Quote:
Originally Posted by Jetijs
Peter,
I watched your video about the dynamo meter again and a question arised. Why do we need the wheel? Why can't we just load the shaft with that leather strip? I mean if we know the shaft diameter, we can calculate the circumference. If my shaft is 8mm in diameter then the circumference would be 2 x phi x R, or 2X3.14X4=25.12mm. Right? and we can easily convert this to foots.
Of course I will build the wheel, but it is not as easy as I thought and it will take more time.
Jetijs |
Jetijs,
You are correct. The wheel is not necessary. You just need a "known circumference" to do the calculations. The major benefits of the wheel are to save one step in the math, and to lower the amount of side force on the shaft. Try what you have, and see if you can develop consistent results over a series of test. If you run three tests, and the measurements are all within 2% of each other, then you can be pretty confident of the lowest number.
Also, if you rig up a hinged frame to hold the scales, then one person can hold both scales quite still, and you can get the rpm reading and other inputs reliably.
Good luck.
Peter