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[peter]

BSDThw

I wasn't responding to the question about growling, I was responding to this comment of Karl's from Feb 25:

<Looks like I have to take the '13 XU back to the dealer for service anyway -- the bike boots up, but doesn't run -- throttle doesnt do anything.  This problem was intermittent before, and nobody has tried to ride the bike since December...>

hth
Peter

[kensiko]

"The term "rare earth" can be misleading as these metals are not particularly rare or precious;[1][2] they are about as abundant as tin or lead."

http://en.wikipedia.org/wiki/Rare-earth_magnet


You can replace them with an electromagnet as well as in the Tesla Model S induction motor.  I imagine that is at some cost to efficiency (resistive losses), or at least some complication.

Thanks for the info. I know I would have found my answer by googling it, but having an answer from someone is always pleasant.

[aelwero]

Yes, the term "rare earth materials" is misleading. They are not rare in the usual sense of the term. However, they were very expensive until the use of the magnetic material exploded with the advent of computer hard drives. All hard drives have those magnetic materials in them. The massive increase in computer use caused a huge increase in demand so mining the materials increased greatly, thus bringing the prices down considerably and still dropping.

One of the largest rare earth mining operations is located in the Eastern California Mohave Desert, very close to Las Vegas NV. China has bought up rights to other deposits around the world. They tried to buy the CA deposit but it was not for sale.

Trikester

Sounds like a good plot for a Clive Cussler novel..

[Doug S]

You can replace them with an electromagnet as well as in the Tesla Model S induction motor.  I imagine that is at some cost to efficiency (resistive losses), or at least some complication.

Permanent magnet motors have advantages and disadvantages to field coil motors. Long story short, a PM motor typically shows more torque and higher efficiency at low speeds, but doesn't put out nearly the amount of horsepower on the top end that a field coil motor does. That's why a Zero SR (permanent magnet motor) puts out 106 ft-lbs of torque but only 67 hp, where the Mission RS (field coil motor) puts out 120 ft-lbs of torque but 160 hp on the top end...it's a much more powerful motor overall, but the low-rpm torque isn't that much greater.

For me, I just don't need that much top-end horsepower; at 52 yo I can't even remember the last time I wanted to go 100 mph. But I do LOVES me some torque!