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Need help with 12v DC air compressor wiring

Discussion in 'The Garage' started by randy88k5, Sep 4, 2006.

  1. randy88k5

    randy88k5 1/2 ton status

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    Ok, some background. I purchased ths pump a long time ago. They still have them on ebay

    http://cgi.ebay.com/12v-1-5-gal-air-compressor-Puma-6-50-Ship_W0QQitemZ180022942095QQihZ008QQcategoryZ11751QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


    [​IMG]

    So, about a year ago, I decided to take off the pressure cut off switch and wire the air compressor through a relay, and controlled by a rocker switch in the cab. So, I would leave the regulator plumbed into the air line, and just have the compressor running when I need the air, and just have the excess bleed out into the engine compartment (I have it mounted under the hood [now] with remote air resovoirs [future])

    Well, after I have already wired it to the relay, I am having second thoughts. I am going to use this to supply air for my ARBs mainly, but also to run air tools if needed.

    I was thinking that if I turned the compressor off while offroading locked, and the air bleeds down without my noticing (I have an air gauge easilly seen), the ARBs could unlock while in use, and I dont want that.

    So now, Im thinking about wiring that switch back into the mix, but I want to be able to turn it off electrically with a rocker switch regardless of pressure. So, I took it apart over a year ago, and I dont realy remember how it works. I have pictures...

    In the picture of the regulator portion, I had left a screw loose so I knew what one to reattach it to if I wanted, but I forget if it was the positive or negative wire (the compressor has the customary red/black wires). The screwdriver is pointing to that particular screw.

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    I am using the standard 4-pin style box relays. How would one go by wiring this. Thanks for the help guys and sorry for the long read. Just wanted to put the info out there.
     
  2. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    Screwdriver is the red/hot/positive post......I think. Ground/negative/black is the one closer to the bow off valve.

    If it's 12VDC, it will run back wards if you connect it back wards. If it does, just swap 'em.

    Don't forget to use a fuse or circuit breaker!
     
  3. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    How about a photo of it beside something to judge the size of it by. :laugh:
     
  4. randy88k5

    randy88k5 1/2 ton status

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    Yeah, I knew it would run backward, just didnt really want it too.

    I cant remember if 1 or 2 wires went into this thing. The 2 smaller screws near the blow-off valve are for setting the cut-on and cut-off pressures. All of the other screws are tight, so I dont think I took anything else off. There is a ground screw near the rubber gromet though, but it weas not loose either.

    Um, I cant find any tape measure right now, but the screwdriver in the picture is the Craftsman precision ones, and the silver part to the tip is exactly 3".

    Yes, it is wired to a fuse right now.

    So, would the relay load wire go to one of those "motor" screws?
     
  5. Muddytazz

    Muddytazz 1 ton status

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    There should be 2 wires going in/out of the pressure switch.....1 would be a wire going to the pump motor and 1 would be from the power source.

    When I wired in my york, I have a relay in my circuit and a in-cab manual switch.
     
  6. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    I was interested in the size of the whole compressor. :wink1:

    Power supply------positive from the manual switch/fuse/CB or the relay
    Ground------------to ground
    Motor-------------to the motor

    You would use the manual switch to turn on the relay that then in turn, turns on the pressure switch, which then turns on the motor.........
     
  7. randy88k5

    randy88k5 1/2 ton status

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    Sorry Dontoe, I misunderstood :doah:

    I borrowed that pic from Ebay

    Heres what you wanted:

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    [​IMG]
     
  8. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    That's a nice compressor......Hmmmmmmmmmmm.......I need to upgrade!



    My "little" one............
    [​IMG]
     
  9. diesel4me

    diesel4me 1 ton status Premium Member

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    Tell me how!..

    How are you going to run that compressor,that on the tag says its 125V AC or 250V AC,on 12 volts??(or is that the pressure switch I'm looking at??--if so,will it work on DC as well??)..using an inverter or generator??...just wondering...:crazy:
     
  10. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    Yep, that's his pressure switch.
     

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