In article ,
Roger Mills wrote:
Many Jap cars use a Denso starter which uses a smaller but faster
motor and reduction gearing. Said to use a lot less current and
produce more torque. And I can buy one with a specially made mounting
for my engine. For more than an exchange Lucas one - but not so much
as to be out of the question.


I don't understand that - it appears to defy the laws of physics! So the
motor itself runs at higher speed and lower torque - working through
reduction gearing - but the engine needs a certain amount of *power* to
crank it - based on the product of cranking torque and cranking speed.
The starter motor has to produce that power , so - unless it's
dramatically more efficient - it's wattage will be the same as the
original Lucas motor. Since watts = volts x amps, and you can't do much
about the voltage, then surely the current is going to be the same?

I *think* it's because a series wound motor isn't very efficient at stall
or close to that. They are very much better at their natural quite high
speeds. I've been told the Denso has a permanent magnet motor but can't
confirm this. Certainly old car wiper motors etc used to be series wound,
but changed to permanent magnet when better ones became more affordable.

--
*Plagiarism saves time *

Dave Plowman London SW
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