# Precious Metal Motor Brushes



## DarkspARCS (Mar 6, 2011)

Hi folks... Once again I'm sharing more info on items I research - this time I found info on drive motor, and similar mini motors (like camera motors), that contain Precious metals in the motor's brushes.

These brushes are tiny, similar looking to the PM brushes found in hard drive armeratures, and are located under the metallic motor end cap plate, embedded in plastic. It's also said that commutators can possess PM values as well.

Devices using these motors are cd/ dvd rom drive motors, the motors found in copier machines, univeral joints, digital cameras, electric shavers, electric toothbrushs, etc. A good referrance page can be found at Jency Motors

Motion Control Online gives some details:



> Choice of brush material is another degree of freedom that can be useful in medical designs. Precious metal alloys such as silver, gold, or even platinum provide lower contact resistance and lower electrical noise operation, while copper-graphite brushes ensure long life even under extreme load conditions. Although there is some overlap, precious metal brush motors are typically utilized in motors rated for at 10 W and below.


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## stihl88 (Mar 7, 2011)

CD and DVD ROM drive motors are always Brushless motors and therefore don't utilize brushes.

Copier machines usually use stepper motors that have brushes but it's doubtful that they use PM material for the brushes.

Electric Toothbrushes typically use a 6mm pager motor that have two micro all steel brushes, not sure what they are made of but when ever i repaired them the brushes were always silver in color but more Nickel colour.


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## DarkspARCS (Mar 9, 2011)

> CD and DVD ROM drive motors are always Brushless motors and therefore don't utilize brushes.



That might be true on some of today's optical drives, I haven't gone and looked, however the CD/ DVD drives and players I've taken apart for thier boards, pins, laser reader apparatus, and *motors* all had 3 motors, multi disk players had 4... one to operate the disk tray, one to spin up the disk, and a smaller motor to operate the laser reader apparatus' forward/ backward movement along the stainless steel track it's attached to. Multi disk players had a fourth motor operating the disk elevator.

Within every motor casing end cap I've peeled from the bigger motors I've discovered exactly what I said I did in this post, which the technical docs I've reviewed on them also states:

On the inside of the motor housing end cap there is a hard plastic part rivetted to it, that houses a pair of mini motor brushes made from Precious metal. I haven't opened any of The smaller laser reader controllers, so I can't vouch for what's inside of it.

Copier motors, and any other device I've mentioned in this post have all been listed within either the pm brush motor's manufacturer's tech docs, related patents I've personally investigated, as well as have physically verified myself.

All you have to do is run a search within 'google' for the phrase "Precious Metal Motor Brushes" to discover this documentation yourself...


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## stihl88 (Mar 9, 2011)

I believe you mate...

I was just making people aware that the actual drive motor of CD/DVD ROM drives are Brushless.

I'll take a look at the brushes next time i crack one open, Ive got hundreds of Floppy drives and CD ROM drives


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