# Air compressor help...



## Jumpmaster (Apr 5, 2005)

I don't know if this is the right area to post, but is anyone around here good with troubleshooting air compressors?

I inherited my dad's Grainger 150psi compressor. It's wired for 220v...I have three problems with it:

First, it doesn't shut off...the motor just bogs down and gets slower and slower. Power continues to be applied until I unplug it.

Second, even after it starts to bog down a lot, it's not to full pressure. I only get around 40psi out of it.

Third, there is voltage present on all metal parts of the compressor. I know this will need to be addressed by an electrician.

As a result of research on other forums, I have replaced the pressure switch, the pop-off valve, and the unloader valve. I also replaced the regulator and valve there, as well as the wiring and wired it exactly the same (the old wire was just wrapped in electrical tape and didn't look very safe). The wiring I used is industrial grade 4 conductor, each conductor is 12ga. The electrical shop I bought it from pulled out a little calculator and said the wire would be fine for a 220vac 2hp motor.

Please be kind...I haven't messed with compressors much before now. I know it'd probably be better to just go buy a new compressor but this was my dad's and it has sentimental value to me. And it appears to be in decent shape...especially since I've replaced many of the parts on it. /ubbthreads/images/graemlins/smile.gif

Any help would be much appreciated...thanks!

JM-99


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## ABTOMAT (Apr 5, 2005)

1. When you say "it doesn't shut off", is it at a point where it _should_ shut off (ie: when it's reached kick-off pressure)? Yes would mean bad pressure switch, no wouldn't be a problem.

2. At what pressure does it start to bog down? A single-stage compressor should never be run over 125psi (max) regardless of what the gauge says.

3. That's two problems. First, that there's a voltage leak in the first place. Second, that the grounding isn't taking care of it. Have a motor shop check the motor for a voltage leak. I'm guessing there's a loose winding or something that's shorting to the housing. In addition to making sure the ground wire is correct on the machine, make sure your outlet and plug are the right type. Should be a two-pole grounding setup, not one like an old dryer with a common and no ground.

Assuming it's all plumbed and wired right (motor should have a little diagram, and don't use long runs of wire) you could be dealing with a few things. First, the motor (is it original?) could be malfunctioning and not making full power. Second, the compressor head is either binding (using the right oil?) or, less likely, has some kind of valve problem. Lastly, the check valve where the head line runs into the tank could be damaged or blocked.

With all the stuff you replaced there's very little o go wrong. And keep the old parts. They're probably not bad. Switch is OK unless it wasn't cutting off at whatever you had it set for. Unloader is OK unless it's hard-starting. Pop-off valve is OK unless it was leaking or wouldn't pop in an emergency situation. The regulator and all that stuff deals with the other end of the machine and wouldn't change how the pump works.

Don't get a new compressor unless the pump is shot or the tank is rotted. It was probably made by either Campbell-Hausfeld or Champion.


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## MoonRise (Apr 5, 2005)

Do you by chance have a 3-phase motor (industrial-commercial power required) and are trying to run it off of 2-phase power (standard household power)? You can get converters to change 2-phase into 3-phase, but they are a bit pricey. IIRC, they are a two phase motor that back-drives a 3-phase motor to act like a generator. Efficiency is not so good. It's usually cheaper to replace the motor with a properly sized 2-phase motor.

That could explain the low pressure output (motor doesn't have enough oomph to compress more).

If it never gets up to about 120 psi (some newer compressors go to 150 or 175 psi), then the high-limit (pressure switch) never even comes into play.

3-phase is 3 hots 120 degrees out-of-phase plus a ground/neutral wire. Standard 2-phase 220 (also called 240) is two hots each 180 degrees out of phase plus a neutral. Hot-to-hot is 220V (or 240 or230V) and either hot-to-neutral is 120V (or 110 or 115).


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## Jumpmaster (Apr 5, 2005)

[ QUOTE ]
*ABTOMAT said:*
1. When you say "it doesn't shut off", is it at a point where it _should_ shut off (ie: when it's reached kick-off pressure)? Yes would mean bad pressure switch, no wouldn't be a problem.

