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I recently bought a brand new TECO-Westinghouse Electric motor .

3 phase
HP: 1
Volts : 208-230/460
RPM: 1750
HZ: 60
Fr: 56
Cat no: ZA.0014TE2/56
Type : AEFAZA
Enclosure : TEFC

I would like to run this off of my household power. My understanding is that I need a 1 phase(household) to three phase converter to do this. What size wires do I need for the plug from from the house to the on/off switch? From the switch to the converter and from the converter to the motor?

I would like to plug this into a regular 15 amp receptacle-the motor will be about 75 feet from the receptacle.

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    Why not simply return the motor and purchase a different one which is better suited for the place where it will be installed? – user23752 Oct 21 '14 at 13:18
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    Get a single phase motor $150 or a 1HP VFD $340 – mikeytown2 Oct 21 '14 at 22:18
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    You would need a phase converter, and you would need to plug into your 240V power (like an electric range) to have enough voltage to run it. The current drain would not be all that high, on the order of 8 amps or so, but the starting current could be much higher. – Hot Licks Oct 22 '14 at 1:48
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I'm sorry, but from the tone of your question, and the fact that you even suggest plugging this motor into a regular 15A receptacle tells me you are so far over your head your only valid option is to hire a pro to wire this. This is NOT a simple DIY job and you cannot simply ask questions to get every little detail out of an internet message board to do this job properly and safely.

I'm sure I'll get negative marks for this answer but I stand by it firmly.

The other, and cheaper option is to unload this 3-phase motor and get a single-phase motor. I bet a 1hp single-phase motor is cheaper than the phase converter itself. 1HP is not that big and single-phase versions are readily available. You'll still need a new dedicated circuit for it but it'll save you quite a bit in the long run.

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    "You don't when you have to ask here" was my immediate thought when I saw this question on the hotbar. – PlasmaHH Oct 21 '14 at 14:23
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    +1 for @Speedy's warning. You really need a decent understanding of electrics to do this right. That being said, many industrial facilities use 3-phase motors with speed control devices called Variable Frequency Drives (VFD's). These basically work by converting their 3-phase power supply to high-voltage DC internally, then inverting that back to 3-phase AC to drive the motor at whatever frequency/voltage is called for at the moment. If you can get a VFD that is rated for your motor or better and can take a single phase input (they do exist), then you might be okay. – AaronD Oct 21 '14 at 14:38
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    There can be good reasons to do it (primarily variable speed drives). Yet I agree with Speedy Petey; for one thing you'll need at least a 20 amp input circuit (16 amps drawn by converter) if using 115VAC, and 230VAC input makes the whole business much simpler (and cuts the currents by half, of course.) – Ecnerwal Oct 21 '14 at 15:42
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My understanding is that I need a 1 phase(household) to three phase converter to do this.

Yes. Usually these are used if you need to control the speed, torque, or another aspect of the motor. If you just need a constant 1750 RPM with a max 1HP, then you can purchase a single phase AC motor that doesn't require a converter.

If you need to control the motor speed or torque, though, then your motor choice is fine.

A single phase to three phase converter is usually referred to as a motor drive in this case, since you aren't merely converting the single phase to three phase, but driving the motor with specific parameters.

Make sure your motor drive supports 120VAC input, and 230 or 460VAC output. One such driver is a Schneider Electric ATV12H075F1. It should run your motor just fine, but consider talking with a specialist to verify - I've not personally used this drive or the motor you've chosen and have only given each a cursory glance. It may not drive your specific motor, so consult both data sheets or work with an expert.

Again, while you can buy a simple converter that doesn't attempt to drive the motor, there's little reason to do this - just get a single phase motor.

What size wires do I need for the plug from from the house to the on/off switch? From the switch to the converter and from the converter to the motor?

From the driver to the motor:

Your 1HP 3 phase motor will draw 3.3A at 208-230VAC, or 1.7A at 460VAC. While you should consult your driver for the voltage and thus find out the amperage, the reality is that you shouldn't use anything smaller than 14awg wire for this job, and 14 awg wire will handle both currents well, so plan on 14awg wire for this run.

From the power source to the driver:

Your motor drive will have an efficiency rating, indicating that it will use more energy to run the motor than the motor will output. Further your motor won't be 100% efficient either. 1HP is about 750 watts, but due to loss of efficiency you can expect to use a quarter or more of that at the power source. So we'll round up to 1,000watts, or just under 10A at 120VAC from your plug to the driver. Assuming the driver is located close to the motor, and this single phase run is 75 feet, then you could safely use 14 awg, but you'd have a 5 volt drop in this run, and at 10 amps you're losing 50 watts heating the wire. I'd feel more comfortable with 12 awg wire for this run.

I would like to plug this into a regular 15 amp receptacle-the motor will be about 75 feet from the receptacle.

I'd recommend keeping the driver close to the motor, as you'll need to run four or more wires between the driver and motor, vs 3 between the power source and driver. This will reduce your total wiring cost. However, the higher voltage and lower current of the 3 phase means the wiring losses are lower, so the setup is slightly more efficient if the long run is 3 phase. The difference in efficiency is negligible, though, and if you have any other requirements that suggest a specific placement for the driver then they should probably weigh more heavily than initial wiring cost or overall efficiency.

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  • Also note that you can't just give it 208 or 460 and expect it to draw the stated current. The motor itself will have lots of wires and you'll have to short them in the correct combination for the voltage that you're using. – AaronD Oct 21 '14 at 14:58
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A Steinmetz connection is what you're after!

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    Awesome! Do you know if they're available as a commercial product that can be safely plugged into a household power supply? Also, please answer the other aspects of the question about wire sizes. Thanks, and welcome to the site. – Niall C. Aug 6 '15 at 20:59

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