Run 3 ph motor on singlephase

Yes, the answer is certain. You can connect your 3 phase motor to a single main line. But you have to add a mideum equipment to splite off the single power into 3 phse power. If your motor is small power you can use a capacitor for the goal simply (say,from 5uf -- 20uf). if yours is somehow greater one and you hope the motor rotate stable, you can use a inductor and a capacitor together to get a analoge 3 phase power. different power different parameter to choose.
some people use a transformer and a motor to implemtnt it.
There are some factories they produce the equipment. howeer, the facility is rarely using in urban now only but some railway line area.

c

you would refer to your starter manual. it will give a guid.

Many domestic supplies while apparently only single phase do in fact have a three phase cable brought into the house, you should talk to your supply company.

If the motor is 1.5hp or less, you can buy a Variable Frequency Drive that will run off a single phase supply.

Why 1.5 Hp or less?

For Additional current requirements over 1.5hp, the VFD's internal DC bus doesn't receive enough power to maintain required level from single phase.

Here is a previous thread that deals with this subject: http://cr4.globalspec.com/thread/3768#newcomments (Rotary Phase Converter)

no! dont try it. you will loose your motor. it better to sell it & purchase new one.

Sometimes people amaze me. Why in the world will someone, and this is you in this case, make a statement about something they don't have the slightest knowledge about?

grdpande,: don't listen to this ignorant. It can be done and very successfully so.I have been through this Rcapper in reply #6 gave you the link to my thread. Go read it. In order to answer you more intelligently, give us the following: Your motor size in HP, number of motors you want to operate, the duty cycle, and whether the electrical entry to your house is single or 2 phase, meaning do you have neutral and 1 phase, or neutral and 2 phases.

You can choose between STATIC converter and a ROTARY converter. the static is somewhat less efficient but a lot less complicated as it has just few parts. While a rotary converter needs three phase electrical motor to be used as the 2nd, and 3rd. phase generator. also referred to as "IDLER MOTOR"

According with your needs and info, I can send you some schematics so that you can build your converter .

Wangito

Dear,Thank you for your interest and serious question.

Motor size in HP: 2.0
Number of motors I want to operate: One
the duty cycle :Continuous
I you have neutral and 1 phase.

I heard from somebody but forgot now,that a 3ph motor of above size can be operated on 1 phase without the help of a converter/ VFD.

Pls,reply

Your best bet will be the static converter.

here's a good link: http://www.homemetalshopclub.org/projects/phconv/phconv.html

There you will find all the necessary information. If not satisfied come back here.

And NO you can not operate a 3φ motor outright on 1φ supply system.

Good luck enjoy your project, and a happy new year.

Wangito.

Maybe a word of caution is in place here:

Static phase converter is really not a phase converter, but merely a starter. In any event, a motor connected to such a device will only produce about 2/3 of it's rated power. There is a chance that it will not operate at all or operate unsatisfactorily.

It is definitely not a high quality solution,The point is that it is dirt cheap, and worthwhile trying. but be careful.

Wangito.

grdpande wrote: "1.Is it possible to run a 3 ph induction motor on single phase supply?"

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Absolutely!

Not only can you run a 3-phase motor from a single supply, but you can use the motor as a rotary converter to generate 3-phase power to run other 3-phase loads, if this is your application (you didn't say).

Years ago a friend found several great deals on lathes, milling-machines, and other machine shop tools at an auction, but all of them required 3-phase power which he did not have available at his home. To power his new acquisitions, he built a rotary phase converter using a 5 or 10 h.p. 3-ph motor to generate 3-phase power from his mains. I've since lost contact with my friend, but this website may have all the info you need even if it might not address your specific application.

Have a great Christmas!

-e

Is it possible? Yes it is. But, it is certainly nothing that should be done long-term as it canl damage the motor. Virtually identical to what happens during a partial power outage to a facility that is supplied with 3-phase power for its 3-phase motors and one "leg" or phase is temporarily lost. If they are merely "idling" there tends to be little if any damage. But if they are under load the fields and windings overheat and destroy the motor very quickly.

