Replacing upper board with pot. for treadmill motor speed control.

[HazMatt]

Hi everyone.
Im brand new to the forum and know nothing of electronics.
I have a treadmill motor i plan to use for a belt grinder but don't want the bulky display and original buttons/ controls. I do have everything from original set up and motor works with all the factory wiring.
I want to switch to an analog potentiometer for speed control to eliminate the upper (treadmill display) board but don't know if the motor control board will work independently of it.
I Will appreciate knowledge sharing. Thanks for looking. HM.

 

[Minder]

Looks like J1 is the control input, it could either be a variable linear pot style input or a PWM signal,
You could try a 5k -10k pot first to see if it works.
M.

 

[HazMatt]

Looks like J1 is the control input, it could either be a variable linear pot style input or a PWM signal,
You could try a 5k -10k pot first to see if it works.
M.

Looks like J1 is the control input, it could either be a variable linear pot style input or a PWM signal,
You could try a 5k -10k pot first to see if it works.
M.

Nice. I guess if the pot doesn't work, I'm stuck with the original board then correct? Thanks for the quick response Minder.

 

[Minder]

If the pot doesn't work you could whip up a PWM circuit to try.
http://www.discovercircuits.com/DJ-Circuits/simplepwm2.htm
The transistor could be a 2n7000 fet or you may not even need it.
M.

 

[HazMatt]

If the pot doesn't work you could whip up a PWM circuit to try.
http://www.discovercircuits.com/DJ-Circuits/simplepwm2.htm
The transistor could be a 2n7000 fet or you may not even need it.
M.

I'll take a peek at the PWM circuit you suggested. Thanks for the input.

 

[HazMatt]

I tried various combinations of connections between pot and j2 terminal, no dice.

 

[Minder]

The PWM may be the answer then?
M.

 

[HazMatt]

The PWM may be the answer then?
M.

May be. With my infantile grasp on electronics and no circuit building experience I feel it will be more direct to use the existing controls. However, now I'm super curious and want to build that circuit.
That's all I need is another hobby! Any one stop shopping for sourcing the components ?

 

[Minder]

My go-to source is Digikey, next day air delivery to Canada.
There are ones on ebay for $1.50, you could strip the unwanted power components off and just use the 555 circuit only if you just wanted the PWM controller part only to play around with.
M..

 

[Alec_t]

The original control board ensures the motor speed ramps up from zero at power-up as a safety feature. Do you want/need to replicate that feature?

 

[Minder]

That reminds me, most that use a pot, that requires that it has to be zero when the units is powered for the speed pot to work.
Did you ensure it was zero when you tried it with the Pot?
M.