GOVERNORS FOR REGULATING THE SPEED OF MOTORS DRIVEN BY ELECTRICITY to be as follows:
Year: 1884

page_text: I, FLEEMING JENKIN of 3 Great Stuart Street Edinburgh Civil Engineer do
hereby declare the nature of my invention for "GOVERNORS FOR REGULATING THE
SPEED OF MOTORS DRIVEN BY ELECTRICITY to be as follows:-
"
The object of my invention is to regulate the speed of motors so that this speed
shall not rise above a certain maximum nor fall below a certain minimum and to
give a simple and trustworthy means of obtaining an average speed between
these limits.
If the simple centrifugal governor be employed to regulate the speed of a motor
as has been proposed by Moncel Desprez and others the place where contact is
broken becomes rapidly fused or oxidised by the voltaic arc or sparks which pass
between the metallic surfaces-these remain when the critical speed is renched
chattering together making and breaking contact with immense rapidity and give
rise to waste in the form of heat even when they continue to act. I avoid these
evils by my invention. I arrange the centrifugal governor so that at a given
speed say 500 revolutions per minute the weights fly out through a considerable
range until directed in a new position by a stop. They do not fall back to their
first position until another lower speed of say 450 revolutions per minute is
reached but remain unchanged in the second position while the speed falls from
500 to 451 revolutions per minute. This result is obtained by using a spring to
restrain the diverging weights of such length and so placed that the force with
which it restrains the weights increases less rapidly than the centrifugal force
increases as the weights diverge. At the two critical speeds the weights are in
unstable equilibrium.
I connect the make and break arrangement with the diverging weights by a
system of links and it is easy to see that the large and rapid divergence of the
weights at the critical speed will open the make and break suddenly to a great
distance obviating the chattering described before-a few sudden breaks occurring
three or four times a minute are substituted for innumerable small sparks. Any
approved make and break may be employed but I prefer to use the following.
arrangement which is not in itself new. I arrange two adjustable carbon rods as
supplementary contacts so that when the break occurs two metal surfaces are first,
TD 031

page_text: separated, the current then flows through the carbon contacts; the carbon contacts
are next broken giving a momentary flash of electric light. The reverse action
occurs when contact is made-the current goes for a moment through the carbon
and then permanently through the metal pieces. Although this arrangement is
not in itself new the use of this arrangement is only rendered possible by the 5
adoption of the other parts of my invention.
Governors for Regulating the Speed of Motors Driven by
Electricity.
I, FLEEMING JENKIN of 3 Great Stuart Street, Edinburgh, Civil Engineer do
hereby declare the nature of my invention for "GOVERNORS FOR REGULATING THE
SPEED OF MOTORS DRIVEN BY ELECTRICITY" and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
The object of my invention is to regulate the speed of motors so that this speed
shall not rise above a certain maximum nor fall below a certain minimum and to
give a simple and trustworthy means of obtaining an average speed between
these limits.
If the simple centrifugal governor be employed to regulate. the speed of a motor
as has been proposed by Marcel Desprez and others the place where contact is
broken becomes rapidly fused or oxidised by the voltaic arc or sparks which pass
between the metallic surfaces-these remain when the critical speed is reached
chattering together making and breaking contact with immense rapidity and give
rise to waste in the form of heat even when they continue to act. I avoid these
evils by my invention. I arrange the centrifugal governor so that at a given
speed say 500 revolutions per minute the weights fly out through a considerable
range until directed in a new position by a stop.. They do not fall back to their
first position until another lower speed of say 450 revolutions per minute is
reached but remain unchanged in the second position while the speed falls from
500 to 451 revolutions per minute. This result is obtained by using a spring to
restrain the diverging weights of such length and so placed that the force with
which it restrains the weights increases less rapidly than the centrifugal forces
increases as the weights diverge. At the two critical speeds the weights are in.
unstable equilibrium.
I connect the make and break arrangement with the diverging weights by a
system of links and it is easy to see that the large and rapid divergence of the

page_text: weights at the critical speed will open the make and break suddenly to a great
distance obviating the chattering described before a few sudden breaks occurring
three or four times a minute are substituted for innumerable small sparks. Any.
approved make and break may be employed but I prefer to use the following
arrangement which is not in itself new.
- I arrange two adjustable carbon rods as supplementary contacts so that when
the break occurs two metal surfaces are first separated, the current then flows
through the carbon contacts; the carbon contacts are next broken giving a
momentary flash of electric light. The reverse action occurs when contact is
made the current goes for a moment through the carbon and then permanently
through the metal pieces. Although this arrangement is not in itself new the
use of this arrangement is only rendered possible by the adoption of the other
parts of my invention.
The annexed drawing Figure 1 shows a governor for an electro-motor arranged
in accordance with the invention.
a is a spindle driven by the motor, it has a bearing in the bracket b. The
horns cc are fast on the spindle a and the weights d d are connected with them
by joints.
It is convenient that the weights should when together form a cylinder enclosing
the spring e and the lower part of the spindle a. The spring surrounds the spindle
and has an abutment upon it, it also presses against a sleeve which is capable of
aliding on the spindle. Surfaces fifl on the sleeve are caused by the spring to
abut against horns d' d' which are fast with the weights d. At a certain speed
of rotation the centrifugal force is sufficient to cause the weights to diverge to the
position in which they are represented by dotted lines. The horns did then
move the sleeve along the spindle a. g is a lever having its fulcrum on the
frame at g', projections on this lever enter a groove or neck on the sleeve ƒ and
consequently the divergence of the weights causes the lever g to assume the position
indicated in dotted lines. When the speed of the spindle a falls sufficiently below
that at which the divergence occurs the spring e overcomes the centrifugal force
of the weights and the weights are again closed together to the position in which
they are represented by the full lines of the drawing. By employing springs of
different lengths with different degrees of compression the divergence and the
return may be obtained at various speeds. The speed at which the divergence
takes place depends on the amount of compression of the spring and the speed at
which the return takes place will differ more and more from the speed at which
divergence occurs as longer and longer springs are employed. The spring is always
to be sufficiently long to ensure that over a considerable range of mean speed the
weights are in stable equilibrium in either extreme position.
The current driving the motor flows from a dynamo or other source in a circuit
which is completed by the conductor h. This conductor is connected with the
insulated spring box i and thence the current passes by the metallic contact
comb of which a plan is shown at Figure 2 to the lever g and so to the frame
of the machine. This frame is connected either through earth or by a direct wire
back to the driving dynamo or other source from which the conductor his brought.
The spring box i contains a tubular carbon holder m in which a carbon rod n is
fixed. m is a flange on the carbon holder and a spring o acting upon the flange
presses the carbon holder downwards. The carbon rod n then abuts against the
similar rod p fixed into the lever g. When the speed becomes excessive the
weights & diverge with the effect as already explained of first opening the metallic
contact at k and then that between the carbon rods n and p. A spark appears at
the carbon contacts but it is not injurious and it does not occur frequently for
the fly wheel action of the rotating parts of the motor causes it to run for some
time before it loses velocity so far as to admit of the weights d again closing
together. The secondary contacts n and p although preferably of carbon may
be metallic.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what,
I claim is
(1.) A governor regulating the speed of a motor driven by electricity and con-
sisting of rotating masses a spring controlling the said masses and electrical contacts
which are separated by the divergouco of the masses; the parts being so arranged
that at and about a mean speed the weights are in equilibrium in either of the
extreme positions substantially as described.
(2.) The combination with a governor such as that described above of double:
contact parts, a main metallic contact which is first opened and a carbon or
other secondary contact which is opened immediately afterwards substantially as
described.