CDROM Spindle Stepper motor

geoff wrote:
fritz wrote:

You don't understand what a spindle motor does, obviously.
It just spins the disk, it has nothing to do with the tracking of the
laser, which I
have already explained. The spindle motor has feedback to spin the CD
at
the right speed, usually with Hall effect sensors. The coarse
tracking is controlled
by a separate motor with position feedback, and fine tracking is
controlled with
a 'voice coil' suspension connected to the laser lens.

Dude, I think I know eactly what a spindle motor does - I fix Denon,
Sony, and Nad ones every week and have don for decades. Also DVD and
DVD/CD-ROM/RWs.
Sorry - slip of the keyboard. The Denon, Sony, and NADs are not, of course,
stepper motors but CDs and DVDs....

geoff
 
geoff <geoff@nospam-paf.co.nz> wrote in message news:1f-dnfA7JelcerHVnZ2dnUVZ_gCdnZ2d@giganews.com...
fritz wrote:

You don't understand what a spindle motor does, obviously.
It just spins the disk, it has nothing to do with the tracking of the
laser, which I
have already explained. The spindle motor has feedback to spin the CD
at
the right speed, usually with Hall effect sensors. The coarse
tracking is controlled
by a separate motor with position feedback, and fine tracking is
controlled with
a 'voice coil' suspension connected to the laser lens.

Dude, I think I know eactly what a spindle motor does - I fix Denon, Sony,
and Nad ones every week and have don for decades. Also DVD and
DVD/CD-ROM/RWs.
Maybe you just have a problem with expressing technical English clearly......

geoff wrote...
Are you sure ? How can a stepper motor, with it's "quantised' discrete
stepped positions track a continuous spiral groove ? My understanding is
that all CD spindle motors are servo-controlled , to enable accurate
tracking.
So what has the tracking of the 'groove' (sic) got to do with the spindle motor,
which always was the obvious subject ?










None of these contain stepper motors, and I can't see how any other CD
could, given the pusly buzzy motion that a stepper can only supply. I have
never seen a CD with a spindle motor or a sled motor, that is a stepper. I
have seen stepper motors in telex machines,printers, and iindustrial process
machines.

Stepper motors move one discrete finite 'step' (surprisingly ?) for each
discrete DC pulse that is sent to drive it. All CD motors I have ever seen
are driven by a continuous DC, the voltage of which is finely varied to
control the speed of the spindle, or the position of the sled.

Grateful you specify which make/model CD contains a stepper motor.

by DC. To get either type to spin requires a controller to drive the
coils
in the correct sequence. The main difference is the coil
terminations, steppers
bring out all coils separately while so-called 'DC brushless' motors
usually have
the coils connected in star or delta (for 3-phase types).


So now you are trying to fudg the distinction between stepper motors and the
type you really mean. OK, I concede the I can therefore never 'win'.....


geoff
 
Phil Allison <philallison@tpg.com.au> wrote in message news:6941bsF303breU1@mid.individual.net...
" fritz the ASD fucked fuckhead "


** You clearly are a narcissistic, nit picking idiot who cannot take being
corrected.

Brushless DC motors and stepper motors are the NOT the SAME - each type
is suited to particular applications and they have very different
characteristics.

http://en.wikipedia.org/wiki/Brushless_DC_electric_motor



Fuck off and Die - you MORON !!
YOU really are the pathetic little nit-picker that you imagine in everyone else.
Your abusive posts are clear evidence that you have serious mental problems.
The evidence is clear from your previous posts, anyone can see your bad
behaviour by simply searching Google Groups aus-electronics.
You should be ashamed of yourself.
 
Phil Allison <philallison@tpg.com.au> wrote in message news:6941a7F2uc567U1@mid.individual.net...
" fritz the ASD fucked fuckhead "


** You clearly are a narcissistic, nit picking idiot who cannot take being
corrected.
YOU really are the pathetic little nit-picker that you imagine in everyone else.
Your abusive posts are clear evidence that you have serious mental problems.
The evidence is clear from your previous posts, anyone can see your bad
behaviour by simply searching Google Groups aus-electronics.
You should be ashamed of yourself.
 
