"B.B." u wrote in message
news
In article ,
Jon Anderson wrote:

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

I had a teacher who built a dyno with a hydraulic pump & a flow
meter. He'd use a valve to build up back pressure and monitor the flow.
After allowing for pump efficiency he could calculate the horsepower
running through the system. Knowing pump displacement he could
calculate RPM.
Simple and scalable to just about any size you need.

--
B.B. --I am not a goat! thegoat4 at airmail.net

BB

I've got a little pump-dyno here where I mounted the pump so it is free to
rotate. Then, when the flow is restricted, the pump tries to rotate.
When I measure the torque imposed on the pump and the shaft RPM, I assume I
can calculate HP with Excel. But, the idea of several GPM at a thousnd +
PSI scares me enough that I dont want to test it in the garage. I might
get courage to test it on a fractional HP motor. All the other dyno loads
I've tried get too hot when loaded for even a few minutes. Water spray
helps extend the test run time, but even the water makes a little mess.

Jerry