Air compressor 220v single phase wiring question

[Advanced Design]

I purchased a new air compressor and the dealer dropped it off without the paperwork or manuals.

Really wanting to wire this up and to learn how it is supposed to be wired to try the new tool (toy) out this week end.

Yep, I am going to be safe and if I am not 100% sure I will call in an electrician.

I am pretty sure the input wires should be connected at the top of the magnetic starter on L1 & L2. Am I right?

The wires at the top go to the pressure switch and the wires at the bottom go to the motor.

This is 220v single phase.

Here is a pretty good indication....http://constructionasphalt.tpub.com/...4-24-1_661.htm

Thank you!

[Wingnut1]

I don't know the answers, but they can probably be found below or asked:

http://www.garagejournal.com/forum/f...splay.php?f=30

[franken]

Yes, L1 and L2 are the 240V feed. You'll want to connect the ground to the box.
You may want to connect a switch in the line with the pressure switch so you can disable it from running. I'd get a 2x4 conduit box and a half inch bushing and hang the box off the side of the contactor box if you can find a knockout in the right spot. Or get a toggle switch.

That looks like someone replaced the motor and pump with better ones. Is that a 1725RPM Baldor motor, rated about 25A? Sort of looks like a Quincy pump. Pretty nice setup.
Chances are that'll put out 175PSI. You may want to look at the tank tag and see what it's rated at.

[Daddy'O]

Double check here -

http://chpower.com/manualsearch/

[tinydb84]

Open that black box and take a few pics for us. That is where I wired into but mine didnt have the side box you have.

This is what I watched. The wiring comes in around the 6 minute mark. https://www.youtube.com/watch?v=iWtNdr_-7Iw

I wired mine to a dryer cord with a 6-50 NEMA plug on the end so I can disconnect it when needed (I have one 220/50amp outlet in my garage and need to plug my welder in too).

[Advanced Design]

Originally Posted by franken

Yes, L1 and L2 are the 240V feed. You'll want to connect the ground to the box.
You may want to connect a switch in the line with the pressure switch so you can disable it from running. I'd get a 2x4 conduit box and a half inch bushing and hang the box off the side of the contactor box if you can find a knockout in the right spot. Or get a toggle switch.

That looks like someone replaced the motor and pump with better ones. Is that a 1725RPM Baldor motor, rated about 25A? Sort of looks like a Quincy pump. Pretty nice setup.
Chances are that'll put out 175PSI. You may want to look at the tank tag and see what it's rated at.

Guys thanks for all the input! Franken, you have a good eye. Baldor motor (I think) rated at 31 amps. I was looking at Quincy and Champion too. Kinda referred a Quincy and for my purposes this one will be sufficient. 23.7 cfm at 90 psi. Will put out 175 psi.

Anyway, a friend has the same compressor in his shop and sent me this picture showing the feed going to L1 and L2. After church tomorrow I may wire it up and take her for a spin.

[franken]

At 31A it must be a 7.5HP motor?
Something looks odd w/ the P-switch wiring. I'd look at the contactor to see how its wired and what the coil voltage is. I'd guess its a 240V coil but some are 120V. Got a better pic?

The next question is where's your panel and how do you plan to wire it? Mine was fun since the panel is on the opposite corner of the house so it couldn't get much further away Since mine's 5HP and it was a long run, I used a 40A breaker and 8AWG cable.

Tiny, your setup doesn't use a contactor so its wiring is somewhat simpler.

[Advanced Design]

It is a 7.5 hp motor. I plan to plug it into the wall outlet behind the compressor. The old compressor was 15 amps and was plugged into a 30 amp circuit. Also available is a 50 amp circuit I put in for the welder. Will probably use that one as the welder has always been on another plug in and I haven't taken it to that side of the shop in 15 years.

[Wingnut1]

Anything over 3hp (actual running HP) needs to be hard wired. There are no plugs and outlets rated for 5hp, let alone 7.5. What gauge wire did you use for the welder? My HH187 can use 14 gauge wire, but I went heavier.

