I want to run a 3 phase induction motor on a single phase power supply. I'm aware of the low operating power & low starting torque in this configuration. My load & duty cycles are also not big, so I'm fine with the under performance.
I also have an additional requirement that I need the ability to change the rotation direction of the motor by a 3 position switch (forward, stop, reverse).
As you can see, it is a "break before make" type of switch.
Also, we need to apply just enough force to put SW1 in neutral position from any of the 2 extreme positions. If we apply too much force, the SW1 will be pushed to the other extreme position.
This circuit works, but with problems.
- I keep SW1 in neutral position, then connect the AC power & turn on the AC mains, I get a humming in the motor. When I push the SW1 to forward position, the motor turns forward.
- Same as step 1), but now instead of pushing SW1 forward, I push it Back & the motor turns reverse.
- While the motor is turning, if I push SW1 back to neutral, I can see & hear a spark occurring inside SW1. But the motor does not stop after this happens. So, I need to disconnect the mains power to turn the motor off.
- While the motor is turning, lets say, forward, if I accidentally push SW1 too much & put it in reverse position, the circuit protection switch in my house gets triggered & I have to disconect the motor & reset it.
Any idea whats happening here?
I suspect the Cap is storing residual voltage, which gets added up to the voltage from the mains & causes a spike. Or, maybe the coils of the motor act as inductors & create a voltage spike when the circuit gets broken.
Please also suggest how I can achieve my desired function using minimal additional components & the setup that I have. For eg, If I get the double pole 3 position switch, will that help?