How to determine negative and positive of the hard disk motor...anyone have a good idea. Thanks in advance

 

How to determine negative and positive of the hard disk motor...anyone have a good idea. Thanks in advance

If you mean the motor proper, it's likely a 'stepper', in which case it is -in essence- a poly-phase AC motor (sort of) -- In the case of a servo (i.e. 'encoder motor') arrangement - you need merely apply the power and observe the direction of rotation...
On the other hand: If you are referring to the motor+controller as a unit -- the easiest method of determining connection assignments is attention to same during disassembly - Given more information I'll be happy to offer further assistance

Best regards
HP

 

If you mean the motor proper, it's likely a 'stepper', in which case it is -in essence- a poly-phase AC motor (sort of) -- In the case of a servo (i.e. 'encoder motor') arrangement - you need merely apply the power and observe the direction of rotation...
On the other hand: If you are referring to the motor+controller as a unit -- the easiest method of determining connection assignments is attention to same during disassembly - Given more information I'll be happy to offer further assistance

Best regards
HP

I read somewhere the harddisk motor is a brushless motor and it requires special circuit to power it...do u have a simple schematic that i can follow

 

Hello,

The links on the following page of the EDUCYPEDIA will give you info on the BLDC motors:
http://educypedia.karadimov.info/electronics/motorBrushless.htm

Bertus

 

I read somewhere the harddisk motor is a brushless motor and it requires special circuit to power it..

Correct -- they are generally (albeit, perhaps, not exclusively) of the form of 'stepper motors'....

do u have a simple schematic that i can follow

Not to hand -- However if you are certain that the motor in question contains no integral electronics you may determine it's winding characteristics via (electrical) observation of the lines while manually rotating the spindle - whereafter application of 'generic' stepper-motor controller design applicable to said characteristics is a straightforward matter! -- Please be advised that a far less labor intensive approach may be realized via salvage of the spindle motor controller along with said motor!

Best regards
HP

 

If you mean the motor proper, it's likely a 'stepper',

It looks old so most probably.

 

It looks old so most probably.

FWIW I'm using the term 'stepper motor' v-e-r-y loosely!

Best regards
HP

 

You cannot just apply power to the motor and have it run. You have to provide commutation signals in the proper sequence to get it to move. In that sense the motor has no polarity.

 

in which case it is -in essence- a poly-phase AC motor (sort of)

You have to provide commutation signals in the proper sequence to get it to move. In that sense the motor has no polarity.

@Papabravo I must confess -- I like your explanation much better!

Very best regards
HP

 

A test for internal electronics is to back-feed or externally rotate the motor and either measure, or preferably scope the three stator connections. See PDF example.
BLDC is an often used term and stands for brushless DC which indicates that only two winding's are powered at any one time, and represents a DC brushed motor turned inside out.
A Practically identical motor in almost every physical way is the AC synchronous, and this has the identical stator and P.M. rotor but is powered with a true 3ph signal to the stator.
Another test which also detects the number of poles is to short all three stator wires and turn it by hand and count the number of 'bumps' felt/rev. If electronics in between, no poles are detected.
Max.

 

You cannot just apply power to the motor and have it run. You have to provide commutation signals in the proper sequence to get it to move. In that sense the motor has no polarity.

Do you know any simple circuit to run it like transistor? Most of the one i found on Google using IC which i don't have

 

Most of the one i found on Google using IC which i don't have

Fabrication of a controller from 'discretes' is both 'fiddlesome' and labor intensive! -- Again, it seems your best solution is to salvage the controllers with the motors

Best regards
HP

 

The minimum circuitry I can imagine is a microcontroller, with three Hall Effect Sensor inputs and three FET switch outputs. Other than that I think your going to have a very tough time.

http://ww1.microchip.com/downloads/en/AppNotes/00857B.pdf