Can a 3 phase motor be run on 230 volts?

Question

hi i am just about to get a 3 phase lathe. a good friend of mine in his mid 70;s tells me that years ago he helped many people run their 3 phase motors on 230 v useing a capacitor wired in series but can no longer remember the calcalations needed to work out watt size capacitor to use does this ring a bell with anybody many thanks in advanced , jonny

Answer 1

There are converters that convert 1-phase to 3-phase.  The 'good' ones use a rotary conversion method with another 3-phase motor, but it is possible to do what you suggest.  I wouldn't recommend it, though.  You need to do some calculations as to starting torque (even with the lathe unloaded), to find an optimum value of capacitor.  It may be you need several 10s of microFarads of 400V oil capacitors.

Search Yahoo or Google, "3-phase rotary converter", for more details.

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Answer 2

Yes 3phase motor can run on 230volts.same type of capacitor used in the motor

Answer 3

I have seen motors rated 3-phase,230 Volts motors run with a cpacitor wired in series to one phase. This was a trial and error done by lathe machine electricians. The torque developed may be small to start turning the machine and we fear the drive motor might fail in cases of heavy load.

Answer 4

If you live in a town, the easiest thing to do is take a feed from each next-door neighbour, and you will have instant three-phase power!  This works because adjacent houses are wired on adjacent phases of the mains .....  so if you're on "yellow", then your neighbours one side will be on "blue" and the other side will be on "red".  Note that the feeds must all be taken from upstream of any ELCB / RCD.

It is possible to use a capacitor to artificially generate a leading phase and an inductor to artificially generate a lagging one; but the motor will run out-of-balance and will lack power.  You can also run on just two phases, at a cost of even more power and needing a push to start it once out of every 3 times  (obviously this is no good if there is a worm-drive reduction gearbox).

To calculate the inductor and capacitor values required, you will need to know the resistance and the reactance of the motor windings at mains frequency.  It's then just a case of applying Ohm's Law with complex numbers, using Z = R + jX and making sure that the phase is shifted forwards 120° in one winding and back 120° in the other.  This is all assuming "star" connection:  if the motor is designed for "delta" connection, then it just plain won't work.

A purpose-made, three-phase inverter drive would be better, though more expensive.  Or, you could just try and find a single-phase motor of the correct kilowattage .....  that may well work out the most satisfactory solution.

Answer 5

Ronk Electricial Industries makes "phase converter" equipment that allows the operation of 3-phase motors on singe-phase service.  

Both solid-state and rotating versions of phase converters are available.  Follow the link below for more details.

Answer 6

You can get a 3 phase motor to turn this way but its not going to give you the power or torque that it would at 3 phase. Also consider the voltage. Is it 230v 3 phase or 415v?

Your best option is to get a single phase motor. Depending how handy you are, you may be able to get something from a junk yard of similar speed and power and adapt it.

Converters are available but its probably going to cost you more. Many variable speed drives can be bought as single phase input. Rotary converters expensive and inefficient.