This motor apparently has 3 coils with one end common to
all three. The motor came from a Western Digital drive. Does
anybody know the pulse pattern to the coils?

Nidec will never reveal nothing.

On Sun, 27 Jan 2008 07:40:28 +0000, Lord Garth wrote:

This motor apparently has 3 coils with one end common to all three. The
motor came from a Western Digital drive. Does anybody know the pulse
pattern to the coils?

Nidec will never reveal nothing.

Sounds like it wants 3-phase sinewave power. You wouldn't want a stepper
for a spindle motor; the application needs constant angular velocity.

On Sun, 27 Jan 2008 04:24:30 -0600, "Stephen J. Rush"
wrote:

On Sun, 27 Jan 2008 07:40:28 +0000, Lord Garth wrote:

This motor apparently has 3 coils with one end common to all three. The
motor came from a Western Digital drive. Does anybody know the pulse
pattern to the coils?

Nidec will never reveal nothing.

Sounds like it wants 3-phase sinewave power. You wouldn't want a stepper
for a spindle motor; the application needs constant angular velocity.


Or 3-phase electronically commutated DC motor.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

On 27/01/2008 Lord Garth wrote:

This motor apparently has 3 coils with one end common to
all three. The motor came from a Western Digital drive. Does
anybody know the pulse pattern to the coils?

Nidec will never reveal nothing.

Plenty of information about brushless DC motors on the wibble thingy.
Best to start he

http://en.wikipedia.org/wiki/Brushle...electric_motor


--
The Force is dark on one side, light on the other and holds the world
together.

Hmmm, just like Gaffer Tape then.

"Jim Thompson" wrote in
message ...
On Sun, 27 Jan 2008 04:24:30 -0600, "Stephen J. Rush"
wrote:

On Sun, 27 Jan 2008 07:40:28 +0000, Lord Garth wrote:

This motor apparently has 3 coils with one end common to all three. The
motor came from a Western Digital drive. Does anybody know the pulse
pattern to the coils?

Nidec will never reveal nothing.

Sounds like it wants 3-phase sinewave power. You wouldn't want a stepper
for a spindle motor; the application needs constant angular velocity.


Or 3-phase electronically commutated DC motor.

...Jim Thompson


The trick will be getting a tap onto the underside of the board. It looks
as if it will be a 30 gauge wire solder job so nothing to difficult . This
motor
has compression contacts to the PCB.

"Stephen J. Rush" wrote in message
. ..
On Sun, 27 Jan 2008 07:40:28 +0000, Lord Garth wrote:

This motor apparently has 3 coils with one end common to all three. The
motor came from a Western Digital drive. Does anybody know the pulse
pattern to the coils?

Nidec will never reveal nothing.

Sounds like it wants 3-phase sinewave power. You wouldn't want a stepper
for a spindle motor; the application needs constant angular velocity.


Thanks for that, I'll look into it as soon as I can get the scope over here.

"Lord Garth" wrote in message
t...
This motor apparently has 3 coils with one end common to
all three. The motor came from a Western Digital drive. Does
anybody know the pulse pattern to the coils?

Nidec will never reveal nothing.

Is it a 4 lead or 3?

If 4 lead, look up 3 phase unipolar drive.
If 3 lead, look up 3 phase bipolar drive. This is the most common and is
driven by three push-pull outputs. It probably does not have any hall effect
sensors. Spindle motors are often started like a setp motor in a forced
commutation sequence and then above a certain speed, rely on the back-emf
sensing of the off coil to give velocity feedback for speed control. In the
commutation sequence, one of the three coils is always off and is used for
bemf sensing.

Lots of motor manufacturers have phase sequence charts for these types of
motors. There are plenty of drive and IC manufacturers with appnotes on the
subject. google for "sensorless bldc"

Hope that helps
Oppie