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400 Volts 3 phase to 240 Volts Single phase Motor Answered

Hello we bought a cutter from Europe.  It came with 400V 0.75W  3 phase  motor. The motor has leads
W2, U2, V2
U1,V1, W1
To convert to the 240 V single phase we jumped (W2,U1), (U2, V1), (V2,W1). We also put 50uf capacitor between (W2,U1), and (V2,W1) .See attached pictures.
However the motor starts and spins for about 5mins then it trips the breaker. The motor heats up .
Voltage reading
Between (W2,U1) and (U2, V1) =240v
Between (W2,U1) and (V2,W1) = 370v
Between (U2, V1) and (V2,W1) =240v

We thought  (W2,U1) and (V2,W1) = 370v was little high.
Also the resistance between winding W1W2 is 36 ohms, U1U2 20 ohms, V1V2 20ohms

Can someone help? I will really appreciate you help



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3 years ago

You can't just run a 3-phase motor on a single phase, simply won't work.
You are lucky the breaker saved your motor!

Back in the day we used some beefy capacitors to cater for the missing phases but this requires some meaningful calculations and the right type of capacitor, hard to find items these days.
Modern option is a so called "motor drive".
The use single phase input but provide 3 phase output for smaller motors up to about 1HP, above that these toys get really costly.
Good thing about them is that you program how the motor starts, the max speed and thanks to frequenzy control you can even let it run faster than designed.
And at low speeds you still get the max possible torque.