coleman powermate air compressor ac motor problem

Discussion in 'General Electronics Chat' started by james69z28, Jul 18, 2011.

  1. james69z28

    Thread Starter New Member

    Jul 18, 2011
    4
    1
    My dad has removed both the start and run capacitors on his 6.5 hp ac motor but due to previous strokes and health problems his sketch didn't match when he tried to put the 6 wires back on. I went and checked and the new cap he bought checks good (run cap) and the start cap checks good but I tried several different ways and can get it to start and run un til it is charged with air pressure then it will not start back up it trips off the protective breaker. so it appears that the starting cap is not wired correctly. to save a lot of trial and error I was wondering if someone had any pics of theirs so i can see the wire colors?
    the model of the ac motor is magnetek century ac motor model # 8-186372-01 3450 rpm.
    right now I have an orange and white wire on the run cap (which has the lower capacitance value ) don't remember but maybe 30 micro farad.
    on the starting cap there are 4 wires a white, blue,blk,and red.

    since I never saw it before he disassembled it it may have 3 wires on each cap I can't find any wiring diagrams anywhere? HELP pleas!

    the compressor is a coleman powermate model # cv6548049 80 gal 6.5 hp

    I did pull the back motor end off and internally there is a starting centrifugal switch that has a white wire on one side contact and a red on the other side, this should kic out the starting cap once the motor is spinning---It appears??? answer to james69z28@aol.com Thanks for the help.
     
  2. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
    141
    Are you sure it isn't a 13 or 15 hp compressor? The marketroids at the air compressor companies are known for grossly underestimating the true power of their air compressors. :p

    Sorry, can't help with the wiring, but I couldn't resist a bit of levity...
     
  3. james69z28

    Thread Starter New Member

    Jul 18, 2011
    4
    1
    the tag states 6.5 hp and 80 gal. tank
    i am pretty sure that it is 6.5 hp if it were more they would jack the price up.
     
  4. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    how can you get it to start and run if the starting cap is not wired correctly?

    When the breaker trips, you have reset the breaker; it won't reset itself.

    a 6.5 hp motor on single phase (I assume 120v?) is going to draw a ton of amps. the load is going to get higher the more pressure you build up. it's likely your breaker is undersized and you compressor is wired correctly
     
  5. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    If it starts and runs OK when the tank is empty but fails to start when the tank is pumped up, it sounds more like the unloader valve isn't doing its job. It is a valve that allows the air pressure in the line between the tank and the compressor to relieve to zero PSI when the motor shuts off. That allows the motor to get started with little load other than getting the flywheel moving.
     
  6. Pencil

    Active Member

    Dec 8, 2009
    271
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    Here's a manual. It doesn't have a wiring diagram.

    Parts Manual

    I appears to be 208-230V, 22A, single phase.

    Unloader valve is shown

    Edit: I had a whole different post, BillB cut to the chase while I was typing.
    I was probably wrong any way.

    Good Luck
     
    Last edited: Jul 20, 2011
  7. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Do compressor manufacturers have a different formula for calculating horsepower? I was a little suspicious of my "5HP" single phase 110V compressor. The motor is (physical size) no larger than a common 1hp or fractional horsepower motor. What's the deal?
     
  8. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Many manufacturers grossly overstate the HP of the motors on their compressors as a marketing ploy. I bought a "5 hp" Campbell/Hausfield compressor years ago that runs on 120vac. If it were really 5hp, the motor would draw around 31A while running. It draws less than half that.

    I'm afraid I can't help our OP with their question either.
     
  9. strantor

    AAC Fanatic!

    Oct 3, 2010
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    That's the brand of 5HP compressor I have. Walmart brand.
     
  10. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,765
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    I suppose some manufacturers believe their customers don't(or won't) do simple math to figure out what is and is not possible.

    1 HP in electrical terms equals 745(or 743) watts, depending on the book you consult.

    The average household 110V 15 amp electrical circuit can supply a maximum of 1650 watts. This equals a maximum horsepower rating of 2.22, which can be drawn from the circuit without causing circuit breakers to 'pop', or fires to start inside the walls of your home

    :)
     
  11. EVETS

    New Member

    Jan 29, 2011
    21
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    It's possible it's wired correctly. If the compressor turns off and you hear air coming out for a while, the unloader's ok. If air is coming out constantly, the check valve may be stuck. It's the spring loaded fitting that goes from the compressor head to the top of the tank. They get gummed up with burnt oil and heat. You can pull it and clean it or replace it. They're pretty cheap. I've seen a lot of them.
     
  12. james69z28

    Thread Starter New Member

    Jul 18, 2011
    4
    1
    ok, guys I got everyone off subject some but here's more info, i have swapped the wires around several different configurations and so far the way i have both caps wired will start the compressor (0 air press.) and it runs fine until it shuts off at 175 psi but when we drain it down it doesn't have the torque to restart and yes the unloader appears to be working correctly, i had even maually unloaded it and the same results. both caps are good, so through all the troubleshooting I have done, it appears that I just have a couple of wire combinations wrong that's why I was hoping someone had one of these coleman powermates and could take a pic and post it to help?
    and obviously the reply was correct if this was 120 v the amp draw would be way way too high-- it is a 230 v motor.

    more clarifications: when I let it try and restart after pressurizing up and draining to get it to start it attemps to start and deadheads until the manual rest breaker trips. hope this clears up some questions, still hoping someone can post a pic or two. thanks for the link to the manual, but we have it, and of course they just buy century ac motor (with caps already on it) and bolt it on so it won't show the wires i'm looking for. I went to Lowes today and removed the cover from 3 different compressors all different brand motors (1 was a century- like ours) but they are all wired with different colors and number of wires than our much older one?
     
  13. EVETS

    New Member

    Jan 29, 2011
    21
    2
    It's possible your wiring is not up to the task. If you're a distance away from the service, you may be getting a huge voltage drop at the motor. Under load, the "5 hp" motors draw a lot of amps. If you can, check the voltage at the pressure switch when the motor starts. I've seen motors draw the line voltage to 180 volts when starting. It won't work. Just a thought.
     
  14. whale

    Active Member

    Dec 21, 2008
    111
    0
    Hey guy, the problem is your motors high current protective switch trips of due to overload. And the air pressure at your compressor is not the problem for overload. The input wire for your motor draws more current and thus the protective switch trips off in order to protect your cable. This is because your capacitor sinks more current. You would have fixed a capacitor with more farad than required.
     
  15. james69z28

    Thread Starter New Member

    Jul 18, 2011
    4
    1
    OK, problem fixed! finally!
    guys thanks for the input, I found two problems,
    1. the wiring for the caps was obtained from AO Smith distributor, he was nice enough to take my motor model # and call AO Smith and within 10 min. they e-mailed me the wiring diagram, for everyones future reference when running across this thread here it is:
    the run capacitor (in this case 50 MF) had the Blue and White wire on one termminal then on the other terminal an Orange jumper went from the other run cap term. to a terminal on the starting cap. which also had a Black wire on it, then on the other term. of the starting cap there was a red wire. the other ends of the red and white wire went to the centifugal switch contacts under the rear motor cover. hope this makes sense!
    2. the check valve that was screwed into the tank and all air flowed through it into the tank then when the compressor shuts off the check valve closes as the air tries to flow back out of the tank it was sticking so the unloader switch just kept spewing air until the tank pressure dropped from 175 (cut off setpoint) til it was down to about 110 psi. I removed the check valve and cleaned it and put it back in and now on the second start (after the tank is charged up) it isn't starting against air pressure (empty compressor head cylinders)
     
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