merrill L sanders
I'm using a PMDC motor from an old treadmill. The controller in a treadmill does a soft start, that is it always starts up at zero speed. This is very bothersome when working on a lathe so I need a controller that starts up at the last speed used. I'd like to build a PWM controller for the loads involved but since I'm really not knowledgeable in electronics I don't know how to select the correct components. There is lots of stuff online but usually for little motors.
I've copied one design- converting AC power to DC using a bridge rectifier. I varied the AC and was able to get a corresponding variable DC, but it would not run the motor. I know motor works because I can run it with my power drill batter.
I've take a power supply from an old computer so I have a source for DC and it will run the motor very slowly. Not sure how to speed it up or how long the power supply would last with the motor loaded.
Sci
Dominic
Jbarlow1007
Jesse Tolvanen
I'm looking to do the same. I have a 120v 2hp treadmill motor that I'd like to add to my band saw so I can cut metal with it. I see lots of 555 timer circuits for PWM. I believe that we can use the bridge rectifier and a mosfet to use the 555 circuit. I'm just worried that I won't select the right components. I'm planning on trying to get some that are well over sized so I don't blow anything. I did use an SCR to change the AC voltage to feed the bridge rectifier, but the motor sparked like mad when I used it. I was worried about over voltage so I tested it with my voltmeter. Sadly, I didn't have an video recording when the lead blew off my voltmeter. Sorry you had to miss it, it was pretty good.