Anyone an Electrician?
 

A friend of mine gave me an old air compressor for the shop that needed a rebuild and I'm almost done with it. I have some questions about the motor on it though. He wasn't sure if it was two or three phase. Is there any way for me to look at the wiring on it and tell? My shop isn't wired for three phase so if the motor is in fact three phase would it be more economical to get a two phase motor or get a transformer for the three phase unit?

three phase is not hard to wire, you can always run a new line from your panel if you have enough room in it. I would say change one of the receptacles over from a two phase to a three but im sure most of them are run together so that wont work, take the receptacles off and see if 2 wires are running into the box or if it's just one.

the cheapest way would be just to run a new line IMO

you cant get 3 phase power out of a 110/220v service without a phase converter


it would be more economical to change the motor. just look at the leads inside the motor alot of times they are wired from the factory in different configurations

as stated, a phase converter is going to be pricey, and swapping the motor our for a SINGLE phase 240 volt motor shouldn't be an issue. Its not 2 phase, 2 phase does exist, but is obsolete and only available in very old areas of some cities/industrial areas. It predated 3 phase

As for seeing if it is 3 phase, there is almost always a plaque on the motor which will tell you what the specs of the motor are, if not, you need to open the wiring compartment for the motor and see how many wires /terminals you have. Depending on age you could have just 3 wires in the box, or if is a multi voltage motor you can have up to 9, ties together is different fashions.

If its a 3 phase motor there is no way to change how its wired to make it single phase

Grab a pic and i can tell you for sure.

-Phil

ok well I'm gone til monday but I will look better then and let you guys know. I know there's an info plate on the motor just don't know what all it lists. I remember 60hz but thats it.

60 HZ is pretty much the standard frequency here in the US

yea, 60 hz is pretty standard, the plate should has a spot where it indicates phase, it will say 1 or 3, as well as voltage

ok I'll look when I get home tomorrow and post up my findings up

I was able to get the rest of the tag on the motor clean last night without wiping out the writing. I'm in luck! Phase: 1

Now I just need the rest of the bearings to rebuild the compressor and I'm set.

yey!