Any folks know 220 wiring ?

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grassy

grassy

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My air compressor isn't large enought to push a sand blaster..even though I was told it would. Drove 1.5 hours (one way) to pick up a bud's 220 compressor.

It has three prongs. My dryer outlet has a BIG plug so that was out and my generator has a 4 hole 220 plug.

I took off the plug and there are only three wires on the generator..I put a plug that fit my gen on. I tried wiring with one wire left off..I believe that it is a nutural but with no joy.

Went to a trailer supply store that sells generators that has been around for years and a couple of places like Home Depot looking for info or an adapter or a way to wire it..no luck. The Internet hasn't been much help either.

How can I wire the compressor's 3 wires into the 4 prong plug of my gen or has this whole trip been for nada..?

A pic..

HPIM7080-L.jpg

Grassy
 
Go to Home depot or lowes., wherever you can get electrical stuff and get a 50amp 240VAC plug and recepticle. They are large, probably more than you will need for the compressor but better too much than not enough. Then you can wire it in the same circuit as your wife's clothes drier... If you are going to use it with your generator you need to know the pin out of the plug. 220VAC has 2 hots and a neutral (common) plus a ground is required in most locales. Use a volt meter with your generator running to see where your voltages are. Between either hot and a neutral you will get 115VAC. Between 2 hots you will get 240VAC. Once you have those figured out, you need to determine which is neutral and which is ground since you will get the 115VAC on either one. Turn off the generator and make sure the breaker for that recepticle is off. Change the multimeter to ohms and go between each pin and a ground on the generator frame. You will only get a readin from the ground since the breaker interupts all 3 of the other wires.
 
You say the compressor has three wires. This means it has "two hot legs" AND a GROUND. This is NOT neutral

A 4 wire device will have "two hot legs", a GROUND AND a neutral.

On your three wire dryer plug, the ground will be the "center pin." It should have either a light colored or green colored screw

PLEASE don't do this by trial and error ---you could end up with the compressor being "hot to ground."

Some of the alleged colors "do not meet current code," but it might be 'your' reality

The compressor cable should have white or green or bare as the ground

The two hots could be white/ black, with bare ground,

or with white or green ground the hots could be black/ red or black / black.

THE WAY TO IDENTIFY THE GROUND is to check with a meter. The ground wire will show zero ohms right to the frame of the compressor.

NEITHER of the two hots should show ANY (infinite) resistance to ether the ground wire or the equipment frame.
 
My preference is to work with the compressor...less to p off the wife.

My compressor wires are hotblack/white and green ground.

I will do a walk through as Ihearold suggested (thanks !) but I am still confused as to what to do with the neutral ?? Split the ground between the two ? ..or pull the ground off (on the 4 plug) and ground to the compressor and used the green as the neutral ?

Grassy
 
No, you don't have a "neutral." Even though ground and neutral are bonded together at the main box, they are then treated as "different" throughout the rest of the system.

Sounds to me like your colors are

black--one hot leg
white other hot leg

green ground

Now if you are going to hook this to the generator, we need to see the REAR of the generator plug.

You should have two dark brass screws, (hots)

One light/ silver screw (neutral which you WILL NOT use)

green for your ground.

The ground prong on a 4 prong connector is almost always the largest, most oddly shaped. IF ANY DOUBT use an ohmeter from the generator metal frame to the connector and see which one is ZERO ohms to the frame.

Make sure the connector is rated for the compressor current. They will have an amperage rating right on the connector (15A, 25A, etc)

Some light reading about connectors:

http://www.hubbellcatalog.com/wiring/catalogpages/section-b.pdf

http://www.frentzandsons.com/Hardware References/twistlockplugandreceptacle.htm

You also need to make sure the generator will handle the STARTING CURRENT of the compressor. DO NOT try to run it with a long extension cord
 
Is it a portable compressor? If not, don't worry about a damned plug. Just hard wire it.
 
StrokerScamp said:
Is it a portable compressor? If not, don't worry about a damned plug. Just hard wire it.
Click to expand...


I don't think he has anything to hard wire it TO. Sounds to me like his original was 120V, the only 240v sources he has handy is the dryer plug and his generator.

