Need a method to measure output of water wheel

[boatmon]

Have a patent, made a model (1:12) and need a method of testing the output. There is a water testing facility at a nearby university that we plan to use, but need some form of machine to measure the power generated at given speeds. I am sure differing load conditions could increase or decrease the operational efficiencies, but don't know where to begin.

 

[Timelord]

How about a torque sensor on the output shaft? That plus the RPM gives you the power.

Timelord

 

[boatmon]

Thank you for the lead. After googling torque sensor, and seeing 3 to 6 thousand dollars, I am now googling torque sensor rentals.
(I wonder how Da Vinci did all this)

 

[GregLocock]

The thing you are looking for is a brake dynanometer. At its simplest it is a leather strap and a weight pan.

This book will give you some hints

Stronger Than a Hundred Men: A History of the Vertical Water Wheel By Terry S. Reynolds

However, these days we'd just plug it into an electric motor.






Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[greengineer]

Since it's just 1/12 scale, hook it up to an alternator and measure the output. If you want to do it really cheaply, dump the power into a load resistor, and measure the voltage with a voltmeter. Then use P=V^2/R to find the power.

 

[Apakrat]

If it is not invasive, what is the actual measurements of the 1:12 prototype?
Diameter?
Axis?
Foil Depth?

At 74th year working on IR-One2 - - UHK PhD - - -

 

[boatmon]

I am about a month from releasing the overall design to the public, and would like to keep it offline for a little longer. I will post then, but for now we are going to just try and scale up the numbers that we get from the model that we built.
Thanks and I will make it a point to come back and post some numbers that can compare actuals to model, formulas to reality.

 

[unclesyd]

The use of a brake dynamometer as posted by GregLocock is the way to go. Lookup Prony Brake for information. For RPM measurement a simple mechanical speed indicator will do the job.