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Re: (ET) 48 volts
At 06:54 AM 5/4/2006 -0700, Eric Adams wrote:
I have been wondering about the 48 volt Elec-trak as well. Higher voltage
be a little more efficient, and 48 volt components are a little more
via the forklift markets.
There has been talk of overspeeding the mower motors by raising the
but I can't help but wonder about that. I would assume that the system was
designed to safe with a fully charged 36 volts pack, which is ...what?...
volts? And we are all painfully aware how much the voltage sags under load
flooded batteries. So, would a 48 volt pack sag down to a safe voltage for
A couple of points to keep in mind.
First a fully charged 48V battery will be up to 55V. I've had
field report of hot batteries (just off charge) with voltages up to 60V
Second the speed of the PM motors on the deck will be
approximately proportional to the applied voltage. The energy contained in
the blades will be proportional to the square of the speed. This means the
energy in the blades will be more than 70% higher.
Third, the wind resistance and mechanical resistance will keep the
blade from reaching that speed but at the expense of increasing the current
(higher torque to overcome the resistance and compensate for IR drops) so
the motors will run hotter.
None of this means it can't work but it's not necessarily a minor change.
" 'Freedom' has no meaning of itself. There are always restrictions, be
they legal, genetic, or physical. If you don't believe me, try to chew a
radio signal. " -- Kelvin Throop, III