Announcement

Collapse
No announcement yet.

wiring 240 volt magnetic starter for compressor

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • wiring 240 volt magnetic starter for compressor

    Thought I'd ask about wiring a magnetic starter switch for a 240 volt compressor.

    Looked at one done similar, but forgot most of how it was wired up.

    Anyway , What I figure I have to do is run the power leads to L1 and L2

    And the motor leads to T1/T5 and T4/T8.

    The pressure switch to the L1 and L2 positions..even though no seperate spot to hook them on this mag switch.

    Hook the ground to where ever the end up, on the pressure switch, mag switch and power waire from source.

    I plan to use 8-3 for the power and the wire to motor. Can I assume 12-3 will do for the presusre switch.

    Pic attached of mag switch . motor plate. Mag switch list 5 hp single phase on side also. Motor sems a bit heavy draw at 26 amp at 230 volt.

    I'm not doing it toddya..but finnaly have the stuff to do it I figure.

    Looking for a bit of re-assurance I'm on the right track.

    I have a 1976 devilbiss with a 432 head with 60 gallon tank.

    I'm going to see if I can make it run off a 5000 watt HONDA generator, which probably only will give 18.8 amps.

    I saw a few posts on changing pully size to reduce amp draw. It will be an attempt first anyway.

    Thanks,
    Knuk
    Attached Files

  • #2
    stop, that starter is way to light duty for your motor! That is a 5 hp starter, you have a 26 hp continuous duty motor. On a side note, that motor may draw up to 60 amps when it starts(at full load, on startup), that generater will never start it let alone run it. How much air do you need, that a 26 hp motor is creating?
    Trailblazer 302g
    coolmate4
    hf-251d-1
    super s-32p
    you can never know enough

    Comment


    • #3
      How you figure he has a 26 hp motor? But I agree it isnt even worth thinking about the genset on this comp and one would wonder "why" anyway?

      Comment


      • #4
        Compressor Mag Start

        The mag start will probably work, you usually want to over rate a starter though. You have a 5hp comp , I would go to a 7 hp rated starter. The 26Amps is probably a startup amperage (inrush). This will probably go down once the compressor is running but that 5500watt gen set won't handle the inrush voltage it will take to start the unit. Actually the inrush voltage will probably be closer to the 30 amp range. I have a comp similar to yours (5hp dual stage 80 gal) the start up amps on it are 34,(actual with a clamp on meter) then they drop to 18 when the comp is running. Even wired for high voltage (220/240) that gen will not handle the amps.

        Hope this helps

        Comment


        • #5
          You need to bring L1 & L2 from power source to L1 & L2 at the top of the starter

          Take L1 & L2 from bottom of starter to line side of pressure switch (assuming you have a 2 pole pressure switch)

          Wire motor leads to T1/T5 and T4/T8 to load side of pressure switch.

          26 amps is Full load Amps for a 5 hp motor and the Inrush amps could be twice that. Does your compressor have an unloader?

          Your honda generator sill never be able to run a 5 hp motor

          Bruce

          Comment


          • #6
            I appologize, I was looking at 26 amps, and thinking 26 horsepower. Sometimes I am an idiot.
            Trailblazer 302g
            coolmate4
            hf-251d-1
            super s-32p
            you can never know enough

            Comment


            • #7
              Knuk,

              Bruce gave you the correct wiring info. I couldn't see the contact rating on the mag starter's nameplate, but that motor will draw 26 amps at full load, and, as stated, depending on it's winding and capacitor arrangement, might pull anywhere from 35 to 50 amps to start, especially if your compressor has no unloader.

              There's no hope of running that motor from a 5KW genset, even by changing the pulley arrangement.

              Hank
              ...from the Gadget Garage
              Millermatic 210 w/3035, BWE
              Handler 210 w/DP3035
              TA185TSW
              Victor O/A "J" series, SuperRange

              Comment


              • #8
                I was reading the numbers on the mag switch cover which to me looked like this mag can handle 35 Amps max load. Pic attached.

                The mag has another sticker on the side saying single phase 230 volt 5hp rated, pic attached.

                The compressor is a 1976 Devilbiss with a 432 model head and 60 gallon tank, pic attached. Unloader.....not sure? I heard it run and seemed to exhaust at end of cycle to clear things out and avoid starting motor on compression.

                I thought I was there with what I needed...am I way off?

                I can see the amps of a generator not covering it...but I was hoping I could drop the amp draw somehow.

                I could maybe get a 3hp motor with a swap type deal.

                Remote location, so no power but generator.
                Attached Files

                Comment


                • #9
                  The pressure switch has 4 poles. Only 2 seem ever used.

                  The bottom of the mag switch has markings of T1-T2...while the top has L1-L2

                  I would need a counter clockwise rotation according to the arrow on the compressor head, so I think I was right in the T1-T5, & T4-T8

                  I thought that the power was just activated by the pressure switch, not connected to it in it's path to the motor.

