tion and
fitting of those special auxiliaries necessary to carry on the test.

[Illustration: FIG. 74]

It is customary, when carrying out a first test, upon both prime mover
and auxiliaries, to place every important stage in the expansion in
communication with a gage, so that the various pressures may be recorded
and later compared with the figures of actual requirement. To do this,
in the case of the turbine, it is necessary to bore holes in the cover
leading to the various expansion chambers, and into each of these holes
to screw a short length of steam pipe, having preferably a loop in its
length, to the other end of which the gage is attached. Fig. 74
illustrates, diagrammatically, a complete turbine installation, and
shows the various points along the course taken by the steam at which it
is desirable to place pressure gages. The figure does not show the
high-pressure steam pipe, nor any of the turbine valves. With regard to
these, it will be desirable to place a steam gage in the pipe,
immediately before the main stop-valve, and another immediately after
it. Any fall of pressure between the two sides of the valve can thus be
detected. To illustrate this clearly, Fig. 75 is given, showing the
valves of a turbine, and the position of the gages connected to them.
The two gages E and F on either side of the main stop-valve A are also
shown. The steam after passing through the valve, which, in the case of
small turbines, is hand-operated, goes in turn through the automatic
stop-valve B, the function of which is to automatically shut steam off
should the turbine attain a predetermined speed above the normal, the
steam strainer C, and finally through the governing valve D into the
turbine. As shown, gages G and H are also fitted on either side of the
strainer, and these, in conjunction with gages E and F, will enable any
fall in pressure between the first two valves and the governing valve to
be found. Up to the governing-valve inlet no throttling of the steam
ought to take place under normal conditions, i.e., with all valves open,
and consequently any fall in pressure between the steam inlet and this
point must be the result of internal wire-drawing. By placing the gages
as shown, the extent to which this wire-drawing affects the pressures
obtainable can be discovered.

[Illustration: FIG. 75]

On varying and even on normal and steady full load, the steam is more or
less reduced in pressure after passing through th