The very first upgrade that I made to my PM-30MV mill – and long before I ever thought about starting a YouTube channel – was to add a simple Z-axis power feed. The total cost was well under $100 – and it worked beautifully.
A few months later, I also added power feed to my mill’s X-axis, using the exact same wiper motor, controller, switches, and housing. It shares the same power supply so was even cheaper for parts – although there’s more involved in machining its belt-drive mechanism.
I showed the mechanical aspects of these in one of my very first YouTube videos: https://youtu.be/v5eqgtVek-A?si=UAO97oDlGhpPzP_A It turned out to be my most popular video, by far! In it, I overviewed the electrical setup and hinted that I might open up one of the controller boxes to show the connections in a later video – but never got around to doing that.
So in this follow-up video, I’m going to show the end-to-end electrical setup and wiring. It’s quite simple.
In the earlier video, I also mentioned that I had to isolate the ground of one of the motors. This is CRITICAL if you plan on having two or more power feeds, as I'll explain in this video. And I'll detail how to do that minor surgery to you motor(s).
The motors actually have two possible +12V input connections: the red wire for fast (100%) speed and a green wire for slower (50%) speed wipers. These use two different motor winding circuits and would normally be run as red-black or green-black circuits. But after isolating the negative black wire from the ground, I found experimentally that I can get the motors to run at 150% of their normal speed by applying +12V to the full-speed red wire and 0V to the slow-speed green wire (with no connection to black).
This evidently uses BOTH motor windings together in an “additive” way. It was purely luck that this happens, but I used it to advantage for my X-axis feed, as I sometimes want the extra speed to move the table quickly. (Not for milling operations, but for positioning the part/vice in preparation for milling.)
While I have my Z-axis motor apart (to show the ground isolation), I’ll also make this simple speed-up wiring change for that axis, as it would be nice sometimes to be able to move the head up and down a little quicker. Of course for both motors, the PWM potentiometer sets the actual motor speed so it can be as slow or as fast (up to the maximum) as you want.
And finally, while I have the Z-axis assembly apart, I’ll modify the bracket/spacer/shroud around the screw coupling (that connects the motor and the mill’s Z-axis crankshaft). My original design for this simple part completely enclosed the coupling so that it’s difficult to disconnect. The mod provides a better way of securing the motor to the mill crankshaft coupling.
Electrical parts list:
Adjustable 0-48VDC 480W power supply: https://www.amazon.com/gp/product/B07SZSWZ6Z (I have mine adjusted to output 16VDC)
12VDC windshield wiper motors: https://www.amazon.com/gp/product/B00VVFNHXA
PWM controllers (2 pack): https://www.ebay.com/itm/235259402115 (includes rocker switch, potentiometer, knob, LED readout)
Momentary push buttons (8 pack): https://www.amazon.com/gp/product/B07NXPPKDZ
Aluminum project box: https://www.amazon.com/gp/product/B07KYFS9S7
4-pin M/F connectors (kit of 2-,3-,4-,5-pin connectors): https://www.amazon.com/gp/product/B07F5B5LLX
Or here's a 5-pack of just the 4-pin connectors: https://www.amazon.com/DGZZI-5Pairs-Circular-Aviation-Connector/dp/B07PQF2RDL
Roller lever limit switches (10 pack): https://www.amazon.com/gp/product/B08736NP44
Wire: I used 22ga between the PWM controllers and limit switches (very low current requirement) and 16ga elsewhere: https://www.amazon.com/gp/product/B07FMLVF84
Wiring diagram:
https://drive.google.com/file/d/14CZ8E1yJlR4mCGL8qpRzT79pF34FJ6UD/view
Note: A full mechanical parts list (belts, pulleys, bearings, etc.) is included in the description under the original video.
Music:
Kurraba by Peyruis - https://soundcloud.com/peyruis
Licensed under a Creative Commons License https://creativecommons.org/licenses/by/3.0/
Support by RFM - NCM: https://www.youtube.com/watch?v=KIiKGBhVCi0
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Coastline by Ikson - https://www.soundcloud.com/ikson
Support by RFM - NCM: https://www.youtube.com/watch?v=rNoz39fCOvs