How do I put this electric motor back together?!

[Naio]

Got my shave ice machine motor back from the repair guy. Started to put it on the machine. Turned the shaft and it was rough and clunky.

Since it was Christmas Eve, I decided to see if I could fix it myself. Opened the motor up, found that one of the permanent magnets had come unglued. After a quick Google, I sanded the interface and glued it down with J-B Weld, clamped it overnight.

But yes, in all this, I managed to lose track of which end had the brushes on it and which end was the shaft. There don't seem to be any markings to tell me. I'm also not a hundred percent sure that I got the magnet oriented right, although I am maybe 75% sure. Yes, it was a bad day.

So, at this point I'm hoping one of you retired engineer types can help me out. Again.

Does it matter which end the brushes are at?

Will I ruin everything if I have the magnet switched around wrong?

Sigh. Merry Christmas.

[drsteve]

Flute Man wrote:
I wonder if the magnet came loose due to rough handling by the shipping company or someone else.

Next time you might want to take a picture before taking something apart.
As a professional maintenance guy I’ve made those kind of mistakes in the past myself.

X2 on taking pics.

[Flute_Man]

I wonder if the magnet came loose due to rough handling by the shipping company or someone else.

Next time you might want to take a picture before taking something apart.
As a professional maintenance guy I’ve made those kind of mistakes in the past myself.

[larry_cad]

Naio wrote:
A problem for tomorrow, but one that is back in the realm of my knowledge. Unlike the inside of the motor, which I know nothing about!

Well, you do now!!! 🙂

[Naio]

All I can figure is that it was a matter of alignment, that they were teeny teeny bits of slop in how the pieces fit together, and after putting it together about eight times I hit on the perfect combination.

It's in the machine now, and still turn smoothly! I have now, of course, a different problem. something electrical is going on. Maybe a crossed wire or something. The potentiometer that is supposed to control the motor speed is not doing so. It is full blast or nothing. A problem for tomorrow, but one that is back in the realm of my knowledge. Unlike the inside of the motor, which I know nothing about!

[pianotuna]

Perhaps Santa fixed it for you?

Even experienced techs make mistakes, or have things "fix" themselves. That was the case for me in the spring of 2018--my water heater would not work on the 120 volt setting. I got a new heater rod--and after it was replaced the water heater still would not work on electric.

Then after disconnecting and reconnecting bingo--it started to work!

[midnightsadie]

well don,t let us hanging we want to know if you fixed it.

[Naio]

Thanks you guys!

I took it apart and put it back together multiple times, trying to figure out what was going on. Then a friend suggested that I use a Sharpie to mark up the magnets and the middle part and see what was rubbing. So I took it apart again, put the markings on, closed it up, and miraculously it is not rubbing any more! Either Sharpie makes a good lubricant or I just got lucky. I think it's a Christmas miracle. I'm not going to take it apart again and find out :-).

And Merry Christmas to all, and wish me luck when I reinstall it in the machine 🙂

[wa8yxm]

Ok on one end of the windings is a big "barrel" like thing with slats running the same way as the shaft. It is called as best as I can spell it the commutator

This is what the brushes... brush.

[time2roll]

I would just run it and see how bad the noise actually is.

[riven1950]

I have no idea how to fix it but if I were in that situation I would either have the repair guy do it right or buy a new motor or a new unit. I would be paranoid about a short and fire. Not worth the risk. JMO

[Johno02]

Stopping when it rotates is normal. if it doesn't drag, apply power carefully and see it it rotates the right way

[Naio]

Naio wrote:
Okay, new question. Boy do I wish I had some clue what I was doing here.

When I put the motor together and turn it by hand, it has a sort of a scraping feeling. It doesn't have the clunking feeling it had when the magnet was loose.

When I open it up again, I can move the inside around to each of the four magnets, so I can tell that there is a little air space before each magnet like there ought to be. But I don't know if still maybe my glue was too thick... Is it okay to put it together and let it kind of wear in?

Replying to Dennis:

There isn't any way to see in it if I put it back together enough to get the scraping feeling.

[Naio]

Oh. I pulled out the wires I had holding the brushes back, and now the wobble is gone. Still a little bit scrapy

[alaska_dennis]

It will not wear in the magnets shatter like glass. Put it back together and spin it without power and then check for clearance problems.