US642627A - Electric-lighting system. - Google Patents

Description

Patented Feb. 6, I900.

A. C. M. PRUCKER.

ELECTRIC LIGHTING SYSTEM.

(Application filed Sept. 2, 1899.)

(No llodel.)

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UNITED STATES PATENT OFFICE;

AMAND CARL MARIA PRI ICKER, OF HANOVER, GERMANY, ASSIGNOR TO THE SIEMENS & I-IALSKE ELECTRIC COMPANY OF AMERICA, OF CHICAGO,

ILLINOIS.

ELECTRI C-LIG HTING SYSTEM SPECIFICATION forming part of Letters Patent No. 642,627, dated February 6, 1900. Application filed September 2,1899. Serial No. 729,339. (No model.)

To all whom it may concern:

Be it known that I, AMAND CARL MARIA PRUCKER, a subject of the Emperor of Austria-Hungary,residing at Hanover, in the German Empire, have invented a certain new and useful Improvement in Electric-Lighting Systems, (Case No. 239,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates to systems of electric lighting, and has for its object the provision of means and a system wherein contact parts of electric lamps maybe exposed without danger of having shocks imparted.

As is Well known, incandescent electric lamps now commonly employed have their contact portions soinclosed that they may not ordinarily be touch ed, to prevent shocks. The exercise of this precaution in the manufacture .of incandescent lam ps is costly, as the plug portions of the lamps have to be surrounded by insulating material and the whole inclosed by a suitable casing.

In accordance with my invention I employ the IIopkinson three-wire system of directcurrent distribution, constituting a seriesmultiple system, the incandescent lamps being connected across the mains and with a compensating conductor. The compensating conductor is grounded at the generating-station. The lamps in accordance with my invention each have that terminal which is connected with one of the main conductors inclosed so as normally to be inaccessible, the other terminal of the lamp constituting the casing for the plug portion thereof and which is connected either directly with the ground at the district of distribution or with the compensating conductor. I am thus enabled to produce a lamp when it is employed in a threewire system constructed as specified, wherein an exposed metallic contact portion may be employed without danger. This metallic contact portion may be in the form of a metallic jacket provided with screw-threads. adapted for direct connection with a metallic pipe, for example, having connection with the grounded or compensating conductor and through which a wire may be led connected with the which are connected the mains b b, supplying 1 two groups of translating devices 0 0, these translating devices being separated into groups by a neutral or compensating conductor cl, preferably extending from the district of distribution to the point of division between the generators. The compensating condoctor is grounded at the generators.

I have shown an incandescent lamp 6 connected between the compensating and a main conductor. The external screw-threaded metallic coveringf of the lamp is in direct connection with a contact part g of the lamp. This covering preferably has threaded engagement with the metallic nipple h, which in turn preferably has threaded engagement with another metallic nipple 2'. The latter nipple may in any suitable manner be connected directly with the earth, preferably by having threaded engagement with a metallic interior conduit 70, connected either to earth or directly with the grounded compensating conductor. Inside of the hollow cylindrical portion formed by the covering of the lamp I preferably place a hollow insulating-block-m, within which is disposed a ring of porcelain n. Within this ring of porcelain I place a metallic contact-ring 0, to which is connected the conducting-wire 19, having connection at its other end with a main conductor of the system. I interpose a switch between the latter condu ctor, extending from the main and the filament of the lamp, rather than in the conductor unit- 'ing the other terminal of the filament with the compensating conductor, so that when the lamp is out of service the exposed metallic parts thereof will not be charged with current from the main wire to avoid shocks which might otherwise occur if the switch were included in the connection with the compensating conductor.

It will be seen that I dispense with two wires threading a conduit for connection with the lamp, a single wire and a metallic conduit inclosing the same being used to carry the current without danger.

I do not wish to be limited to the precise form of lamp mechanism shown; but,

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In a system of electrical distribution, the combination with a source of current connected with main and compensating conductors, the compensating conductor being grounded, of a translating device, a conductor leading from a main and connected with one terminal of the translating device, a grounded metallic conduit through which said conductor is led,

having connection with the other terminal of the translating device, and a switch in the last aforesaid conductor, substantially as described.

2. In a system of electrical distribution, the combination with a source of current connected with main and compensating conductors,

combination with a source of current connected with main and compensating conductors, the compensating conductor being grounded, of an incandescent electric lamp having one terminal connected, or adapted for connection, with a main conductor, a switch included between the said main conductor and the said terminal, the other terminal being grounded, substantially as described.

4. In a system of electrical distribution, the combination with a source of current connected with main and compensating conductors, the compensating conductor being grounded, of a metallic conduit,an incandescent electric lamp, one of whose terminals is adapted for connection with said conduit, the said conduit being grounded, a conductor inclosed by said conduit uniting the otherterminal of the lamp with the main conductors of the system, and a switch included in the conductor uniting the latter terminal with a main conductor of the system, substantially as described.

5. In a system of electrical distribution, the combination with a source of current connected with main and compensating conductors, the compensating conductor being grounded, of a translating device having one terminal connected, or adapted for connection, with a main conductor, a switch included between the said main conductor and the said terminal, the other terminal being grounded, substantially as described.

In witness whereof I here unto subscribe my name this 4th day of August, A. D. 1899.

AMANI) CARL MARIA PRUOKER.

Witnesses:

LEoNoRE' KASGH, KIRKE LATHRor.

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