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Subject: Re: Hard drive motor question
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NNTP-Posting-Date: Fri, 18 Oct 2002 10:25:57 EDT
Date: Fri, 18 Oct 2002 15:33:11 -0400
I good number of the data sheets I have been looking at do not require
sensors. Instead they use the "back-EMF sensing technique to sense the
rotor position" An example: Philips TDA5143T data sheet, which just
happens to be the chip on one of the drives I salvaged. The schematic in
this data sheet is typical of what I am finding for the "sensorless" drive
circuit ic's....three coil winding connections plus the ground are the 4
motor connections and there are usually 6 or so capacitors rquired. Unless
I'm just missing something in reading and understanding these data sheets, I
can't tell if this is ALL that is necessary to run the motor or not. I may
have to unsolder this IC and find a way to breadboard it (ug...soic, not
looking forward to that).
If this is so, this might be a SIMPLE method to control these motors (there
are some versions of these controller chips that are available in DIP
Of course this begs the next question....how is the RPM of the motor
controlled using this method? Maybe the chip is controlling the motor
speed to ONLY one rpm....not user variable....not that important to me, but
might be something I'd like to keep in the back of my mind.
"Chuck Simmons" wrote in message
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