I finally managed to get my modem apart I've temperary fitted the fan with out cutting a hole to fit a grill for the fan so at the moment it fitted internally which is fine but I'm stuck as to how to power it (I know NOTHING about electronics). I used to but then I got old and forgot everything I learnt at college. I did hope it would be a simple matter of soldering the red and black leads directly to the USB Cable Pins On the Inside (I Know stupid of me but I thought something But go easy for once) when iu do connect them red one fine no difference connect the black one all power stops. change it the other way around same thing happens. now remembering I'm A noob at this does anyone know How I should power it sorry for not uploading pics but every time I try the pics are either really dark or blurred or too bright to post.
because of the high intensity leds I intend replacing the normal Leds with also because if I can get it to work with a normal fan then later on when i get a spare one I'll be able to replace it with a Led fan that will look cool
wtf, i know the BT modems get a bit hot but there is no need for a fan. also high intensity LEDs dont emitt any more heat than a normal led.
guys he asked for help, not flaming because he wants a fan in there i think its a cool idea. hope someone can help
i believe that the problem may be that USB dosent supply enough power for the motor in the fan. i dont remember the voltages but i believe the modem and the fan are trying to draw to much power and thats why it just dies.
there should be a 5v and a gnd connection on the USB line, you can find them with a multimeter, chances are that the gnd is black. But USB has a limited current of 500mA (1/2 amp) and that is already partially used by the modem, so you may need a lower power fan if the USB is cutting out. Something like a 40mm fan should work. They don't draw much power at 12v, and even less at 5v. Though you have to make sure the fan starts at 5v because some (ususally the larger fans) won't start at 5 volts. Plus you can get some nice lit 40mm clear fans, for extra lighting.
if the fan wont start at 5v, spin it a few times in the correct direction. sometimes it like jumpstarts it or somthing.
That's because it's an induction motor. Normally, the motor (and inverter) are designed so the rotor can "catch up" with the 3-phase AC from the inverter. However, at lower voltages, the torque is lower and the slip is higher. This means the motor may have problems starting up. Manually flicking the fan allows the rotor to just catch up, allowing it to spin up. Some big/fast fans actually sense the CEMF from the motor to determine if the rotor is actually spinning (to allow for locked rotor protection, reduced frequency at start up, etc.). P.S. Induction motors don't like running at reduced voltage (the big ones really can't stand it and may burn out, you may get away with it with a small fan). I'm not sure, but some fans might decrease the oscillator frequency at reduced voltage to reduce the stresses.
tbh the leds shouldn't be getting hot .. they are probably on the wrong voltage if they are... also a fan.. imho its just needless noise in something thats already silent
Ok just to set the record stright 1. the modem is a spare modem I have 2. your right a fan is unnecessary but since as far as I know most homes have electric lights so is having lights inside a PC just to see the inside 3. my system including the modem overheats on a regular basis because of its location Unfortunately at the moment its not possible to move it so its sat next to another PC which is sat next to a radiator. 4. I'ed Love the idea of watercooling but where in the world would I find a reservior small enough? and to everyone that gave helpful advice thank you it was appreciated
Be careful not to pull too much power from your USB ports, I've heard of people burning them out on their motherboards from doing that.
i would bet the modem is under the low power class of devices and limited to 100mA. USB is also only 5 volts. A 12 volt fan may not be happy at all. The reason for the start up problem is just simple physics in that it takes more energy to speed somthing up than to simply keep it going. You'll need a toggle switch so you can spin the fan and throw the switch while its moving to prevent the whole thing from shutting down. Red is +5 and black is ground IIRC. The white and green lines are D+ and D-, the data lnes. BTW, the fan's aren't usally inductive. If you take them apart, there is a ring that is a perment magnet. There are 4 coils arranged as two pairs. In the simplest fans, there is a sensor that reports a rough position of the rotor and based on that, one set of coils or the other is 'fired' with a particular polarity of current. In other words, its basically a perment magnet DC motor with electronics replacing the commutator.
