How to tell if a motor is 3-Phase

[woodlandfarms]

I am looking for a drill press for the shop. Something simple. With all the machine shops going under there seems to be a large amount of good used presses. Most say 3-phase (I have single phase I m told).

In looking at a machine or label, is there any way to know for sure?

 

[ultrarunner]

It should say right on the motor data plate...

I run my 3-phase Bridgeport Mill with a single to 3-phase rotary converter I made about 15 years ago...

I think you will find just about all of the heavy duty machine shop equipment is 3 phase...

Anything 110 to 125 volt will be single phase...

Anything that is 220-volt could be 3 phase or single.

3 "Hots" is required for 3 phase

 

[PAGUY]

I believe the electrical plug would be the simplist way. Most are the turn into outlet.

If only bare wire you would have red,black and white with a green neutral wire. Red and black are hot legs and white is common.

 

[Inspector507]

When looking at the nameplate there should be something like:
V 230 3Ø
Or
Voltage 230/3Ø
The voltage could numerous ratings........208, 230, 240, 460, 480.

 

[SPIKER]

quick inspection fastest way may be to look for start cap on side of the motor. if there is one there it is single phase. most equipment of any quality that is single phase will have start caps and many also will use run caps. which will be 2 large caps on side of motor. not talking about the motor peckerhead though. best and only SURE way is to look & read motor nameplate as Inspector said.
dont let 3 phase scare you as there are many inexpensive phase converters also being sold or better a VFD varriable frequency drive which can take single phase and make 3 phase at any speed of motor rotation from 0 to about double motors base speed.
Mark

 

[DanD78]

Look for a Fosdick or Johansson drill press. These were used in machine shops and will last for ever. The bad news is they don't make parts any more but they never break down. I found this three phase Johnsson on Ebay for $200 and built my own rotary phase converter. All gear drive, two speed motor, low speed gears with power feed and reverse for tapping.

Dan

 

[yomax4]

If no ID Plate is on the unit just look at the cord.
3 wires = 1 ph. 4 wires = 3 ph

 

[crazyal]

3 phase equipment can be had real cheap because most people (with out 3 phase power) see it and run for the woods. Turning an old 3 phase motor into a single to three phase converter is real simple and usually used a large 3 phase motor to be used as a converter can be had very cheaply (just like the equipment).

My next door neighbor has a large woodworking shop that he powers almost exclusively with an old 25hp motor/ converter. Most of his tools are between 15 to 20 hp and has no issues what so ever.

If you can't get the information off of the data plate then you should find a cover for the electrical connections. Inside there should be a wiring diagram. 3 phase motors will have 3 power wires (usually labeled L1, L2, L3) while single phase will only have two wires and a ground.

 

[woodlandfarms]

Thanks guys. I am going to do a google search for converters but if you have any links you would like to share I will take them

Locally there are a few 3-Phase, but in LA there are tons of them cheap. Some really nice machines. Guess that is what happens when aerospace moves to China.

 

[lostcause]

since you are new to 3-phase, make sure that when you are searching for a phase converter that you are looking at prices on rotary converters and not static converters. rotary converters are the ones made from electric motors, like the peope here are talking about.

since you say you are looking for a drill press from a machine shop, i'm assuming you are looking at ones that cost at least 4 figures when new. if you're looking at drill presses that would cost under $1000 new, i'm not sure if it's worth it to buy a used 3 phase press and then go buy a rotary converter too. by the time you buy both you're going to have at least $500+ invested i'd assume.

not knowing what your price/quality expectations are, or your budget - you could always consider new ones. jet makes a decent product and from what i understand grizzly does too, and for less. i have been looking for a used press for 6 months on craigslist and ebay, but with no luck, so i've had to expand my search (and price range) to include some newer ones. i live in the far northeast, and we don't have a lot of industry here, so i'd have to freight something in from 300-500 miles. makes used as expensive as new.

when i started looking at new, the one that i was really interested in was the jet jpd-20mf. it's on sale now through all jet dealers at $749. some of the rough specs are: 3/4 chuck/mt-3 spindle, 12 speed: 150-4200, 1 1/2 hp 115v/230v single phase - if i remember, it draws 18a on a 115/120 circuit, so a 15a circuit won't cut it. table is 18 5/8"x16 1/8", and it weighs almost 300lb. i'd have ended up buying this, but i've actually decided on getting a mill/drill, so i'm currently making up my mind on exactly what i want still.