I have a Harbor Freight dust collector (SKU 59726) - it's a 2HP 14A 110V single phase motor. It has been running for several years, and has not been abused (just well-used). However, it now trips its dedicated, non-shared breaker about 3 seconds or so after starting, and I would like help figuring out why. The starting capacitor looks OK. Cables look good. The motor spindle turns freely. Do not recall seeing any magic smoke, or hearing unusual noises. Appreciate thoughts on how to debug, or should I just bite the bullet and get another one?


  1. Regular breaker - not GFCI. Why do I think it's the motor and not the breaker? Because I connected the motor to a completely different outlet somewhere else in the house, and exactly the same thing happened (again, non-GFCI).
  2. Instructions are here: https://manuals.harborfreight.com/manuals/59000-59999/59726-193175483607.pdf It says: Electrical Rating 120VAC / 60Hz / 14A 2HP, Single Phase Speed 3450 RPM Bag Capacity 35 Gallon Bag Filtration Ratio 5 Microns Inlet 4″ Air Flow 1550 CFM

There does not seem to be a plate on the motor itself.

  1. The specific request is: what can I do to stop the motor from tripping the breaker, is there some adjustment on the motor that I can make? Or does my issue mean that the motor has somehow just "died" necessitating a replacement?
  • 1
    Is the breaker that trips an ordinary breaker or AFCI or GFCI? If you are not sure then (a) if it has a TEST button then it is definitely AFCI or GFCI. If you are not sure, upload a picture. But basically there are certain types of problems that can happen with motors over time that will trip an AFCI. Commented Dec 26, 2023 at 20:54
  • 1
    Can you google the instructions? Can you look at the nameplate? What do they say about circuit and breaker size? Commented Dec 26, 2023 at 23:13
  • Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
    – Community Bot
    Commented Dec 27, 2023 at 2:04
  • Thanks for the responses - see my edits above.
    – Adam Mac
    Commented Dec 27, 2023 at 21:06
  • What else is on that circuit? 14A motor plus almost anything will blow a 15A breaker.
    – keshlam
    Commented Dec 27, 2023 at 22:30

2 Answers 2


So I ended up speaking with a company that repairs eletric motors. They were saying that for motors like this, it's often easier to just get a new motor than it would be to take apart, diagnose, and fix. Which I guess shouldn't come as too much of a surprise, as the motor came from Harbor Freight in the first place. So I went and got a new one, and it obviously works just fine.

The biggest problem I had was taking the old impeller off and putting my "upgraded" Rikon version on - there was a bit of rust on the new motor's spindle causing the difficulties, and I had to use my huge 15" adjustable wrench (and plenty of force) to get the thing off with a puller. Bit of sandpaper and WD40 and the spindle is as good as new, and the new impeller went on just fine.


I would start by disconnecting the motor from the frame and see if it trips the breaker without driving the fan/blower. If the motor alone doesn't trip the breaker start looking for an obstruction. It could be a build-up behind the squirrel cage or the cage itself rubbing on the housing. The filter bag may also be clogged by fine particles. If the breaker trips with just the motor start looking for a voltage drop between the breaker and the switch. The check across the switch. If you are running at reduced voltage you are increasing the amperage load.

  • I did my testing with the motor connected just to the impeller. It all looks pretty clean, and the impeller blades turn very easily - don't think that's the issue.
    – Adam Mac
    Commented Dec 27, 2023 at 23:41
  • I did my testing with the motor connected just to the impeller, so no filter bag getting clogged (anyway, I have a custom cyclone thing that feeds into a big barrel, and a massive air filter). With the air filter and cyclone disconnected altogether, it all looks pretty clean, and the impeller blades turn very easily - don't think that's the issue. Generates a good bit of wind, even in that 3 seconds. I also tried connecting to a completely different outlet - same tripping behavior. So unlikely to be a fault with the breaker.
    – Adam Mac
    Commented Dec 28, 2023 at 0:11

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