On 6 Mar 2005 11:59:31 -0800, wrote:

Another thought would be an eddy current brake. Essentially a driven
disk with a magnetic field so eddy currents are generated in the disk.
You would want an aluminum disk. According to someone that I knew a
long time ago that was using one for a car dyno the results are not all
that linear. He thought that at high power levels the magnetic field
was being deflected so less of it went through his disk. He was
wanting something that would present a couple of hundred hp load. or
more.

LOTS of heat. That brake had better be water cooled!

An eddy current brake should be quite linear, but if the disc heats up
its resistivity would change which would change its behavior.

Another large induction motor excited with DC could be the brake at
3450 RPM if it could be sufficiently cooled: forced air perhaps.