How to test a strange power supply?

[AlmostHandy]

Hello.

I picked up a Glory GFB-200 Money Counter, at a yard sale for $2. It works fine.

The power supply outputs are labeled +5, +12, and +24, which is exactly what I need for my CNC machine.

Voltage is labeled, but I would like to know how I should go about testing the current.

Should I put the machine back together, and test the power supply's outputs while the machine is on, with my DMM?

Can I just plug the outputs into my breadboard and test the current with my DMM from there, or does there have to be a load on the supply for it to work right?



Thank you.

[Al_The_Man]

A very few switching supplies require a load before an output appears.
The current is dependant on load, the only way to test the current capacity of the supply is to use it on your required load and monitor it, either for fold back or other symptoms.
You can get a rough idea if you know the nature of the load it was operating in the machine.
Al.

[AlmostHandy]

Thanks Al!

I tested it connected to the original device, and the 24v current was nearly 6A. Way too much for me. Then I checked the 12V, and it was only 1A, which isn't enough.

So, I think I'll hang onto it for another project.

But, I wanted to ask about the feasibility of my latest half-cocked idea. I'll admit, I didn't do much research on this idea, but that's really because I didn't know what kind of search string to use, and everything I tried was incredibly vague, and not at all what I'm talking about. That's probably because I don't know what I'm talking about. :-)

Ok, so what I want to do, is to take three of those laptop style power supplies, and use the same fused mains input for all three of them. There's this joint around the corner from my pad, called RE-PC, and they have these things for a couple dollars a piece. Digging through the bin, I found 5V, 12V, and 24V supplies, all with the current outputs I think I can use in my machine.

So, can I wire a single C14 chassis mount plug to three different C13 sockets, and run all three of the supplies off of the same mains input?

Also, when factoring the amount of current I want from a supply, do I add up the supply current of each device? For example, if my three motors run on 600mA, do I supply them with 600mA, or 1800mA?

[Al_The_Man]

You don't deliver the current per-se the load demands a certain current, it is up to the supply to provide it.
IOW, if your load demands 6amps and the P.S. is capable of 12amps, 6amps is all that will flow.
There are many previous posts here about daisy chaining or combining PC P. Supplies, personally I am not in favour of it, but if they are cheap you don't have much to lose.
Al.

[AlmostHandy]

Right on.

I checked out the daisy-chained ATX articles, but after I thought about my question, I realized it's the same thing as moving one of those $4.99 power strips to the inside of the case. I just wanted have one AC Cord and switch for the whole shebang, and a power strip is really a simple solution. It's just bulky. I'll figure that out. Seems easy in retrospect.

I won't be loading across multiple supplies at all, like they talk about with chaining ATX supplies, and all three supplies will be isolated from each other within the circuit.


Thanks again Al!

Peace!