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Thread: Need help from the motor gurus

  1. #1
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
    Posts
    6,529

    Need help from the motor gurus

    The motor on my Jet 15” 4-post planer stopped working. Was working one minute, then it didn’t turn on. No smells, Magic smoke or anything. I replaced the capacitor to no avail. Could it be the switch?

    heres a video:
    https://youtu.be/6FGsd-BrlcA

    and the motor tag is attached too.

    Any help would be greatly appreciated as I’m in the middle of a commission.

    Thanks
    Attached Images Attached Images

  2. #2
    Couple of things to try - and you may have done some of them.

    First, get a meter and turn power on to the motor and check the voltage on the two wires that are the "line" to the motor (where the wiring goes into the motor - take the plate off and measure at the connections of that wire). If you're not getting voltage, then your off-on switch may be bad. If you have power, go to step 2

    Step 2: You might have a problem with the centrifugal switch. To test for that, take the load off the motor (remove the drive belts) then power the motor and spin the shaft (either way). If it starts, you probably have a problem with your centrifugal switch since you already changed the start capacitor. Take the motor apart and clean the centrifugal switch.

    If you have power to the motor and it won't start by spinning it, you probably have something open in the motor circuit (inside the motor). Check all the wiring and connections and see if you can find anything loose.

    If not, check for continuity across the field of the motor. If you don't have continuity, you have a break in the field wires (very uncommon). If you have continuity, I can't offer any other solutions. Maybe someone else will have some ideas.

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

  3. How comfortable/knowledgeable are you around live circuits? Not knowing this, I'd recommend tripping the circuit breaker and check all the terminal connections from your power panel to the motor. You may just have a loose connection somewhere.

  4. #4
    Yes, David points out an important thing. Make sure you have power at the outlet.

    I often forget that very important step.

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

  5. #5
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    9,876
    Unplug the saw and check to see if there is power at the outlet. Easy to do if it 120. If it is 240 you need something nearby with the same plug on it or a meter. After that follow what the others have said already.
    Bill D

  6. #6
    A couple of important points.
    When checking for voltage, at the C/B, the receptacle, or at the motor connections, you'll want the circuit HOT.
    BUT, when checking for CONTINUITY, make sure you pull the plug.

    Ed

  7. #7
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
    Posts
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    Thanks guys. There is power - if you watch the video you can see the motor clicks on for a second but doesn’t turn over. I’ll dig into the other suggestions this morning, starting with blowing out the motor and switch. I’d really like to avoid removing the motor, as it’s really tucked in there inside the cabinet. But of course I will if I have too.

    Thanks!
    Last edited by Matt Day; 02-01-2018 at 7:46 AM.

  8. #8
    Quote Originally Posted by Matt Day View Post
    ... There is power - ...
    Always a good idea to check voltage with a meter, even if a $15.00 HF or equal. (Think about a car battery on it's last legs - the starter engages, but engine won't turn over - it's the voltage not the connection.) There may be power at your motor, just not enough...? That said, the other replies are sound advice - and assuming you do have correct voltage at the motor - sounds like the motor may need surgery.

    I was taught to look at electrical problems using 'law of halves': check the middle of a circuit for correct power; if it's OK, then the issue is in the downstream 'half'; so check in the middle of that half ... repeat until you isolate the issue.

  9. #9
    Check that the motor is not stuck. Can you spin it freely?


    If you have verified:
    Spins freely/not stuck
    Capacitor good
    Has electricity


    Then as a practical matter - the motor is dead. The problem is "inside" the motor.


    Perhaps a motor rebuilder could get it going.... Usually that money is better spent on a new replacement motor.

  10. #10
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
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    Not exactly John, the magnetic switch is also a possible problem.

    I eliminated the motor as the problem - I bypassed the switch and put a plug directly on the motor, spun right up when plugged in.


    What can I check on the mag starter? I blew it out with air and it didn’t do anything. Also note, that holding the on button doesn’t change anything - in my brief research I found some people saying the machine stays on if it’s manually held down.
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  11. #11
    Join Date
    Jan 2007
    Location
    Ft. Lauderdale, Fl.
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    72
    Is the reset button popped out? did you try and press it? It also looks like that starter is for a 5HP motor. If you look at the current rating on the overload switch it is set for 22Amps where your motor draws 14Amps max.

    Larry

  12. #12
    If you have a meter, set it for continuity/resistance (ohms), unplug the planer, and put the meter test leads on #1 and #2 lugs. Then manually engage the starter (Press the 'H' under the "JDE" label). The meter should read at or near 0 ohms (certainly less than 8-10ohms).

    Repeat this for #5 / #6 lugs.

    If either shows high resistance, you can move the associated wires to the unused L2 pole (#3 / #4 lugs). If both the L1 & L3 poles are reading high you can: 1. disassemble and try to gently file the crud off; 2. get a re-build kit for your contactor and replace the contacts; or, 3. get a new contactor.

    ...my best guess.
    Last edited by Malcolm McLeod; 02-01-2018 at 12:27 PM. Reason: typo

  13. #13
    Ok, so it's the starter, not the motor.

    And when you press and hold the button, it doesn't turn the motor on.

    So: just double-triple check that you have 240V on the black and white wires at the top of the contactor. If so, check the voltage on those 2 brass bars between the contactor and the overload (the "top piece" and the "bottom piece"). The voltage between those brass bars should go to the input voltage when you press the black button in.

    If you have voltage on those, but not on the red/black wires going to the motor, then your problem is with the overload. As Larry said, is it tripped? Press the red reset button.

    If you don't have voltage on those brass bars, you've got some contacts in the contactor that are fried.

  14. #14
    Join Date
    Dec 2005
    Location
    West Lafayette, IN
    Posts
    6,529
    Great, thanks for the advice guys. I’ll do some testing later this afternoon.

    I noticed on the bottom left of the contractor sticker that there appears to be a brown burn type mark.

    I’ll report back.

  15. #15
    Oh, one other thing - by "on button", are you referring to the little square black button? That button applies voltage to the contactor coil - essentially an electromagnet that pulls the main contacts closed. The "H-shaped" button (that Malcolm mentions) is attached directly to the main contacts, and can be pressed to manually close the main contacts (without the use of the coil).

    So: if you press the little black button and nothing happens, you could have a failure of the coil, or of the contacts.
    If you press the big "H" button and nothing happens, your problem is certainly with the contacts.

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