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Motor: single phase, or 3 phase.

Hello everyone, I’m trying to figure out if my motor is single phase or 3 phase.
Does anyone know if the info on the plate is enough to know this?

image: motor.jpg


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Doesn’t it say 3 stamped into the tag next to a label that reads PH. Near the right side rivet?

Looks like 3 phase to me.
How many wires are there?


Hmm… :(

As I remember, a 3 phase motor can be wired to single phase 220, but it is not as efficient, and will cost more to operate. Your motor plate definitely states that it is a 3 phase motor (last number on the second line. See if you can find a small electric motor repair person in your area and ask them what you need for this specific motor, and if it can be adapted.


It is fairly certain that the first 2 posts are correct, it does appear to specify 3 (three) phase, @ 1 1/2 (1.5) horse power, and although the voltage is specified at 240 volts knowing that U.S.A. Voltage is or was (and maybe still is) 110 volts, would imply that, as here in the U.K.(normally) 3 phase voltage specification, on the legend plate is, approximately double the single phase normal, i.e. 220 x 2 = 440, therefore U.S.A. style would logically be 110 x 2 = 220, but as the frequency is stated as 50 cycles (this between the 220 volts and the 3 phase sign) would seem to be from a long time ago, but still quite usable!!!, we use 50.cycles per second here, your normal appears to be 60 cycles at 110 v, although that difference is not normally a major problem with a simple device like a motor. Complications arise when as a perfect example, my Jukebox by Seeburg out of Chicago came into the U. K. running at 110v x 60 cycles, installing a step UP transformer was easy, but the variation in the frequency, had to be overcome by mechanically altering the gears, that drove the turntable, problem sorted and still running!!!>>>>>>>Further 100% (from the horses mouth) verification, even if General Electric doesnt exist in its original form, (as here in U.K) there is almost certainly concessionaires, giving technical back up, for such major concern, find there address, give them, Model, Frame size, R.P.M., Voltage, Frequency, and Type, all visible on the Legend Plate, and you must get Chapter, Verse, and Paragraph.


As I understand it, You’re in Mexico, which, according to Wikipedia, had areas with 50Hz power until the 70’s, which would explain the frequency of this motor.

This is definitely a 3 phase motor. It will run on single phase power at reduced capactiy, but it will not start on single phase power. I’ve started 3 phase motors on single phase power by winding a short length of rope around the shaft to get it started in the right direction. You give it a pull like you’re starting a lawn mower, then connect the power. Not necessarily the safest thing to be doing.

As Mick pointed out, this is a 220 volt motor. But, contrary to what many people in 240 volt countries think, 240 volt circuits are very common in North America. 240 volt service is delivered to almost every single home, the difference being that it is delivered as two 120 volt circuits which when combined produce 240 volts. The benefit is that a 240 volt circuit produced in such a manner is never more than 120 volts above ground potential, making it safer than how it’s done on Mick’s side of the Atlantic.

For reasons that only trigonometry can explain, the voltage of a 3 phase circuit is 1.73 times the voltage of a single phase circuit, not double the voltage. A North American 3 phase circuit is commonly regarded as operating at 208 volts. That’s all moot, though, if you don’t have three phase power available at your breaker panel.

Luckily, you’re not out of luck. There are devices called ‘Variable Frequency Drives’ that are perfect for these situations. They can take single phase power at one voltage and frequency on their input, and generate three phase power at a different voltage and frequency on their output. A common one with is the Teco FM50:

And finally, you could always look at just swapping out the motor!

Keelan, Thanks Buddy, its nice to see somebody shooting from the hip, and telling it as it is, with constructive info, for the prime benefit of the one that wants to know!!>>>>>>>>>>>> Thanks and Regards Mick.

Wow, great info everyone. Thanks a lot.

This motor is the one that came with my C&P Craftsman 10x15.
It is a variable speed motor or at least it has the variable speed box to operate the speed.

I really want to be able to run my C&P at slower speeds.

But I don’t have 3-phase installation on the shop, and its something costly to get installed.

So a Variable Frequency Drive would be the solution?

I have been running a regular smaller motor maybe a 1750 rpm with a very small pulley but I think it’s still too fast for me.


Like every has already said that is a 3phase motor, you can not start or run that motor on 240v 1phase it will burn up and destroy the windings. 3phase has 3 lines of power 120deg apart from each other, 1phase has two lines of power 180deg from each, so you can see how they are not interchangeable. 240v is the amount of power which is standard US power, sometimes its labeled 200, 210, 220, or 240 but they are all the same. What it is is your standard power that is in your house 120v or (110) which is one line of 120v and a common, its two lines of that power to make to make 240. In 3phase 240v you have three lines along with a ground.

You can purchase a good new 240v 1phase motor like a balador for $250-350 , or to use that motor purchase a rotary phase converter, around $300-400. The motor you have is 1.5hp so you will want a 3hp rotary phase converter. Do not get a static converter which is only made to start 3phase motors on single phase, they are not made to run a motor. A rotary converter uses a 3phase motor to pull power to capacitors which basically fakes the third leg or line when your motor is turning. It becomes a more balanced power source and does not damage motors.

Both options will be around the same price, but you have to think about the future, if you are not going to have a 3phase line dropped to your building a phase converter is a good investment if you are wanting to get other pieces of machinery.

Also if that motor has a variable speed box that runs it then you will not need a VFD. That will be the same thing as what you already have, the only difference is that your box that controls that motor acts as a large resistor kind of like a dimmer stitch for lights in your home. My Kluge has a nice speed control box as well and I’m sure it is the same thing cause the motor looks like yours.

If you are ever interested in selling the motor and control box give me a shoot