PWM not causing motor to turn until 50%
September 25, 2008
I built a Pulse Width Modulator to control the speed of a 12V DC motor, but the motor doesnt even turn until the potentiometer is at 50%. How can i fix this?
Let me give more background. I took apart a Skil 12VDC 1 Amp Drill and removed the motor, gearbox, transmission, and chuck all in a single unit, and wanted to control that motor much like the trigger on the drill did...slow to fast, at full torque.
So I built a PWM to do it... I got it from here....http://www.bakatronics.com/shop/item.aspx?itemid=383
The PWM turns the motor but not until the pot resistance has been reduced by 50% or so...if I leave it at 50% the motor turns slowly at first then gains speed...this was not the control level I was looking for...
can anyone help me figure out what is going wrong?