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cmimotors 09-15-2009 03:26 PM

help wiring an air compressor
Can someone tell me how to wire up this air compressor , it is 5hp , 60 gal .. here are the wires .. I don't know how to hook up the reset button and the pressure switch ..

The pressure switch has "line" and "motor"

frenchelectrican 09-15-2009 06:10 PM

C'est simple.,,

P1 go to line one black cord conductor { yellow wirenut will fit this }

The T-1 and red and bleu that those three conductor you will need wirenut { I don't think yellow will fit there so red wirenut will fit it just fine }

The white and black that will tie to the remarked white cord conductor that you will need either red or yellow wire nut

You will need 10-3 SO cord { keep in your mind there is diffrence between the two } between pressure switch and motor I will give you details in a second for pressure switch set up.,

You will need NM clamp it will be tight fit but it will fit in there and yeah make sure you have green cord conductor to motor green conductor you will need yellow wirenut for this one.

Now next step is pressure switch from the motor lead to the prssure switch the bottom two are for motor connection so take the black one to lower left screw then take the remarked white to lower right screw and green conductor to green screw { a tip do the ground conductors first on both motor side and line side}

Now for line side you will need 10-3 SO cord or go with hardwire { this will make the diffrence there basically both are same way as you will see in a second }

take the cord the black one to upper left side of pressure switch connection and the remarked white to upper right side of pressure switch and green conductor to grounding screw { see the tip above }

With cord verison get 10-3 SO or 10-2 NM cable { if go hardwire route }

{ the 10 AWG will be tougher to bend but it will be doable }

If more quesiton just holler one of us will steer ya in right way.


A note here It will be better suited to use all 10 AWG cable or cord size due you are on the boarderline with 20 amp rated motor there.
Also you will need 6-30P and 6-30R with 30 amp due I just double check the chart for that motor useage.

220/221 09-15-2009 06:18 PM

The diagrams on the motor are pretty straight forward. I don't know if it is supposed to be colckwise or counter clockwise.

It is currently set up for CCW rotation.

On this 240 volt installation, L1 and L2 are the two #10 gauge hot wires coming from the 2 pole, 30 amp circuit breaker. A third #10 ground wire attaches to the green wire to make the installation safe.

L1 (one hot wire) wirenutted to P1

L2 (the other hot wire) wirenutted to black/white

Blue, red and T1 wirenutted together.

Green (or bare) wirenutted to green.

cmimotors 09-16-2009 09:38 AM

Ok ... I think I have the motor wired right.. but the 10-3 has 4 wires (red,black,white,green) where do they go ..

Is this picture of wiring right..?

cmimotors 09-16-2009 10:18 AM

I guess the 220 wires are not actually "red,black,white,green" but are "red,black,white,bare copper" wires ..

J. V. 09-16-2009 10:42 AM

No. The power, 230 volts goes to:

P1 - line
wht/blk or wht/red - line

cmimotors 09-16-2009 11:22 AM

What do you mean ..?.. I don't understand ..?.. Is the picture I have above right for the compressor..?..

wirenut1110 09-16-2009 12:28 PM

1 Attachment(s)
See if this will help. Sorry, I have to hand draw it, don't have any drawing software:( With your cable, you won't use the neutral, just 2 hots and a ground.

cmimotors 09-16-2009 02:49 PM

When I wired it as shown it popped a 30a fuse .. Checked wiring again and tried again and it popped another 30a fuse ..?.. what is wrong..?

frenchelectrican 09-16-2009 06:24 PM

Which way you have it hook up and you say fuse or circuit breaker ?

If you follow the connection as Wirenut draw it out there is no way it can pop the breaker out unless you got one of the strand or a wire pintched somewhere.

Check it again to make sure there is nothing pitched at all.


cmimotors 09-16-2009 08:13 PM

The garage has a small power box/fuse box with 2 fuses (both 30a) .. It blows 1 everytime you turn the power switch on .. I checked all the wires & marr connectors everyting is good.. When you turn the power on the compressor motor starts to start but it blows 1 of the 30a fuses .. I checked the power at the pressure switch (with the motor wires dis-connected) it has 244 volts .. Could there be something wrong with the motor or the reset button..?. The motor is wired as the wiring instructions on the side of the motor .. The compressor is brand new ...How can I check the motor ..?.. Can the wires be checked with an ohm meter and if so what would the resistances be..?

kbsparky 09-16-2009 08:37 PM

Where did you connect the incoming white wire? :huh:

If you have correctly wired this, then that white wire should =not= be connected to anything. :no:

frenchelectrican 09-16-2009 09:07 PM

Ok .,

Let start at the motor source what colour conductor you hook up at the motor and pressure switch the reason why I ask due somewhere something got transponded { got mixed up } on the conductor colours.

To check the motor winding get the ohmmeter on ohm scale { make sure you have power supply to this motor is really 100% off otherwise it can ruin your tester }

take any leads like T1 or L2 or L1 at the motor termal and take one ohmeter lead to one of any pair of conductors and the other test lead to the motor housing if the needle or it show zero or super low number then you have a serious current leakage on the motor btw you may want to check the capaitor to see if it is damaged as well.

If damaged it will useally swell or one end budged and also make a open reading as well.

that is should be very basic to find the curpit.


micromind 09-16-2009 10:24 PM

Are the fuses screw-in, or cartridge type?

In either case, for a motor to operate, the fuses must be time delay. They cost quite a bit more than the fast-acting ones. Most of them are labelled 'dual-element time delay'.

The screw-in time-delay type might not start a motor this size at all, the cartridge one likely will. A 5 HP motor that draws 20 amps will push the limits of even the best 30 amp fuse.


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