[/ QUOTE ]

The switch is a Square D 9013 FHG for 95psi on and 125psi off. Replaced the old switch with one of the same model and specs...old one was Square D also.

[ QUOTE ]
2. At what pressure does it start to bog down? A single-stage compressor should never be run over 125psi (max) regardless of what the gauge says.

[/ QUOTE ]

It only ever gets to about 40psi.

[ QUOTE ]
3. That's two problems. First, that there's a voltage leak in the first place. Second, that the grounding isn't taking care of it. Have a motor shop check the motor for a voltage leak. I'm guessing there's a loose winding or something that's shorting to the housing. In addition to making sure the ground wire is correct on the machine, make sure your outlet and plug are the right type. Should be a two-pole grounding setup, not one like an old dryer with a common and no ground.

[/ QUOTE ]

Yeah...that's a REALLY bad thing. I will get the motor checked out.

[ QUOTE ]
Assuming it's all plumbed and wired right (motor should have a little diagram, and don't use long runs of wire) you could be dealing with a few things. First, the motor (is it original?) could be malfunctioning and not making full power. Second, the compressor head is either binding (using the right oil?) or, less likely, has some kind of valve problem. Lastly, the check valve where the head line runs into the tank could be damaged or blocked.

[/ QUOTE ]

Used about 2 feet of wire...and I think I replaced that valve that goes from the pump to the tank.

[ QUOTE ]
With all the stuff you replaced there's very little o go wrong. And keep the old parts. They're probably not bad. Switch is OK unless it wasn't cutting off at whatever you had it set for. Unloader is OK unless it's hard-starting. Pop-off valve is OK unless it was leaking or wouldn't pop in an emergency situation. The regulator and all that stuff deals with the other end of the machine and wouldn't change how the pump works.

[/ QUOTE ]

Well...yeah, the stuff was all old/corroded, etc. The regulator was cracked (cosmetic, but wanted to replace it anyway), the pop-off valve leaked a lot...pressure switch *appeared* to not work, but you're right...it's probably ok (but was really badly corroded...case needed blasting and repainting...my dad lived in Galveston...)

[ QUOTE ]
Don't get a new compressor unless the pump is shot or the tank is rotted. It was probably made by either Campbell-Hausfeld or Champion. 

[/ QUOTE ]

True...it's a good workhorse...my dad used it for several years before he passed away.

Thanks for the tips!

JM-99


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## Iron_Man (Apr 6, 2005)

Not to pic nits, but I will anyway, House current is single phase. The two hot legs are just mirrors of the other one, with no phase shift. 

If the motor is 3 phase forget a static converter, build a rotary one, or replace the motor with a single phase unit.

Les


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## hacker (Apr 6, 2005)

Is it possible that the rings in the motor are shot and it can't build up enough pressure in the air tank as a result?


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## ABTOMAT (Apr 6, 2005)

Unless it's causing lots of heat and binding, bad rings wouldn't cause the thing to bog down. Usually just lots of oil contamination.

After the thing starts bogging down, shut it off and take the belt off. See if either the motor or compressor are hard to turn.

There actually is such thing as 2-phase electricity, but I don't think it's been used for anything in about 80 years.


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## Jumpmaster (Apr 6, 2005)

Well, I posted the following at another site requesting help and was lambasted by one of the moderators. I was told, in not so many words, to get the f%#$ out of the garage and call someone else to fix the wiring. Great...thanks for the help, pal...an inspiration to do-it-yourselfer's everywhere. /ubbthreads/images/graemlins/icon6.gif...on a DIY website, of all places.

Anyway, here's the information about how it's currently wired...you guys are fellow flashlight nuts...hoping you'll be a little easier on me. /ubbthreads/images/graemlins/smile.gif :

If you're viewing the pressure switch with the adjustment screw to the top (away from you) using the terminals L1, T1, L2, T2 from left to right as follows...
The "O" is the screw holding the cover on...

O
| L1 | T1 | L2 | T2 |

Black from the power cord goes to L1 on the pressure switch, white from the power cord goes to L2 on the pressure switch.
T8 and T4 from the motor go to T1 on the pressure switch. T1 from the motor goes to T2 on the pressure switch.

