Microhydro Applications

[btmkspgs]

Just out of curiosity. What would be a typical micro hydro turbine shaft speed?

BTMKSPGS

[mab]

How long's a piece of string?

it depends on head, runner radius and possibly, type of turbine.

with my setup (under construction) I've got ~100ft of head and pelton runner radius ~3.5"  so my ideal rpm is ~1250

[btmkspgs]

What a setup! The reason I asked was the application of an APMA. Mine have not been tested above 600 rpm. The 1400 is a basic well built system similar to the Otherpower design. My 2800 is mine, all mine, but again not tested above 600 rpm. Because of the quality molding of the stator and rotors I can keep a very small airgap without fear of rotor strike.

Do you see many with a gearbox of some sort? I know that derails the simplicity and decreases mean time between failure but is it used? Have you an idea on the amount of shaft torque?

BTMKSPGS

[mab]

the optimum rpm is when the water hits the runner spoon and transfers the most energy - i.e. when it comes off the spoon at 90°. if the rpm is too low the water bounces back towards the nozzle; if it's too high the water still has forward momentum.

if you want to keep it below 600 rpm you could (I think) just use a large radius runner (though you would need a lot of spoons which might make it expensive).

i.e. for my setup a 7" radius would bring optimum rpm down to 625.

there's a useful spreadsheet here though if you can't match the numbers to your hydro source you may need to use a different runner size to those on the table:-
http://h-hydro.com/

[btmkspgs]

Thanks,

The link is very helpful

BTMKSPGS