The set up

The set up
5.46mm jet delivering 0.68 l/s to the pelton which is rotating at 900 rpm and generating 135 watts into the grid.

Sunday, 9 November 2014

Going with the flow

Today has been a good day: the increasing flow available, now up to about 1.75 lps, has meant I've needed to put a bigger nozzle in.  I kept the same one on the bottom and only changed the top one from ∅ 3.64 mm to ∅ 4.96 mm.  An early rule I learnt was only to change one nozzle at a time, - more drastic action usually led to the header tank emptying.

Doing this lifted flow delivered to the pelton from 1.48 to 1.74 lps, and power into the grid from 343 to 421 W.

Small hands are essential and good access to the front of the turbine is helpful.

Off with the glazing

The nozzle to be put in

Nozzle retainer spanner

It's a tight fit getting to the top nozzle

Note the cloth to stop anything dropping into the tailrace

There is space only in the bottom corners to remove a nozzle

The "whole arm in" technique to screw on the nozzle retainer

I use 9 different nozzles to give me flows from 1.18 to 3.43 lps

...and best of all: 421 W generated, thus exceeding usage by 8W

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