220v to 110v

[BoisBlancBoy]

Hey guys. I'm wiring up my still dragon controller kit. I was just going to order a 220v cooling fan but I found laying around in all the stuff I've collected over the years a wall wart and a 12v computer fan. Figured I might as well use it since I have the space in the box. But I just want to be sure I'm doing this correctly.

I am using my 30 amp 4 prong dryer outlet for power. I also used 10/4 wire. So to get 110v for the wall wart can I just use the white/neutral and 1 hot leg(black or red)? I just plan on using a household receptacle so I can plug the wall wart right in.

Thanks for the help.

[still_stirrin]

...to get 110v for the wall wart can I just use the white/neutral and 1 hot leg(black or red)?

Yes.

[BoisBlancBoy]

...to get 110v for the wall wart can I just use the white/neutral and 1 hot leg(black or red)?

Yes.

Thanks SS. I'll post a picture of the wiring handy work once I'm finished.

[still_stirrin]

If you're making "glamour shots", be sure to use zip ties to dress your wiring. Neat and tidy...organized.
ss

[BoisBlancBoy]

I think we will use the term glamour shots very loosely! I left a fair amount of extra wire just in cause I change add or delete anything in the future.

[still_stirrin]

Quick follow up 3B's,

'zis thing working? I expect it is, so "thumbs up"?
ss

[BoisBlancBoy]

It's working for fanstastic! The cooling fan is way overkill so I would like to install a POT to slow it down some. Make it a little quieter, just nit picking really.

[still_stirrin]

It's working for fanstastic! The cooling fan is way overkill so I would like to install a POT to slow it down some. Make it a little quieter, just nit picking really.

How about using a light dimmer control instead? A potentiometer works as a voltage divider with the fan motor. A light dimmer is a triac controller which adjusts the duty cycle instead. It would be much less likely to burn out the fan motor. And, they're relatively inexpensive at the big box stores (<$10 USD).
ss

[BoisBlancBoy]

It's working for fanstastic! The cooling fan is way overkill so I would like to install a POT to slow it down some. Make it a little quieter, just nit picking really.

How about using a light dimmer control instead? A potentiometer works as a voltage divider with the fan motor. A light dimmer is a triac controller which adjusts the duty cycle instead. It would be much less likely to burn out the fan motor. And, they're relatively inexpensive at the big box stores (<$10 USD).
ss

Thanks for the tip! I'll go that route. Do I want to wire that dimmer in between power coming in and the receptacle that the wall wart plugs into or between the wall wart and fan?

[still_stirrin]

What is the output of the wall wart?

If it's 12VAC, then put the dimmer before the wall wart, ie - before the receptacle, or between the receptacle and the wall wart.

If your fan is actually a 12VDC fan, then I'm not sure if the dimmer will work. In fact, I don't think it will. The voltage divider (potentiometer) is a better solution, because power is proportional to the voltage, which the pot would "divide".

Electricity is an interesting thing....more than just "ones & zeros". It's shocking!
ss

[BoisBlancBoy]

What is the output of the wall wart?

If it's 12VAC, then put the dimmer before the wall wart, ie - before the receptacle, or between the receptacle and the wall wart.

If your fan is actually a 12VDC fan, then I'm not sure if the dimmer will work. In fact, I don't think it will. The voltage divider (potentiometer) is a better solution, because power is proportional to the voltage, which the pot would "divide".

Electricity is an interesting thing....more than just "ones & zeros". It's shocking!
ss

The output of the wall wart is 12v dc, 500-900 mA I believe. I don't have the box open but I know those numbers are close.

[still_stirrin]

OK. Its a DC fan then, huh? So the light dimmer may not be the best solution.

If you have a linear potentiometer (10k, 20k, 33k, or even 100k ohms), put it in the 12VDC output from the wall wart (transformer/rectifier).

1) Connect one lead of the pot to the (+V) output of the transformer.
2) Connect the "wiper" (the center tab on the pot) to the other end of the wire you cut from the wall wart output (+V).
3) Now, the voltage (12VDC) is divided between the fan motor and the potentiometer. A full turn in one direction (doesn't matter which direction) will either turn the fan "full on" or "full off".

If you've got a switch in this circuit, it should be "before" the pot.
ss

[BoisBlancBoy]

Thanks SS,

This work: https://www.amazon.com/gp/aw/d/B0111U39 ... ref=plSrch" onclick="window.open(this.href);return false;" rel="nofollow

[rad14701]

Thanks SS,

This work: https://www.amazon.com/gp/aw/d/B0111U39 ... ref=plSrch" onclick="window.open(this.href);return false;" rel="nofollow

If it is rated for 1 - 2 Watts it should work just fine...

[shadylane]

The simplest way to slow down a DC motor is too add resistance in series with it.
Just a guess , without doing any math but I'd say 100 ohms or there abouts would cut the fan speed in half.
On a side note is the fan brushless
If it is, controlling the speed may be a little more problematic
A link for head scratching
http://electronics.stackexchange.com/qu ... s-dc-motor" onclick="window.open(this.href);return false;" rel="nofollow

[cob]

The simplest way to slow down a DC motor is too add resistance in series with it.

or just supply it less voltage. I would try a 6v or 9v wall wart and see if you get a speed you like.

every one has a box of unused wall warts don't they?

[papapro]

What is the wattage / current of that 12 v dc motor, as I see the 10K pot will be too much resistance to move that motor.
Lets say if it is 2 W then the curr

Code: Select all

ent to run that motor will be 2/ 12 = 0.166A if you set that pot on half at 5 K ohms hen 12 v/5 k = 0.0024A
not enogh to run it. AS suggested 100 or even less would be better.

Regards PapaPro

[papapro]

What is the wattage / current of that 12 v dc motor, as I see the 10K pot will be too much resistance to move that motor.
Lets say if it is 2 W then the curr

Code: Select all

ent to run that motor will be 2/ 12 = 0.166A if you set that pot on half at 5 K ohms hen 12 v/5 k = 0.0024A
not enogh to run it. AS suggested 100 or even less would be better.

Regards PapaPro