The diagram on the motor for 220vac is as follows:

T1 | T3 T8 T2 | T4 T5
_____ | ________ | _______
Line | Tape(?) | Line

Below this, it states for CCW rotation (which the compressor specifies it is), interchange T5 and T8. Sorry I couldn't get the diagram to look right...under T1, it says "Line"...under T3, T8, and T2, it says "Tape"...under T4 and T5, it says "Line".

I'm not an electrician...obviously. As such, I'm completely baffled...but I reckon you already knew that. /ubbthreads/images/graemlins/confused.gif

Thanks again for your patience and help...I'm sure whatever the problem is will just be jumping out with neon signs to those of you that understand this. /ubbthreads/images/graemlins/help.gif

If the diagrams don't make sense, let me know and I'll try and take pics and label them.

JM-99


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## ABTOMAT (Apr 7, 2005)

A photo of the diagram would help, although without knowing which wire goes to what winding it's a little hard to diagnose over the web.

A good place with lots of motor knowledge is the rec.crafts.metalworking newsgroup. And if you want a real compressor pro, try the Tools board on ytmag.com. A guy named Roger knows or can get info on almost anything.


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## hacker (Apr 7, 2005)

Wouldn't worn rings cause the motor to labor excessively as the tank pressure increased? There will be a certain amount of force required to push the air into the tank. Even if the valves that protect the air backflow are in perfect shape, I see even on new compressors that the motor labors more as the tank pressure increases. If the motor can not generate the push because of worn rings, wouldn't it labor more?

[ QUOTE ]
*ABTOMAT said:*
Unless it's causing lots of heat and binding, bad rings wouldn't cause the thing to bog down. Usually just lots of oil contamination.

After the thing starts bogging down, shut it off and take the belt off. See if either the motor or compressor are hard to turn.

There actually is such thing as 2-phase electricity, but I don't think it's been used for anything in about 80 years. 

[/ QUOTE ]


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## ABTOMAT (Apr 7, 2005)

I'm not sure I follow your logic. The motor would actually labor less if the compressor's rings are shot. Instead of forcing all the air out of the cylinder, some of it would blow by the piston. Lower pressures would be generated and thereby make the compressor easier to turn.


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## Amonra (Apr 7, 2005)

I know this must sound stupid but noone mentioned it - 
are you using it on 110V ? if not, are you using a converter from 110V to 220V ? if so, can the converter handle 2hp (approx 1500W)(actually it would need to handle more than that maybe even 2500W, since 1500W is the no load wattage) ? if not, that is why the motor is bogging down since as the pressure rises the motor gets more load and consumes more electricity. if the converter cannot handle the power the motor bogs down and stops at 40psi.

i dont think you have a problem with the pump since it can only load the motor further if it is jammed (i.e. stuck conrods/pistons, no oil, jammed bearings) and that would trip the reset switch (if you have one). If you have a problem with the rings or valves it would not bog the motor down but let it run more freely and you would get much less than 40 psi.

i think your motor is just not getting enough power.
or it is burnt which might explain the leaking electricity


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## hacker (Apr 7, 2005)

Not to beat a dead horse, since the voltage problem is more important and might provide a clue to what is going on, but sure, worn rings would cause blow by. But as the motor had to push harder, it would labor more and would fail to increase the pressure in the tank, both symptoms that the poster reported. 

Why isn't the motor increasing the pressure in the tank? If the valves are all ok, it is because the motor doesn't have to power to do so.

And worn rings on old compressors are common. In fact, it is the main reason that a lot of old compressors are very safe. The oil pushes past the worn rings and coats the inside of the tank, making it rustproof. Users just have to filter the air output to make sure that the air is relatively clean. But once th rings wear enough, it's motor rebuild time.

[ QUOTE ]
*ABTOMAT said:*
I'm not sure I follow your logic. The motor would actually labor less if the compressor's rings are shot. Instead of forcing all the air out of the cylinder, some of it would blow by the piston. Lower pressures would be generated and thereby make the compressor easier to turn. 

