motor 3phase to single phase

Leadfoot said:

I have seen PLANTS with single phase power from the utility run 3 phase motors and drives using the OPEN DELTA method of connection.

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Most farms are wired this way, also.

Some never have problems.

Some eat motors like candy.

I was at an open delta plant, which ran three months a year. We replaced 20% of the motors anually.

regards.....casey

Mike mentioned it first but I will repeat it, the motor is fractional HP so depending on location etc it may be just as easy to obtain a single phase motor, the drive Mike mentioned may be less than a motor though.

Many stated that it was not possible to use a capacitor but it is, the correct statement is "you can not use a capacitor alone", an inductor and resistor is needed. The process is called static phase converter and may require derating the motor HP %50 (wye-wound its around %67). This picture shows 2 methods.


Alaric has shown an example of using a static phase converter in conjunction with a motor to create a rotary phase converter. I dont know if it was mentioned but the idler motor should be at least %50 larger (HP) than the 3 phase motor.

Their is another method showing how to obtain 3 phase from single phase at: http://www.patchn.com/3phase1phase.html

Yes you can

In post 504bloke`s post #12 will work. To size your capacitor you can start with a 2 mfd at leased 240 volts. You may have to start the motor turning manually. Once the motor is turning measure the voltage on the developed phase to one of the other lines. You can add or subtract capacitance until the developed voltage is about the same as line voltage. This will give you the correct capacitance you need to run the motor. The motor may not start on it`s on. If it doesn`t you may have to add a start capacitor in parallel with the run capacitor, but the start capacitor has to be switched out of the circuit almost imediantly or you will let the smoke out of it.
Good Luck

:site:

1) This thread brings to mind the ol' "how many whateverwhos it takes to change a light bulb" joke..

2) The "unregisterd" poster never responded after 17 post responding to his question.

Kinda funny....

elevmike said:

1) This thread brings to mind the ol' "how many whateverwhos it takes to change a light bulb" joke..

2) The "unregisterd" poster never responded after 17 post responding to his question.

Kinda funny....

Click to expand...

True he never responded..But i sure picked up a thing or two!!..I knew about the Motor Generator type that Ron has at his site but i didnt come across the capacitor one before..(Not unless it was in a phase converter)..Good to know..As ron says on his site 3phase motors are usually thrown away becouse most people dont have it..

D

Hi

I just read all of your response to my question and they really a good, Thank you guys for sharing your knowledge.

So we just decided to buy a new single phase motor to replace that 3 phase one, we'll just keep it for future use.


domo arigato goseimasu to all!

billy

Just forgot to say that actually I have tried this once before connecting a capacitor to three phase motor to run it on single phase and it work well on my friend's shop long ago. We just got the capacitor on a junk box and it so happend that capacitor solve the problem however the shop is not there anymore and it's stuff. And now I encountered the same problem.

That's why I tried asking that question, maybe someone out there know the way to size a capacitor instead of making too much trial and error.

Anyway thanks to all and I learned something from this thread.

Thanks once again

billy

I thought you read all the replies.