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Hard drive motors? Answered

I need to get a harddrive motor up and running, it has four pins for power, does anyone know exactly what these pins or which is which, the motor is from a harddrive from an old xbox, i worked hard get this wretch out all the way down to the motor, honestly microsoft should build bomb shelters, and the casing of the hard drive is pretty tough, on of the boards on it needed some friendly persuasion from a hacksaw and a hammer after I removed the apparent retaining screws, all 7 million of them, by the way I may do an instructable on how to open an old Xbox with nothing more than a swiss army knife, and it doesn't get damaged at all. To figure out the pins is all I need, left to right arrangement would do I have figured out which way up the bottom is but the crazy hieroglyphis in microscopic size reveal little about the connections,


I didn't answer the question at hand , can you use a pc fan brushless motor to run a stepper motor . Yes I'm sure it's possiuble

You know you're answering a 6 year old question don't you ?

Has anyone tried taking the controller circuit from a brushless DC computer fan, and wiring it to a hdd "stepper motor"? They appear to operate under the same principles.

Yes ! Pc fans do run other brushless motors ive done it , bysoldering 4 wire onto the 4 copper wire terminal terminations usually marked" wxy" no4 wire is soldered onto ground or "gnd" , next step is soldering the 4 newly connected wore to your 2nd parasite motors copper wire "wxy and gnd" terminals. some of the time the terminals are not marked and you must use guess work to connect what you beleive are the correct corresponding terminals on the parasite, sometimes if you connect the wrong terminals together the motor really struggles to spin without randomly changing direction , it may also spin but its low rpm and bery limpyyou gotta be really careful not to damage courier . You must have the two bearings and retaining clip and fan magnet back on the housing . Because to run a parasite motor off your host motor the host motor must be running as normal, I've tried this method twice connecting a pc fan to a VCR Billet Ring brushless motor.

they are incompatible in 2 ways. it still may work and may not work phases - hard drive is 3 phase motor and fan circuit provides 2 phases only (it may still work with some inefficiency though) power - hard drive motor is more powerfull than fan so it may overload the fan circuit most hard dive circuit boards will spin the motor if you give them 12 V (without drive heads or ide cable connected)

You can use a brushless electronic speed controller (Brushless ESC) like the kind used in R/C cars and aircraft. I actually have a quick write-up here, from a project a couple years ago: http://www.double-oops.org/projects/toxic-asset/repurposedharddrivemotor

You can use the magnets from inside your HDD and a 75 cent reed switch to get that stepper motor spinning super fast. No complicated circuit required.

Here's the video tutorial: http://jaytube.org/share/PueF3b3XXBo

did you keep the controller board?

Isn't that a stepper motor ?

Hi, it is not easy to get such a motor running. Look for BLDC motor drivers on the internet. Microchip has a good application note describing how it can be done http://ww1.microchip.com/downloads/en/AppNotes/Sensorless%20BLDC%2000901a.pdf . The solution is some sort of overkill ... but hey, they like to sell their chips :-)
Try to find the motor controllers on old floppy disc drives and hard drives. Try to find the chip data sheets on the internet and experiment with it.
Keep in mind that this kind of motors work best on a certain speed. hard disk motors often turn very fast ... 7200rpm ... is a high rate. The motors are not very powerful. Hard disks need some time starting up and getting the disks spinning ...

This is a great time to say that I also ripped a scanner to bits today to find the same type of motor with seperate chip... hopefully I can bodge something... only thing is it's likely to be far too slow... I could make an analogue version based on three contacts and the idea of a distributor, it would be needlessly complicated and very very useless but oh so fun to build...


10 years ago

No, more like this, with the 4th wire being the center point. For maximum efficiency, you drive the 3 phases with sine-waves that are 120 degrees out of phase with each other, carefully timed WRT to current position and speed of the rotor. The disk drive has a special chip that does most of the hard work. Do a web search for "three phase motor" and you'll find lots of info.


Ah had someone said three phase i would have got it, so all I need is something like a combination of a PWM and a second timer to create a circuit to drive it so a given speed of 5000rpm would mean 5000/60 then divide by three to get my pulses per second number, then use a simple (damnit i forgot the name of the chip it counts up) that does each three in turn repeating to transistors to actually give driving...


10 years ago

In general, hard drive motors work a little like steppers. Your 4-lead motor probably has 3 coils (and "common"), and you get it to spin by applying power to each coil in the correct sequence. A real PITA for anything short of special purpose circuits or a microcontroller.

there's common then two directional and a negative, is that the idea?