[/ QUOTE ]


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## turbodog (Apr 7, 2005)

Check which voltage it is wired for. Do not use a convertor.

Check the amp draw right after starting when there is very little air pressure.

Check the amp draw after it really starts to labor.

How MUCH voltage is present at the frame? 110/220/???

Worn rings=low pressure=LESS load on motor

Does sort of sound like it's wired for 220 and you're feeding it 110.

And to pick some nits, house wiring is phase shifted. 1/2 the house (approx) will be on 1st phase, other half on 2nd phase, and 220 volt stuff (stove/water heater/dryer) will use both phases.

Voltage leakage concerns me, especially if it's a lot. Motor could be burned, but would likely throw a breaker if it was. I worked on rebuilding electric motors for years, several years ago.

Another idea is that maybe the neutral is not connected properly. It's relying on the frame as a return current path. This would account for your voltage at the frame, and the low power output due to this being a REALLY crappy way to have a return path routed.


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## Jumpmaster (Apr 7, 2005)

Ok...I'm going to try to draw a diagram outlining what every single thing is connected to from the wall outlet to the pressure switch tonight. I will include pictures of the wiring diagrams, best I can with my camera.

What I need is, "Oh...I see what the problem is -- hook A up to X and B should hook up to Y..." I figured if I provided all the diagrams I have and how it's hooked up now, an electrician would be able to see what the problem is immediately and tell me how to hook it up.

I don't have access to a multimeter to take 220vac amp readings.

Once it's hooked up correctly, then can focus on what the bogging down/low pressure issue is. Right now, the electrical problem concerns me the most. Those very experienced with wiring should be able to look at the diagrams and tell me "hook blah up to blah", etc...am I wrong? I'm beginning to think this cannot be done...I don't understand why -- maybe I'm just stupid. /ubbthreads/images/graemlins/icon23.gif

BTW, the motor can be wired for 220vac or 110vac. It is currently wired for 220vac (as my father had been using it) and I'm plugging it into the 220vac dryer outlet in the house. No converter.

Thanks for the ideas, folks...

JM-99


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## ABTOMAT (Apr 7, 2005)

Hacker, why do you think there would be more load on the motor? With good rings it has to displace 100% of the cylinder through the valves and into the tank, against tank pressure. With bad rings a certain amount of air is being pushed into the crankcase which is atmospheric, or likely a vacuum if the crankcase check is working properly. With bad rings it would keep running but not generate more pressure.

I'm betting that the problem is motor-related, although bad head valves or a binding bearing could be a problem.

Turbodog, No neutral should be on this thing, it would be dangerous. The motor runs from the 220V hots. You need a safety ground but that's it. Only clothes dryers or ovens (or etc, like a welder with a 110V convenience outlet) need a neutral, since they also have 110V components that need a return. In past years you were allowed to use a grounded neutral. Nowadays you need a four-wire setup with seperate ground and neutral.

Jumpmaster, motors usually have one start winding and two run windings. For 110 the run windings are connected in parallel, for 220 it's in series. I'd have to see this motor. The voltage leak has nothing to do with the way it's wired. No wires should go to the housing.

Assuming this is an old dryer outlet (6-30R, I think), make sure you're connecting to the two slanted prongs. On your compressor the L prong should be ground. Make sure the outlet itself is wired correctly, and that it's grounded. For maximum safety (as long as you're not going to use a dryer) either:

A. Disconnect the neutral in the wall, leaving only the ground, or:

B. Replace it with a grounding-only outlet (either 5-20, or 5-30 I think) wich would be the correct thing for a tool like a compressor.

It's a Dayton, isn't is? That's Grainger's store brand. See if they can provide anything.


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## Jumpmaster (Apr 7, 2005)

Ok...just checked continuity on the power cable (that goes to the wall)...it's wired up all wrong. And I mean ALL wrong...even with my extremely limited knowledge of AC circuits, I can tell that... Details will follow...

BTW, yep...the motor is Dayton...can't modify the wall plug because we plug the dryer into it when we need to use the dryer and unplug it and plug in the compressor when we need to fill it.

