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I tossed in 29" diameter and found
that it took over 7000 rpm to make
the recommended speed; what blades can be run at
that speed and
last? Or won't they fatigue? I've seen
car water pump fan blades
that fatigued (developed cracks, some came apart
destructively to
their surroundings) when run in excess of 7000
(engine rpm, don't
know what the blade rpm was, anyone have a vehicle
with the older
style water pump mounted fans that could measure
the pulley ratio?).
----- Original Message -----
Sent: Wednesday, August 27, 2003 9:30
AM
Subject: RE: (ET) Mower blade speed
The speed
is right when the batteries are doing well and the voltage hasn't been drooped
by excessive current.
Yes,
re-winding will add speed, and take a ton more current to power. For
electro-magnets, the governing factor is the
FIELD. The field is proportional to the current times the
number of turns of winding. Reduce the number of turns and
the current
has to go up by the same amount to preserve the field. The power is just
the product of the current times
the
voltage. Since would still be powering with the same voltage, and the
current would be higher, the power would be
higher.
Double
blades do up the current a bit. Whether it lets you cut faster is
questionable; you are now cutting at two heights and
mulching as
well. There isn't any free lunch.
Larry
Elie
Does anyone know what the minimum blade tip speed
should be before the blade tears the grass versus cutting it
clean?
I found the following links that calculate
this speed. It looks like our Elec-Trak blades max out at 155
mph.
Should a person rewire the motor for 24 volts and
run it at 36 volts to raise the rpm? Maybe run 2 blades per
motor in a +?
Any thoughts?
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