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RE: (ET) Mower motor strength requirements
I adapted a deck motor to a 2" water pump normally powered by a B&S 3 hp.
engine at 3600 RPM several
years ago. I measured the water lift and volume, and ran it for a number
of hours keeping track of
the duty cycle (it cycled because I was asking for more than the
continuous torque rating). The duty
cycle was about 80%. My calculations were between 800 and 1000 Watts
electrical, and between 700 and
900 watts mechanical for continuous use. The only significant error was a
tiny shaft mis-alignment
which caused a pump bushing failure after a day or so, and the motor was
putting out the power to
burn the bushing too. Pretty good. More or less an honest 1 HP. To give
you the contrast to a current
generation motor designed for an admittedly very short duty cycle, the
Visteon (used to be part of our
Ford group) gear drive starter motor used on most applications is 1200
Watts input for 200 seconds, a
pretty similar output but no where near continuous. The GE has some real
ratings, but they are on Bill's
prints. I asked once, but he didn't remember.
From: elec-trak-bounces cosmos phy tufts edu
[mailto:elec-trak-bounces cosmos phy tufts edu]On Behalf Of Markus Lorch
Sent: Friday, June 04, 2004 3:46 PM
To: 'Elec-trak list'
Subject: (ET) Mower motor strength requirements
With all the discussion about electric push mowers I am
curious how strong electic motors that drive one cutting
blade for push mowers need to be.
I know that small ICE mowers have around 3HP but I assume
that the B&D and Ryobi mowers have much smaller motors as
24V*18Ah should yield a max. of about 400 Watthours, prob.
even less as the batteries are probably rated at a much
lower discharge amperage. Thus if these mowers run for 1 hour
or so then I assume the motors are about 300W. Does anybody
know how strong the ET mower motors are (they drive a smaller
Also I assume the right cutting speed for such a mower is
around 3000 rpm (just guessing from the typical ICE speed).
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