Year: 1893

page_text: The electro-magnet coils C, K and D are to be so proportioned that when the
current is able to overcome the normal resisting torque of the springs, its strength
will be such as to bring the electro-magnets up to, or very closely up to, the point
of saturation. In this way a field of uniform strength is produced, and not a field
which varies with every change in potential in the current which affects the
instrument.
Referring next to the apparatus shown in Figs. 4 to 12 inclusive, this is a simple
means of connecting an electrical measuring instrument, such as the foregoing, in
an incandescent lamp circuit, at any lamp; so that wherever a lamp exists in the
circuit there measurements may be made. This saves artificial interruption of the
circuit, and makes it needless for an inspector to go to special points to find places
where his instrument may be connected. The device consists, first, in an
66 adapter"
which may be applied to the fixed part of an incandescent lamp socket, after the
lamp has been removed, and, second, in a plug which carries the circuit terminals
through which circuit is closed through a measuring instrument and which is
constructed to engage with the adapter.
Figs. 4, 5, 6 and 7 represent different forms of adapters suited to different types
of lamps.
Fig. 8 shows an adapter with the plug in place.
Fig. 9 is a section of the plug.
Fig. 10 is a bottom view of the adapter shown in Fig. 7.
Fig. 11 is a sectional view on line 8, 8 of Fig. 9.
Fig. 12 shows the adapter and plug in place in the fixed portion of a lamp
socket.
In Figs. 4 to 12 similar letters of reference indicate like parts.
The adapter Fig. 4 is suited to a lamp socket of the Weston type; in Fig. 5 to
one of the Thomson-Houston type; in Fig. 6 to one of the Westinghouse type and
in Fig. 7, to one of the Edison type.
The adapter consists of a cylinder, A', of rubber having an opening, B', con-
taining springs, C¹ D'. These contact-springs are connected respectively to fixed
contact-plates on the exterior of the adapter, and so arranged as to make contact
with other plates in the fixed socket. Thus, in the Weston adapter, Fig. 4, the
contact-spring C' connects by wire a to plate b, and contact spring D₁ connects by
a wire, b, to the screw plug c. The screw plug c and the plate 6 make contact
with the circuit terminals when the adapter is put in place. In Fig. 5, the
spring C¹ connects by wire d to a plate, e, and the contact-spring D' connects by
wire to a threaded nut, g. The other plate e and the nut o make contact with
the circuit terminals when the adapter is in place. In Fig. 6, the contact-
spring C connects by wire, dotted lines, with the cylindrical plate h. The
spring D connects by wire i to the pin j. Here the plate and the pin j meet
the circuit terminals when the adapter is in place. In Fig. 7, the spring C₁ cou-
nects by a wire, dotted lines, with the screw threaded plate k. The spring D
connects by wire, dotted lines, with a pin l. Here the plate and the pin / meet
the circuit terminals when the adapter is in place. The plug shown in Fig. 9 is.
made of insulating material and is formed with a body portion, E', and a knob or
handle, F. The body portion E¹ carries two contact-plates, G and H. On
opposite sides of said body portion are indentations, m, n, and the plates G'
and H are correspondingly indented to fit therein. In operation, the body
portion E of the plug is inserted into the opening B¹ of the adapter; so that the
plate G makes contact with the plate C₁, and the plate H' makes contact with the
plate D¹.
A bent-out portion, o, of the plate C₁ then enters the indentation m
of the plate G¹, and a similar bent-out portion, p, of the plate D' enters the
indentation n of the plate H'. In this way the plug is held in place after it is
inserted. Hence when said plug is introduced into the adapter, it closes circuit
from one contact, as 1, Fig. 7, through the contact-plate D' to contact-plate H' on
the plug, and then to the circuit wire q, and so to the measuring instrument, then
back by circuit wire r to plate G¹, plate C¹ and contact-plate k.

page_text: The inspector will be provided with a suitable measuring instrument having con--
nected to its terminals the plug shown in Fig. 9, and with as many different kinds
of adapters as there are different sorts of lamps in use on the circuits to be
examined. On reaching a given circuit, he notes the kind of lamp in place, takes
off one lamp wherever may be most convenient, and in place of the lamp inserts:
the proper adapter. Thus, if it is an Edison lamp, he will be put in an adapter
suited to the Edison form, such as is shown in Fig. 7. He then inserts his plug, so
establishing circuit from the line through the instrument Q, Fig. 12, and makes
whatever measurement he desires. He then removes his plug and adapter and
replaces the lamp.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to.
me by my foreign correspondent, I declare that what I claim is :-
1. The construction and arrangement of the electrical measuring instrument
hereinbefore described including an electro-magnetic system, J, A, B, producing a
field of force, a coil, R, movable therein and an adjustable spring, Q, opposing the
movement of said coil; so that a current traversing said coil and said electro-
magnetic system will cause the coil to move against the elasticity of the spring,
and also magnetize practically to saturation said electro-magnetic system.
2. An adapter and plug for establishing connection with electric lamp circuits.
at any lamp, constructed and arranged substantially as hereinbefore described.
Dated this 10th day of January 1892
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.