Wiring a 220v air compressor
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Wiring a 220v air compressor
I am wiring a new 220v air compressor. The wires on the compressor are black, white, and green. My first thought was that the white would be the neutral wire, but after wiring the plug the motor barely runs.
So, my second thought is that the green wire must be the neutral and black and white must be the hot wires. This would also explain why there is not enough power to run the motor.
Anyone care to give me their input?
So, my second thought is that the green wire must be the neutral and black and white must be the hot wires. This would also explain why there is not enough power to run the motor.

Anyone care to give me their input?
Last edited by pcteky; 09-12-07 at 10:18 PM. Reason: forgot
#2
the 240 volt power for air compressor is it own circuit.
to use the 12-2 NM romax cable if you have black and white what you have to do is remark the white to other colors and the wire in the breaker box it should be on double pole breaker and the repectale is proper one for 240 volts
also check the motor connection as well.
all the 240 volt motor do not used netual wire at all so that why it have to be remarked
DO NOT USE GREENWIRE AS NETRUAL this is illegal to do that for safety reason
what circuit you have it on now ??
that will make the diffrence there
Merci , Marc
http://graphics.x10.com/images6/hd245color.jpg
this photo will show what the 240 volt repcatle will look like it is not the same as 120 volt verison will show
to use the 12-2 NM romax cable if you have black and white what you have to do is remark the white to other colors and the wire in the breaker box it should be on double pole breaker and the repectale is proper one for 240 volts
also check the motor connection as well.
all the 240 volt motor do not used netual wire at all so that why it have to be remarked
DO NOT USE GREENWIRE AS NETRUAL this is illegal to do that for safety reason
what circuit you have it on now ??
that will make the diffrence there
Merci , Marc
http://graphics.x10.com/images6/hd245color.jpg
this photo will show what the 240 volt repcatle will look like it is not the same as 120 volt verison will show
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The receptacle is already wired and is for the dryer and works fine. My question arrises from how to wire the plug. I am not able to easily get to the wiring on the compressor motor as it is a brand new unit that wasnt made to be easily accessible to the end-user.
The plug that I wired it for is for a standard 30 amp dryer receptacle. Like I said my first thought that I went with was that white is alway neutral so white went to the "L" shaped lug and green and black went to each of the angled "hot" lugs. The problem is that the air compressor starts to power on and kind of dies.
It's almost like it's only getting 120 volts of power. Unfortunately since the air compressor is made in china there is a serious lack of documentation. I suppose that the compressor could be bad, but I just need to make sure that it's not wired incorrectly before I take the thing back and get another one and find out it's my wiring problem.
Thanks
Jeff
The plug that I wired it for is for a standard 30 amp dryer receptacle. Like I said my first thought that I went with was that white is alway neutral so white went to the "L" shaped lug and green and black went to each of the angled "hot" lugs. The problem is that the air compressor starts to power on and kind of dies.
It's almost like it's only getting 120 volts of power. Unfortunately since the air compressor is made in china there is a serious lack of documentation. I suppose that the compressor could be bad, but I just need to make sure that it's not wired incorrectly before I take the thing back and get another one and find out it's my wiring problem.

Thanks
Jeff
Last edited by pcteky; 09-12-07 at 11:16 PM. Reason: adding info
#4
ok , my main conderation is the air compressor cord and size therefore i will ask you few question along the way
1] the HP and amp it willbe labeled on the motor it will tell you the number of HP and amp
2] the cord for aircompressor what size it is? again it will be marked on it like example 12-2 with ground etc.
2] is the motor is allready hook up for 240 volt like factory wired [ it will useally marked in motor nameplate or wiring connection in the peckerhead it will be either on the side or back {most common is back of motor } ]
3] this part it can get tricky here is the dryer plug is 3 or 4 wire repectale you can tell by number of slots if it is three it will show like crowfoot type expect the netrual will have a L shape
the reason why i ask you this questionare to make sure we are doing the right thing to do in safe manner
for dryer / range repectale both useally are very simuair connection expect of netural which it will either have straght blade or L shape depending on amp rating
http://view.atdmt.com/NFX/iview/btcm...B%7Esscs%3D%3f
you will see the photo of this there is 3 or 4 wire that will make the big diffrence there
normally for most small 240 volt air commpresser useally will have 20 amp breaker for this but for larger unit it will reqiried proper sized breaker depending on the motor itself
the other thing that why i asked for amp rating on the motor second is hp rating becuse this way i can able guide you in safe manner in case something go wrong with motor and also if the wiring is hook up properly then we can go from here for basic trouble shooting on single phase motor
Merci , Marc
p.s. make sure you have green wire for grounding
1] the HP and amp it willbe labeled on the motor it will tell you the number of HP and amp
2] the cord for aircompressor what size it is? again it will be marked on it like example 12-2 with ground etc.
