Driving 220V Electromagnetic Vibrator Conveyor Belt Motor With SSR and PWM Control

Hey all,

Quick question, we have been asked to upgrade a machine that has proprietry control circuits for everything, including an electro-magnetic vibrator conveyor belt (see below pic) it runs on 220v single phase and i gather that the frequency is modulated to get speed control of the conveyor. I would like to know if I can drive it using a solid state relay and PWM (i.e chopped frequency as opposed to modulated) any thoughts?

 

Thanks

Why do like to use an SSR with this conveyor? PWM is still modulated so I guess you could still use that.

Solid state relays are the only way of switching the power fast enough to keep up with the PWM and can handle the high frequency switching without burning the contacts like a relay would.

Also basically the modulated sine wave is function of an AC voltage oscillating between V+Max and V-Max from 0 - 50hz whereas the PWM approach supplies the motor with V+Max to V-Max at 50hz constantly but chopping out parts of the sine wave throughout the oscillation thereby reducing the total supplied power by the duty cycle of the PWM.

What I want to know is if it will work as I am not entirely certain of the following:

1) If the pwm chopping out parts of the sine wave will in essence be it's own sine wave (all be it a saw-tooth style) and cause harmonic issues with the conveyor design.

2) The supply to the motor will still only be 50Hz and this could mean that the vibrations are at the same oscillation but the amplitude changes which may end up with products that need a different frequency to 50Hz for them to move more effectively which I cant do all I can change is the PWM duty cycle.

I am not able to access the machine for testing these items until we are approved as the contractors for the upgrade but to get approval we need to submit a quotation which leaves me in a catch22 situation.