Well I just got a fan from a car's ac system (fan and motor) . I an on making an air gate to use with it, but I am having trouble trying to figure out how to provide power to it. The wall outlets that I would like to use as the power source are 110v ac and the motor and fan unit fund off 12v dc, so theirin lies the Problem..... Also I wanted to have an inline switch to just turn the power on and off, so please let the ideas flow...... Thanks

You need a transformer suitable for the rating on the motor, maybe a battery charger would work? Others may know

if you get a small battery like a motorcycle battery and a trickle charger that would probably work, the fan should say how many watts or amps on it along with the voltage, that should give you an idea of what size battery you might need. You can also get a transformer, which will be rated in VA which can be used as watts in your case. So if the motor says 50 watts you would need a 50 va transformer, 12o to 12 volts. If the motor is rated in amps 2 amps X volts would be 2 x 12 = 24 watts . IF you get a transformer that is too small you will burn it up and loose the money. If you decide to do this you will need to wire it safely with no exposed 120 volts terminals. If you do a google search you should be able to safely wire this. It would also be easy to put a variable speed on the motor since it is DC. You can get a variable resistor setup, and then you would not need a gate. You can also google that to see how to do it and what you need. good luck

A transformer by itself won't be enough. Output from the transformer is alternating current.

A six amp battery charger should work.

sorry, you are right, I an getting senile I guess, if it is a brush motor it would work, but it is probably not, so you would need a rectifier to convert the ac to dc.

This is why I've never tried to mess with using this type of fan as a blower!

Use one of these on the output of a transformer. Hook each of the the "~" to the transformer output, and the "+" and "-" to the motor

http://www.goldmine-elec-products.com/prodinfo.asp?number=G14531

http://www.allelectronics.com/make-a-store/item/FWB-256/25_A_600_PIV_BRIDGE_RECTIFIER/-/1.html

Not good enough by itself for most things, but just fine for a DC motor. If you put an ordinary light dimmer on the transformer input, you can control the speed of the DC motor.

my first forge used a car heater blower, I ran it with a toy train transformer ($1.00 at junk store) - gave a speed control that way too. Universal motors like this will run off DC or AC.

In my case, I found the cheapest option was a trickle charger, 12V motor bike battery from the local recycler, and an air gate on the fan inlet. You need the battery between the charger and the fan motor to give the charger a load - it won't operate wired directly to the motor.
The charger was less than $25, the battery was 'free' in return for taking my scrap to them. Double_edge2 has very kindly sourced the fan for me.

thanks for the rectifier source it could come in handy for other things.

my first forge used a car heater blower, I ran it with a toy train transformer ($1.00 at junk store) - gave a speed control that way too. Universal motors like this will run off DC or AC.

Quite right about universal motors, Grant. Your train transformer puts out DC, though. (That's why toy trains can go in reverse.) Some car motors are universal and some are not.

But yes, a universal motor does not need DC.

Good to see all the responses ! I havnt any idea how to tell if the fan I have would work off a train control

Well I just got a fan from a car's ac system (fan and motor) . I an on making an air gate to use with it, but I am having trouble trying to figure out how to provide power to it. The wall outlets that I would like to use as the power source are 110v ac and the motor and fan unit fund off 12v dc, so theirin lies the Problem..... Also I wanted to have an inline switch to just turn the power on and off, so please let the ideas flow...... Thanks

Radioshack sells 110v AC to 12v DC inverters for cheap. I have one...its nice...i would put a light dimmer on the motor side of the wires...so you dont need an airgate.

Thanks for that info.... I'll have to get over there and take a looksee when they aren't workin me to deathon the rr, that should make it quite simple ....

dc motors have brushes for the most part

Good to see all the responses ! I havnt any idea how to tell if the fan I have would work off a train control

It will definitely work off the train controller which puts out dc. It might not work on a simple transformer that only puts out 12v ac.

Most 12v power sources floating around put out DC. Heck, I think you might even be able to use a power source out of an old computer: I believe they provide 3, 5.5, and 12 volts DC.

Heck, I think you might even be able to use a power source out of an old computer: I believe they provide 3, 5.5, and 12 volts DC.

If one uses an old ATX supply, one must short the PWR_ON pin to ground for the thing to work. That's pin 14 if one has a 20 pin connector, or pin 16 if one has a 24 pin connector.

It's great to see all the responses, havnt had a chance to toy with it yet been working too much. Anyhow keep it flowing it's really interesting to see how many ways there ae to skin the cat!

Use an old PC power supply, they are cheap, provide 5VDC and 12VDC at high current,
more than enough for your needs, all in a nice neat package.

Hey guys , I,ve been looking to use a 12v blower from a car .I wanted it to have a variable air flow on a switch using dimmer switch or potentiometers and resistors , trouble is heat build up in the resistors and dimmer the 150 watt one I'm am going to use pulls 19 amps on start up constant at about 9 on full running .Probably all cars have a few blower settings but never heard of one with a full variable switch .Also all that heat build up is a huge waste of energy .

I researched a bit more and came across PWM's ( Pulse Width Modulators ), basically the modulator just switches on and off really fast , the off longer to varying degrees to give a lower fan speed . I got one on order from ebay , coming from Hong Kong so may be a couple of weeks till I can let you know how it works but looks promising .

I want to use my forge whilst out camping sometimes so has to be 12v , at home I'll use something like this power supply not cheap I know but sure I'll find other uses .