OMO, back EMF brushed dc motor speed control
 

so who amongst us knows what i'm talking about and if so i'm needing a circuit. needs to be temperature compensating and no PWM.

i already have a hall effect servo design which i can hack the speed change out of to bolt onto the front end of the back EMF circuit.

its only two speed with no reverse of brake needed.

once i have a schematic i can work out the voltage etc.etc from the motor and adjust the design.

Bibs

Re: OMO, back EMF brushed dc motor speed control
 

Not a clue but does it look like this ???

Re: OMO, back EMF brushed dc motor speed control
 

Alas I have no idea what you are describing. But that photo is brilliant. ☺

Re: OMO, back EMF brushed dc motor speed control
 

I do understand what he's talking about, but way above my pay grade to actually do what is being asked !!!


What's wrong with PWM ?

Re: OMO, back EMF brushed dc motor speed control
 

PWM can cause instability under varying load.

PWM is ok for RC cars and such but not as good in critical speed situations.

Re: OMO, back EMF brushed dc motor speed control
 

I hope this is an electric SV project. SV240VAC anyone?

Re: OMO, back EMF brushed dc motor speed control
 

this is interesting

https://sites.google.com/site/hobbyd...g-back-emf-sen

Re: OMO, back EMF brushed dc motor speed control
 

Don't think that lot will power a SV very far !!

Re: OMO, back EMF brushed dc motor speed control
 

Never designed one, just bought and used industrial versions. They had AC supplies so used Thyristor bridges, and used tacho-feedback for best speed control.
Used some small DC supplied ones that used MOSFETs, similar arrangement to a SMPS Buck circuit so with PWM.
I have old textbooks on power electronics that give the basic circuits.

Re: OMO, back EMF brushed dc motor speed control
 

well i designed one and have sent the pcb files off for manufacture. will it work.. ermm will have to wait and see. whats it for.. its for a hifi turntable.

this is the reason i have not been on the forum.