Maker Pro
Maker Pro

A/C adapter for DC blower fan

Scott Hanson

Aug 27, 2015
7
Joined
Aug 27, 2015
Messages
7
I'm trying to power the following fan:
http://www.amazon.com/gp/product/B001O0DE8K?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

...off an A/C outlet. I've read numerous projects where guys have used this fan in this manner but can't find how/what power supply they used. I tried this one first (after cutting to the wires)
http://www.amazon.com/gp/product/B003TUMDWG?psc=1&redirect=true&ref_=oh_aui_detailpage_o02_s00

The fan runs for a second, then stops for a second, runs for a second, stops for a second. And so on and so on.

Am just not sure what I'm missing or what I'm doing wrong. The adapter seems to have enough power but I don't know why it keeps stopping?

Any help greatly appreciated, thanks--
 

Minder

Apr 24, 2015
3,272
Joined
Apr 24, 2015
Messages
3,272
I suspect it may be inrush shutting the SMPS supply down?
I would obtain a linear supply for it, confirm it by testing on an automotive battery.
M.
 

Minder

Apr 24, 2015
3,272
Joined
Apr 24, 2015
Messages
3,272
A linear supply is unregulated the one you show is SMPS, Switch mode.
Linear is usually a simple transformer, bridge and capacitor.
Better suited to motor function.
M.
 

Scott Hanson

Aug 27, 2015
7
Joined
Aug 27, 2015
Messages
7
Thanks for the help! After searching around on eBay, I'm still pretty unsure what I should try to buy. Searching for "Linear Adapter" and "Unregulated Adapter" is bringing up mostly international results on eBay - and on Amazon I'm getting things with digital readouts ... am I using the wrong search terms to find this?

Thanks--
 

Minder

Apr 24, 2015
3,272
Joined
Apr 24, 2015
Messages
3,272
AC adaptors that are old style linear are hard to find now, just pick up a small 120v/12v secondary transformer and a rectifier bridge and you are away.
M.
 

HellasTechn

Apr 14, 2013
1,559
Joined
Apr 14, 2013
Messages
1,559
As a power source you should get a 120 to 13 volt step down transformer rated at least 4 amps and then use a bridge rectifier (same amps rating) and at least one 3300mf 16volt smoothing capacitor (or even better two of them in paralel).

Though the PSU on the link you provided should be enough to run this fan. I dont know maybe it is damaged ?

I dont think this is an inrush current situation. theese are desinged for high loads.
 
Last edited:

Minder

Apr 24, 2015
3,272
Joined
Apr 24, 2015
Messages
3,272
This what the old style wall warts looked like.
Basically for a motor load you can do without C1
D1-D4 comes in a block of 4.
M.
unregulator-power-supply.jpg
 

Minder

Apr 24, 2015
3,272
Joined
Apr 24, 2015
Messages
3,272
As a power source you should get a 120 to 13 volt step down transformer rated at least 4 amps and then use a bridge rectifier (same amps rating) and at least one 3300mf 16volt smoothing capacitor (or even better two of them in paralel).

Though the PSU on the link you provided should be enough to run this fan. I dont know maybe it is damaged ?

I dont think this is an inrush current situation. theese are desinged for high loads.
He says it works OK on a battery, 13vac will result in 18v smoothed.
M.
 

HellasTechn

Apr 14, 2013
1,559
Joined
Apr 14, 2013
Messages
1,559
Not that much besides under load it will drop to 13 again

Keep in mind that devices that run on 12v battery can also run on 14-15 volt
 
Top