> There are several reasons the [inverted rotor/stator] design was not
> used in cars:
>
> * Motors like this make for heavier wheels; the `unsprung weight'
> increases. I have yet to read a discussion of how important
> this factor is now; all I know is that engineers have always
> told me that an increase in `unsprung weight' is a problem.
Among an interesting series of comments, "Robert Seeberger"
<[EMAIL PROTECTED]> asked
Do you think that the newer generations of lighter weight
permenant magnets would alleviate this concern?
I wish I knew. This might well be the case. I hope so, but would
like to hear from someone who knows.
I think that is a good example of an entrenched design moderating
a manufacturing economy.
Yes -- this happens all the time. It is called the QWERTY effect,
after the keys on a conventional US/English keyboard: the key
arrangement is not optimal, but was designed to prevent two keys from
bumping in to each other as they slowly fell back under gravity (no
springs at that time). But even though better key arrangements
exist, few people have shifted over to them because the cost of
relearning is too high.
Put another way, entrenchment is an opportunity for an individual to
do something that continues through history. (Please do the right
thing. I am furious that Christian Europe adopted an Indian/Arabic,
heathen, base-10 numerical system rather than a better base-12 system
in the 13th century. We are still stuck with base-10. Base-12 fits
the number of Christain Apostles, the number of eggs in a dozen, the
number of months in a Christian solar year, the number of signs in the
Zodiac, the number of hours in a day (counting from dawn to dusk, with
variable length hours), and the number of visible knuckles and finger
tips on your hand, when you bend your fingers and look at them.
Moreover, when you bend your fingers to look at them, you can readily
divide them into two groups of 6, or four groups of 3 or three groups
of 4.)
> Would the inverted rotor/stator design be for direct
> current, which was the least expensive before modern
> controls and which has the best low power torque? If so,
> the problem of shorts becomes very serious.
I get the idea (and this is just a guess) that since all their
calculations are at 48V and 96V that they are running DC.
Hmmm.... they might be running low voltage/high amperage AC. With
contemporary frequency controls, AC might be the way to control speed
and power. Does anyone know whether DC still provides the most
starting/low speed torque? Or have the variable frequency AC
controllers improved AC motors enough?
By the way, what is the maximum wattage for a typical car motor? What
is average cruise wattage?
I think it is important to note though, that the design they show
for passenger vehicles is a remote motor with a drive shaft.
<sigh> That is not so interesting. It suggests that they are
worried by unsprung weight. Another problem from unsprung weight is
that the bounces reduce the efficiency of the vehicle; the energy
heats the air in the tire.
--
Robert J. Chassell Rattlesnake Enterprises
http://www.rattlesnake.com GnuPG Key ID: 004B4AC8
http://www.teak.cc [EMAIL PROTECTED]
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