" fritz the ASD fucked fuckhead "


** You clearly are a narcissistic, nit picking idiot who cannot take being
corrected.

Brushless DC motors and stepper motors are the NOT the SAME - each type
is suited to particular applications and they have very different
characteristics.

http://en.wikipedia.org/wiki/Brushless_DC_electric_motor

Fuck off and Die - you MORON !!





....... Phil
 
" fritz the ASD fucked fuckhead "


** You clearly are a narcissistic, nit picking idiot who cannot take being
corrected.

Brushless DC motors and stepper motors are the NOT the SAME - each type
is suited to particular applications and they have very different
characteristics.

http://en.wikipedia.org/wiki/Brushless_DC_electric_motor


Fuck off and Die - you MORON !!






....... Phil
 
" fritz the ASD fucked fuckhead "


** You clearly are a narcissistic, nit picking idiot who cannot take being
corrected.

Brushless DC motors and stepper motors are the NOT the SAME - each type
is suited to particular applications and they have very different
characteristics.

http://en.wikipedia.org/wiki/Brushless_DC_electric_motor


Fuck off and Die - you MORON !!





....... Phil
 
Phil Allison <philallison@tpg.com.au> wrote in message news:696madF311tfrU1@mid.individual.net...
" fritz the ASD fucked fuckhead "


** You clearly are a narcissistic, nit picking idiot who cannot take being
corrected.

Brushless DC motors and stepper motors are the NOT the SAME - each type
is suited to particular applications and they have very different
characteristics.

http://en.wikipedia.org/wiki/Brushless_DC_electric_motor


Fuck off and Die - you MORON !!





...... Phil
YOU really are the pathetic little nit-picker that you imagine in everyone else.
Your abusive posts are clear evidence that you have serious mental problems.
The evidence is clear from your previous posts, anyone can see your bad
behaviour by simply searching Google Groups aus-electronics.
You should be ashamed of yourself.
 
Phil Allison <philallison@tpg.com.au> wrote in message news:696m7rF2poh9eU1@mid.individual.net...
" fritz the ASD fucked fuckhead "


** You clearly are a narcissistic, nit picking idiot who cannot take being
corrected.

Brushless DC motors and stepper motors are the NOT the SAME - each type
is suited to particular applications and they have very different
characteristics.

http://en.wikipedia.org/wiki/Brushless_DC_electric_motor

Fuck off and Die - you MORON !!





...... Phil
YOU really are the pathetic little nit-picker that you imagine in everyone else.
Your abusive posts are clear evidence that you have serious mental problems.
The evidence is clear from your previous posts, anyone can see your bad
behaviour by simply searching Google Groups aus-electronics.
You should be ashamed of yourself.
 
Phil Allison <philallison@tpg.com.au> wrote in message news:696m98F317r2rU1@mid.individual.net...
" fritz the ASD fucked fuckhead "


** You clearly are a narcissistic, nit picking idiot who cannot take being
corrected.

Brushless DC motors and stepper motors are the NOT the SAME - each type
is suited to particular applications and they have very different
characteristics.

http://en.wikipedia.org/wiki/Brushless_DC_electric_motor


Fuck off and Die - you MORON !!






...... Phil
YOU really are the pathetic little nit-picker that you imagine in everyone else.
Your abusive posts are clear evidence that you have serious mental problems.
The evidence is clear from your previous posts, anyone can see your bad
behaviour by simply searching Google Groups aus-electronics.
You should be ashamed of yourself.
 
