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Help! Having motor issues!

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Forum topic by gawthrrw posted 02-22-2014 10:19 PM 745 views 0 times favorited 21 replies Add to Favorites Watch
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gawthrrw

187 posts in 1142 days


02-22-2014 10:19 PM

Good evening everyone,

Its been a while since I’ve posted due to moving from MI to TX. Anyhow, I ran across a great deal on an old Powermatic model 81. Unfortunately, I wasn’t able to try it out before getting it home. After plugging it in, it will run for about a minute then it gets hot and the thermal switch shuts it off. There is no burning smell or anything. I double checked the wiring and all seems to be good. I bought and installed new bearings, checked the wheel and such on the machine to ensure it wasn’t getting overloaded and everything checks out fine. What else could be causing this? If I cant fix it myself I guess I’m going to take it to a motor shop. Anyone here have a recommendation in the Dallas, Fort Worth area? Any help would be appreciated.

-- Rob, Dallas TX


21 replies so far

View bondogaposis's profile

bondogaposis

2617 posts in 1046 days


#1 posted 02-22-2014 10:24 PM

I’d replace the capacitor.

-- Bondo Gaposis

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gawthrrw

187 posts in 1142 days


#2 posted 02-22-2014 11:27 PM

I thought about that. Would that cause the motor to heat up?

-- Rob, Dallas TX

View Dallas's profile (online now)

Dallas

3057 posts in 1182 days


#3 posted 02-22-2014 11:37 PM

Did you happen to clean all the old sawdust out of the armature?

There is a small impeller inside that draws air through the motor for cooling. If you build up enough crud inside, the motor will overheat.

edit: I just noticed you are in the Metroplex. If you get board sometime jump in the car and drive down here for the day. I’ll send you home with some green lumber! LOL.

-- Improvise.... Adapt...... Overcome!

View mrjinx007's profile

mrjinx007

1721 posts in 462 days


#4 posted 02-23-2014 12:27 AM

It could have something to do with the polarity of the motor itself; hopefully not as it would be difficult to change those magnets around the armature.

-- earthartandfoods.com

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gawthrrw

187 posts in 1142 days


#5 posted 02-23-2014 07:48 PM

I did clean out the motor when I changed the bearings. It could be the polarity. It makes a loud noise when running. I thought it was the bearings but it still sounds the same.

I will take you up in that offer Dallas. Coming from MI, it’s like finding a 4 leaf clover getting wood down here lol!

-- Rob, Dallas TX

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Dallas

3057 posts in 1182 days


#6 posted 02-23-2014 08:10 PM

Rob, you will be welcome anytime. BTW….. some of my best friends are Yoopers, but I wouldn’t want my sister to marry one, LOL.

If you’ll remove the motor and take down to your local electric motor repair shop I would bet you could get it fixed up for a lot less than the cost of a new unit.
I think those PM motors were made by Baldor and really robust.

-- Improvise.... Adapt...... Overcome!

View Kennyl's profile

Kennyl

40 posts in 557 days


#7 posted 02-24-2014 11:26 PM

Any chance motor set up for 120 or vice versus depending on your power supply?Polarity should not be an issue but stranger things have happened.If the capacitor is bad the motor lacks kick in the butt push,which causes very high amp draw.Any chance the belt is very tight?Also bad bearings either internal of motor or external faulty bearings,should have enough food for thought now.

-- Kennyl

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mrjinx007

1721 posts in 462 days


#8 posted 02-24-2014 11:34 PM

It could also be an issue with the length and gauge of the wire connecting into it.

-- earthartandfoods.com

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gawthrrw

187 posts in 1142 days


#9 posted 02-25-2014 02:41 AM

The wire is 10 gauge I believe. Also the belt was very tight on the machine when I got it. I have been running it without hooking the belt up since changing the bearings. I am going to try to get a new capacitor and see if that helps. If not, does anyone know a good motor repair shop near Dallas? Can’t seem to find anything on the web. I wonder if some of these places may not have websites.

-- Rob, Dallas TX

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gawthrrw

187 posts in 1142 days


#10 posted 02-25-2014 02:42 AM

Oh, and I know it’s not set up for 110. I have wired it several times now to check it. I followed the wiring diagram on the motor.

-- Rob, Dallas TX

View bigblockyeti's profile

bigblockyeti

1667 posts in 416 days


#11 posted 02-25-2014 03:25 AM

My thought is that if it’s doing it after only a minute, the centrifugal switch might not be actually be switching. If this happens, the motor will be running on the start windings only, and they’re designed to be energized only for a short time as whatever is being driven gets up to speed. Could be stuck weights on the rotor, bad contacts within the switch or the motor doesn’t have enough power to get the load up to the required speed for the switch to open.

View exelectrician's profile

exelectrician

1673 posts in 1122 days


#12 posted 02-25-2014 06:06 AM

Loud noise could be that the starting switch is stuck ON and the starting winding never switches off, this happens to many first time motor mechanics.
Strip the motor down again and pay attention to the way the centrifugal switch interacts with the switch mounted to the end shield.
The web has many videos describing this in detail.

-- Love thy neighbour as thyself

View gawthrrw's profile

gawthrrw

187 posts in 1142 days


#13 posted 02-25-2014 03:25 PM

Good advise. I will try that. Thanks!

-- Rob, Dallas TX

View SCOTSMAN's profile

SCOTSMAN

5439 posts in 2280 days


#14 posted 02-25-2014 04:16 PM

It seems so unfair that although you did not get a chance to try it out,you would think the guy selling it to you must have known about these problems beforehand. I fail to see how he could not have known.Someone is being very dirty regarding this I would contact him and see what he has to say.Sorry you bought a lame pup . Alistair

-- excuse my typing as I have a form of parkinsons disease

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gawthrrw

187 posts in 1142 days


#15 posted 02-25-2014 06:18 PM

The guy I got it from had bought the warehouse and some of the tools came with it. He didn’t know anything about them. I had originally went there to look at an old dewalt radial arm saw which I bought. He didn’t have any 220 outlets to plug them in. I was able to use that to get the price lower though. While there I saw the 81 hiding in the back corner and asked about it. He didn’t know anything about it and didn’t even know if it worked. I offered him a low price and he accepted. I only have $600 invested in both so I feel like I got a fair deal. The 1030 RAS works great! Now to just get this one running. Besides the motor the bandsaw is complete and in great shape considering its a 1965 model. Here is a few pics.


Sorry about the pics, couldn’t figure out how to turn them.

-- Rob, Dallas TX

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