hard disk motor

  • Thread starter Thread starter Andrea Mazzolari
  • Start date Start date
A

Andrea Mazzolari

Hi all, i need a motor with a high rotational accuracy, so i 've think
to re-use a motor of a hard disk.

Here are some questions:
1) considering the smallest rotation permitted with a motor of this
type, which is the corrisponding rotating angle?
2) where can i find some tutorial/guide/or any other information on
how to write a software to control an hard diks motor ?

Any help will be appreciated.
Best regards,
Andrea
 
Previously Andrea Mazzolari said:
Hi all, i need a motor with a high rotational accuracy, so i 've think
to re-use a motor of a hard disk.
Click to expand...
Here are some questions:
1) considering the smallest rotation permitted with a motor of this
type, which is the corrisponding rotating angle?
Click to expand...

Huh? This is not a stepper-type motor....
2) where can i find some tutorial/guide/or any other information on
how to write a software to control an hard diks motor ?
Click to expand...

You cannot. You have to build your own driver electronics, since
a HDD will not spin the motor unless it can also get the rest to work.
Or it will spin-down pretty soon again.

Arno
 
Huh? This is not a stepper-type motor....
Click to expand...

The rotation motor is, the head actuator isnt.
You cannot. You have to build your own driver electronics, since
a HDD will not spin the motor unless it can also get the rest to work.
Or it will spin-down pretty soon again.
Click to expand...

You can obviously replace the microcode on the logic card.
 
zappo said:
The rotation motor is, the head actuator isnt.
Click to expand...

NEITHER is a stepper motor.

Actuator motor used to be a stepper in drives like ST225 (20 MB formatted),
but even 100 MB generation already could not be implemeted on a stepper.
 
Both the spindle motor and head actuator are servo motors with perm-magnets.
You could look up a servo controller chip datasheet with google.
I doubt the motor will position accurately, it is not designed for that.
 
NEITHER is a stepper motor.
Click to expand...

Wrong with the rotation motor.
Actuator motor used to be a stepper in drives like ST225 (20 MB formatted), but even 100 MB
generation already could not be implemeted on a stepper.
Click to expand...

Irrelevant to the rotation motor.
 
NEITHER is a stepper motor.
Click to expand...
Actuator motor used to be a stepper in drives like ST225 (20 MB formatted),
but even 100 MB generation already could not be implemeted on a stepper.
Click to expand...

Indeed. The spindle motor is what is called a "servo controlled DC
motor". To the uninitiated it may look like a stepper, but it is
not. It cannot really be used for positioning without severely
misusing and potentially overloading its coils. The driver circuit on
the HDD PCB cannot do this. It is designed to provide a very smooth,
linear spin at a specific frequency.

One main difference is that a spindle motor has a "stepping angle"
of 120 degrees, while in a stepper 1.8 degrees or the like are typical.
Also steppers are designed to be able to hold a specific position
very precisely and against force. Spindle motors are not.

Arno
 
Arno Wagner wrote:

Indeed. The spindle motor is what is called a "servo controlled DC
motor". To the uninitiated it may look like a stepper, but it is
not. It cannot really be used for positioning without severely
misusing and potentially overloading its coils. The driver circuit on
the HDD PCB cannot do this. It is designed to provide a very smooth,
linear spin at a specific frequency.

One main difference is that a spindle motor has a "stepping angle"
of 120 degrees,
Click to expand...

Because it's a multi-phase brushless design, not because it "steps".
 
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