In message <RMmdnU8_MoLcLLHVnZ2dnUVZ_sninZ2d@giganews.com>, geoff
<geoff@nospam-paf.co.nz> writes
Clint Sharp wrote:
In message <6Z-dna1E4eoSD7bVnZ2dnUVZ_hSdnZ2d@giganews.com>, geoff
geoff@nospam-paf.co.nz> writes
fritz wrote:


Why have you got 'steper motors' stuck in your 'brain' ?

CD players and CD-ROMs do NOT use stepper motors. None. Never.
Well, with respect Geoff, I have disassembled probably far too many
and an awful lot of them use a stepper to move the laser sled. As to
the definition of the spindle motor, I don't really see the difference
between a stepper and a brushless but I admit I'm not sure how you
define the two types to see the difference, maybe you can clarify
that?


Are you sure ? How can a stepper motor, with it's "quantised' discrete
stepped positions track a continuous spiral groove ?
Easily if the multiple CD/DVD-ROM drives I own are anything to go by,
they all seem to manage fine.
My understanding is
that all CD spindle motors are servo-controlled , to enable accurate
tracking.
So what? Do you think you can't achieve high enough resolution with a
stepper?
Could it be that people are not aware of what stepper-motors are.
Well, I'm fairly sure I know what a stepper motor is and how it works,
I'm also fairly sure I know what a brushless DC motor is and how that
works. Where I'm unsure is in what the difference between the two types
is because they both operate in the same way, albeit one has far less
poles than the other (which may be the difference!).
They are
NOT the same as a multi-pole DC motor, as the OP seems to think, from his
description ...
OK, so define a multipole DC motor and let's see where the difference
lies. AFAIK the type of motor you think is exclusively used in CD and
CD-ROM devices is a multipole brushed DC motor but I could be wrong,
please enlighten us.
geoff


FWIW, the only brushed DC motor I have seen in a CD-ROM drive for a very
long time is the one used to open and close the tray.
--
Clint Sharp
 
In message <g0l7k4$u2t$01$1@news.t-online.com>, fritz
<fritz@address.com> writes
geoff wrote...
Are you sure ? How can a stepper motor, with it's "quantised' discrete
stepped positions track a continuous spiral groove ?
Easily, the multiple CD-DVD-ROM writers and readers in my PCs are fine
examples.
My understanding is
that all CD spindle motors are servo-controlled , to enable accurate
tracking.
Umm, yes, as far as I know they are. So is the sled, so are the focus
coils on the lens assembly. What, exactly does that have to do with the
type of motor?
So what has the tracking of the 'groove' (sic) got to do with the
spindle motor,
which always was the obvious subject ?
I raised that subject I'm afraid, lots of CD/DVD-ROM drives use a
stepper to position the sled. I am still no more enlightened as to what
the difference between a brushless DC motor and a stepper is though.
Apart from a 'traditional' stepper motor having many more poles I see no
differences in terms of operation.

I think he is generally correct in stating that domestic CD players
don't use stepper or brushless motors for the spindle and laser sled but
almost all the CD-ROM/DVD-ROM drives I have ever disassembled do. Indeed
if he were to do a little research on CD/DVd drive spindle motors he
will find a *huge* amount of information about their operation and
drive.

Another mistake Geoff makes is that he assumes that a stepper has to
have jerky motion, using phase drive on a stepper you can achieve very
smooth motion and the rotating mass of the driven parts makes a nice
flywheel. He appears not to understand how a worm driven sled can have a
much higher resolution than the discrete steps would suggest.
--
Clint Sharp
 
In message <J8FtyePhesLIFwAi@clintsmc.demon.co.uk>, Clint Sharp
<clint@clintsmc.demon.co.uk> writes
FWIW, the only brushed DC motor I have seen in a CD-ROM drive for a
very long time is the one used to open and close the tray.
And having said that, I gutted a *very* old Toshiba XM-5401 SCSI CD-ROM
drive today to find three brushed DC motors, one for the spindle, one
for tracking and one to open the tray.
--
Clint Sharp
 

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