Control panels, I/O board,PLC type question
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is this DC?
---------- Post Auto-Merged at 18:17 ---------- Previous post was made at 18:16 ----------
draw yourself out a sine wave and decide where you think 0v is.
---------- Post Auto-Merged at 18:17 ---------- Previous post was made at 18:16 ----------
draw yourself out a sine wave and decide where you think 0v is.
bahmoggy,
I need to understand your question before I can provide an answer!
I suspect that you may be referring to a 24V d.c. power supply, where the +ve is the +24V rail & the -ve is the 0V rail.
Neutral is a particular term applied to 3 ph a.c. systems where you have a transformer with a centre point which is earthed, i.e. star, there this star point is earthed.
The current return for imbalance and single phase loads is the Neutral, thus it has no place in supplies which are derived from local d.c. power supplies or 2ph to RLV transformers for example.
I need to understand your question before I can provide an answer!
I suspect that you may be referring to a 24V d.c. power supply, where the +ve is the +24V rail & the -ve is the 0V rail.
Neutral is a particular term applied to 3 ph a.c. systems where you have a transformer with a centre point which is earthed, i.e. star, there this star point is earthed.
The current return for imbalance and single phase loads is the Neutral, thus it has no place in supplies which are derived from local d.c. power supplies or 2ph to RLV transformers for example.
as I said, draw yourself a sine wave, look where is + and where is - and then decide where 0v would be to see the difference,
remember, DC doesnt oscillate (terminology?) the same as AC.
remember, DC doesnt oscillate (terminology?) the same as AC.
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Someone you have been talking to has been sloppy with their terminology.
the "wrong" thing in that statement is "24v-"
This sort of kit is powered by a 24V DC power supply. Think of it as a big 24V battery if that helps you to understand it.
It has two terminals one being + and the other being -
Now, the "+" terminal of the power supply is referred to as "+24V" or just "24V"
And the "-" terminal is just refered to as 0V.
Logical really as there is 24V potential difference between them.
Anyone talking to you about "24V-" is just talking BS and does not know what they are on about, unless, in some cases, there really is a negative 24V rail, but that's extremely uncommon.
You NEVER connect 24V DC stuff to the AC neutral. They are completely different things. You never connect 24V dc stuff to "earth" either.
kind of, if you do a 24v sine then you have a peak of 24v+ at the top, a trough of 24v- at the bottom, and 0v dead centre,
as DC doesn't oscillate then where do you have your +24v, -24v and 0v?
if you went from peak to trough you would have 48v PD, much in the same way as a 110v AC Tx is in fact a centre tapped 55v supply.
am I making sense to anyone but myself?
I know this isnt strictly speaking correct, Im just trying to do it so the OP can get his head round where 0v actually lies.
as DC doesn't oscillate then where do you have your +24v, -24v and 0v?
if you went from peak to trough you would have 48v PD, much in the same way as a 110v AC Tx is in fact a centre tapped 55v supply.
am I making sense to anyone but myself?
I know this isnt strictly speaking correct, Im just trying to do it so the OP can get his head round where 0v actually lies.
ElectekAir
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0v is technically the - everything will have a 24v connection and a 0v one
Current will always flow from the more +ve to the more -ve in DC circuits
So
"24V wrt 0V" is the same as "0V wrt -24V",,,, the current will flow the same way
However
"24V wrt 0V" is not the same as "-24V wrt 0V" ,,,, the current will flow in opposite directions!
So
"24V wrt 0V" is the same as "0V wrt -24V",,,, the current will flow the same way
However
"24V wrt 0V" is not the same as "-24V wrt 0V" ,,,, the current will flow in opposite directions!
ElectekAir
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If you measure with a multimeter and switch the leads black to positive and red to negative you will read -24v hth
its 'isolated' from true earth,
simpe separation I think they call it,
example, open the bonnet of your car and touch the positive terminal,
NOTHING,
it cant flow through you as it has no reference to the ground you are standing on.
simpe separation I think they call it,
example, open the bonnet of your car and touch the positive terminal,
NOTHING,
it cant flow through you as it has no reference to the ground you are standing on.
What would the benefit be??
oldtimespark
Senior Member
Looking back through my old notes on DC rectifiers circuits I found this circuit, I've recreated it in pdf format attached.
Best to search with Google on dual power supplies.
View attachment 3970
psu diagram.pdf
Best to search with Google on dual power supplies.
View attachment 3970
psu diagram.pdf
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Sorry just picking this thread late. Now you have understood the fundamental 24V DC supply systems do you understand where DC systems are used and applied? What is it you are doing with DC and are you required to understand logic etc? To me, the power supply is the most basic part of the circuit.
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