[kosho]

I have a machine.. it is pump.. it works on 3 phase.. 2 horse power is the m/c... but I only have single phase at home.. how can I connect it as the power is small enough to work on 2 phase?
Reply
Thanks

[Scleros]

I've had success with phase conversion devices such as Phase-A-Matic Rotary & Static Phase Converters on machine tools. An AC drive such as FM50 Series Sub-micro AC Drive may be another option. For either solution contact the manufacturer for design and sizing assistance for your particular application.

[danar]

I've had success with phase conversion devices such as Phase-A-Matic Rotary & Static Phase Converters on machine tools. An AC drive such as FM50 Series Sub-micro AC Drive may be another option. For either solution contact the manufacturer for design and sizing assistance for your particular application.

check the price of the above mentioned phase converter it migth be more cheaper buying a single phase 2hp motor or trade-in your old 3ph motor with single phase motor.

[danar]

have heard about the steinmetz circuit? Try this it might work.

SINGLE PHASE SUPPLY TO RUN 3PH MOTOR

Operation of three-phase Motors in single-phase supply Induction motors with a three-phase stator winding can either be driven from a three-phase supply or from a single-phase supply when suitably connected with a capacitor (Steinmetz circuit). A three-phase induction motor with its stator connected in star for a 380V three-phase supply has 220V as phase voltage. The motor can therefore also run on a 220V threephase supply when delta connected. If the motor is designed for 125/220V then its phase voltage is only 125V and the motor must be connected in star for a three-phase supply of 220V. The Steinmetz circuit gives similar characteristics to three phase operation but with a single-phase supply.The motor runs as a three-phase machine, if the capacitor voltage causes a symmetrical voltage star at the rotor windings as with a three-phase supply. A symmetrical voltage distribution can however only be obtained with a certain capacitor at a certain load. For all other loads an asymmetrical voltage star is formed at the rotor, so that the
motor can no longer operate under optimum conditions. The starting torque is reduced and the heat
generation in the motor can become higher at no load than at full load.
Experience has shown that with a voltage supply of 220V, a capacitance of 70 mF/kW of motor power is necessary in order to give a starting torque of 30% of rated torque and in operation about 80% of the rated three-phase power.
In order to obtain a higher starting torque, a starting capacitor with about double the capacitance must be connected in parallel. This must be switched off during run up to avoid overloading the motor. The direction of rotation can be reversed by connecting the capacitor to the other supply connection. The voltage across the capacitor terminals in the “Steinmetz” circuits is, at the rated power of the motor, about the value of the supply voltage, and under no load about 15% higher. If the “open star circuit” should be used for a special application please state this when ordering in order that the correct capacitor can be supplied. This circuit can be used when 125/220V three-phase motors are to operated from a 220V single-phase supply.