I got this old fan laying around and decided to do something with it. Got a 9V battery, shaved the 3pin connector off and connected red to + and black to - and fan did spun, but slowly.
Can I take 8 AA batteries (8x1.5V) and connect them in series to the fan to make it spin in full RPM? (12V)
Also, can I do anything with the yellow wire? Or am I restricted to using a potentiometer (or whatever a variable resistor is called) to change the RPM?
>>971462
Yellow is for monitoring rpm. Use red and black to power the fan.
>>971475
So, yellow is output? Maybe I should use Google...
Update: pics of insides, it's brushless and ball bearing, well, that was written on the label anyway
>>971481
>Update: pics of insides, it's brushless and ball bearing, well, that was written on the label anyway
it's a normal PC fan. it is brushless, but the driver circuit runs off 12vdc. (at least, it's supposed to run at full speed when connected to 12vdc)
you can control the speed by adding different amounts of resistance to 12vdc.... but using a potentiometer is risky, since the current flow is inversely proportional to the potentiometer's resistance.
,,,,,,
Normal potentiometers are *not* high-current devices, usually 2 watts or less. What happens when you adjust the resistance very low, the relatively high current (moving through the tiny active portion of the adjustable resistor) burns out a small section of it.
The 'correct' way is to use either a fixed-value resistor, or (if you want the motor speed to be easily adjustable) you use a potentiometer controlling the bias of a transistor capable of withstanding the motor's current rating.
Pic related: what the inside of a Zalman Fan Mate looks like.
>>971482
on the upper-left of that pic, the silver aluminum thing with ridges is a heat sink. There is some (?) kind of power transistor (a TO-220 package) underneath it. I could see it at odd angles, but couldn't photograph it, and couldn't get the heatsink off without unsoldering the transistor (the heatsink is held on the transistor by a screw) so I didn't bother to find out what transistor it really was.
If you want to build a transistor-style speed controller but don't know what transistor to buy,,,,,,,
There is a method to figure out what parameters you need when selecting a transistor or mosfet, but I don't bother with that often.
The mosfet I usually use for controlling moderate-sized DC loads is the IRL-Z34.
It has way more current and voltage capacity than this example calls for, but anyway. It would certainly work.
>>971482
>The 'correct' way
The correct way is using PWM. You don't use resistors to control power (fine for LEDs but certainly not motors).
>>971486
only normally true now days. Back in the day when drives were shit this was very common in industrial settings.
http://www.powerohm.com/pdfs/MCCAT00.pdf
>>971486
It is perfectly correct but like any motor application you need to know more than 'just enough to make it work' to do it right/safe/reliable
>>971482
Man, these little zalman controllers get hot. I'm talking egg frying hot. I had 2 of these on my first build. Wish I hadnt thrown them away.
>>971462
>put fan in a PVC pipe with the appropriate size
>stick PVC pipe up your rectum
>cooldown your colon after mad gay orgy
i think that you can fit the batteries in the pipe too
PS.
(no homo)
>>971486
>pwm on a brushless motor
555-come-on-now
the circuit inside the fan uses feedback to figure out what magnet to fire, using pwm will just cause the fan to not turn at all.
>>971486
>The correct way is using PWM. You don't use resistors to control power (fine for LEDs but certainly not motors).
um accuse you? (pic related)
for a long time, many nicer PC fans came with a resistor included, if you wanted to slow them down
It's not the most power-efficient way to do it, but it does work
Also as noted: you can't PWM a motor that already has its own speed-control circuit on it,,, and brushless motor drivers are a speed-control circuit.
(I thought PWM was mainly a brushed-motor thing? Im not 100% sure tho)
>>971519
>Man, these little zalman controllers get hot. I'm talking egg frying hot. I had 2 of these on my first build. Wish I hadnt thrown them away.
they have a plastic case? they couldn't get that hot.
{---I thought the news said that Zalman was to be liquidated, but there's been Zalman-branded fans and PC crap around ever since the bankruptcy was announced. Just not quite as many as before...? And a lot of it is still available, even now.... maybe somebody else bought the name and kept rolling out the same stuff---}