Ok...here are some pics...
Data tag from compressor...






Pressure switch...





Diagram that came with the pressure switch...





Wiring diagram on motor...note the text referring to CCW rotation which the compressor states it should be...





T2, T3, and T5 from the motor are twisted together and not connected to anything else.

Power cable...





JM-99


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## turbodog (Apr 7, 2005)

[ QUOTE ]
*Jumpmaster said:*
Ok...just checked continuity on the power cable (that goes to the wall)...it's wired up all wrong. And I mean ALL wrong...even with my extremely limited knowledge of AC circuits, I can tell that... Details will follow...

BTW, yep...the motor is Dayton...can't modify the wall plug because we plug the dryer into it when we need to use the dryer and unplug it and plug in the compressor when we need to fill it.

JM-99 

[/ QUOTE ]

You know..... if it's really messed up. You could be:

1) running the motor from 110v
2) the OTHER 110 leg could be connected to ground and making the frame "hot"

Ouch.

I have seen worse though...... a building's entire electrical system..... all the ground wires in the fuse box were tied NOT to the ground bus, but to the expansion lugs (hot, ouch!) instead. Ask me what happened when you touched something with a grounded frame like a table saw. I still have electrical burn marks on my body.


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## Jumpmaster (Apr 7, 2005)

Holy crap, man!!! Yeah ouch!! Worst I've been hit with was an 80v ground loop...and only briefly!

My buddy got the shock from the compressor...I told him not to touch it (instead, to let me shut the compressor off from the breaker box), but he didn't hear me...

JM-99


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## ABTOMAT (Apr 7, 2005)

All right, we have some wrongness here. If the motor is really wired to the two prongs in your photo, you're doing what a dryer does to get 110V for its motor. That would explain the lack of power. Turbodog's also right that the second hot might be wired to the machine's chassis ground.

OK, step by step:
1. That's an old-style dryer outlet. In the wall, the two angled connectors should be black or red hots and the L should be ground+neutral (which isn't current code but is allowed for old work).

2. In your compressor, the two line connections on the pressure switch should go to the two angled prongs. The L prong should go to the chassis as a ground with the cord's green wire, and nothing else.

2a. If you want to be more code-ish, paint the white line wire red any place you can see it. White is just used for neutral, and you're not using one. Paint turns a neutral wire into a hot in the eyes of the inspectors.

3. I can't be positive, but T5 and T8 should be your start circuit. T1 and T3 (or T1 and T2) should be one run winding and T2 and T4 (or T3 abd T4) should be the second.

4. But the above description is just for understanding purposes. Without seeing the motor in person it doesn't count for anything...

5. ...which luckily doesn't matter since you have that lovely digram printed on the tag. That shows exactly how it should be wired. In your case, now that you know 2,3,5 are connected together, make sure that 1 is alone and that 4,8 are connected. Make sure all the connections are good (try wire nuts or a tight twist) and wrapped with tape.

Whew. Check all this stuff and fire it up again. If nothing's damaged you should be good to go. Make sure you have good oil in the compressor and that the intake filter is clean and working.


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## ABTOMAT (Apr 7, 2005)

Oh yeah, can you get an overall shot of the entire thing? I just want to see which one it is.


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## turbodog (Apr 7, 2005)

MA must have different electrical code than MS. Dryer outlets are allowed different wiring around here.


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## hacker (Apr 7, 2005)

The outlet should be like this:

http://users.ev1.net/~oschmidt/pwrout.html

The "L" should be the white (neutral), the other two would be one black and one red. The picture shows that there are 110 volts from the "L" to each other slot and 220 across the two non "L" slots. The black and white would come from each side of the bus in the main box. That gives it 220 volts across the two non "L" slots.


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## Jumpmaster (Apr 7, 2005)

[ QUOTE ]
*ABTOMAT said:*
Oh yeah, can you get an overall shot of the entire thing? I just want to see which one it is. 

[/ QUOTE ]

Ok, here ya go...










