12v drives

[chester1957]

I am adding three axis cnc to a unimat mini lathe and have 2 pc power supplies ranging from 12v1.5a to 12v7.5a or 5v10a to 5v20a.
This being a small machine stepper motors should be dirt cheap, my question is can I get drivers to work with the above power supplies and later upgrade the power supply and motors but still use drivers for a planned cnc benchtop mill.

Any help would be greatly appreciated.

[pminmo]

Depends, 12V isn't going to get you great performance, and some drives have a minimum voltage requirement. Probably the best place to start is to use two 12V pc supplies in series to get 24V. Used PC supplies are dirt cheap or even free. look towards the bottom of the tables on my website, there is a link named linking PC supplies that will take you to a good writeup.

[chester1957]

Found the link. Thanks for the info, I'd like to get the best drives I can afford and upgrade the rest later.

[chester1957]

Originally Posted by pminmo Depends, 12V isn't going to get you great performance, and some drives have a minimum voltage requirement. Probably the best place to start is to use two 12V pc supplies in series to get 24V. Used PC supplies are dirt cheap or even free. look towards the bottom of the tables on my website, there is a link named linking PC supplies that will take you to a good writeup.

Great write up, thanks a bunch. 23.8v 10a, one supply gave me fits as no matter how I wired it up, I could only get it up to 7.8v. Doing some research on the web I found beside a load on the 5v, I possibly needed a load on the 12v wire in the same bundle as the green wire. Being new to this and not having many components I wired a 10w 1ohm resistor for a test and grounded the green wire. Didn't take long to fry the resistor and the wife thought I'd set the house on fire, but I had 11.8v. Next test was 2 fans drawing .32a this wasn't enough, as it would fire for a second or two and shut down. I took my last resistor and glued a large heat sink to it and added it to the two fans and ran it for a minute or so. Still 11.8v, not sure if it's my meter, but at least I am close.
BTW- the resistor glued to the heatsink cracked in about 4 places, so the seach is on for some that will take the load.
Thanks again for the reply.

[neilw20]

Automotive Light bulbs are more difficult to fry (LOL)

[chester1957]

Originally Posted by neilw20 Automotive Light bulbs are more difficult to fry (LOL)

I thought of that and searched my messy garage for a couple, but 17 degrees outside and a 98 cent resistor seemed pretty cheap, and as a newbie it most likely won't be the last thing I fry.

[neilw20]

Originally Posted by chester1957 I thought of that and searched my messy garage for a couple, but 17 degrees outside and a 98 cent resistor seemed pretty cheap, and as a newbie it most likely won't be the last thing I fry.

It was 40C(104F) here yesterday, probably 43C(109F) tomorrow.
I will happily work in an open shop on these days.
You need leather gloves to take parts out the car. Steel block was 80C(176F).
Put on another jumper!

[chester1957]

Originally Posted by neilw20 It was 40C(104F) here yesterday, probably 43C(109F) tomorrow. I will happily work in an open shop on these days. You need leather gloves to take parts out the car. Steel block was 80C(176F). Put on another jumper!

I had to work in weather like that when we moved my son home from Phoenix Az.
I dove in the pool about every 1/2 hour or so, otherwise I think I would have died. I don't envy you one bit sir.

[neilw20]

It's OK. Still another 3 degrees to go before it gets bad.
Dry heat here so a bit of a breeze feels good.
1000 mile north of here it is HUMID too. That IS bad.
Had a pool once, now with drought you need a permit to fill one,
Soon we will need carbon credits to filter it.
I downsized my yard, and upsized the house, and gave away the dog.
I will buy myself a beer.

Happy new year to You, Your Family and all of the CNCzoners.
Maybe we need a New Year string?

[chester1957]

Originally Posted by neilw20 Automotive Light bulbs are more difficult to fry (LOL)

I added the 12v light bulb as suggested to the 12v side and a resistor w/heatsink on 5v side and hooked ps together ,24.2v.

Working on enclosure to insulate ps wo/case ground and start search for 2 more free 10a ps as in the end with 2.5v motors I'd like 48v, but you gotta start somewhere.

[vger]

light bulbs are found in a lot of places.... The original BOSE 901 speakers had a light bulb wired in series with the speaker voice coils. Too much power to the speakers, no problem, the lightbulbs just lite up, get hot, increase resistance, and thereby limit the power getting to the speakers...