Hence the reason that one sees phase loss detection and protection (immediate power shutoff) in facilities know to experience these problems. I remember one (1) large facility of a former employer that had its own gas-fired power generation because of spotty power delivery concerning lost phases, as well as many transients and much switching "chatter" that caused problems with sensitive equipment. And this operation was in an industrialized area that had sufficient current, just poor quality when it came to phase presence and voltage regulation and homogeinity.

And, 3-phase power can be produced from 1-phase through the use of a phase convertor-essentially a properly-sized 3-phase motor with a large capacitor bank that helps start the motor (cum generator) in rotation. The one (1) solution used in many small machine shops located on a farm or inside someone's garage.

Ing. Robert Forbus

I had a friend several years ago who ran a 3 phase mill from 220 volt using the motor method. He explained that the only problem was that the thing only ran at 2/3 the rated rpm.

Bill

This is much worse than a crime, it is a stupidity. ( Napoleon.)

thanks for this.

i simply was advising as the methods which are stated above somtimes costlier than the cost of motor it self. but if Napoleon has landed, best of luck

This Napoleon catchphrase goes with all of my threads, and wasn't meant for you personally, but rather for one of his generals. I never said that your post was worse than many others, but your definite conclusion -NO- was totally wrong and out of place.

I didn't mean to be , but maybe the years made me too abrasive.

This probably could teach us both something.

Wangito.

1. It is possible and feasible

You do not need to buy but a capacitor of enough capacity and enough peak voltage.

The power output of the 3 ph motor will be less when used as a single fase motor.
The idle speed will be the same, and the on load speed , a little less.

It is very simple to do.

the main criterium you must keep in mind is that the electrical intensity through the windings should not exceed the rated intensity of the 3 ph motor.

I could give you a connection diagramme if you give me several data:

Rated voltage of the 3 ph motor, and power output, and speed or number of poles.

Delta connection or star connection?( of the 3 ph motor )

Are all of the 6 terminals of the 3 ph motor accesible?

Monophase voltage you whish connect to, the 3 ph motor as single phase motor.

I have done this conversion from 3 ph to single phase in one motor I have to run an air compressor.

2.- Follow the installation data of the 440 V motor and that of the delta star equipment, to verify if they match each other. If yes , follow the connection diagrammes.

Best regards,

Arturo Pérez
Industrial Engineer.

Mr.Arturo Pérez
These are the details you needed

440Volts,1.5KW,2800rpm,2Ploes
STAR
Yes All 6 terminals are accesible
240 Volts Single phase

Thanking you.

I wished to send you the wiring diagramme and the definition of the capacitors by e-mail, but my scanner does not work properly with my new PC. At the end I have got a way to send you the required info, but that will take several days. Sorry.

I confirm you that that the power output will be between 50% and 75% of the rated output of the 3 phase motor, depending upon the sice of the capacitors and the connection disgramme.

Best regards,

Arturo

In my humble opinion, this has been a big exercise in semantics, not engineering. To directly answer the original question AS POSTED, the answer is NO, there is no "connection method" that will start and run a 3 phase motor from a 1 phase supply.

At least not without augmentation. The form of that augmentation can either be a starting capacitor only, in which case the motor must be drastically derated, or a phase converter of some sort. If you simply use a starting capacitor, the typical power derate is at least the square root of 3 (58% of normal) but if it is a high inertia load this may not even be enough because the torque application becomes discontinuous, leaving a high inertia load to slow down too much under load and the motor may overload trying to recover. I use a 50% derate to be safe. So in the case of tyour 2HP motor, if you want to use it as a 1HP motor, then you are probably OK with using just the starting capacitor method.

The phase converter can be further broken down into 3 sub categories; Static, Rotary and VFD. The comment that a phase converter will cost more than a replacement 1 phase motor is, I think, a very valid point, however there are a lot of circumstances where there is no choice. Since you didn't want a phase converter there is no further need to discuss that option however.

To reply to question No 1:-

You have a few options, depending on the size of your motor, and whether it may be configured in star or delta.

If your motor is 3kw or less, a Versatile solution would be to use an inverter, these are obtainable from quite a few sources, we use Siemens inverters quite a lot, there are many others on the market though.

The extra versatility you would gain would be speed control, extended speeds, soft start, increased power and torque, electronic overload settings, easy motion reverse, and very much more. Hope this helps.