Jon

I recently built a dyno for testing 3 phase motors. It'll probably
handle 10 HP. It uses a spinning aluminum disc for the load. I mounted an
electromagnet that is free to rotate about the disc's axis. As the
magnetic field strength is increased, the spinning disc tries to force the
magnet to rotate. Its rotation is restricted by a pressure sensor.
I use a couple of multimeters to record the pressure and RPM then let
Excel do all the HP computational work.

It seems real easy, now that I have finished it. Fitch got me started and
showed me how to use Excel. Then Don Foreman was patient enough to guide me
thru the refinement of this dyno till he finally got me to do it right.

If your friend wants to know about dyno design, get in contact with Don
Foreman. If your friend wants pictures, I can show him what I have here.

Jerry

"Jon Anderson" wrote in message
...
I have a customer that among other things, rewinds obsolete air coil
electric motors. He has asked me about building a dyno so he can test
motors to something other than 'yep, it turns' under power.

Looking through SIC I only find one article on building a dyno. It looks
to be a fair bit of work. As he called me while on the road today and
the connection was bad, we couldn't really get into details. I am unsure
what HP and torque the motors develop, though it's not a lot. I also
don't know what rpm range he wants to test.
Did a bit of Googling and didn't find a whole lot on small model engine
sized dyno building.

Anyone know about web resources for different approaches?


Thanks,

Jon Anderson