help hooking up large air compressor

[55chevrolet]

hi. would someone be able to direct me in right direction .compressor powered now by 5 hp.single phase motor .would like also to wire in a small switch so to turn compressor off when not in use .not sure where wires go .10 guage wire ,30 amp breaker.will post pics

 

['04 Cummins]

What voltage is the contactor coil? 240v I assume?

If so, run a 12/3 cord from the contactor to the pressure switch. Ground the green wire on both ends. In the pressure switch, land the black wire on #1 line, land the white on #2 load.

In the contactor, with a female sta-con, land the black wire from the pressure switch on one of the brass-colored male spades sticking up from behind L2. Pick yourself up an on/off switch from an electrical supply house meant for the face of a starter cabinet like you have. Land the white wire from the pressure switch on one side of the the switch. Jump from the other side of the switch to the male spade for the contactor coil (looks like the silver colored spade next to the one that has the red wire with the blue sta-con on it.

It looks like the red wire from one side of the contactor coil probably goes down to one side of the overload terminal. Bring a wire from the other overload terminal up to the brass-colored male spade attached to L1.

If the coil voltage is other than 240v, you'd have to wire it differently, so you'll have to check that first. Also, it looks like one of the overloads is missing. You'll have to get the correct overloads for that particular motor anyway. Use the FLA number on the motor nameplate and there should be a chart possibly on the side of the contactor or on the inside of the cover for overload part #'s.

 

[madosta]

What is going on in the motor?

You "probably" shouldn't use that NM looking wire for that connection in pic 1. If you have a disconnect or box nearby (plug) a SOOW type cable should be used for flex and vibration among other things.

 

[Charles (in GA)]

Also, it looks like one of the overloads is missing. You'll have to get the correct overloads for that particular motor anyway. Use the FLA number on the motor nameplate and there should be a chart possibly on the side of the contactor or on the inside of the cover for overload part #'s.

Only one overload is used on a single phase motor. There is a copper ******** the right side in the place of where the heater would go if it were a three phase starter.

Indeed, you need the correct heater element for the amperage of the motor. Some smaller motors have a overload reset button on the end of the motor. Larger motors do not have this button. This heater takes the place of that. The heater simulates the heat generated by the motor. Under normal use, there is no problems but if the motor overloads, the additional amperage drawn thru the heater causes it to heat to the point where a set of contacts opens in the heater. The coil circuit is wired thru these contacts, via a set of wire terminals on the bottom LH side of the starter, you really have to get down and under the starter to see them.

I just made a video that might explain the wiring better than taking a pic and marking it up with paint (which I'm no good at).

The video is kinda rough but shows a Square D contactor just like this one, and the pressure switch, coil and heater wiring.

I will post it when it finishes uploading to Youtube.

Charles

 

['04 Cummins]

Only one overload is used on a single phase motor. There is a copper ******** the right side in the place of where the heater would go if it were a three phase starter.



Charles

Yeah, I forgot about that.

 

[Charles (in GA)]

Youtube video should appear shortly at this link................

Charles

 

['04 Cummins]

Nice video, that explains it much better than my typed response.

 

[Charles (in GA)]

I'm no movie producer, thats for sure. I'm sure Jack Olsen could have made one ten times better, oh wait, he's made a bunch of videos a thousand times better. This one was unscripted and unplanned, as evidenced by the duhs and uhs and pauses and calling stuff the wrong thing and forgetting things and going back to them.

What I didn't show was the sticker for the coil and its voltage. Its just in front of the two coil terminals, runs from one to the other, will give the applicable voltage and cycles it is made to work on. The front of the heater will have a number stamped into the strap and it will correspond with the table printed inside the cover. Make sure it is the right heater. If its for a larger motor, it will not overheat and trip out when it should, and if its for too small of a motor, it will be tripping in normal operation.

Charles

 

[Charles (in GA)]

Never did address the "small switch to turn the compressor off when not in use" issue.

The best thing you can do, is have a disconnect on the wall at the compressor for this purpose. It will break both of the hot circuits to the motor starter, the best way to kill it.

If you insist on a remote switch by the door, you can interrupt ONE of the wires going to the pressure switch and install a switch in this wire, or by running two wires to wherever you happen to mount it. The problems is, the starter is still hot. Other issue is that if you turn off the switch while the compressor is running, or by switching off the wall disconnect for that matter (you should never switch it off while running unless it is an emergency) is that the pressure switch will not open and vent the pressure off the head. The next startup, the pump will be trying to start against pressure sitting on the head and may stall out and trip the breaker. You need to let it run till it shuts off on its own, and thus venting the heat pressure. Compressors with head pressure vented via oil pressure controlled valves or centrifugal operated valves are not affected by switching off while they are running, as they will vent when the pump stops turning.

