Op-Amp to vary speed of motor

Thread Starter

Adam D 1

Joined Mar 7, 2016
1
I'm looking to build an electric go kart, but I'm having trouble figuring out how to vary the voltage going into the motor in order to vary the speed.

Would a voltage divider with a variable resistor connected to a non-inverting amplifier, which is then connected to the motor work?

I want around 36v to the motor, so at 85% of the input I would want to supply the op-amp with around 48v and not have it go much higher than the 36v.

If anyone has any advice or alternative methods that'd be great. Thanks.
 

#12

Joined Nov 30, 2010
18,210
There is no such thing as a kilowatt op-amp. Your start ideas are fair, but you will need a lot more beef to control that amount of current.
ps, How much current does the motor use? We need both the start surge and the running amps.
 

adio9182

Joined Mar 7, 2016
2
It has been a while since I've looked at this project, found this (http://www.ebay.co.uk/itm/12V-24V-48V-20A-DC-Motor-Speed-Controller-Driver-PWM-NE555-25KHz-JGB37-520-RS360-/281467788102?hash=item4188c99b46:g:LNoAAOSwU9xUPQ29) PWM on eBay, would it be suitable to control say a 24v motor and allow for varied speed for a small vehicle?

I would look into replacing the dimmer mechanism of this set up with either a lever or pedal set up, any ideas on equipment required to achieve this?
Thanks for your help, appreciate it.
 

mcgyvr

Joined Oct 15, 2009
5,394
It has been a while since I've looked at this project, found this (http://www.ebay.co.uk/itm/12V-24V-48V-20A-DC-Motor-Speed-Controller-Driver-PWM-NE555-25KHz-JGB37-520-RS360-/281467788102?hash=item4188c99b46:g:LNoAAOSwU9xUPQ29) PWM on eBay, would it be suitable to control say a 24v motor and allow for varied speed for a small vehicle?

I would look into replacing the dimmer mechanism of this set up with either a lever or pedal set up, any ideas on equipment required to achieve this?
Thanks for your help, appreciate it.
If your motor draws less than 20 amps it should work just fine..
 
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