Finished the new power supply

[rippersoft]

I just finished up the new power suply last night. I have 4 24VAC 4 amp transformers wired individually to separate bridge rectifiers and then separate capacitors. After the capacitors, the wiring is merged (Paralleled) to a Banana Jack (new drink...).

The components are mounted in a salvaged PC case and has 2 fans pumping air in and 1 fan pulling air out. The fans are wired to a 12VDC wall transformer that is wired into the AC inside the case.

My surprise was that when I fired up the PS, not only did everything hum properly, no smoke, no rude noise, but that there was more DC out than calculated. 24VAC x 1.4 = 33.6VDC.

The actual output at the jack is 38.5. A proper load on the PS may bring this down to the 34VDC range. Not sure. I will also have to look at the transformer outputs and see if these actually put out 24VAC and not 26 or so.

Next stop, mounting the driver board in its' box with fan and wires. Followerd by setting up the computer. This just gets all the brain cells firing and tingling.

[Al_The_Man]

If you just went by the label voltage of 24ac then in all probability you will find the open circuit voltage to be a bit higher, allowing for diode drop and the DC you are getting off-load, it should be around 28.7vac.
Al.

[ViperTX]

I suspect that the rating is 24VAC at the max. secondary current.

[smarbaga]

put a light bulbs or 2 on the supply and see what the output is.
you can load the thing down with several bulbs to see when things start to get hot,
maybe each supply at a time, and perhaps wire each supply to each drive
if each individual supply will deliver enough juice per drive
this way if something goes bad in the power supplies you will know which one is the culpret, and maybe only one system will get fried
just a sugestion
good luck, how about a picture ?

[rippersoft]

Thanks for the info and suggestions. The unit is running pretty good. I am going to put a bleeder resistor in the circuit with a switch so that I can work on the supply without problems.

The driver board will be mounted in a separate box with a power switch. This way I can power down the driver and then power down the PS and then bleed it.

A bit of a process, but this will protect components at the driver end.

I will post pictures this weekend and I will get pictures up showing the router machine, aptly named "Butt Ugly Router". When you see the experiment, you will see that the name fits.

I will be "prettying it up" with decals for parts used and maybe some racing decals as well. Suggestions welcome.

[rippersoft]

Here are some shots of the new PS. I fired up the PS with the drivers and motors last night. Boy what a thrill to see the machine jog!!

[joecnc2006]

Ok, i have one question, It is my understanding that if you wire psu's in seriaes yes it will increase the voltage, because i have 3 computer 12v 8a psu's in series with a floating ground and yield 33.8v, however because of the 8 amps for units, isn't that the Max amps i can get out of it, meaning you increase your voltage but you do not increase your amps?

So if that is true you get the 38v as stated in previous post but only can achieve 4 amps?

Joe

[Al_The_Man]

I took it they were wired in parallel,If so his voltage will stay the same as a single supply, so his current rating for each will be additive.
Al.

[rippersoft]

The final output from each capacitor is wired in parallel which adds current, not voltage. Each capacitor reads 38 volts and the output at the Banana Jack is 38 volts.

In theory, if you were to wire the 3 PS you have in parallel, then you would get 12 volts out and 24 amps. I don't how those switching PS would react wired in parallel.

[joecnc2006]

Originally Posted by rippersoft The final output from each capacitor is wired in parallel which adds current, not voltage. Each capacitor reads 38 volts and the output at the Banana Jack is 38 volts. In theory, if you were to wire the 3 PS you have in parallel, then you would get 12 volts out and 24 amps. I don't how those switching PS would react wired in parallel.

Actually i get 32.8v into my controllor board I can not read amps do not have a meter for it., but volts meter shows 32.8v, one single PSU showed slightly more than 12v, then wired three in series (with floating ground) and same wires read 32.8v, no floating ground gives me 12v still.

[smarbaga]

myself , i wouldn't trust 2 or 3 switching power supplies connected in series,
i am not saying that its not a good thing but i think the current is going to have to go through those little transformers in that board,
i actually don't know unless i study the schematic ....
then i would probably be more confused......

[joecnc2006]

Originally Posted by smarbaga myself , i wouldn't trust 2 or 3 switching power supplies connected in series, i am not saying that its not a good thing but i think the current is going to have to go through those little transformers in that board, i actually don't know unless i study the schematic .... then i would probably be more confused......

Well with three in seriers it increased mt torgue alot with these 100oz temp. motors, and i cut MDF and HDPE at a constant 30ipm, with one 12v PSU it just lost way to many steps, now it missed none.

Footprint of machine 36"x60" cutting area 24"x45"

http://www.cnczone.com/forums/showpo...8&postcount=70

Joe