                  The motor has 3 capacitors on the top of it. Not sure how there wired, but it did work.

                  Looks like this model could of had an unloader according to the devair site, although its probably the older style which dosent seem to be shown.
                  http://www.devairusa.com/Devair_Pump...ns_pdf/432.pdf


                  Thanks.

                  Comment


                  • #10
                    Just thought I'd throw it back up top to see if anyone had any tips.

                    The mag switch good enough to go?

                    Pic of the compressor head in above post...dosen't look to be an unloader as shown on the devair site link, but that's newer style in link compared to pic of actual.

                    Knuk

                    Comment


                    • #11
                      Originally posted by Knuk
                      Just thought I'd throw it back up top to see if anyone had any tips.

                      The mag switch good enough to go?

                      Pic of the compressor head in above post...dosen't look to be an unloader as shown on the devair site link, but that's newer style in link compared to pic of actual.

                      Knuk
                      You have a better chance of starting a 3 HP motor. If you put a pully on it half the size of the one you have so, you would slow the compressor by half so 3 hp should work with half the output---unless of course it is a compressor that expects the higher speed to make the lubrication system work or something and then soon you have no compressor.

                      IF you happen to have a Miller Bobcat around--- even the older 16 HP
                      models---they put out 8KW and will start a 5 hp motor---barely.
                      rvannatta
                      www.vannattabros.com
                      Miller Bobcat 225G
                      Miller Big 40 ('79 gasser)<gone>
                      Miller 375 Plasma cutter<gone>
                      Lincoln Vantage 400
                      Lincoln Pro-Cut 80

                      Comment


                      • #12
                        Knuk,

                        How did you arrive at the 5-hp motor decision? From the pic's of the pump, I'd say it's a 10-horse, or at least 7.5.

                        What is the displacement of the two cylinders? Is it stamped on the pump? Units I've seen with pumps that big are usually driven by motors larger than 5-horse.

                        Hank
                        ...from the Gadget Garage
                        Millermatic 210 w/3035, BWE
                        Handler 210 w/DP3035
                        TA185TSW
                        Victor O/A "J" series, SuperRange

                        Comment


                        • #13
                          The specs for this compressor head were available on line in the .pdf I had linked above. This is it http://www.devairusa.com/Devair_Pump...ns_pdf/432.pdf

                          It's a 4 cylinder pump...2 cyl's are 3.25 and 2 cyl's are 1.75. The stroke is 3.5.

                          Specs say the pump will run on a 3 hp up to a 10 hp.
                          It was running on this 5 hp as shown now attached in this pic. It ran on that motor so thats what I happened to get. I traded off my 3hp motor I had to friend who has a 3 phase 3 hp... hence needed a single phase for his Ingersoll Rand 1963 era Model T30.

                          My devilbiss has 19 inch flywheel and the motor pulley is 8 inch ( outside edge diameters). So with a 1740 rpm motor according to this site http://www.aircompeq.com/formulas.html
                          the pump should be running at 733 RPM. I've seen 10hp motors that were less in size than this one...its a fair size 5hp.

                          I dont have it hooked up yet so its up against the wall... I heard it should be back 12 inches off the wall to give the flywheel some air to move the cool the head.


                          The pump has a tag saying low speed 600 high speed 900. So it's good as is I figure for pump rpm.... and I could slow it down some yet probably to 618 RPM with a 6.75 inch pulley on motor.

                          I believe it's a 1970 now..found stamp on tank that year so figure pump probably near the same.

                          It may not have an unloader, but looks like one can be added as per the pdf devair site link.

                          I'll plug away at it or it will sit till I get a good power source somehow..might have to move to get that...
                          Attached Files

                          Comment


                          • #14
                            To Hank

                            Originally posted by hankj
                            Knuk,

                            How did you arrive at the 5-hp motor decision? From the pic's of the pump, I'd say it's a 10-horse, or at least 7.5.

                            What is the displacement of the two cylinders? Is it stamped on the pump? Units I've seen with pumps that big are usually driven by motors larger than 5-horse.

                            Hank
                            Hank, When i sold my building,and alot of the older equipment, i had the twin to that ,wished i could find the pics(somewheres in the basement,in a box) and mine was 15 hp.went from 0 to 175 in under 3 mins.,,Dont know if that helps you or not,But had plenty of Juice at the old Joint,Jack

                            Comment


                            • #15
                              Knuk,

                              Sounds like it'll be a super set up. Your motor, being a "real" 5-horse and not a "special" like the ones you find on the cheaper machines (mine included) that draw 15-amps but are "rated" at 5-hp., will definitely make a difference. I'd think with the combo you have, no changes will be needed.

                              Keep us in the loop, and don't forget pictures of the final-final!

                              Hank
                              ...from the Gadget Garage
                              Millermatic 210 w/3035, BWE
                              Handler 210 w/DP3035
                              TA185TSW
                              Victor O/A "J" series, SuperRange

                              Comment

                              Working...
                              X