CDROM Spindle Stepper motor

"fritz"

The three wires go to a dedicated, variable frequency speed controller.

...... Phil

In message , fritz writes

You'll find a lot of information about controlling them in the RC aero modelling groups, they modify them for flight. Other than that, look out for hard disk motor control and brushless dc motor control.

The one I have is clearly a stepper motor. You could say all stepper motors are 'brushless DC' motors if you think about it..... You apply a current to the motor terminals and it moves to a fixed position.

I haven't had much luck in searching for such sites using Google. (including groups) Perhaps you could post a few relevant URLs, I must be using the wrong search terms :(

I haven't had much luck in searching for such sites using Google. (including groups) Perhaps you could post a few relevant URLs, I must be using the wrong search terms :(

"fritz"

Gets thousands of hits - the first page should keep you busy for hours.

.... Phil

Thanks for that.

In message , fritz writes

cd rom motor rc were the search terms I used...

Stepper motor ?!!!

How would you servo control a stepper motor to track a CD pre-groove ?

geoff

Look up 'spindle'. i.e. it spins the disk The motor I was talking about isn't part of the laser groove tracking system at all.....

Thanks for the help.

A stepper motor spinning the spindle - that doesn't sound very smooth !

I think you'll find it is a conventional brushless DC motor - not a stepper motor.

geoff

The spindle motors I have replaced are 2-wire motors with brushes, it's these brushes wearing out that causes motor failure. It's rare to find a bearing failure as a fault condition.

"Fun Tyme"

Bet ya don't.

Specially not the ones that do 48 and 52 times speed.

...... Phil

Strange - that's exactly what I was thinking too. I always had the idea that the disc rotates at a very constant velocity, which stepping motors don't do.

Bob

CD-ROM spindle motors are generally brushless hall effect sensor types (at least all the ones I've seen recently are) but isn't that just a variant of stepper motor? Not trying to be argumentative, I'm just not sure where the lines are drawn.

You are correct of course, I meant CD players as in shitbox consumer "HiFi". I didn't read properly - a combination of age, general stupidity and drugs. Now I will have to wreck a CD-ROM unit and find out what spins ...

"Fun Tyme"

The thing that " spins " look far to simple to even work.

Bit like a small jet turbine - I fancy.

... rgds, Phil

"Phil Allison"

..... Phil

No. CD motors spin continuously.

Stepper motors action is to , surprising, step, one distinct step for every driving pulse. Would not give a very nice clan smooth spin, even at high speed.

geoff