JM-99


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## turbodog (Apr 7, 2005)

old school


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## Jumpmaster (Apr 7, 2005)

Hey now! Don't be hatin' -- It was my dad's! /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/smile.gif /ubbthreads/images/graemlins/smile.gif

JM-99


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## ABTOMAT (Apr 7, 2005)

What's it like in MS? I actually haven't looked at MA code. Dryers and ranges have been granted a grounded neutral exception in the national code traditionally. Now I think that about three years ago the NEC started requiring four-wire seperate-ground connections for new work. Canada has required grounding all along for several decades.

Jumpmaster, That's a great compressor. It's made by Champion for Grainger--might be the best all-aluminum pump design. The 2001 catalog shows these. I actually have a nearly identical Champion/Speedaire in a slightly smaller size. Just one pulley groove on mine. Make sure those goofy felt air filters are in good shape.

How does the unloader valve connect? I can't tell from the photo.


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## Jumpmaster (Apr 7, 2005)

Ok...this is what was described to me as the "unloader valve", though I've been told those are only on gasoline compressers?

Here's a pic...





JM-99


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## BVH (Apr 7, 2005)

Just a related word of caution. Might be a good idea to take out the tank inspection plug and (since this is a flashlight forum) use a flashlight to check for any really bad rust/pits/flaking on the inside. Would hate to get it working right and have the tank give way on you.


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## Jumpmaster (Apr 7, 2005)

Yes...good idea -- thanks! Fortunately, have plenty of illumination options for that... /ubbthreads/images/graemlins/grin.gif

JM-99


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## ABTOMAT (Apr 8, 2005)

What all am I seeing there? Safety pop-off at the bottom, pressure switch at the top. What else?

There are two kinds of unloader valves. The type you were told about is a continuous unloader, for a compressor that never shuts off like some gas models. Keeps venting when a certain pressure is reached.

_ALL_ good electric compressors use a second type. There should be a little valve on one corner of the pressure switch. A small tube is supposed to go from it to the section of plumbing between the compressor head and the main tank check valve. When the switch kicks off, the unloader will decompress the line going into the tank. That allows the compressor to restart without facing tank pressure until it's up to speed.


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## ABTOMAT (Apr 8, 2005)

Here's a compressor I built from parts a while back. A little weird but the plumbing does a good job of showing a typical layout:


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## Jumpmaster (Apr 8, 2005)

Yep...I should've put labels in there...reload page 3 of the thread and check again -- I put in labels...

Oh and you're right...the switch does have a valve on it, but the geniuses at the industrial supply shop that sold me the switch said, "Oh, if your old switch doesn't have one, just don't attach anything to it..." in a heavy, Texas drawl...

First, I specifically asked for a Square D 9013 and they tried to give me a Siemens switch.../ubbthreads/images/graemlins/rolleyes.gif Then, they told me not to bother with that valve... /ubbthreads/images/graemlins/icon3.gif

Thanks!

JM-99

BTW, what part of MA are you in? My buddy (that got shocked) is from Groton, MA.


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## turbodog (Apr 8, 2005)

My unloader doesn't look anything like that. It's a little one-way valve that sits in a T right out of the compressor.

MS code..... don't know specifics, but I do know that only mobile homes have to have a 4 connector plug. My new house that got built last year has a bonded ground and neutral for the dryers.


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## ABTOMAT (Apr 8, 2005)

Jumpmaster, unless that little dingus on the head line blows off air, it's not an unloader. Maybe a check valve? If it is a check (and you don't have another check at the tank) put a tee in somewhere on the head side of it. Plumb to the unloader on the switch. You'll hear a little hiss as the machine shuts off.

I think that either your compressor was built from off-the-shelf main components, or someone replumbed it along the way.

Turbodog, how does your unloader do its job? Continuous run? The vast, vast majority of electric compressors use a variation of the type I detailed above. Gas compressors that throttle down use a similar type connected to the pressure throttle. Continuous-run compressors (either gas or electric) use some kind of venting unloader--works like a safety popoff but is meant for normal use.

Those are the types you normally see. There are some other kinds on specific brands. Like a centrifugal unloader that blows the head line when the pump stops spinning, or a type that blows when the pressure from the pump is no longer present.

