Improvements in Apparatus for Electric Lighting.
Year: 1897

page_text: Date of Application, 8th Mar., 1897
Complete Specification Left, 7th Dec., 1897-Accepted, 15th Jan., 1898
I, JAMES HARDIE MCLEAN, of 45 Broad Street, in the City of Oxford, M.I.E.E.,
do hereby declare the nature of this invention to be as follows:-
-
This invention is intended principally for use in connection with arc and incan-
descent lighting in streets, where the arc lamps are used from say dusk till
midnight, and the incandescent lamps are switched on at midnight,
when the arcs are put out. The object of the invention is to switch on
the incandescent lamps automatically when the arc lamps are switched off or
should the arc lamp become extinguished from any other cause than the switching
off at the proper moment, the incandescent lamps will be automatically switched
into circuít.
For this purpose a solenoid, consisting of a great many turns of fine insulated
wire, is connected permanently across the terminals of the arc lamp. The iron
core of the solenoid is connected to the incandescent switch.
When the arc lamp is alight, the core of the solenoid is held up, the incan-
descent switch then being off. Should the arc lamp become extinguished from
any cause, the core drops and contact is immediately made at the incandescent
lamp switch and the incandescent lamps are lighted. The current for the arc
lamps can either be from a high tension circuit, the arc lamp forming one of a
number of lamps in series, or from a low tension circuit where the lamp may be
connected directly across the mains, or where two or more lamps may be connected
across the low tension circuit. The current for the incandescent lamps is derived
from the low tension mains which in the ordinary course would be supplying
consumers along the route of the arc lamps. To extinguish the incandescent
lamps at daylight, an automatic time switch can be employed.
.
3002
Improvements in Apparatus for Electric Lighting.
I, JAMES HARDIE MCLEAN, of 45 Broad Street, in the City of Oxford, M.I.C.E.,
O 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:
This invention is intended principally for use in connection with arc and incan-
descent lighting in streets, where the arc lamps are used from say dusk till

page_text: midnight, and the incandescent lamps are switched on at midnight
when the arcs are put out. The object of the invention is to switch on
the incandescent lamps automatically when the arc lamps are switched off, or
should the are lamp become extinguished from any other cause than the switching
off at the proper moment, the incandescent lamps will be automatically switched
into circuit.
For this purpose a solenoid, consisting of a great many turns of fine insulated
wire, is connected permanently across the terminals of the arc lamp. The iron
core of the solenoid is connected to the incandescent switch.
When the arc lamp is alight, the core of the solenoid is held up, the incan-
descent switch then being off. Should the arc lamp become extinguished from
any cause, the core drops and contact is immediately made at the incandescent
lamp switch and the incandescent lamps are lighted. The current for the arc
lamps can either be from a high tension circuit, the arc lamp forming one of a
number of lamps in series, or from a low tension circuit where the lamp may be
connected directly across the mains, or where two or more lamps may be connected
across the low tension circuit. The current for the incandescent lamps is derived
from the low tension mains which in the ordinary course would be supplying
consumers along the route of the are lamps. To extinguish the incandescent
lamps at daylight, an automatic time switch can be employed.
The drawing is an elevation of the apparatus employed, the casing being shown
in section.
A is the solenoid and B its core. C is a brush fixed to the bottom of the core B
and insulated from it by a piece H of vulcanite or the like. C is a conducting
plate on which the brush Crests when the arc lamp circuit through the solenoid
is broken. is an insulating plate carrying the conducting plate C¹ and a
conducting plate G which is connected to the brush C by a flexible conductor K.
T is one terminal of the incandescent lamp circuit and T the other. D) is a
spring for carrying part of the weight of the core B which is employed in cases
where the solenoid A is insufficient for that purpose and E is an adjusting
screw. M is the casing.
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 solenoid in the arc lamp circuit for operating the switch of the incan-
descent lamp circuit.
2. Apparatus for electric lighting substantially as described and shown in the
drawings.
Dated this 2nd day of December 1897.