Doesn't sound to me like he wants to be digging into the main panel
 
If he has the correct panel, he could always install a breaker and run the correct romex and wire the compressor to a dedicated circuit in the breaker box. It is not that difficult of a task to add a breaker. Probably would need a 200 Amp panel
 
Thanks...time to catch up.

No room in the breaker box..maxed out. Would prefer not to use the dryer plug because it messes with the mom..

It is a portable generator. It is a 4000 watt 7.5 hp machine with a 120/240 20 amp plug. The compressor is a 2 hp craftman 240 that has the old style 3 prong plug. the wires are hot black / white with green ground.

I have a 20 amp. 125/ 250 volt 3-Pole 4-Wire Grounding plug that I am trying to wire up with the 3 wires. On the back of the plug I have a green and three brass screws. However, if I spin the plug around as in the picture above and put the ground TDC, the prong directly below is silver so I am assuming that this is neutral. I am borrowing a curcuit tester tomorrow to verify which is which.

Before I was thinking, I did wire up the plug with what I thought were hot and ground and the compressor didn't seem happy since I thought the 4th plug, neutral I gather, wasn't necessary.

I looked for extra specs on the compressor but it is an old one..early 80s I think.

Wouldn't hard wiring it be the same think that I did ? Would it matter which hot I put the black/white to ?

Is my gen large enough ?

Thanks
Grassy
 
67Dart273 said:
No, you don't have a "neutral." Even though ground and neutral are bonded together at the main box, they are then treated as "different" throughout the rest of the system.

Sounds to me like your colors are

black--one hot leg
white other hot leg

green ground

Now if you are going to hook this to the generator, we need to see the REAR of the generator plug.

You should have two dark brass screws, (hots)

One light/ silver screw (neutral which you WILL NOT use)

green for your ground.

The ground prong on a 4 prong connector is almost always the largest, most oddly shaped. IF ANY DOUBT use an ohmeter from the generator metal frame to the connector and see which one is ZERO ohms to the frame.

Make sure the connector is rated for the compressor current. They will have an amperage rating right on the connector (15A, 25A, etc)

Some light reading about connectors:

http://www.hubbellcatalog.com/wiring/catalogpages/section-b.pdf

http://www.frentzandsons.com/Hardware References/twistlockplugandreceptacle.htm

You also need to make sure the generator will handle the STARTING CURRENT of the compressor. DO NOT try to run it with a long extension cord
Click to expand...

Thank-you. I hate wiring and this helped..
 
grassy said:
It is a portable generator. It is a 4000 watt 7.5 hp machine with a 120/240 20 amp plug.

The compressor is a 2 hp craftman 240 that has the old style 3 prong plug. the wires are hot black / white with green ground.

I have a 20 amp. 125/ 250 volt 3-Pole 4-Wire Grounding plug On the back of the plug I have a green and three brass screws. However, if I spin the plug around as in the picture above and put the ground TDC, the prong directly below is silver so I am assuming that this is neutral. Would it matter which hot I put the black/white to ?

Is my gen large enough ?
Click to expand...

Just reading the gen. specs it SOUNDS large enough, but nowadays "specs" can be pretty "imaginative" I'd check the book or go online check the generator model and look for "starting HP"

MAKE SURE the compressor is actually wired for 240 and not 120V. 2HP is right in that range where many of them can be rewired for EITHER

It sounds to me like you have the plug figured out.


I'd say, depending on size, get rid of that extension cord. Too small wire in many cords will affect motor starting ESPECIALLY on a generator which is marginal
 
My compresser didn't push enough air for sandblasting/air gun so I added a couple 100lb.propane tanks in line...lots of volume now!
 
Did everything right...got the wiring right...my generator will not push the compressor over the starting hump. The old electricial engine must pull one whack of power.

Plan c I guess. Going away for a small vacation and to watch my kid play V-ball for Nova Scotia against the other atlantic provinces. Should be good.

Moparchunk67...where did you get these tanks and were they expensive ? And where can you buy sandblasting sond or do you use road sand that is in bags ?

