Connect small transformer to fan
CyrilReboul
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fmq Posted messages 4899 Registration date Status Contributeur Last intervention -
fmq Posted messages 4899 Registration date Status Contributeur Last intervention -
Hello,
I have a pebble in my shoe and it's starting to get tiring :-)
I need to connect a small AC/DC transformer 12 V to a 12 V computer fan as well.
The transformer provides 3 A and the fan draws 0.17, so there should be no issue; it should work.
But ... :-)
So far, it doesn't seem too bad except when it comes to connecting the wires.
When stripping the wire of the transformer, it's not straightforward because it's a jack plug: There's a coated wire inside a stripped wire, and no ground wire. In other words, 2 wires: one coated and the other not, which is wrapped around the first one.
For the transformer wire, there are 4 strands: one black, one yellow, one green, one blue.
I test each of the wires on all possible connections to the transformer wires and there's no movement.
Of course, I checked if the current is coming out of the transformer ;-)
Any ideas on the solution?
Thanks
Configuration: Windows / Opera Next 56.0.3051.116
I have a pebble in my shoe and it's starting to get tiring :-)
I need to connect a small AC/DC transformer 12 V to a 12 V computer fan as well.
The transformer provides 3 A and the fan draws 0.17, so there should be no issue; it should work.
But ... :-)
So far, it doesn't seem too bad except when it comes to connecting the wires.
When stripping the wire of the transformer, it's not straightforward because it's a jack plug: There's a coated wire inside a stripped wire, and no ground wire. In other words, 2 wires: one coated and the other not, which is wrapped around the first one.
For the transformer wire, there are 4 strands: one black, one yellow, one green, one blue.
I test each of the wires on all possible connections to the transformer wires and there's no movement.
Of course, I checked if the current is coming out of the transformer ;-)
Any ideas on the solution?
Thanks
Configuration: Windows / Opera Next 56.0.3051.116
Hello FMQ, 
for a brief moment put to at most one battery
brief contact...just to see if the fan turns
will it pass or will it smoke!!
ciao ciao
It doesn’t work and it doesn’t smoke ;-)
A tech friend in IT explained to me that it’s probably because this kind of 4-wire connection needs to be plugged directly into the motherboard since these are fans dedicated to its cooling and it's the motherboard that should manage the power supply. I find it a bit hard to swallow, but that's the only explanation I have.
...
it's the variation of t that affects the rotation speed
t short = low rotation speed
t long = high rotation speed
and t is always less than T ; about 80% max for high speed ; and about 20% min for low speed
for you, you would need a chassis fan or an AMD fan or a separately purchased heatsink fan ; which manage a voltage level between +5 volts and +12 volts