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Thread: Blowing fuse on Cyclone dust collector

  1. #1
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    Blowing fuse on Cyclone dust collector

    I have a PSI Tempest 1535S that's been running fine for 4 years in my shop. Now, it's blowing a 15A slow-blow fuse on one leg when I start it (240V, 30A breaker, 3.5 Hp motor). There's been no recent change to my circuits. Before I begin troubleshooting, I hope someone has ideas on where to start.

    Thanks,
    Mike

  2. #2
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    sounds like starting capacitor or centrifugal start switch hanging up

  3. #3
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    Time the coast down and see if that is noticeably shorter. If so bearing is bad. I agree check starting capacitor and if that is not it blow dust out of the switch.
    There is a chance the switch gear needs contacts cleaned. I would try to start it and watch voltage supplied to the motor.
    Bill D

  4. #4
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    Quote Originally Posted by Mike Stelts View Post
    I have a PSI Tempest 1535S that's been running fine for 4 years in my shop. Now, it's blowing a 15A slow-blow fuse on one leg when I start it (240V, 30A breaker, 3.5 Hp motor).
    Thanks,
    Mike
    I'm confused. Where in a 240 volt 30 amp circuit would you have a 15 amp fuse?
    NOW you tell me...

  5. #5
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    Quote Originally Posted by Ole Anderson View Post
    I'm confused. Where in a 240 volt 30 amp circuit would you have a 15 amp fuse?
    Good point. Still, why after 4 years did it start blowing fuses? What is the FLA (full load amps) number on the motor's data plate? A 3 h.p. 240 motor typically draws 12 - 15 amps @240 volts so 15 amp fuses would be maxed out. Maybe beg, borrow or buy a clamp-on ammeter and see how that number compares to what the motor should be drawing.

  6. #6
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    Thanks everyone. I'm waiting until I've finished installing windows (without using my shop) and I'll figure this out.

  7. #7
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    Just an added note from someone who has had bad caps and bad cent switches in the past. I'm no expert, just been there. A blown cap is easily detected if it is good enough to blow its innards all over the inside of the cover. Less dramatic failures will show an oily, waxy, or stringy residue at the rupture or inside the cover housing / area. Some just swell badly at a specific point like a bad battery or canned food that's gotten lost at the back of the pantry for too long.

    A bad cent switch is a little trickier if you aren't familiar with how they work or normally sound. If your motor is in the shop you are probably familiar with the small change in sound just before the oomph of the startup cycle sound changes to the normal speed sound of the motor. You are probably also familiar with the click of the weighted switch arms snapping closed once the motor slows down once the power has been turned off.

    You are possibly experiencing something like this right now:
    - You turn on the unit like normal.
    - It makes the usual oomph sound at startup.
    - The oomph sound lasts a bit longer than normal.
    - The breaker trips.

    Here's what I would be looking for under those circumstances (its my first guess so ignore this if I'm off target):
    - Unplug the beast.
    - Remove the capacitor covers or cover plate.
    - Look for the signs mentioned above for a cap failure.

    Everything looks good? Moving in . . .
    - Remove the motors bell cover opposite the fan end.
    G0440-cent-clutch 1.jpg
    - Remove the fan.
    G0440-cent-clutch 2.jpg
    - Remove the dust cover.
    G0440-cent-clutch 3.jpg
    - Look at the cent switch under the dust cover.
    G0440-cent-clutch 4.jpg
    - I use a felt pen to mark the shaft and clutch so I can put it back in the same place / height.
    G0440-cent-clutch 5.jpg



    If there is nothing obvious like small pieces of plastic of metal that have broken off, look at the contacts. There may be some minor electrical burn from years of use but they should otherwise be nice and clean. In fact the whole are should be nice and clean. If it is full of crud for some reason, blow all that out and re-test . . . you may have just fixed it ;-) That's quite a list so let's get that far and see where we are.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  8. #8
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    Quote Originally Posted by Ole Anderson View Post
    I'm confused. Where in a 240 volt 30 amp circuit would you have a 15 amp fuse?
    Motor protection. It's more common to have an overload relay but a fuse is also acceptable. Typically 115-125% of FLA if no overload relay is present.

  9. #9
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    I tried a simple shortcut to move on with without diagnosis. I have this unit hanging near the ceiling, so any diagnosis is at least 3 hours. I changed the fuses on both legs to 30A. So far, so good.

