AC torque motors: Triacs and Variable Transformers

Hi Guys,

I have done some research on the AC Torque Motor control problem (I need to vary the voltage via a controller that can also interface with a PLC). Some mentioned using a triac and I was wondering if someone had some information about that. Also I know you can use a variable transformer but I have only seen variable transformers that are controlled with a manual knob and don't connect to PLCs. Does anyone have an suggestions? Thanks a lot.

Tenbaum

Yes, look into the Watlow Power Controllers I linked in the first post about this. They use back to back SCR's (essentially a triac) in order to vary the output voltage by phase controlling the SCR firing time. Still 60Hz, but 0 to (Vin).

Also, you can check Oriental Motors controllers, or find a brake controller that can be configured for a 0 to (Vin) output. At one time, I believe Saftronics made one.