Dean_Fuller

I need help with this. I have moved my 220V compressor to a shop arte that does NOT have a 200v outlet nor will I be allowed to add one. However I do have a gas generator that has a 240V outlet. ( see pic) My issue is the compressor and OLD dryer plug I did use only has 3 wires. The generator has a 4 prong plug set up. From what I am reading...I can forgo NOT using the neutral wire....is that correct?

Here is some 928 content....Pulled dash and pod from Dennis car and will recover along with a pod for another Rennlister.


Cant upload pics for some reason right now...will try again in a few minutes.

Dean_Fuller

Finally got the pix to upload.

Ducman82

Yes you can forgo it. I had to so the same thing for my old welder. Welder was 3 wire, was 4 I have a pic some where

Dean_Fuller

Thanks.....I just wanted to make sure. Me and electricity don't mix.

dr bob

There are potential issues with this only if you sometime decide that you want to split the 240 into two 120 legs. At that point your 'neutral' isn't bonded to ground anywhere, and the voltage on the two 120 legs will vary a lot based on the load imbalance between the legs. That said, there's a very good case for adding a safety ground from the generator frame to a good ground point in your shop. You might be able to connect to the ground that is adjacent to the service panel, or drive a copper ground rod into the soil as close as possible to your generator.

More options: Most 240V induction motors less than maybe five horsepower offer an option for wiring for 120V. Usually there's a diagram on the motor itself that shows the connection options.

Compressor motors present a pretty high starting inrush load to a portable generator, especially 3600 RPM motors trying to start into a partially-charged tank. 200% inrush demand is not uncommon. In a hardwired system the short-term overcurrent is managed by using slow-blow fuses or a thermal breaker with a little lag in it. On the generator, the inrush draws the generator engine speed down with the sudden load increase. In the end you'll typically trip the breaker on the generator and trip the thermal protection on the motor.

Dean_Fuller

Thanks dr Bob....a lot of that is very close to the limits of my electrical knowledge.

This is the compressor I have...just a few years older but the specs are the same.
http://www.harborfreight.com/5-hp-60...sor-93274.html

I will post the generator when I find it. If I remember its a 8500 watt max.

I will do some research on how to properly ground the generator. Its on wheels and will be wheeled outdoors when needed.

waynestrutt

If the new place has a breaker panel then you have 240v .If you have 3 wires 2 black one white coming into your panel plus a bare ground simply connect directly to these or put a stove breaker in the panel and connect directly to it. I had the same issue with mine taking it to different residences each job and had adapters to connect to the panel, or to the dryer plug, or the stove plug.

Dean_Fuller

Thanks Wayne...the landlord furnishes the electricity for the shop area. No separate fuse boxes for each unit. He has already stated he does NOT want anyone to run 240 lines so his electric bill is as low as possible. Don't want to "rock the boat" as the shop is a 50' x 50' space with shop lights and water furnished in with the rent. I was renting 2 storage units for my belonging when I moved here in 2009. That was about $100 a month with NO electricity and units so small all I could do was store boxes. Now with the shop space...I can store my stuff and have room to work on cars and bikes year round.

depami

That sounds awesome Dean. Post pics of the shop when you get a chance.

If you connect the ground at the compressor to building ground you should be good to move the generator at will. Ignore the neutral (N) on the generator. Just use L1, L2 and GND.

I would leave the compressor on 240 rather than switching to 120.

Dean_Fuller

A very nice place to work.

jeff spahn

Your 928 steals the show hands down.

WICruiser

Make sure you run the generator away from the building and away from any open doors or windows. Most gasoline generators put out a lot of CO emissions that can be a problem in a hurry in any confined space.

Dean_Fuller

Thanks Roger...will do. The generator sits just inside a big overhead door. When in use it will be rolled outside and around the corner.

Speedtoys

I looked up that Generator..it wants at least a 25A 240v connection to run, with a peak inrush of 40a.

A portable generator isn't gonna do it, without burning something up over time, if it doesn't simply pop itself straight away.

Jim Devine

Look for something like this- they show up on Craigslist from time to time.

http://www.tractorsupply.com/en/stor...air-compressor
You can feed it to your tank for more capacity.
Or you can probably find a big industrial compressor with a 3 phase motor pretty cheap & convert it to gas powered.
As Dr Bob pointed out the starting load of your compressor is a lot more than the running load.
Not good for the start winding on your motor.
When I was a paint contractor, the airless repair shop got lots of units with burned up motors that
painters tried to run off generators.

Great workshop!