Originally Posted by jfsp
Simple question : How would you control the flow of a DIY peristaltic pump when you don't want to run it at max speed ? I see 3 choices :
1) regulate/reduce the voltage to get lower speeds (would that work with an AC motor or would I just loose torque?)
2) run at full voltage, but pulse the current (x times per seconds)
3) run at full voltage, full current (max speed), but take breaks every z seconds (for example, run 5 seconds, stop for 5 seconds ...)
Lets assume stepped motors are not an option.
4) Variable frequency drive. This is how AC operated motors in industrial applications have their speed modulated. Instead of changing the voltage, you change the frequency of the electricity from its usual 60Hz to something else. That changes the rate of rotation of the motor. These are generally used on 3-phase motors.
Looks like automationdirect.com can put you in a 1/4HP VFD for $100.