Increase Volt or Amps to 12v device?

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  #1  
Old 03-10-12, 11:23 AM
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Increase Volt or Amps to 12v device?

I have a home-made solar thermal air heater set up pushing hot air into my basement. Works pretty darn good but for now is only a proof of concept contraption and it will be a permanent fixture in the future with a more powerful fan (> cfm).

The fan I have now is an old 12v .56a computer fan with unknown cfm. I have it hooked up to an AC adapter from some random old electronic device. The tag on it says the output is 12v .75a.

Today when I plugged it in, for a few seconds the fan was turbo charged! I mean like triple RPM! Then it turned back down to normal. It has never done this before.

What do you think caused it? Higher starting voltage? Momentarily pushed more amps?

I'd quite like to get this fan running running like that all the time. What kind of discarded AC adapter should I look for (higher volts, amps etc).

I don't really care if it seriously reduces the life span of the fan as I have a box of them.

Thanks!
 
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Old 03-10-12, 11:38 AM
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Yeah...for whatever reason... I imagine the voltage increased...not the amps. You'd see the same thing if you used a 16V p/s vs the 12V. If the V goes up, normally the A go down. You could play around with a multi output unit from RS or similar.....or just find one with higher V and equivalent A.

To have things last without any hazard...I'd look for a higher speed or larger fan and an appropriate P/S.
 
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Old 03-10-12, 11:42 AM
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What do you think caused it? Higher starting voltage? Momentarily pushed more amps?
Either could have but best guess would be a short spike in voltage from something.

Did you plug the AC adapter into a standard 110v outlet ? Hard to say what caused it if only a one time anomaly. Might want to have a volt meter handy next time to be sure voltage is stable and where you expect it. Sounds like a capacitive effect coming from something you might be doing.
 
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Old 03-10-12, 11:54 AM
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Yeah, it was plugged into a normal 110 ac outlet.

When I install it permanently I will definitely be adding a larger fan, but now I know I can speed up this one I can test better for the perfect size with my anemometer.

It is currently blowing out 125*F air and the temp inside the panel is still 130*F. The fan only brings it down by about 10*F so it can handle a much larger fan to get every degree possible out of it.

I'll try messing around with higher voltages.

What is an "RS"?
 
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Old 03-10-12, 12:27 PM
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Radio Shack......was just what I have around here....
 
  #6  
Old 03-10-12, 12:28 PM
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I suspect Radio shack.

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