A type of impulse turbine that
is similar to Pelton turbine but
can handle higher flow rates although it is somewhat less efficient. The
runner (wheel) of a Turgo turbine is like a Pelton wheel sliced in half.
The incoming jet of water strikes the plane of the runner on one side –
usually at an angle of about 20° – and exits on the other. The
fact that the incoming and outgoing jets don't interfere (as they do in
the case of the Pelton turbine) means that the Turgo wheel can handle a
higher flow rate. Also, because the Turgo runner is effectively a Pelton
runner split down the middle it can generate the same power as a Pelton
wheel with twice the diameter and thus has twice the specific speed of the
Pelton. On the other hand, a Turgo runner is more difficult to make than
a Pelton and the vanes of the runner are not as sturdy as Pelton buckets.
|A small Turgo runner made by Joseph Hartvigsen for
use in a microhydro system
With their smaller, faster spinning runners, Turgo turbines can sometimes
be connected directly to a generator rather than needing an expensive speed-increasing
Turgos operate in a head range where the Pelton and Francis
turbines overlap. Although there are many large Turgo installations,
they are especially also popular for microhydro power applications.