  10. #10
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    Quote Originally Posted by Mike Stelts View Post
    I tried a simple shortcut to move on with without diagnosis. I have this unit hanging near the ceiling, so any diagnosis is at least 3 hours. I changed the fuses on both legs to 30A. So far, so good.
    I presumed most dust collectors came with a magnetic starter with built in overload protection, something beyond fuses. To go from 15 amp overload protection to 30 amp is a risky jump, I would have gone to 20 amp slow blow fuses or simply installed an adjustable magnetic starter in place of the fuses. But determining why the fuses now blow when they didn't previously is important.
    NOW you tell me...

  11. #11
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    Quote Originally Posted by Ole Anderson View Post
    I presumed most dust collectors came with a magnetic starter with built in overload protection, something beyond fuses. To go from 15 amp overload protection to 30 amp is a risky jump, I would have gone to 20 amp slow blow fuses or simply installed an adjustable magnetic starter in place of the fuses. But determining why the fuses now blow when they didn't previously is important.
    I'd go along with the 20 amp fuses. It would still be good to know what the motor is actually drawing compared to FLA (full load amps) on the motor's data plate. If the motor is drawing more than FLA, gotta wonder why. We do have to remember that dust collectors can be starting under a pretty good load unless all blast gates are closed. Even if there is no air moving, the fan on most dust collectors is heavier than a table saw blade for example so more mass to get up to speed.

  12. #12
    Quote Originally Posted by Mike Stelts View Post
    I tried a simple shortcut to move on with without diagnosis. I have this unit hanging near the ceiling, so any diagnosis is at least 3 hours. I changed the fuses on both legs to 30A. So far, so good.
    Trouble-shooting any electrical system by blowing fuses can get expensive in a hurry. If for no other reason, I'd look hard at a resettable thermal overload, or properly sized supplementary 2-pole CB (even if you install it on/at/in the DC motor controller). Example Depending on your supply panel CB size, I'd probably use a 20A C- or D- trip curve.

    One other issue to consider is the supply voltage. I've measured as much as 258VAC at times on a nominal 240VAC circuit. If Mr. Stelts' utility provider has been consistently delivering 'high' voltage in the past, but for some reason reduced it now (plant maintenance?), then a 15A fuse may no longer suffice....?

    ...a good quality DMM (meter) is a beautiful thing.
    Last edited by Malcolm McLeod; 06-20-2022 at 11:57 AM. Reason: NEMA lookup says 20A, not 15A (see other post)

  13. #13
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    Quote Originally Posted by Mike Stelts View Post
    I tried a simple shortcut to move on with without diagnosis. I have this unit hanging near the ceiling, so any diagnosis is at least 3 hours. I changed the fuses on both legs to 30A. So far, so good.
    Not as bad as a penny in the fuse socket, but it's a good idea to understand the original issue and use the correctly sized fuse. What is the current rating on the motor? The nameplate also sometimes has a KVA code which gives an indication of the locked rotor current.

  14. #14
    Quote Originally Posted by Curt Harms View Post
    Good point. Still, why after 4 years did it start blowing fuses? What is the FLA (full load amps) number on the motor's data plate? A 3 h.p. 240 motor typically draws 12 - 15 amps @240 volts so 15 amp fuses would be maxed out. Maybe beg, borrow or buy a clamp-on ammeter and see how that number compares to what the motor should be drawing.
    ^+1
    Something seemed off, so I pulled out a handy old pocket motor handbook. NEMA. But it's old. And it doesn't list 3.5hp motors. And it's old. And it's mostly for wire sizing. However, a 3Hp, 1-ph, 230VAC (nom) motor is listed with a FLA of 17A. So, some quick napkin math says 3.5Hp would need right at 20A to run at full rated Hp capacity.

    I'd guess that using long and/or small duct(s), and a good measure of luck, are all that allowed Mr. Stelts to ever operate this DC on 15A fuses. Certainly seems like it can't have been producing its rated power.

    (30A may be overkill, but they're better than 15A - - assuming proper wire size.)

  15. #15
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    Thanks for all the useful comments. I will save this information. (I've never figured out Sawmill search.) I forgot to mention that the fuses are in a custom-made industrial control box that handles my remote switches, timer, and bin-full sensor. They are in addition to any current-limiting in the dust collector (and the circuit breaker). The motor's current rating is 19A, so 20A Littlefuse CCMR should be sufficient.

    For that reason, and the fact that I don't want to pull down a 250 lb. unit from the ceiling right now, I'm going to assume that my power usage has increased slightly and the under-size fuses are no longer appropriate. I realize a good clean-up would be appropriate; but, my schedule can't accommodate it right now. I've already scheduled a filter cleanout and will check the points everyone described then. I'll probably also replace the starter cap, because it's sure to fail soon if I don't (Murphy's Law).
    Last edited by Mike Stelts; 06-20-2022 at 1:07 PM.

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