AC Motor Phase Transformation

Many others would as well...

If the hp of the motor is not too large, a Variable Frequency Drive may be used to convert 1Ph to 3Ph. I have used them for years. You might be looking for a roto phase unit, a much older design. They cost quite a bit to operate. No easy solutions, except buy the correct motor for the application.

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First, you must recognize that you will not develop the power that would be possible with a bona fide three phase supply.

You will need to determine the capacitor size empirically. Use oil capacitors, like the ones found on old air conditioners totalling up to perhaps 20 uF to 60 uF, or perhaps more. See what value spins the motor up to speed fastest. You can do this at lower line voltage using a Variac at first. Once you determine the optimum capacitor size by that method, run it at rated voltage, and measure the capacitor current with a clamp-on ammeter to insure that it is not excessive.

One word of caution: If you are in North America, you will be working with 230V to 240V. Motors meant for 3 phase AC in North America are rated for 200V to 208V between phases. So, you will want to use a transformer which has a 240V primary and about a 36-40V secondary, with the secondary connected to buck out the excess single phase voltage. You may find one more easily with a 115V primary, which is OK too. Just make sure that the secondary current rating is high enough for the motor. If you don't do this, you may saturate the stator iron in the motor.

Bernie Katz