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Topic: Electric Circuit - Power Supply Issue (Read 921 times) previous topic - next topic

Jebt

#5
Mar 23, 2013, 01:06 am Last Edit: Mar 23, 2013, 02:14 am by Jebt Reason: 1

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So, how would I prevent this 12v power supply from overheating... as I'm guessing the issue is that the power has no where to go and is just being held in the wires.


LOL, Whatever the root cause of your problem I can assure you that it's not because of anything being 'held in the wires' because it doesn't have anywhere to go.

Only with a posted schematic drawing of your complete wiring setup can anyone do more then a wild ass guess of what might be wrong.

Lefty



Lmao, like I said I know nothing of circuits and I'm not even studying Electrical Engineering.


What is the spec of the 12V supply?
What is the rating of the desktop fan?
Is the supply powerful enough to drive the fan?

Bear in mind breadboard connections are good to 200mA to 500mA or so, put too much current
through and you'll ruin it - high current wiring best done with screw connector blocks which are
rated 5A, 10A etc.

BTW the common ground point is ideally at the motor driver since thats where signal levels meet high-current
circuitry.


Spec of 12v supply? I'm not sure... I'm using the one I posted which is 12 volts of power via 8 AA batteries.

Fan rating- it's a 12 volt DC fan, 0.16 A 3 wire red black yellow

Model #-CM A12025-12CB-3BN-F1

Yes the power supply is enough to drive the fan, it's 12 volts.

I'm curious in what usual case would the power supply overheat if a circuit is in the off position vs it's allowed to run?

Is there some sort of code that could stop the current from being drawn? I think when my switch is off, I'm drawing a current, but not doing anything with it.

Or perhaps this is a grounding issue? I noticed in the off position when I powered this off a 9v, the battery got fairly hot, but nothing was melting and the wires were fine.

Is it possible that the wires connected to the PSU are just shit? They do appear to have a smaller diameter than the ones I'm currently using in the rest of my circuit.

JimboZA

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like I said I know nothing of circuits


You don't need to know anything about circuits to draw a sketch of how you have connected everything. You explained it, after all, earlier on, so you do know what you have. It's just difficult for others to follow the words, rather than the pictures! Give it a try.... draw each of the items as blocks at least... the fan, sensor etc etc, and join them up with lines to represent the wires. Label all the components and their terminals (like eg Battery + and Battery -).... then we might get a better idea of what you have.

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I'm curious in what usual case would the power supply overheat if a circuit is in the off position vs it's allowed to run?

Is there some sort of code that could stop the current from being drawn? I think when my switch is off, I'm drawing a current, but not doing anything with it.


I think it's likely that when it's off your circuit is shorting something so that yes there's a current, but as a short circuit (little or no resistance) rather than a nice load which would explain the melting.

All the more reason to draw a sketch of the circuit so others can have a look...
Roy from ITCrowd: Have you tried turning it off an on again?
I'm on LinkedIn: http://www.linkedin.com/in/jimbrownza

Jebt

Yea, I might get around to drawing a circuit for you guys. After this one question though; I just inspected my 12 volt power supply, and noticed the wires are stranded, not solid. Could this be the issue? I know the Arduino is specifically supposed to use solid wires for the circuit, the rest of my wires are solid.

JimboZA

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I know the Arduino is specifically supposed to use solid wires for the circuit,


Don't know where you got that from?- it's usually suggested that you don't use stranded wire in breadboards since they often bunch as you push them in, making for bad connections. Also bits break off and block the holes.

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Yea, I might get around to drawing a circuit for you guys.


.... we might get around to helping.

Roy from ITCrowd: Have you tried turning it off an on again?
I'm on LinkedIn: http://www.linkedin.com/in/jimbrownza

tack

It sound like you have some short when your fan is switched off.

My guess is that your 9v battery is a PP3, in which case the reason you're not seeing the same overheating/melting issues with the 9v is nothing to do with the voltage but actually the batteries inability to supply high current.

I also suggest all grounds get commoned as you could also have a path back through other components. Strange things can happen when you forget to reconnect all your grounds together.

Without a drawing of what you actually have then your not going to get any further wit help.

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