Grassy
 
Purchase harbor freight 13 hp electric start gasoline motor. Drive air compressor at proper rpm using proper pulley. Set compressor to releive head pressure or set up a gas motor control circuit.

I did it with a 3 cyl American made eaton compressor and a 11 hp harbor freight china elec start gas motor. I run my compressor at 850 rpms to 150psi. It takes 2 - 3 minutes to go from 0 to 150 in my 60 gallon tank.

I Built an auto start / kill circuit based on the factory air tank pressure switch. Cycles like a champ. . Sustains 80 psi to a pretty big sand blaster. I must have hundreds of hard hours on this build and it is totally reliable. I have run it all day rarely cycling off many days. It kicks off at 150 and on at 90.

I have a homelite chinese 7000 watt generator, I run a harbor freichgt 110 amp 220 volt wire feed welder. I have used this setup for several years of handy work w/o any issue. I can weld 3/16 quite well with it. I put the set on a cart so I can pull it behind my truck or roll it around the yard easily.

I reckon I dont like chinese products, but 3 of the 4 items I mentioned are such and they are running well for several years.

I can send you a wiring diagram and part numbers if you want to build a pressure switch electronic start / stop for the gas motor. Cost me about 30 bucks for the controller.


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..................Sure hope your insurance co. doesn't see that wiring.......................
 
67Dart273 said:
..................Sure hope your insurance co. doesn't see that wiring.......................
Click to expand...

12vdc .2amp :) fused at 1 amp 12vdc.
Also, it has several different safety cut offs and a manual cut off / on.

It is just a signal circuit that triggers the factory start solenoid built on the gas engine which also then triggers a pressure release coil for the head unloader.

But yea they would probably have to verify it was low volt / amper before they stopped crying.


Thanks for the concern.

:burnout:
 
220 is not rocket science. You have three legs coming in to your box. Lets make this simple there are two sides to every breaker box. Each side is 110 On your breaker panel with out breakers if you look there will be two rows for breakers . This is two of the legs. 110 each

Each row from the top down alternates which side the small 110 breeker pulls from. If you add a wider two leg 220 breaker it pulls off opposite sides two diffrerent hot legs. This gives you your two hot legs for 220

Now the nuetral and ground . They get hooked to the third leg. This is the nuetral and the ground going to the same leg coming in. My compresser is hooked up with a number 10/3 Romex for 110 . I have two hots black /white and a uncoated ground. This is 220 . Some inspections require a nuetral and a ground but its not needed. You only need three Wires.

I also have 3 phase eqipment . I was told I would need a $700.00 -$1000.00 roto phase converter to run all these pieces at one time . I have a $100.00 static phase converter. I use the first machine started and turn my static phase converter to a roto phase . I can run all mills and lathes and saws at one time . If I need a slow speed on the lathe motor I just start another machine.

Two hots and one ground you got 220. But the hots have to come from separate legs off the breaker or power source. That was easy.

Your generator may not have enough power to run your compressor. Mine is a 5500 generac and it won't run the lights, AC and compresser at the same time in my race trailer. Its a very small 110 compessor. But I do run alot of lights.
 
Grassy:

How far is the dryer outlet from the area you want to run the compressor in?

You can simply buy a plug that matches the dryer outlet, a length of 10/3 SO cord & a cord cap that males with the 20 amp plug on that compressor.

Unplug the dryer, plug in the cord & blast away. I doubt the dryer runs all day everyday. Just clean the laundry room up a bit when you are done. You should clean behind the dryer anyway.

Now before the NEMA-nancy's start to whine... I am aware that the 30 amp dryer breaker will not properly protect the 20 amp device on the end of that adaptor cord. Most portable compressors are equipped with some sort of thermal overload, so the only thing in that setup "at risk" is the cord cap & plug. If the cord cap or plug were to overheat, it would require a direct short to open the breaker.

Not much of a risk in this case because the connection should be well outside the house & in plain view. The cord itself will have enough conductor area to be safe.

B.
 
Hey Guys..... Look at the date of this thread. 08-03-2011, 07:26 AM is the last time grassy posted. I think you are trying to feed a dead horse.
 
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