2] is the motor is allready hook up for 240 volt like factory wired [ it will useally marked in motor nameplate or wiring connection in the peckerhead it will be either on the side or back {most common is back of motor } ]
3] this part it can get tricky here is the dryer plug is 3 or 4 wire repectale you can tell by number of slots if it is three it will show like crowfoot type expect the netrual will have a L shape
the reason why i ask you this questionare to make sure we are doing the right thing to do in safe manner
for dryer / range repectale both useally are very simuair connection expect of netural which it will either have straght blade or L shape depending on amp rating
http://view.atdmt.com/NFX/iview/btcm...B%7Esscs%3D%3f
you will see the photo of this there is 3 or 4 wire that will make the big diffrence there
normally for most small 240 volt air commpresser useally will have 20 amp breaker for this but for larger unit it will reqiried proper sized breaker depending on the motor itself
the other thing that why i asked for amp rating on the motor second is hp rating becuse this way i can able guide you in safe manner in case something go wrong with motor and also if the wiring is hook up properly then we can go from here for basic trouble shooting on single phase motor
Merci , Marc
p.s. make sure you have green wire for grounding
#5
please note that the link is bad let me get the correct link
here is the correct link http://www.doityourself.com/invt/u764522
this is a 4 wire repectale
the next link will show 3 wire verison http://www.doityourself.com/invt/u245712
this is the 3 wire
so let me know which one you have then i can able tell you the connection there
did the breaker tripped out ?? because the way you describe the connection is very dangerous
the L shape is used for netual only [ if three wire setup it will be combation both netrual and grounding ]
for 4 wire the netrual and ground is seprated and for other blades it is hot [ line 1 and line 2 ]
did the air commpressor came with factory plug or you add the plug yourself ?? if it came with factory plug you should not cut it off if not standard size please do post it back
Thanks
Marc
p.s. for 240 volt usage on the cord if you have black and white that white should be remarked with marker so you know it is hot and green is resvered for ground only nothing else
here is the correct link http://www.doityourself.com/invt/u764522
this is a 4 wire repectale
the next link will show 3 wire verison http://www.doityourself.com/invt/u245712
this is the 3 wire
so let me know which one you have then i can able tell you the connection there
The plug that I wired it for is for a standard 30 amp dryer receptacle. Like I said my first thought that I went with was that white is alway neutral so white went to the "L" shaped lug and green and black went to each of the angled "hot" lugs. The problem is that the air compressor starts to power on and kind of dies.
the L shape is used for netual only [ if three wire setup it will be combation both netrual and grounding ]
for 4 wire the netrual and ground is seprated and for other blades it is hot [ line 1 and line 2 ]
did the air commpressor came with factory plug or you add the plug yourself ?? if it came with factory plug you should not cut it off if not standard size please do post it back
Thanks
Marc
p.s. for 240 volt usage on the cord if you have black and white that white should be remarked with marker so you know it is hot and green is resvered for ground only nothing else
#6
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Your compressor needs no neutral. If you are connecting a neutral to the compressor then that is your problem, and you MAY damage the compressor.
A white wire does not always mean a neutral. There are many instances where a white wire is a hot wire, and this is one of them.
The black and white wires on the compressor are for the two hot wires. The green wire is for the ground wire.
If you have a four wire dryer connection then ignore the neutral and use the other three wires (two hots and a ground). If you have a three wire dryer connection then you use all three wires.
A white wire does not always mean a neutral. There are many instances where a white wire is a hot wire, and this is one of them.
The black and white wires on the compressor are for the two hot wires. The green wire is for the ground wire.
If you have a four wire dryer connection then ignore the neutral and use the other three wires (two hots and a ground). If you have a three wire dryer connection then you use all three wires.
#7
And please, for your own safety, ask us here before you guess. We're happy to help. Your method of trying different combinations so far hasn't hurt anybody or your compressor, but that's just because you've been lucky. Let us take some of the luck factor out of the equation for you.
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Consider connecting the motor to a 2-pole switch instead of a cord-plug connection --- you than have one device - the 2-pole switch - instead of two -- the cord-plug and the receptacle.
This advise presumes the compressor remains "in-place" after it's wired.
What type of Wiring Method-- Non-metallic cable or amored cable -- extends from the panel to the compressor location? Grounding-connections depend on The type of W-M .
Does the instructional material refer to motor over-load protection which is required to prevent "smoking" the motor ? The C-B in the panel is NOT overload protection- it protects the conductors from the panel ONLY - not the motor.
Good Luck, & Learn & Enjoy from the Experience!!!
This advise presumes the compressor remains "in-place" after it's wired.
What type of Wiring Method-- Non-metallic cable or amored cable -- extends from the panel to the compressor location? Grounding-connections depend on The type of W-M .
Does the instructional material refer to motor over-load protection which is required to prevent "smoking" the motor ? The C-B in the panel is NOT overload protection- it protects the conductors from the panel ONLY - not the motor.
Good Luck, & Learn & Enjoy from the Experience!!!
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Thanks for all the info. The green wire was the ground as racraft specified. This would be much easier if it was automotive wiring. I am starting to learn all the correct terminology and specifics of household wiring. It cant be that hard as long as I dont electrocute myself in the process. Thanks for everyone who provided input.
One question that I still have is this. I have read and been told that electric motors can be wired for 110 or 220. Is this really true? I thought about attempting this with my other 110v compressor, but did not want to fry myself or the motor in the process.
One question that I still have is this. I have read and been told that electric motors can be wired for 110 or 220. Is this really true? I thought about attempting this with my other 110v compressor, but did not want to fry myself or the motor in the process.