in this font pi() looke like n

P = τω = τ *(2* Pi())*rps = τ *2* Pi() *rpm /60 = τ* Pi() *rpm /30

However the turbine capacity looks to be too large

at a shaft torque of 0.955 Nm i don't know a few mm dia shaft may do it

What is the turbine for i wonder

Pretty low RPM for a turbine, unless it's a small water turbine? In a teeny tiny hydroelectric dam for gremlins maybe?

Even for a water turbine I don't know tap water as the source ? may be ? only 50W - OK may be my fan can run through the output - it is 60W i think. 500RPM at 50W -

But no fun for me. with a shaft dia of 0.5mm or so you don't need me to do anythig to it, a ant hit is likely to brak the turbine.

The water inlet is likey to require a 10 micron filter otherwise the dust in it is likely to create the pulsations and fatigue the shaft.

(may be accountant post ?)

A beer flowmeter, maybe? I know a few chaps who prolly expend 50 watts during a good chug!

I think a brilliant idea- while the beer is served , you get free power - but are you sure the head will be enough or we have to put the keg on third floor or so.

(again not calculating the Head or Q- just uncalculated remark)

sb - your figure 0.955 N.m assumes 100% generator efficiency.

But ignoring that, I can't agree with your shaft diameter. 0.5mm gives a torsional stress nearly 39000 MPa !

5 mm giving 39 MPa more like it, allowing for some bending forces from unbalanced loads, turbulence etc on the turbine.

Cheers.......Codey

1) it is the turbine output and no mention of generator connected -hence 100% efficiency

2) seeing the amount of stress - didn't stress myself to design the shaft- the size was given as just an off-calculation remark.

Hope don't mind.

By the way who has heard of a 500rpm hydro turbine generating as large as 50W ?

I am sorry but I think that you do not read the text or have the wrong spectacles. Please take a lens to see better.

You correct a right text assuming that it is wrong.

I used the symbol for "Pi" from the "Ω" file which is "π" and not "n" ( you see the differrences? dont you?) you should not assume that people are totally stupid and can write what you assume they wrote.

Any way thank you for the attention you gve to my text and to the many ways one can write same thing.

Thank you for the positive comment. I am accustomed that most GA are given for not technical comments and my goal is not to gain GA but to help. I would not object to a GA since it gives the satisfaction of a good work done.

The shaft diameter is for a shear stress usually used around 3.5 mm, the 5mm suggested are correct.

The speed can be right if the turbine is a wind turbine or a hydraulic one not Pelton type. I think even that the value is too high for a possible application as mentioned above.