Improved Method of and Apparatus for Synchronizing Alternating Current Dynamo Electric Machines and Switching them On and Off Mains.
Year: 1894

page_text: Date of Application, 1st Jan., 1894
Complete Specification Left, 28th Sept., 1894-Accepted, 3rd Nov. 1894
PROVISIONAL SPECIFICATION.
Improved Method of and Apparatus for Synchronizing Alternating
Current Dynamo Electric Machines and Switching them On and
Off Mains.
I, JOHN AUGUSTIN KINGDON, of No. 29 Marlborough Hill, Saint John's
Wood, in the County of Middlesex, Electrical Engineer, do hereby declare the
nature of this invention to be as follows:-
It is known that alternating current dynamo machines of the same periodicity and
electrical pressure will run in parallel synchronously.
The usual method of connecting such machines in parallel is to switch one into
connection with another when the two machines appear to be synchronous, the
moment of corresponding phase being judged of by watching a pilot lamp. This
method, depending on the skill and quickness of the operator, is attended with
considerable danger.
My invention relates to means of synchronizing alternators in such a manner as
to avoid the risks to which the present method is liable. For this purpose, I employ
alternators mechanically coupled together in pairs. The two alternators which
form a pair have the same periodicity, phase and voltage, but may be of the same
or of different output. Besides the pairs, there may be separate alternators in the
central station. I provide a special conducting bar with which each alternator may
be connected, and which may be termed the synchronizing bar.
Assuming that there is a pair 1 and 2 of which 2 is idle, and that there is another
pair 3 and 4 both idle, but that it is desired to connect 4 to 1 which is connected to
the main, supplying current, I first run the pair 3 and 4 till they have approximately
the same periodicity as 1 and 2. I then connect 2 and 3 to the synchronizing bar,
and gradually supply exciting current to their field magnet coils, so that they
gradually become synchronous and have the same phase.
Since 1 is synchronous with 2, 2 with 3 and 3 with 4, 1 and 4 are obviously also
synchronous and have the same phase. 4 can therefore be excited to a suitable
electrical pressure and switched directly on to the omnibus bar or the mains. I
prefer, however, to switch it first on to the main through an impedance coil, the
impedance of which can be gradually reduced by shifting an iron core or otherwise;
after switching on the alternator when the impedance is a maximum, I gradually
reduce the impedance, and finally connect the alternator directly to the mains.
Thus the alternator 4 is gradually put in parallel with 1 so that sudden fluctua-
tions of electric pressure, and sudden strains on the armatures or the insulation of the
alternators or their accessories is avoided.
Either of the alternators 2 or 3 may be disconnected from the synchronizing bar
and connected to the mains first through an impedance coil.
One alternator of a running pair is preferably kept idle and connected with the
synchronizing bar, so that it can be used for synchronizing an additional pair of
alternators say 5 and 6.
Each of the alternators may be disconnected gradually from the mains by
introducing impedance into its circuit.
An alternator which is not one of a pair may be connected in parallel with a
pair by synchronizing it first with an idle one of the pair and then connecting the
two together to the mains, employing impedance as above described.
Dated this 1st day of January 1894.
ABEL & IMRAY,
Agents for the Applicant.

page_text: Improved Method of and Apparatus for Synchronizing Alternating
Current Dynamo Electric Machines and Switching them On and
Off Mains.
I, JOHN AUGUSTIN KINGDON, of No. 29 Marlborough Hill, Saint John's
Wood, in the County of Middlesex, 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 :-
It is known that alternating current dynamo machines of the same periodicity
and electrical pressure will run in parallel synchronously.
The usual method of connecting such machines in parallel is to switch one into
connection with another when the two machines appear to be synchronous, the
moment of corresponding phase being judged of by watching a pilot lamp. This
method depending on the skill and quickness of the operator, is attended with
considerable danger.
I
My invention relates to means of synchronizing alternators in such a manner as
to avoid the risks to which the present method is liable. For this purpose employ
alternators mechanically coupled together in pairs. The two alternators which
form a pair have the same periodicity, phase and voltage, but may be of the same or
of different output. Besides the pairs, there may be separate alternators in the
central station. I provide a special conducting bar with which each alternator may
be connected, and which may be termed the synchronizing bar.
1 then
Assuming that there is a pair 1 and 2 of which 2 is idle, and that there is another
pair 3 and 4 both idle, but that it is desired to connect 4 to 1 which is connected to
the main supplying current, I first run the pair 3 and 4 till they have approximately
the same periodicity as 1 and 2, as tested by a speed indicator or otherwise.
connect 2 and 3 to the synchronizing bar, and gradually supply exciting current to
their field magnet coils, so that they gradually become synchronous and have the
same phase.
Since is synchronous with 2, 2 with 3 and 3 with 4, 4 and 1 are obviously
also synchronous and have the same phase. 4 can therefore be excited to a
suitable electrical pressure and switched directly on to the omnibus bar or
the mains. I prefer, however, to switch it first on to the main, through an
impedance coil, the impedance. of which can be gradually reduced by shifting an
iron core or otherwise; after switching on the alternator when the impedance is a
maximum, I gradually reduce the impedance and finally connect the alternator
directly to the mains.
Thus the alternator 4 is gradually put in parallel with 1 so that sudden fluctua-
tions of electric pressure, and sudden strains on the armatures or the insulation of
the alternators or their accessories is avoided.
Either of the alternators 2 or 3 may be disconnected from the synchronizing bar
and connected to the mains first through an impedance coil.
One alternator of a running pair is prelerably kept idle and connected with the
synchronizing bar, so that it can be used for synchronizing an additional pair of
alternators say 5 and 6.
Each of the alternators may be disconnected gradually from the mains by
introducing impedance into its circuit.
An alternator which is not one of a pair may be connected in parallel with a pair
by synchronizing it first with an idle one of the pair and then connecting the two
together to the mains, employing impedance as above described.
Fig. 1 of the accompanying drawings, illustrates diagrammatically an arrange-
ment of 4 dynamos A' A" A³ A' and their connections for operating according to
any invention. Maud R are the two mains, and S is the synchronising bar, B are

page_text: the connections to M, and C the connections to R, each of which is provided with
a switch D, T indicates the shaft or other connection of each pair of dynamos such
that A A run at equal speed and at the same phase and periodicity, and in like
manner A and A'. Assuming the switches to be as shewn, A' connected to the
mains M and R, and that it is desired to synchronise A with A¹, then A³ and A³
being connected through M and S become synchronized, and A' being synchronized
with A it follows that A³ and consequently A* is synchronized with A'. On the
field of A being now sufficiently excited, it is connected to the main R as well as M
so as to work in parallel with A¹. In the connection to R there is introduced the
impedance coil I. As shewn in Fig. 2, a fifth dynamo A can be synchronized
with A by first synchronizing it with A and then connecting both A and A' to
the main. In this manner any number of dynamos may be synchronized.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
The herein described method of synchronizing alternate current dynamos and
connecting them to mains, by mechanically coupling some of the set of dynamos in
pairs connecting the idle one of a pair, and an idle one either single or one of
another pair to a synchronizing bar, exciting the field of the last or of the other
one of the pair to which it belongs, and then connecting to the mains.
Dated this 28th day of September 1894.
ABEL & IMRAY,
Agents for the Applicant.