HELP: AC motor control with an H-bridge

Discussion in 'The Projects Forum' started by ozgur84, Feb 8, 2013.

  1. ozgur84

    Thread Starter New Member

    Feb 8, 2013
    Hello Everybody,

    I am new in forum and I am not an electronic engineer,I am a Physicist. That's why I need some help for a basic motor control circuit which I want to make some additions to control an AC gear motor.

    I found a basic DC motor controller circuit which can drive a low voltage DC motor. Here you can see the circuit diagram.

    I also found a good electric gear motor 1r/min which can perfectly work for my application in the local store. However the motor is an 230V 50Hz 3Watts AC motor.

    My plan is using the connections of two 555 IC Timer (3rd legs, at where the motor leads are connected on the circuit diagram above) with two NPN transistors (MOSFETs I think) which are capable of working at 230V. I think, I can supply the Transistor part of the circuit with 230V separated from the timer circuit and I connect the 3rd legs of 555s to the 1st connections (base) of the NPNs.

    At this point, first, I want to know which transistors I can use and second, what sort of extra additions should I make :)

    Thank you all in advance...

    PS: I think I can supply the 555s with 3 to 15V. There is no limitation here.
  2. crutschow


    Mar 14, 2008
    You can't control an AC motor with an H-bridge, that only works for DC motors.

    Better and easier to use a commercial AC motor speed controller such as one of these.
    ozgur84 likes this.
  3. ozgur84

    Thread Starter New Member

    Feb 8, 2013
    Thank you for replying crutschow. After writing this thread, I realized that I can also use a relay instead of a complex transistor circuit :) I was too concentrated on using some NPNs from another stepper motor controller circuit and basically I could not see the easy solution :)