# Power Feed With Limit Switches



## GreatOldOne (Mar 21, 2016)

I know a lot of you have already made power feeds for your mill, but this may be of some use / help / interest.

I built my power feed using a 24V 3Amp 150rpm geared motor , an off the shelf PWM speed controller, a 24v PSU and a couple of switches.




The speed controller was one of these:

https://www.kemo-electronic.de/en/T...M171-PWM-Power-control-9-28-V-DC-max-10-A.php

Which came with supplied with the correct potentiometer for the speed control. It was all wired as per this circuit:




This gives you directional control, and limit switches to cut the motor when you hit a stop, but due to the diodes / rectifiers, you'll still be able to change directions and have the motor move the table (or whatever) away from the tripped limit switch.

All of it was housed in a shop built enclosure, along with the normal sliding coupling to engage the castle-ated fitting on the lead screw, and the limit switches are mounted to the front of the table.




The table will travel until it contacts the bar that's under the vice in the pic, when it will trip and stop the motion. The position can be fine tuned by screwing in or out the cap head that is in each end of the bar.

It works well - I essentially used the same circuit for the powered head lift / lower, but instead of the PWM module the speed and direction is handled by trigger of the old drill that powers it.

Cheers

Jason


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## David VanNorman (Mar 22, 2016)

Darn nice job . I like the motor.


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## TOOLMASTER (Mar 22, 2016)

what do you use to engage the motor?


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## TOOLMASTER (Mar 22, 2016)

GreatOldOne said:


> https://www.kemo-electronic.de/en/T...M171-PWM-Power-control-9-28-V-DC-max-10-A.php




me likey ;-)


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## TOOLMASTER (Mar 22, 2016)

did you consider a cap between the controller and direction switch...or is your supply capped?


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## GreatOldOne (Mar 22, 2016)

Here's some more pics which will hopefully answer your questions. 

Here's the coupler that engages with the fitting that used to engage with the handle. It's machined to match the 'tooth' pattern of the fittings.




When the power feed is in use, it just slides over on the leadscrew shaft. 




Here's the power socket where the 24v laptop PSU plugs in. The the rocker switch turns the whole unit on, and the red led on the front tells you if it's on or not.






TOOLMASTER said:


> did you consider a cap between the controller and direction switch...or is your supply capped?



If you mean capacitor, no - not really. Pretty sure the PSU will be filtered and protected, what with it being an ex laptop one. Final pic shows a velcro strap on the back that secures the cable to the power feed, so it won't get pulled out when it moves.




And finally - in glorious youtube-o-vision, here it is in action:






Cheers

Jason


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## TOOLMASTER (Mar 22, 2016)

She's a screamer


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## TOOLMASTER (Mar 22, 2016)

i have the same mill enco branded...finally got dro set up after 15 years.lol..


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