Re: [Amc-list] ELECTRO-RAMBLER =revisited=

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

" From: farna@xxxxxxx
" 
" In theory, yes -- hook it right to the driveshaft or axle. But in
" practice, you need a hefty motor to get something heavy moving. So
" there's a compromise between motor size/weight/heat generated, and
" the current draw required. Seems it's better in the long run to use
" a transmission -- at least a two speed job as Andrew keeps
" mentioning. That's why I figure a BW OD would be a good, light, easy
" to operate trans. That's only if you can electrically reverse the
" motor though. And have an electric lock-oout for the OD, which won't
" work in reverse. That's easy enough to accomplish with a relay to cut
" power to the solenoid. Since multi speed automotive trannys are
" readily available and easy to use, may as well use a smaller motor
" and take advantage of all the gear reduction already there. 

the power to accelerate from a stop [in a given time] is a constant.
the tradeoff is that while in the torque-limited part of the
performance map a smaller motor may not be able to supply that power.

this is why i think a wide range 2sp would be the ticket.  a 'granny
gear' to get rolling [just like a large truck] and a top gear for
everything else.

how about the planetary from a t/c?  ~2.6:1...

" ------------------------
" From: Ken Ames <ameskg@xxxxxxxxx>
" 
" Aren't electric motors like steam engines? Maximum torque at 0 rpm?

inherently true of series-connected dc motors.  parallel motors shine
at higher speeds.  you can switch between connection modes -
locomotives did.  separately excited motors can imitate both.
inverter controlled synchronous ac motors act like seperately excited
dc.  dunno offhand how inverter driven induction motors act.

" Should be able to run the driveshaft off the motor. The electric buses here have
" no tranny.

just thought - those electric buses [we have them in boston too]
probably won't go over 35 mph.  and they run off overhead wires, so
efficiency isn't a factor.
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh@xxxxxxxxxxxxxxxxx                       and think what none thought
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