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Thread: Oneida Air Mini Gorilla tripping breaker- help

  1. #1

    Oneida Air Mini Gorilla tripping breaker- help

    Hello,

    As the title says, my new Mini-Gorilla is tripping the breaker on startup about half the time when cold-starting. It seems to start fine once it has been running and is shut off for a short period of time. It runs on a dedicated, non-GFCI circuit that has been checked and rechecked with a diagnostic tool, the 20A 120V breaker has been swapped out without changing the problem. The line indicates 122.4V at the outlet.

    Here are the specs from the motor plate: 60Hz, 115/230V, 1.5HP, FLA 16.0/8.0, SF 1.15, SFA 17.6/6.8, KVA Code J

    From what I read online, KVA Code J is 7.1-7.99 kVA/HP. Using this:

    "The general equation for single-phase devices is the following: LRA=1000*(kVA/HP)/Voltage. "

    I get 1000(7.5/1/5)/122 = ~40A

    40A will obviously trip my 20A breaker but perhaps I am misunderstanding what the KVA Code means. I think it refers to a locked rotor- is that at all similar to a rotor in a less than ideal starting position? Or in other words- am I using the wrong thing to calculate the max load that motor can place on the circuit?

    Any suggestions on how to fix the problem appreciated. I am getting tired of walking over to the circuit breaker so often!

    I have sent 2 emails to Oneida customer service without a reply. To be fair, the second one was just this afternoon, Friday.

    Thanks!

  2. #2
    Join Date
    Apr 2017
    Location
    Clarks Summit PA
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    416
    Randy, I have the 115 Volt Oneida Mini Gorilla on a 20amp line and breaker and have had no problems since I bought it 2 months ago. Oneida, in my experience, has good customer service. Mark

  3. #3
    What size (gauge) wire is between the breaker and the outlet ?

    How many feet is that run between both ?

  4. #4
    Join Date
    Mar 2012
    Location
    Napa Valley, CA
    Posts
    902
    I have a small compressor that used to trip breakers on start-up. I changed the oil to 10w/30 motor oil and the problem stopped. 30 years ago, and it's still going strong. YMMV

  5. #5
    Join Date
    May 2008
    Location
    MA
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    Just summarizing:

    This only happens at startup.

    Which means it is not a run time issue. Motors do pull more current at startup (inertia, and field slippage is out of phase). But it sounds like it is 'close' to not tripping or only trips half the time.

    My first attempt would be to simply change the breaker that it is wired to. I have had them give out or get 'sensitive' and trip at a lower than normal level. Maybe a different breaker behaves differently.

    If the motor had higher than usual friction it might draw more. Due to heavy or cold grease, or a misalignment binding. If it gets better after running for a while first, then that might suggest warming up helps. Small misalignments help once it wears in for some time.

    Then a high voltage drop between the breaker and motor might contribute, as suggested make sure the wire is rated for the current and as short as possible.

    But I wouldnt automatically assume your breaker is working exactly as theoretical.

  6. #6
    Join Date
    Aug 2015
    Location
    N. Texas
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    1,159
    Just scatter-shooting - -
    All circuit breakers have a trip curve - the higher the amperage overload, the faster they trip.

    Most US household breakers use some version of a G trip curve. I've always assumed this means 'General purpose', but never asked. I glanced at the graph for Eaton's household CBs, and they indicate their G CBs will trip in 30-50 seconds with a 200% load - equal to your Locked Rotor Amperage calculation. (Trip times drop to 0.01 seconds as the load increases.) But bottom-line, this overload tolerance should easily allow you to ride-thru your DCs high in-rush current.

    CBs get weak and will trip prematurely if they are tripped often. Since you've swapped CBs, you can probably rule this out - - but you might consider a new one if the panel is old and you don't know the history?

    You don't mention if this is a GFCI CB? ...or has arc-flash sensing? Either of these can result in erratic performance.

    Another option is to look for CBs with a slower trip curve. Consult an electrician to make sure the wire will support this.
    Molann an obair an saor.

  7. #7
    Join Date
    Jun 2003
    Location
    Northern Michigan
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    407
    How long is the wiring from breaker to tool? Longer runs cause increased voltage drop.
    Is the wiring exposed? It could be upgraded to 10 gauge if voltage drop is an issue. Could also go to a 30 amp breaker then if desired.
    Most likely it is a motor with some startup issue such as stiff lubricant, friction or such. A replacement motor would likely solve the problem. Is this the unit with the motor inside the collector housing?

  8. #8
    Thanks for all the info and suggestions.

    The wire is 12G and the run is only about 20'. My shop is in the below-grade basement, probably 60-65 degrees in there.

    I did try switching the breaker- with another from the panel, not a new one. I will get a new breaker and give that a try.
    Last edited by Randy Hermann; 01-12-2019 at 10:54 PM.

  9. #9
    Join Date
    Apr 2017
    Location
    Clarks Summit PA
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    My electrician ran 12 gauge ( yellow color coded ) for my 20 amp service9792599F-1B7E-476E-8119-F0EB959107C3.jpg

  10. #10
    14 ga is too small for 20 amp circuit, code calls for 12 ga. But with such a short run I doubt it is causing the problem. But it's possible, because with the heavy starting draw, there will be a voltage drop, which actually causes the motor to draw even more current, which increases the voltage drop....

    Since you apparently have a meter, try monitoring the voltage at the motor while the motor is trying to start.

    Any chance you have a bad connection somewhere along the line?

  11. #11
    My mistake. I assumed all white coating was 14G, Yellow 12G, etc. It is 12G and I edited my previous post. Thanks.

  12. #12
    Join Date
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    Punta Gorda, FL
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    Your full load amps (FLA) is 16 @ 115v and 8 @ 230v. Startup amps will be higher. We normally load breakers at 80% of rated capacity, in part because they aren't perfect. You're pushing that 20A 120v breaker. If a new breaker doesn't work, you should either wire the DC for 230v (two hots) and install the extra wiring or replace the #12 with #10 and install a 30A breaker.
    “Travel is fatal to prejudice, bigotry, and narrow-mindedness..." - Mark Twain

    Diapers and Politicians need to be changed often... Usually for the same reason.

  13. #13
    I don't have room in my panel for another 240V circuit so that is not an easy option.

    The real issue is that the Mini-Gorilla is expressly sold to run on a 20A circuit and mine is not doing so reliably. I do not want to have a warranty problem 3 years from now because of a tolerance issue that has accelerated the wear on the motor or fan. Once I hear back from Oneida I will update this post.

  14. #14
    Still in the troubleshooting phase. They recommended an HACR type breaker, which I have. At their recommendation, I removed the air filter and the fan turns freely by hand, only slight dragging noise from the brake mechanism. I plugged a 1500 watt portable heater in to the outlet and turned it on to highest setting then plugged in my old Ryobi table saw which supposedly has a 15A motor- everything worked just fine.

    From what I have read online, it sounds like there may be a problem with the starting capacitor. When did Oneida switch from Baldor to Bluffton Motor Works for their motors?

    Just heard back from them and they are shipping out a new motor assembly. Yay!

  15. #15
    Join Date
    Apr 2017
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    Glad to hear Oneida responded right away. As I said earlier they are a quality company.

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