up on the commy.

I don't know about anyone else but it looks like there's slight arcing too.

 

[hooveru4089]

Very interesting!

Now I wonder why the shaft is not getting lubricated. I have been regularly lubricating the sleeve bearing with 3-in-1 electric motor oil; first cleaning out the sleeve with oil soaked Q-tips and then placing a drop on each felt pad. Could there be a problem with the bearing?

@MPN: What should I use to machine the commutator? Fine sandpaper? I have heard of these electric motor commutator cleaning sticks. Would you recommend them?

 

[MPN]

Well, here goes . . .

"@MPN: What should I use to machine the commutator? Fine sandpaper? I have heard of these electric motor commutator cleaning sticks. Would you recommend them?"

Like I said: A lathe is the best method, if you have access to one.

If you're not going to take that approach, use GARNET or WET N' DRY sand paper.

NEVER USE EMERY or CROCUS CLOTH, as they contain metal that can short the commutator segments and destroy the armature!!!

Also, you'll want to burnish (slightly dull-down) the bearing surfaces on the armature shaft with a Scotch Bright Pad, until the blue disappears so lubricant is able to penetrate into the metal. At this point you have nothing to lose, as Oilite-bronz bearings are impregnated with oil at the factory, that overheating vaporizes away.

 

[hooveru4089]

More pics:

@vacuumlover: Here are the "faces" of the brushes. Hopefully this is clear enough for you to see, but from my perspective, they do look a little scratched up. BTW, the last time I ran the motor by itself without the brushroll and belt attached, the motor was somewhat noisier than it probably should be.

 

[vacuumlover]

Lovely. Thank you for the pictures. Yep, there's dust build up on the commy surface. Quite badly too as they are very scratched. This is causing poor contact with the commy thus causing excessive sparking.

In this case, what I do is ~ wipe down the commy with a soft cloth to remove any dust. Then what I do is use wet and dry sand paper. Starting with coarse and working to fine until the segmentation is gone. What I do to make it easier for the brushes to seat is try and rub the sand paper in a curving motion to try and keep as much shape of the brush as possible. (This makes it less faffing around to seat them)

Hope this helps

Also, it doesn't look like there's any chattering problems. Just over heating which has made the brushes "melt" In this case using the wet and dry sandpaper (just using a fine grade) is rub it evenly from the sides of the brushes.

If it's any easier I can try and get a video.

 

[hooveru4089]

@MPN: I might be able to get my hands on a lathe. Could I use Garnet or wet/dry sandpaper on the lathe or would you recommend something different to machine the commutator? Also, what specific type of Scotch Brite pad should I be using to clean the shaft

 

[hooveru4089]

@vacuumlover: Thank you for the tips. I am learning quite a bit of valuable info from this thread as I do not have much experience servicing electric motors beyond lubricating bearings. Do you use the sandpaper dry or with a liquid?

 

[hoovercelebrity]

If you use sandpaper, do it dry, I imagine.

I personally use commutator cleaning stones and have always had good luck with those; that's what we used whenever I worked in a vacuum store. There's one that is a rubberized abrasive stone which I use before I wash an armature - then I use a diamond seating stone after; before I reassemble the motor to polish the commutator plates. A Hoover Convertible is tricky, because you can't really get a brush stone into the running motor, as you can with other types of motors.

I would also recommend not over-lubricating your upper bearing, that could be causing some of the problem. You should be able to find a new upper bearing relatively easily - you may just want to replace it and be done with it. You might want to find a new pair of carbon brushes, as well.

 

[vacuumlover]

Always use it dry. Make sure you wipe /vacuum the commy and brushes afterwards to remove any dust/sand.

 

[hooveru4089]

Thanks for all the tips!

@hoovercelebrity: If I were to use a lathe, as MPN suggested, I would imagine I could easily use commutator stones, am I wrong?
@vacuumlover: Would 220 grit be good enough, or should I use something finer?

 

[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.