psu/mutimeter question

[novielo]

hi, i got a little question. i bought a psf60-24 psu http://www.escience.ca/hobby/RENDER/000 ... 12118.html . when looking at the case i tought that it was +24 -24v. it seems it's only a +24v because when i use a multimeter, the black lead on the v- and the red lead on the v+ i have a reading of 24v shouldn't i have a reading of 48v? and when i put it on the ground and v+ or v- i got 0v.

is it a +24v only?

thanks alot it's for the modular cabinet that i'm currently working on

[nathanscribe]

Erm, I hate to say this, but the page you linked to may explain things. It says 12V, it says + and -, and it says ground. I would assume from that it ouputs 12V positive, 12V negative, and can provide 5A (2.5A per rail).

Correct me if I'm wrong, but unless you gave us the wrong link, there is no reason to believe this would give a dual 24V output.

Are you sure you're taking the readings correctly? AC/DC settings, correct connections etc?

[Stab Frenzy]

Actually down the bottom of the page there's a few different models, one of them is 24V. They're all just 0V-24V though.

Novielo: I think it would be irresponsible for me to not say this: If you don't understand enough about electricity to be able to know what voltages you should be getting out of this then you shouldn't be doing any mains wiring.

This unit has inputs for Live, Neutral and Ground, and has outputs for 0V and +24VDC.

[novielo]

yeah sorry, the links is ok, same thing but 24 v. it's because they use this link for the whole series.

yes the multi was on dc, i double checked it when i saw the results

thanks stab for the warning. that's excly why is ask questions, so that it doesn't blow into my face. i always try to ask first.

[rjd2]

reading from ground to +, w/ dc setting, you should see +24. from ground to -, -24.

on the safety subject, a safer way to do this is to turn unit off, connect ground to alligator clip, and probe with one hand only. even though i rarely get bit, i try to make a habit of this just as a precaution.

[Stab Frenzy]

reading from ground to +, w/ dc setting, you should see +24. from ground to -, -24.

Not on the power supply that the OP linked to, it doesn't have a negative side to it.

To get the negative rail as well you need one like this. See how it says ±15V? The OP needs one like that but ±24V, the one s/he has is just +24V.

[Maschinengeist]

I'm in the middle of something right now. I will go to the page and come back to you... tomorrow or this weekend.

[Maschinengeist]

Ok I had a quick peek.

L= Live. This output is straight from the line.
N= Neutral. This is the return of the live to the line.
Earth or Ground (the arrow down)= 0V
V+= Positive Voltage.
V-= Negative Voltage.
The other output, I cannot read from the picture. V???

To measure your V+: red probe to V+. black to Earth
To measure your V-: black probe to V-, red to Earth.

[Stab Frenzy]

Ok I had a quick peek.

L= Live. This output is straight from the line.
N= Neutral. This is the return of the live to the line.
Earth or Ground (the arrow down)= 0V
V+= Positive Voltage.
V-= Negative Voltage.
The other output, I cannot read from the picture. V???

It says V ADJ, it's the trimpot for adjusting the voltage. It's not an output.

I already explained what the situation was with this power supply, it doesn't have a negative voltage rail. If people are going to keep giving advice about mains voltages that is wrong/isn't thought through properly we might have to consider banning discussion of mains power in here. I'd hate for this forum to be responsible for someone electrocuting themselves.

To measure your V+: red probe to V+. black to Earth
To measure your V-: black probe to V-, red to Earth.

No, the V- is 0V, V+ is 24V. It's not a -24/0/+24 supply.

[Maschinengeist]

Opps... damn, have I look at the right page???

My apologies. I should have checked more closely the specs. In fact, was there specs?

Sorry!

BTW I didn't mean to contest you. How to explain it?... bah, you know, just didn't read from top to bottom. My bad.

[nathanscribe]

Agh! Dammit. Sorry yes, I was not seeing things right last night either. Listen to Stabs, he doesn's talk as much s**t as me.