NuVinci CVT Developers Kit

[ChuckDickerson]

Fallbrook Technologies has announced that a NuVinci CVT Developers Kit (http://www.fallbrooktech.com/09_LEV_Kit.asp) will be available for $595 starting in December specifically designed to assist hobbiest in development of Light Electric Vehicles (LEVs).

Press Release: http://www.fallbrooktech.com/05_PressReleases_Intermot.asp

I'm sure hoping we see these in the KoP next year! :D

[gorrilla]

hah wowo i was just talking about a cvt transmission at tnt!

[IKE]

While CVTs are often use in industrial equipment with Fixed speed AC motors, you don't often see them in EV aplications because an Electric vehicle motor has the properties that a CVT typically has. Usually with a 2-3 speed transmission you can get all the performance and efficiency you want/need. Also, CVTs are are typically a double edged sword on the whole efficiency thing. Almost all use a cone, ball, or belt and sheave system that invariably has a little bit of conflicting friction at the contact patch. This friction tend to make CVTs have a lower prowerr transmission efficiency. Where they do a lot of good though is with motors that have a very narrow band efficiancy range (think A/C motors, or some genertator or governed engines). On these applications the CVT can vary output speed while the motor stays in it most efficient or powerful state.
I am a huge fan of CVTs and even designed a new one while in college. If you want a great CVT design resource check out:
"Traction Drives: Selection and Application [Hardcover]
By Frederick W., III and Shube, Eugene E. Heilich"
This is a great book that devotes 50% to fixed ratio traction drives (think gear systems without teeth), and 50% to all metal CVTs (sorry no rubber belt system).

[Andrew Schreiber]

While CVTs are often use in industrial equipment with Fixed speed AC motors, you don't often see them in EV aplications because an Electric vehicle motor has the properties that a CVT typically has. Usually with a 2-3 speed transmission you can get all the performance and efficiency you want/need. Also, CVTs are are typically a double edged sword on the whole efficiency thing. Almost all use a cone, ball, or belt and sheave system that invariably has a little bit of conflicting friction at the contact patch. This friction tend to make CVTs have a lower prowerr transmission efficiency. Where they do a lot of good though is with motors that have a very narrow band efficiancy range (think A/C motors, or some genertator or governed engines). On these applications the CVT can vary output speed while the motor stays in it most efficient or powerful state.
I am a huge fan of CVTs and even designed a new one while in college. If you want a great CVT design resource check out:
"Traction Drives: Selection and Application [Hardcover]
By Frederick W., III and Shube, Eugene E. Heilich"
This is a great book that devotes 50% to fixed ratio traction drives (think gear systems without teeth), and 50% to all metal CVTs (sorry no rubber belt system).

I can vouch for that book, very informative, I was curious how they worked and the book did a wonderful job explaining the concepts to me, a very non technical person.

[IKE]

I can vouch for that book, very informative, I was curious how they worked and the book did a wonderful job explaining the concepts to me, a very non technical person.

I was a little bummed that they didn't cover the rubber belt systems used in Snow Mobiles and lots of different machinery, but otherwise though it was a great book.

[Greg Needel]

I got to see this at the makers faire and while it is a cool technology it is very inefficient. They wouldn't tell me the exact amounts but hinted it was not good. Also the ratio range was 3:1 so it would be just a little more then an andymark from top to bottom. I think it would be cool to play with one of these but putting it on a robot doesn't make any sense.