Also, I would want the starter mounted on the compressor itself. It makes disconnecting it an easy task in the case the compressor needs to be moved, and makes for a neater install with less wire running here and there. Mine is all in flex conduit for protection of the wires. Thats the way Campbell Hausfeld made it.

Charles

 

[55chevrolet]

i have some more pics hope this is any help thanks ,daryl

 

[55chevrolet]

i will get some armour cable from starter to motor tomorrow .12 guage ok ,also do i just need 2 hot wires and1 ground for armour cable

 

['04 Cummins]

i will get some armour cable from starter to motor tomorrow .12 guage ok ,also do i just need 2 hot wires and1 ground for armour cable

10 wire for the motor leads. The wire from the starter to the pressure switch can be 12.

10/2 MC cable is what you want, it will be blk/wht/grn. If you choose rubber cord, it would be called 10/3 for the same conductor layout.

 

[55chevrolet]

guiys which way should you hook -up motor cw or counter clock-wise .and what size element would i buy for the starter ,thanks

 

[930dreamer]

Flywheel should have an arrow showing direction of travel.

 

['04 Cummins]

Nameplate says 20.6 amps at 230v. Look inside the starter cover, there should be a chart with overload part numbers. Find the one that corresponds with 20.6 amps. As far as rotation, you have to look at the pump. Which way is it supposed to rotate? Just hook it up and see if it spins correctly, you've got a 50/50 shot.

 

[55chevrolet]

under heading of 1 thermal unit 18.1-20.8 flc is max fuse of 40 amps ,and for 20.9 -23.1 flc use a max fuse of 45 amps . there is a table with all 3 thermal units is that table for 3-phase,and 1 thermal for single phase ,thanks for help

 

['04 Cummins]

Use the one for 18.1-20.8. Usually they are sold as a 3-pack. You may be able to get a single. Go to any electrical supply house that sells Square D with your part number. Home Depot, Lowe's, etc will not have them.

 

[55chevrolet]

pics of heater cover

 

[55chevrolet]

ok want to thank you for all your help ,daryl

 

[930dreamer]

Look at the chart on the left side of the sticker.

 

[Charles (in GA)]

Looking again, you are MISSING the heater element altogether from the lower left, were you supplied one with the starter? It will be a metal strip between the two screws on the lower LH and have a number stamped into it. Mine is a B40, but mine is for a 7.5 hp motor. Yours will be something different of course but it does not appear to be there.

Did you buy the starter locally or did you internet order it/ebay it?

 

[55chevrolet]

starter came from princess auto .guess like tractor supply .glad you told me about element .looks to need a 40 ,will get one

 

[55chevrolet]

will get better pics of motor wires ,looks to be four coming out of cover ,will i use all of these,thanks for help

 

[55chevrolet]

thanks for all your help .runs fine .only one question left .when i bolted in motor fuse in starter box i moved the smell metal strap pointing at me up wards .seemed to work .compressor works great .hope its in proper position .thank again Daryl

 

[55chevrolet]

thanks for all your help .hook-up and start-up works great .awesome sight ,couldnt have done it without you. install black pipe lines next .thanks again daryl

 

[rodm1]

What part is the heater? Is it the lower half of the enclosure?

 

[55chevrolet]

there is what i call a fuse , think called 35 .it fits in on left side gets bolted on with the two shinny screws can see it in picture above .can take another if you want .and behind is what i call magnetic starter ,hope the word is right .seems to be spring loaded somehow ,if things fail this will kick out .someone else might explain better.its helps start a large motor under load .hope this helps

 

['04 Cummins]

The thermal overload, or 'heater', gets mounted as described by 55chevy (it is not a fuse).

There is a thermal strip with a cam on the side that heats and turns the cam as the motor runs. If the motor draw too much amperage, the strip will turn the cam far enough to break the overload contact, which would kill power to the starter coil, killing the motor.

When the heater cools down sufficiently, the reset button (big red bar on the bottom) will re-engage the overload contact.

 

[Jim Johnstone]

Nothing to add, everyone else has things covered. Just curious if that is a Devilbiss 432? I'd kill for a 432.

 

[55chevrolet]

well explained ,thanks not sure which model it is must be a number somewhere.are they good compressors ,do know much about them.will check for you

 

[Jim Johnstone]

well explained ,thanks not sure which model it is must be a number somewhere.are they good compressors ,do know much about them.will check for you

Yeah the Devilbiss compressors are excellent machines. A lot of them have spent years in factories up here in Canada just chugging away making air without any problems at all. A 432 is one of the top compressors on my list for my home shop.

 

[55chevrolet]

yes this is a 432 looks to have great compresson,now to finish shop ,and put it to work.