Improvements in Means for Controlling and Measuring the Power of Steam, Gas, or other Engines and Shafts.
Year: 1896

page_text: Date of Application, 4th Apr., 1896
Complete Specification Left, 4th Jan., 1897-Accepted, 20th Mar., 1897
Improvements in Means for Controlling and Measuring the Power
of Steam, Gas, or other Engines and Shafts.
CHARLES WILLIAM GODSON LITTLE Heckington Lincolnshire Electrical
Engineer do hereby declare the nature of this invention to be as follows:-
My invention consists in applying to two points in a shaft between which points
power is being taken off, two alternating current dynamos which dynamos are so
connected up electrically and adjusted mechanically that when the shaft is
transmitting no power the two dynamos are in opposite electrical phase. When
the shaft transmits power it will be subjected to torsion which will throw the
dynamos out of phase in proportion to the power transmitted. Current will then
pass in an electrical circuit between the two dynamos which is made to pass thro'
an electro magnetic device acting upon the expansion gear or throttle valve of the
engine and thereby controlling its speed. The current can also pass thro' a
recording ampere meter, the records of which will be proportional to the power
transmitted by the shaft.
Dated this Third day of Anil 201ne
C. W. G. LITTLE.
Improvements in Means for Controlling and Measuring the Power
of Steam, Gas, or other Engines and Shafts.
1, CHARLES WILLIAM GODSON LITTLE of Heckington, in the County of
Lincoln, Electrical Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
My invention consists in applying two alternating current dynamos one to each
of two points in a shaft from which power is being taken off, which dynamos are
connected up electrically by a circuit the current in which passes through an electro-
magnetic device acting upon the expansion gear or throttle valve or like regulating
device of the engine so as to control the speed of the engine in consequence of the
fact that when the shaft or the like transmits power it will be subjected to torsion
varying with the power so as to cause the current in the circuit to be corre-
spondingly varied and the regulating device to be actuated proportionately to the
torsional power transmitted by the shaft or the like. The current can also pass
through a recording current meter the records of which will be proportional to the
power transmitted by the shaft or the like.
I will describe with reference to the accompanying diagrams, examples of the
manner in which my invention can be carried into effect. 1 do not limit myself
to the precise details of these examples but they will serve to make clear the general
application of my invention.

page_text: Figure 1 of the accompanying drawings shews generally the form of alternator
which I prefer to employ. It is so arranged that the field magnet can be adjusted
through a small arc a ò which is effected by pivotting the frame of the field
magnet A by means of brackets (one of which is shewn at B) onto the standards
carrying the armature shaft one of which standards is shewn at D.
E is a slot in which the frame of the field magnet can move and be locked in the
adjusted position by the screws F. The machine is provided with collector rings
and brushes which may be done in the usual way. Cindicates the windings of the
field magnet.
By the adjustment of the field magnet the phases of the two alternators can be
adjusted while the machines are in operation. The armature may be built up with
slots for the reception of the windings as shewn, or be of any usual or suitable form.
The field magnets may have as many poles as convenient according to the
frequency required.
If the torsion of the shaft to which the alternators are applied be small it is
advisable to make the pole pieces narrow in order that a small angular difference
between the two working armatures may have a more powerful effect.
I prefer when convenient to excite the alternators from a separate source but the
armatures may if necessary have an extra winding and commutator for the purpose
of exciting them.
In the arrangement shewn in Figure 2 to control the speed of an engine driving
countershafting I connect two alternators A2 B2 to the countershaft E2 by means of
toothed gear wheels a e and be, the distance apart of the said alternators depending
on the maximum amount of torsion to which the shaft E will be subjected, the
greater this torsion the nearer the said alternators can be together and vice versa.
The two armatures are connected in series as shewn by the wires J, K, and pass
through an electromagnet F2. When the shaft is at work there will be a certain
alternating current passing in the electric circuit. If the torsion of the shaft
changes, as it will do if more or less power be taken from the pulleys C, D, the
current in the electric circuit will change owing to the angular displacement of the
armature of the alternator A, with respect to that of B, caused by change in
the shaft due to torsion. This change of current reacts on the electromagnet F
causing its arinature H, to regulate the supply of steam to the engine by acting
upon the valve G. Instead of connecting the two alternators in series as shewn the
electromagnet F, may be wound with two coils and each coil be connected to an
alternator.
Figure 3 shews the application of my invention to the controlling of marine
engines. A and B, are the alternators geared to different points of the propellor
shaft E as herein before described. The action of the alternators is the same as
described with regard to Figure 2. I prefer however in this case to use instead of
an electromagnet a "revolving field" or "induction" motor F, having its field
windings at right angles to each other. An alternator is connected directly to each
field. An induction motor is specially suited to marine governing owing to the fact
that the torque on its armature is an inverse function of the rapidity of the
alternation and a direct function of the velocity of the revolving field. These
functions are such that by properly proportioning the dimensions of air gaps and
resistance of the armature of the induction motor the action on the controlling valve
is made practically constant through a very wide range of speed of the main engine
and only comes into action when a change occurs in the torsion of the propellor
shaft without a corresponding change in speed.
Another view of the induction motor is shewn in Figure 34 shewing the way in
which it is geared by means of toothed wheels fa to the controlling valve G
1, is a spring attached to a pulley by a flexible connection for the purpose of opposing
the motion of the armature.
When the propeller leaves the water the torsion of its shaft changes causing the
two alternators to react on the induction motor and drive its armature in the
direction proper to cut off steam by means of the valve G.

page_text: Figure 4 shews the application of my invention to an engine directly coupled to
a dynamo or other machine C..
A, and B. are the alternators geared to the said shaft as hereinbefore described.
F is the electromagnet, H, its armature and G, the steam regulating valve. The
action of the alternators is the same as is described with regard to Figure 2.
If desirable an elastic coupling may be introduced at D. 1. is a properly
calculated recording current meter by means of which the power given out by
the engine is measured and recorded. Such a meter can be applied to the other
arrangements. One is shewn at 12 in Figure 2.
Having now particularly described and ascertained the nature of my invention
and in what manner the same is to be performed I declare that what I claim is :-
1. For controlling the power of steam, gas, or other engines and shafts, the
combination with the shaft, or the like, from which power is taken off, of
alternating current dynamos driven from different parts of the said shaft, or the
like, and connected with an electric circuit, so that, when the torsion in the shaft,
or the like, varies, the current in the electric circuit (which varies proportionately)
is caused to act upon the cut-off gear, or valve, or other means of regulating the
power transmitted; substantially as herein before described and illustrated by the
examples shewn in the accompanying diagrams; whether or not a measuring device
be used in combination therewith.
2. For measuring the power transmitted by shafts, or the like, the combination
with the shaft, or the like, of alternating current dynamos, driven from different
parts of the shaft, or the like, and connected with an electric circuit in which is
placed a recording electric current meter, so that when the torsion in the shaft, or
the like, varies, the current thereby produced or varied in the electric circuit, will
be recorded by the said meter proportionately to the power transmitted by the
said shaft, or the like.
Deted this 4th day of In
1007
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.