I'm currently making my own custom controller to control my corn burning stove. I have all functions except for one finished - how to control draft to the fire pot.
In its original configuration, the corn stove uses a 120vac 1/8HP motor running at 3600 RPM to blow combustion air into the fire pot. There is a manual draft valve which allows me to adjust how much air blows through the pot.
I would like to try to replace the manual draft with an automatic configuration which uses a 24VDC 1/8HP DC motor - and use PWM to control how much air blows into the fire pot. Now I need to figure out a driver circuit that can handle 4 amps @ 24V to control the motor.
I don't have much experience on the hardware end of things, and was hoping to get some direction on this from someone knowlegable on the subject.
One of the problems you might find with varying the speed of the fan to control draught is the extreme non-linearity of fan speed to volume flow rate. Not impossible to overcome but you might well find you end up operating over a very small bandwidth at the top end of the range.
You might be better considering having the fan running at a constant speed, and then controlling a throttle valve angle, or a bleed-off dump valve. Apart from giving a better control parameter the power requirement of the controller output will be so much less, say a small servo type motor to operate the valve.
Or there again maybe a combination of fan speed and throttle angle
jack