how to convert 3-phase motor to single phase motor?

[hossam77]

I have a 3-phase motor (1.5 HP, 400V)and wnt to operate it using a single phase source (220V). if i was to use the capacitor for this converstion how can i determine the capacitance.

 

[ScottyUK]

This has been covered here numerous times. Either buy a 1[Φ]-3[Φ] inverter, or either a static or rotary phase converter. Try searching the site using the Search function, or try Google - there are loads of suppliers of phase converters out there.

You can't just use a capacitor alone - needs a few other bits too. If it were my motor, I would buy one of the low-end inverters which are now quite inexpensive - you should get one for under £150 if you shop around a bit.


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[RalphChristie]

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[ScottyUK]

I stand slightly corrected - thanks Ralph.


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Start each day with a smile. Get it over with.

 

[OperaHouse]

If you want to use a capacitor, be sure you have an application that uses less than half the motors rated HP and that you are able to start the motor with almost no load. You can get a used 3 phase motor drive for less than $70 on eBay like an AC TECH. You will have to be able to download a manual and understand it unless you get a very old unit that isn't microprocessor based.

 

[LionelHutz]

Operating a 400V motor with a 220V source is going to be a problem unless you use a transformer. You need the source voltage and motor voltage to match if you want to use a phase converter.

If you use an inverter then you want the supply voltage to be equal or more than the motor voltage. Equal is better.

 

[ScottyUK]

Hi Lionel,

Most motors of that size tend to be 400V star / 230V delta, at least in Europe which is where I'm guessing this motor is from based on the rated voltage. 400V delta / 690V star motors do exist in such small sizes but are much less common. Assuming that the motor isn't one of that minority it is usually reasonably simple to reconnect the windings in delta. Even if minor surgery is required to split the star point if it is internal in order to bring bring out all six leads, it is not especially difficult.


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[LionelHutz]

You're right Scotty. I was just pointing out the fact that a 400V motor and 220V power are not compatable without changing the voltage of either the source or the motor.