I'm on the north shore of MA. Up the coast from Boston a little ways.


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## turbodog (Apr 8, 2005)

My unloader is some sort of one way valve with a spring and a weight I think. It helps keep the pump from throwing the breaker, since the pump pulls 15 amps when running. It's right on the ragged edge of what a 15 amp circuit will provide.

Nice compressor though..... I just replaced my old one.


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## Jumpmaster (Apr 13, 2005)

Sorry haven't been around in a few days...just got back from guard drill the other night. Tiresome weekend. Whew...got a slight concussion there too, but that's another story. Lesson: Keep your kevlar on at all times. /ubbthreads/images/graemlins/smile.gif

I'm confused about what to do about the wiring...were you all saying I should rewire the power cord going from the compressor to the wall?

Once I get the dangerous power issue resolved, can focus on the pump cutoff problem...or maybe the power problem will address the cutoff problem also?

Thanks as always for your patience...I'm so thankful for you guys on here as opposed to the [email protected]#$es on other sites. You guys can explain what you're talking about...on the other sites, they never try to explain it (that's usually a sign they don't know what they're talking about...you have to thoroughly understand something before you can accurately explain it to someone else. You guys have got that down! They don't...they just say "Call someone else...")

JM-99


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## Jumpmaster (Apr 14, 2005)

<crickets>

Where'd my experts go??? /ubbthreads/images/graemlins/help.gif

JM-99


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## ABTOMAT (Apr 14, 2005)

As you described it, it looks like one 110V leg is going to the motor and the other 110V leg is going to chassis. If that's the case rewire the cord connections. One angled prong goes to one motor line, the other angled prong goes to the other motor line. The "L"-shaped ground prong should be a green wire and go to the chassis only.

The motor wiring itself looks in order.


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## Jumpmaster (Apr 14, 2005)

Sweetness!!! Thanks so much for the help, as always!

JM-99


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## ABTOMAT (Apr 15, 2005)

So how'd it work out?


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## Jumpmaster (Apr 16, 2005)

Well...still working on this. /ubbthreads/images/graemlins/smile.gif

I cracked open the power plug and found that my buddy had wired the green (ground) wire to one of the angled legs...the other end of the green wire went to the chassis on the compressor. (He said he transferred over the wiring the same as my dad had it hooked up...my dad had a different plug on it because he had a different 220v jack at his house...)

So...it's all jacked up (no pun intended)...and I need to rewire the plug. Need to take the green wire and put it onto the "L"-shaped terminal. Does it matter which 110v leg goes to which on the compressor side? I'm guessing no, but will await verification to avoid being killed. /ubbthreads/images/graemlins/blush.gif

Thanks again so much for being patient and helpful!!

JM-99


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## ABTOMAT (Apr 16, 2005)

Right, doesn't matter. You can line up red vs. black with the way it's in the wall, but the machine can't tell the difference.


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## mattheww50 (Apr 16, 2005)

If it is 110/220 it won't matter, however if it is a 208V motor it may be expect 2 110V that are 120 degrees out of phase. If it is a 208, if you connect the hot legs in the wrong order, the motor may run backwards... (A 3 phase motor WILL run backward if you connect up the phases in the wrong sequence.)


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## Jumpmaster (May 4, 2005)

[ QUOTE ]
*ABTOMAT said:*
All right, we have some wrongness here. If the motor is really wired to the two prongs in your photo, you're doing what a dryer does to get 110V for its motor. That would explain the lack of power. Turbodog's also right that the second hot might be wired to the machine's chassis ground.

OK, step by step:
1. That's an old-style dryer outlet. In the wall, the two angled connectors should be black or red hots and the L should be ground+neutral (which isn't current code but is allowed for old work).

2. In your compressor, the two line connections on the pressure switch should go to the two angled prongs. The L prong should go to the chassis as a ground with the cord's green wire, and nothing else.

2a. If you want to be more code-ish, paint the white line wire red any place you can see it. White is just used for neutral, and you're not using one. Paint turns a neutral wire into a hot in the eyes of the inspectors.

