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Re: (ET) (Fwd) Re: Ariens AMP Mower

If someone can dig up more particulars, I'd love to see them. :)

   And it REALLY makes me wonder why this project was saddled with a power robbing hydrostat.But again, I'm not an engineer, nor do I............................


Ken Muldrew wrote:
On 14 May 2009 at 11:28, David Roden wrote:

However, an electronic motor controller is effectively a continuously 
variable transmission without the inefficiency of hydro drive.  The
a small DC motor controller adequate for a garden tractor is certainly
prohibitive, and much less today than it was 30-35 years ago.
Unless I'm misunderstanding the product description, the Ariens mower uses
a brushless DC motor (a three phase armature with permanent magnets on the
rotor and hall sensors for sequencing). It can't run without a controller
so variable speed and reversing are available at the outset with no 
significant additional cost. The torque vs. speed trade-off could be 
managed through dual windings in the armature or switching from WYE to 
DELTA configurations, but given the limited needs of a riding lawnmower, 
even this seems unecessary. I don't understand why the hydrostat is

Ken Muldrew. 
   \----------------------------+----------------------------+   o_,
 O_/ \    Ken Muldrew, PhD      | Voice: (403) 220-5976      |   <\__/7
 <\__  \  Dept. of Cell Biology | Fax:   (403) 270-0617      |     | /
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               Morning coffee recapitulate phylogeny          L/

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