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Thread: Harbor Freight Dust Collector circuit pops

  1. #1

    Harbor Freight Dust Collector circuit pops

    I added a dedicated 20 amp circuit after picking up a used HF DC. I installed an upgraded impeller from Rikon so I know power draw will be a bit more than stock, but many on the web have done this same upgrade. Unit runs totally fine EXCEPT if I turn it off, let it spin almost all the way down, and turn back on before it has totally stopped spinning. Blows the 20a breaker. If I turn it off and then back on while it’s still spinning pretty fast, it kicks back on with no problem. Any idea what I can try to fix this? I wear ear protection with music and won’t typically be able to hear that this thing is all the way stopped before turning back on and it takes forever to spin down.

    Of course I just spent the last 3 weeks installing this and all the piping. Tons of work so I just want it to work!!

    Craig

  2. #2
    Join Date
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    "EXCEPT if I turn it off, let it spin almost all the way down, and turn back on before it has totally stopped spinning. Blows the 20a breaker. "
    think the centrifugal switch is not engaging until the motor stops, as long as the fan is wound up the motor can speed back up quick enough not to trip the breaker. Could try opening the motor up and cleaning/lubing the centrifugal switch. Could try changing the capacitors also however don't think you will gain much.
    Best choice probably would be to keep the dust collector running when you are needing it more than 6 starts a hour. My dust collector is set up to automatically turn on when stationary tools are turned on also have a switch to turn it on and use the switch when going from machine to machine.
    this keeps the dust collectors from starting too often.

    good luck
    Ron

  3. #3
    Quote Originally Posted by Ron Selzer View Post
    "EXCEPT if I turn it off, let it spin almost all the way down, and turn back on before it has totally stopped spinning. Blows the 20a breaker. "
    think the centrifugal switch is not engaging until the motor stops, as long as the fan is wound up the motor can speed back up quick enough not to trip the breaker. Could try opening the motor up and cleaning/lubing the centrifugal switch. Could try changing the capacitors also however don't think you will gain much.
    Best choice probably would be to keep the dust collector running when you are needing it more than 6 starts a hour. My dust collector is set up to automatically turn on when stationary tools are turned on also have a switch to turn it on and use the switch when going from machine to machine.
    this keeps the dust collectors from starting too often.

    good luck
    Ron
    Ok interesting. Thanks. I have this thing wall mounted up next to my garage door rails and it would be a total bear to take down. Any tips to finding and lubing the centrifugal switch should I decide to do that? I guess this is what I get buying a used unit thinking that these motors are indestructible.

  4. #4
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    Craig, just keep it running while your in the shop, no need to shut it off. If your worried about electric use, just be sure to close all the blast gates.
    Cheers
    Sean

  5. #5
    Ok thanks Sean. I was hoping to keep the noise down a bit for my family (this is in the 3rd stall in my garage) but can keep it running when I know I’ll be bouncing from machine to machine. Seems like an odd problem though that I shouldn’t have to worry about, no? Or totally normal?

    I’ve also read to keep at least one blast gate open while the DC is running. Is that correct? If that’s the case, jumping from machine to machine becomes a lot more difficult (open 2nd machine‘a blast gate, go back and close first one).

  6. #6
    Join Date
    Feb 2013
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    Tippecanoe County, IN
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    That issue may have more to do with your breaker than the motor. The Rikon fan has a lot more inertia than the OEM fan and so it takes longer for the motor to reach full speed. The thermal trip part of your breaker has to withstand about 70A for 3 seconds or so. That's right on the edge of the tolerance band for some breakers. After running the DC for some time the thermal trip has already been "warmed up" and will trip sooner than it does from a cold start.

    Closing all blast gates will reduce the start time by about 15% compared to an open fan inlet and make it easier on the breaker.

    All blast gates should be closed when idling. This reduces current and so reduces motor temperature. Lower temperature means longer motor life.

