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Thread: Burned Out Motor on DC - Looking at Options

  1. #1

    Burned Out Motor on DC - Looking at Options

    The unthinkable happened last week when I was jointing a bunch of maple for drawer sides: the lights flickered and my DC no longer worked!

    The short of it is that my DC motor (Jet DC-1200) has burned out. Was hoping it was just the start capacitor but it checked out good and when I went out to the DC shed (my DC is in an attached shed and vents outside) and tried troubleshooting the centrifugal switch, I saw the dreaded sparks and smoke coming out of the motor. Figuring I couldn't break it any more than it was already toasted, I disassembled it and found what I initially thought were ball bearings but upon closer investigation, found that they were little "welding" beads of copper.

    I doubt the motor is salvageable at this point (but correct me if you think I'm wrong!) so I looked at buying a replacement motor but it's more than twice my targeted budget (preferably <$200).
    So here are a few options I'm considering:

    1. I could get a 3hp 3400rpm 240v motor for <$200 but it'll come with a 5/8" shaft. The impeller is odd sized, it's bore is around 23.5mm or 0.93". I would have to get an adaptor to go from either 5/8" to 7/8" and then find a way to shim the remaining gap, or get one that goes 5/8" to 1" and reduce the O.D. to a snug fit. I'd also have to come up with a way to retain the impeller on the shaft, either by drilling and tapping for set screws or tapping the end of the motor shaft to receive a retaining bolt/nut.

    2. I've considered buying the HF "2hp" DC but I'm sure I would be disappointed going from a 12" impeller to a ~10" one. Plus, I have the DC all wired up for 240V and would have do some extensive rewiring to change the interior switch, etc to 120V (plus, the current 240V circuit is dedicated to DC, if I went to 120V it would be shared with other tools).

    3. Wait it out until I find a similar used DC that's inexpensive. I know patience is a virtue but I'm tired of getting buried in planer shavings and having everything coated in dust. The air cleaner helps but is no substitute for my beloved DC! The good thing is I only need the blower and motor for my setup.

  2. #2
    Take it to a motor repair shop. They can see if a new centrifugal switch can be put in it. If it is too costly or not possible then you have to explore the options.

  3. #3
    Buy the 3HP motor. Then get the 5/8" to 1" adapter and have the impeller bored out to 1".

    If you wanted to commit to a 5/8" motor shaft, have the machine shop bore out the impeller and then weld the adapter into the bore, leaving you with an impeller with a 5/8" bore.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  4. #4
    Join Date
    Sep 2016
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    Modesto, CA, USA
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    9,879
    Are you saying it has sleeve bearings that dried up and melted?
    Bill

  5. #5
    Quote Originally Posted by Bill Dufour View Post
    Are you saying it has sleeve bearings that dried up and melted?
    Bill
    I’m pretty sure the bearings are good. To me it appears that the windings shorted out and burned up, but I’m no motor expert. I could snap a few pictures later today or tomorrow.

  6. #6
    Join Date
    Jan 2004
    Location
    Lewiston, Idaho
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    28,504
    The melted beads of copper he found aren't coming from bearings.
    Ken

    So much to learn, so little time.....

  7. #7
    Join Date
    May 2008
    Location
    MA
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    2,255
    Quote Originally Posted by Ken Fitzgerald View Post
    The melted beads of copper he found aren't coming from bearings.
    An ominous sign indeed.

    If you are really handy/crafty some have been known to rewind a motor themselves. It is not 'trivial', but possible.

    In almost all cases I have experienced it is not cost effective for a motor shop to rewind smaller hp motors. So you are left with purchasing a new one.

    Maybe you get lucky and find something on CL at <$200 and steal the motor out of it. Maybe take a while waiting.

    Since you like the rest of your setup, I am in the camp of suggesting a replacement motor and adapter to make your impeller fit (preferably by finding someone to bore it for you, and ideally then balance it)

  8. #8
    Join Date
    Apr 2017
    Location
    Michigan
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    2,758
    A new motor from Jet would be the best answer. Do it the easy way and get back to work.

  9. #9
    Update: for closure, here's what I've accomplished. It's taken me quite awhile as other house projects and life in general have precluded me from fixing my dust collection issue.

    I ended up purchasing a 3HP motor from Harbor Freight and a 5/8" to 1" bushing from Agrisupply. I then installed the bushing on the motor's shaft, and with the motor running, used an angle grinder to carefully reduce the O.D. of the bushing from 1" to fit the bore of the impeller (about 0.94"). A metal lathe would've been nice but you have to use what you have.

    Once the bushing fit inside the impeller bore, I welded it in place. Then drilled and tapped for a set screw.

    The jerry-rigged solution works and I'm delighted to have dust collection again.

  10. #10
    Join Date
    Aug 2012
    Location
    Elgin, TX
    Posts
    231
    Did you happen to check Tractor Supply? There carry a lot of motors.

  11. #11
    Quote Originally Posted by Matt Schenk View Post
    Update: for closure, here's what I've accomplished. It's taken me quite awhile as other house projects and life in general have precluded me from fixing my dust collection issue.

    I ended up purchasing a 3HP motor from Harbor Freight and a 5/8" to 1" bushing from Agrisupply. I then installed the bushing on the motor's shaft, and with the motor running, used an angle grinder to carefully reduce the O.D. of the bushing from 1" to fit the bore of the impeller (about 0.94"). A metal lathe would've been nice but you have to use what you have.

    Once the bushing fit inside the impeller bore, I welded it in place. Then drilled and tapped for a set screw.

    The jerry-rigged solution works and I'm delighted to have dust collection again.
    Used motors are often available cheap if you are patient.

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