3. I can't be positive, but T5 and T8 should be your start circuit. T1 and T3 (or T1 and T2) should be one run winding and T2 and T4 (or T3 abd T4) should be the second.

4. But the above description is just for understanding purposes. Without seeing the motor in person it doesn't count for anything...

5. ...which luckily doesn't matter since you have that lovely digram printed on the tag. That shows exactly how it should be wired. In your case, now that you know 2,3,5 are connected together, make sure that 1 is alone and that 4,8 are connected. Make sure all the connections are good (try wire nuts or a tight twist) and wrapped with tape.

Whew. Check all this stuff and fire it up again. If nothing's damaged you should be good to go. Make sure you have good oil in the compressor and that the intake filter is clean and working. 

[/ QUOTE ]

Ok...........alllllllll riiiiiiightttt....here we go...

I bought this and have had a little more time to work on the compressor since I'll need it for the new toy...

I rewired the wall plug...added red paint on the white wire (shore looks purty! /ubbthreads/images/graemlins/grin.gif), and now I'm confused -- on the picture here:







Which of those should go to ground? Right now, the red wire on the switch's "T1" goes to one set of motor wires (T8 and T4) and the white wire on the switch's "L2" goes to the other motor wire (T1). I don't know what black and green should connect to.

Here's a pic of the diagram for the switch again...





Sorry to repost the pics...wanted to make it easier for y'all to reference without having to dig through the thread again. If it bugs anyone, please let me know and I'll remove them.

As always, thank you for your expertise and time in helping me. I just do not know what I'd do without your help...except get shocked a lot!!!

JM-99


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## MoonRise (May 5, 2005)

OK, you have 220-240V AC lines in the wall. There are two 'hot' wires, they should be black and red (white insulation painted red or wrapped with a piece of red electrician's tape counts as red here). Those wires should go to a receptacle and be connected to the angled legs. Measure the voltage between those two wires and you should get 220-240V AC. Those two wires and receptacle slots are L1 and L2 (leg one and leg two, or line) for your compressor!

There should also be a green or bare wire in the wall with the two hot legs/wires, that is the ground wire. The ground wire should be connected to the "L" shaped slot on the receptacle. If you measure the voltage from either hot leg to ground, you will get 110-120 V AC.

Next, there is a plug that gets plugged into the receptacle and is wired to your compressor. The plug gets a black wire and a red wire (again, white insulation marked red counts as red) connected to the angled legs. The bare/green wire gets connected to the "L" shaped pin on the plug.

So far we have juice from the wall into the receptacle and then into the plug. All that's left is the wires into the end device itself, in this case your compressor.

Connect the black and the red (again, white insulation marked red counts as red) wires in the power cord to L1 and L2. That's it. T1 and T2 go to the motor and you shouldn't have to do anything there.

If you didn't mess with the extra wires for the motor (T3, T4, T8, etc), the motor should get its 220-240V AC and run properly now.

The green or bare wire in the cord from the plug goes to a screw or lug connected to the frame or chassis of the equipment to ground the frame. Do not connect that bare or green wire to the green wire on T2!!!!!


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## Jumpmaster (May 5, 2005)

AWESOME EXPLANATION! THANK YOU!!!!

Sorry for yelling...just very happy...will go try this after work!!

Thanks again!!

JM-99

UPDATE: Talked to the kind folks at Square D today to have them clarify the diagram that came with the switch -- turns out, T1 and T2 are the innermost terminals while L1 and L2 are the outermost ones. It's all wired up correctly, but will wait until tomorrow to try it out. THANKS AGAIN!!!!! Will let y'all know how it works!!


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## Jumpmaster (May 6, 2005)

Well...it WORKS now!!!!!!! Thank you to all that helped out with my not-very-intelligent questions!!! All of your replies were very helpful!

Now, I just need to get the cutoff pressure adjusted down a little lower...I'm about to go buy an air drill and an air ratchet!!! w00t!!! /ubbthreads/images/graemlins/grin.gif

Thanks again!!!!!!!!!!!!!!

JM-99


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## gadget_lover (May 7, 2005)

We're happy for you. This type of thing is awfully confusing until you get just the right info.

Daniel


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