    Of course it might a sticky centrifugal switch, as others have mentioned.
    Last edited by David L Morse; 04-10-2020 at 7:07 AM.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  7. #7
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    David stated it a lot better than I did.
    You stated you added a dedicated circuit for this dust collector, if it is 12 gauge or heavier copper wire then you could try a 25 amp circuit breaker to see if this eliminates the problem.Not the first choice of solutions however sometimes when dealing with fans that take time to come up to speed due to heavy rotating mass you have to upsize the breakers or fuses. Try the blast gates closed first or preferably let the dust collector run when multiple start/stops in a hour.
    Good luck
    Ron

  8. #8
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    Voltage? extra words to make it count

  9. #9
    Quote Originally Posted by Bill Dufour View Post
    Voltage? extra words to make it count
    Sorry, the HF unit runs on 120v.

  10. #10
    Quote Originally Posted by David L Morse View Post
    That issue may have more to do with your breaker than the motor. The Rikon fan has a lot more inertia than the OEM fan and so it takes longer for the motor to reach full speed. The thermal trip part of your breaker has to withstand about 70A for 3 seconds or so. That's right on the edge of the tolerance band for some breakers. After running the DC for some time the thermal trip has already been "warmed up" and will trip sooner than it does from a cold start.

    Closing all blast gates will reduce the start time by about 15% compared to an open fan inlet and make it easier on the breaker.

    All blast gates should be closed when idling. This reduces current and so reduces motor temperature. Lower temperature means longer motor life.

    Of course it might a sticky centrifugal switch, as others have mentioned.
    Thanks, that’s really helpful info about closing the blast gates and goes against what I intuitively thought (I’m used to my shop vac screaming at me when it gets clogged, and figured this would be similar with my first dust collector). Perhaps what I read about keeping at least 1 blast gate open was for people that use cheaper 30ga pipe or something. Mine is all 26ga so it’s solid.
    Last edited by Craig Andresen; 04-11-2020 at 2:22 PM. Reason: Typo

  11. #11
    Quote Originally Posted by Ron Selzer View Post
    David stated it a lot better than I did.
    You stated you added a dedicated circuit for this dust collector, if it is 12 gauge or heavier copper wire then you could try a 25 amp circuit breaker to see if this eliminates the problem.Not the first choice of solutions however sometimes when dealing with fans that take time to come up to speed due to heavy rotating mass you have to upsize the breakers or fuses. Try the blast gates closed first or preferably let the dust collector run when multiple start/stops in a hour.
    Good luck
    Ron
    Interesting, ok. I did run 12ga copper wire and thought about that potential solution but thought I may have to run new 10ga to do that. You think the 12ga would be ok do ya? Another situation is I have a dual 20a breaker (I added two new circuits in one slot). I have seen dual breakers with a 25 and a 20 so that may actually be a pretty simple solution if I can find one that fits my panel. Ultimately I probably just need to see how this situation impacts my workflow and see if the inability to restart it until the fan stops spinning causes me a lot of lost time if I turn it off but then decide I need to use another tool quickly. When I put these types of things together I want them to work without any potential issues so part of me wants to just go pick up a new unit at Harbor Freight and replace the motor in my setup (although I don’t even know if that would help!)

  12. #12
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    AFAIK #12 copper is 20 amp max breaker size. I would guess a dc is rated as a continuous load so no creativity on the ampacity is allowed. If the FLA is over 16 you are asking too much from a 20 amp breaker.
    Personally 20 amps is too low for 120 volts. Can you switch motor to 240?
    What is the FLA on the motor label?
    Bil lD.

  13. #13
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    Feb 2013
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    Tippecanoe County, IN
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    Quote Originally Posted by Bill Dufour View Post
    What is the FLA on the motor label?
    Bil lD.
    There's no label. See this post for more information.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

  14. #14
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    "so part of me wants to just go pick up a new unit at Harbor Freight and replace the motor in my setup (although I don’t even know if that would help!)"
    probably won't help much if any
    back in the late 70's was working in an old apartment building that had knob and tube wiring, 12 gauge copper fused at 60 amps with no visible signs of damage to it. I don't recommend this and would not do this. However 25 amp breaker, 12 gauge copper wire and dedicated outlet I feel would work good. The load is only there for a brief time while the motor is spinning that heavy impeller up to speed. The wire can take the load.
    Good luck
    Ron

  15. #15
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    Thank you for the information definitely informative.

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