Dust collector just lost power, motor gets really hot

[abernat]

Another troubleshooting question for those who know. I have a 1.5HP Jet dust collector that has been running just fine. Yesterday afternoon it started running slower (less suction). I shut it off after a few seconds and when I checked the motor was hot to the touch and took a while to cool off. The impeller spins freely and there's no feeling of resistance. I'm going to tear it down today and blow out the sawdust.

So, to those who know - what's should I be checking for? Thanks!

[Del Hilburn]

It sounds to me that your system is clogged and there is no back pressure on the blower
Running a blower with no back pressure will cause the motor to heat up

[lkomroff]

You can try running with the filter / bag open to see if it runs at full speed.  My thought is the centrifugal switch is stuck o the start winding is always engaged.  If that is the case, you will need to open the motor then clean and lubricate.

Larry

[fredhargis]

Well, truthfully it's not a clog that overloads a a DC motor....it's moving too much air. When the system is clogged, the motor will actually pull fewer amps since it's not working (moving air). Since you said the motor slowed down and was hot, that would be a symptom of working too hard: moving more air than it can handle. So what might cause that would be a big leak in the duct work or something. Since you would notice that (I think), there must be another cause...but I have no idea what. You said the motor was spinning freely (bearings are OK) so maybe something is jammed on the impeller itself.

[abernat]

The plot thickens...

I've torn the motor down and there wasn't any dust to speak of. The starter looks fine too. Is it safe to run without the starter switch in the circuit to see if that's it? Or will it just stall?

And this is a garage shop so there wasn't a clog. I was vacuuming sawdust off the floor at the time.

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And in case it helps, it's the central shaft that gets hot. The heat eventually bleeds out through the rest of the motor.

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Oh hey, the new forums collapse posts. That's nice.

How do I tell if the centrifugal switch is disconnecting? It's a mechanical device on the end of the central shaft, and from eyeballing while the motor runs its not moving. That said, it's just a couple of springs so I don't see what could have changed.

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And one last update. I just pulled the switch off entirely and the motor still starts, still seems to lack power (or RPMs? It doesn't get to quite the same howl, and the suction is a lot less). And still quite hot even with a wide open airflow and no filter.

I'm officially confused now.

[fredhargis]

Do you have a meter to read the voltage at the outlet?

[abernat]

I'm guessing 220 but I'll check. Yeah; 240v, 120 each leg to ground too.

And how can the motor start with the starter switch disconnected? I pulled the leads. Could it be shorted on somewhere inside the motor body? I can't figure out how to get the impeller off so I can't pull the motor itself apart, just the end cap with the centrifugal switch.

There's a start and run capacitor. Would those going bad cause this? They don't appear damaged but I haven't disconnected them.

[Rick F]

I wonder if the center shaft getting hot would indicate bearings ...

I have an Ammeter on my Dust collector. As Fred said, the more air the machine is moving the more amperage it draws..

I recently installed a new ducting system.. Closed all the gates, and went around sealing all the leaks.. The more you seal, the easier they are to find.. lol. Anyway .. The Amperage dropped .9 of one amp in the 20 minutes it took to find all the leaks and tape them up ..

I was shocked how much of a difference it made

[abernat]

I'll try and pull the impeller and replace the bearings. Looks like the impeller is just frozen on the shaft (yay google) so that shouldn't be too bad.

[fredhargis]

It was for me. I've had to pull mine twice, the first time I gave up and took it to a motor shop...they only charged $15 to pull it off. But it took an acetylene torch (aluminum impeller) to get it off. The second time i did it by laying the motor on the workbench with the impeller (and the blower housing flange) overhanging the edge. Then using a big brass punch and a 20 oz. ball peen I hammered on the shaft, the motor was free to slide back as I tapped. It took and hour or so but it came off.