[_Ogre]

Originally Posted by Wingnut1

Anything over 3hp (actual running HP) needs to be hard wired. There are no plugs and outlets rated for 5hp, let alone 7.5.

hard wired? why?

if you hard wire any equipment then you need a disconnect switch or line of sight to the panel and a lockable breaker.
we have all sorts of equipment in the shop that use a 60 amp plug and outlet for a disconnect
home depot carries both 30 and 50 amp plugs, outlets and sjo cord to handle the amps

[Advanced Design]

We used 6 gauge wire on a 50 amp rated plug on the welder circuit. This is on a back wall of my shop that has its own breaker panel just for that wall. Since initially I haven't wired in an on / off switch, is there any reason I can't use the breaker as the switch for the compressor? There is nothing else on that circuit except for the 50 amp welder, now compressor.
Thanks guys!

[Wingnut1]

I not an electrician, but it has to do with continuous duty and in-rush current. Here is a link to HP ratings. http://www.leviton.com/OA_HTML/Secti...minisite=10251 If you want to be NEC compliant then hardwire.

Apparently this has been explained in some thread about cords and outlets on the forum I linked above, but I got tired of looking for it.

Oh, I have never heard about needing a lockable breaker, but line of sight is limited to 50 ft.

[Wingnut1]

Post 8 of this thread quotes the relevant NEC section and also metions a CB is an acceptable disconnect http://www.garagejournal.com/forum/s...ght=compressor

Since you have a breaker and panel near the desired compressor location then just get a flexible whip like this http://www.cesco.com/b2c/product/100...FZSKaQodb2sA0g or make your own out of 6ga. All the big box stores sell short lengths of the flexible conduit and you could buy the THHN by the foot somewhere I'm sure.

[Advanced Design]

Thank you Wingnut!

[Advanced Design]

Wired up, bolted down on home made vibration plates and making a ton of air.

Thanks again for the input guys.

[68c10airstream]

Advanced design, As a safety note be sure the starter is wired so if electricity is lost for a moment (tree falling on the line and cutting the lines as an example) that when electricity is restored that the compressor should be re-initiated from a start button or something. I wired my new tablesaw with a start/stop button and a commercial contactor and i will sum it up this way: start button puts low voltage into the magnetic circuit to start the contactor to work (contacts closed) and this MUST be a momentary switch. Now the contactor is closed in and working. The output side ( "T" side) now self feeds the magnetic circuit through the stop button. Once you push the stop button you break the magnetic circuit and the contactor opens up. This is the same as line voltage coming into the contactor opening up. Now the motor is shut off. To restart the start button must be re-initiated. Get with someone in the know to work this with the use of a pressure switch. I work at a power plant and with the amperage you are dealing with remember that all switching should be done with low voltage and this switched high voltage/high amperage. All you have to think of is this scenario. You are standing in a puddle of water that is a ground source and you touch a button that has marginal insulation qualities that is carrying 120 volts. You might weld your zipper shut. All switching in our power plant is done with 24 volts that is driven from low amperage transformers to be safe. Do it right once, and never think twice about it. Good luck, Brian F.

[Advanced Design]

Thanks. Dumb question, is that what the reset button on the panel is for?

[_Ogre]

Originally Posted by 68c10airstream

As a safety note be sure the starter is wired so if electricity is lost for a moment that when electricity is restored that the compressor should be re-initiated from a start button

really no way to do that without adding another mag starter and push button station.
unlike a table saw the compressor is designed to safely start and stop by itself.

as for the reset button on the mag starter; if for some reason your motor pulls too much current
the overload heaters will trip, the button resets the heaters, chances are you will never need to rest the overloads
heaters are similar to a breaker but they are sized specifically to the amp draw of the motor

[Advanced Design]

Thanks Ogre.

[_Ogre]

nice work on the isolators, but... with the nuts tightened down they won't isolate much vibration
remove the nuts and you'll probably be good or use a length of rubber hose under the nuts
i've never anchored a compressor to the floor

[Advanced Design]

You are right Ogre. There is about 1/4" space between the lower nut and the top of the support leg. The two nuts are locked together to prevent their movement.