What do I have to do to wire my compressor for 240?

[chris142]

A couple of years ago I bought a Quincy Q12120PQ. IMO it's junk but thats another thread here--->

http://www.garagejournal.com/forum/showthread.php?t=155639&highlight=quincy&page=2

Anyway when its cold out it pulls too many amps and blows my 20a breaker. I had an electrition out and we determined that the motor can be wired for 240v simply by moving a few wires...So we thought.

I never had 240v here so I had him run a new 240Line from the breaker box to the garage. This btw cost me much more than I anticipated but it's done and now I have 240v in my garage( I checked it myself with a volt meter).

We wired the compressor like the pic on the side of the motor shows and it wont work. We also changed the plug on the power cord to a 240v plug.

I'm getting 24v to the black and white wires at the motor. When I turn the compressor on nothing happens. No noise, no sparks...Nuthin.

I put the compressor back to 115v and it starts and runs till it blows the breaker.

I've tried using a thin automotive oil ( I know I Know) thinking that the 40wt in the pump was causing too much drag... Still blows the breaker on 115v.

Is there anything else I need to do to make it work on 240?

 

[Bjm364]

Check the nameplate on the actual motor. If it is dual voltage it will be stamped "115/208" or something similar in the "volts" field. You may have to open the terminal box on the motor to see a high and low voltage wiring diagram.

 

[chris142]

Its a Century 7-177849-20. It says 115/230v. I have looked at the wiring diagram and moved the wires to the different places under the plate. Wont work on 230/240.

 

[Charles (in GA)]

Depending on how the pressure switch is wired, it may need to be wired differently for 240v. Just because the motor can be changed over, doesn't mean there are not other things that need to be changed. The manual with the compressor should have documented the changes. Also need to make sure that jumpers and wires on the motor that were moved from terminal to terminal were correctly installed for 240v.

Charles

 

[chris142]

The manual *****. No mention of swapping it over to 240. It's only got 2 pages and 1 page is dedicated to safety stuff. Page 2 basically says to use their sae40 oil in the thing.

 

[Bjm364]

Good point about the pressure switch. I wonder if it is only breaking one leg of the input regardless of voltage though.

 

[chris142]

I just pulled the cover off the reguator. It's also 115/230v but theres no directions anywhere on it. I really hope that I can use this compressor and dont have to buy another one. Does anybody make a 230v compressor that will fit under my bench?

I give up for the night. Voltage and me dont get along anyway. Dont matter if its 12V in a car or 115/230 in my house. I cant make either work...Ever.

Oh and the wires I moved on the motor are where they say to put them. I remove the brown from #3 and put it on #5 and the Green from #4 to #5....Something like that. Just gotta move 2 small wires.

 

[alwaysFlOoReD]

I'm not an electrician. I have a compressor motor I'm wiring for 220V. My understanding is that there are two 120V lines in and a ground. The two 120V lines are "phased" so that when added they = 220V. There is no neutral. I'm not sure why there wouldn't be a neutral, I don't know enough. I wired my 220V welder plug on the wall (it works) the same way so figure it should work with a 220V compressor motor. I'm subscribing to this thread so I get to hear what others think.

Richard

 

[89GLH]

120+120=220? Please show your work. I know ovens use similar wiring but have a neutral to utilize the 120V components in the controls, and the 240 controls the heating elements. Thats a basic understanding, I'm sure a sparky can chime in better.

 

[Hencini]

120+120=220? Please show your work.

I was told there would be no math.

 

[ezzzzzzz]

The problem appears to be the pressure switch. Remove the cover and you'll should see 4 screws with wires attached. There will be a line side, 1 & 2, and a load side, 1 & 2. The 'hot' leads from your panel will go to the line side, 1 & 2. The 'hot' leads from your motor will go to the load side, 1 & 2. It doesn't matter which color goes where. The neutral wires are bound with a wire cap inside the pressure switch and do not attach to anything else inside that switch. The screw with the spring is your pressure adjuster (on/off switch) that determines when power is applied or removed from the motor. If the wiring at the motor has been done correctly you'll be in business. REMEMBER to kill the 240v circuit breaker in the panel before rewiring. If it is not in line of sight of the compressor then tape over or close and lock the panel. That sounds **** but many a person has been shocked because someone or something tripped a breaker by accident or best intentions.

 

[Norcal]

Good point about the pressure switch. I wonder if it is only breaking one leg of the input regardless of voltage though.

It is code compliant to only break 1 leg of a 240V single phase feed or 2 legs of a 3 phase feed, BTW, it is done all the time w/ A/C equipment, it is not compliant to do that w/ the disconnecting means.

 

[ezzzzzzz]

Failed to mention that you need to drain that auto oil out of your compressor! Only non-detergent should be used in this application.

 

[Kevin C]

You may also want to look into a synthetic 40 wt compressor oil. In general, it should not thicken up as much cold.

Detergent oils till leave more deposits on the valves and in the outlet pipe. IR makes a good one, I have been running Redline.

 

[ezzzzzzz]

It is code compliant to only break 1 leg of a 240V single phase feed or 2 legs of a 3 phase feed, BTW, it is done all the time w/ A/C equipment, it is not compliant to do that w/ the disconnecting means.

It is compliant but I prefer to know that zip nada power is on the downside of any switch/breaker when it is off. Too many years working in a naval shipyard in the electronics & fire control divisions, I guess. I've seen my share of unexpected sparks and shocks... others, not me.

 

[trainer]

Have you tried contacting the manufacturer?

http://www.quincycompressor.com/contact-us-1.html

 

[chris142]

I know I need to change the oil that was just a test to see if it would make any difference. it did not. I have not heard back from the manufacturer

 

[Kevin C]

I would measure the current on 120. If your way off you might have a motor problem.

 

[chris142]

In getting 240v at the wires in the motor.

 

[chris142]

Quincy has still not responded to my email. I brought an electrition home and he went over everything. The motor is the problem. For some reason the 220v side don't work. Maybe thats why I have had so much trouble with it on 115V?

Definatly the last Quincy I buy.

 

[chris142]

The Quincy motor is defective. put one from Harbor Freight and it works fine.ezzzzz... I changed the oil back to a compressor oil this morning

 

[nehog]

Post pictures of:

1. The motor's wiring diagram for 120 and 240 volts.
2. The motor when wired for 120 volts.
3. The motor when wired for 240 volts (and it doesn't work.)

I don't think the motor is defective, I think you have a wiring error.

 

[Jagmandave]

Chris, did you put in a 240 or a 120V motor from HF?

Remember, Quincy doesn't build the electric motor, they just buy them from a motor manufacturer.....they can get a bad one once in a while too.

 

[chris142]

3 hp 230v from hf