US1680420A

US1680420A - Galvanometer

Info

Publication number: US1680420A
Authority: US
Publication date: 1928-08-14
Anticipated expiration: 1945-08-14

Description

Aug. 14, 192s. 1,680,420

J. w. LEGG GALvANouEm Original Filed Sept. 8. 1920 2 Sheets-Sheet l Ff'g. 'j 8 /FIJ /2 '1. a i i IZ' l i l` l l l: l I: Aa LJ J L 7/5 /6 1 .76//6 /5 e 2 3 u 4E //l "Q /4 /5 C3 w Ess 1 mvENToR Q f f V Jaap/lime.

BY wav 61M. ATTORNEY Patented Aug. 14, 1928.

UNITED STATES PATENT OFFICE.

JOSEPH W. LEGG, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOB TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION 0F PENNSYLVANIA.

GALVANOMETER.

Original application filed September 8, 1920, Serial No. 408,954. Divided and this application led May 25,

1925. Serial No. 32,546.

My invention relates to electrical measuring instruments and particularly to galvanometers.

`One object of my invention is to provide a galvanomcter that shall control a plurality of indicating devices by a single magnetic circuit.

Another object of my invention is to provide a galvanometerr that is of unitary construction and capable of being embodied within other electrical apparatus.

Another object of my invention is to provide a galvanometer with a single magnetic circuit having a plurality of air-gaps therein that are so insulated that conductors having varying potentials impressed thereon may be safely inserted in the air gaps.

4It is also an object of my invention to provide a galvanometer that shall be particu larly adapted for insertion into electrical instruments such as oscillographs and the like.

A further object of my invention is to provide a galvanometer that shall be adapted for operation from a plurality of circuits by a single electromagnet.

IThe subject-matter of the present application is a division of my application, Serial No. 408,954, filed September 8, 1920, relating to oscillographs.

In the accompanying drawings,

Figure 1 is a plan view of a galvanometer embodying my invention,

Fig. 2 is a side view, partially in elevation and partially in section, taken along thek section line II--II of Fig. 1,

Fig. 3 is a front elevational view of the vibrating element of the galvanometer, and

Fig. 4 is a side view, partially in section and partially in elevation, of the vibrating element shown in Fig. 3.

My invention comprises, in general, an electromagnet l having pole pieces 2 and 3 between which are disposed auxiliary pairs of pole pieces 4, 5 and 6 for controlling vibrating elements 7, to be hereinafter more fully described.

The electromagnet 1 comprises a winding 8.that may be energized from any suitable source of electromagnetic force connected to terminals 9. The winding 8 should preferably be energized by direct current of constant value. A cylindrical core member l1 is secured within the winding 8 by nuts 12 that also secure thereto the pole pieces 2 Renewed January 6, 1928.

and The pole pieces 2 and 3 extend a. substantial distance at right angles 4to the core member 1l.

The three pairs of pole pieces 4, 5 and 6 are disposed in series relation between the pole pieces 2 and 3.` The pole pieces of each pair are separated by relatively small air gaps 13, the cross-sectional area of pairs of the pole pieces at the air gaps 13 being relatively small to concentrate the magnetic iuX thereat. The cross-sectional area. of the bases 14 of the several pole pieces is relatively large, and insulating members 15 are placed between the adjacent bases and between each ot' the pole pieces 2 and 3 and the adjacent pole piece of the series. This arrangement is provided in order that the various elements shall be insulated from each other and in order to decrease the reluctance of the circuit.

Casings 16 surround each of the pairs of pole pieces and are adapted to receive the vibrating elements 7. Referring particularly to Figs. 3 and 4, each of the vibrating elements 7 comprises a main body portion 17, upon which are mounted terminal members 18 and bridging members 19 over which is disposed a filament 21 that surrounds a pulley 22, and which has a small mirror 23 disposed thereon. The pulley 22 is of insulating material and is mounted at one end of a pivoted member 24, the other end of which is operatively connected to an adjustlng spring 25.

With this arrangement, the member 24 is so balanced as to its inertia that any jars are absorbed and the likelihood of breakage of the filament is greatly reduced. When the vibrating elements 7 are placed in the receptacles 16, the filaments 21 are disposed in the magnetic fields of the air gaps 13 and thus the mirrors 23 will be turned an amount proportional to the current traversing the filament and, if a beam of light is directed to the mirror, this beam of light will be instantly deiected an amount proportional to the instantaneous value of the quantity being measured. Since the energization of the winding 8 of the electromagnet 1 is constant, the flux traversing the several air gaps will be constant, whereby the variable quantity measured is the current traversing each of the laments 21 from the respective terminals 18, the latter being connected to any desirable external circuit.

The mirrors 23 may be located so that the rays therefrom may play upon any desired reflecting surface, film, or the like according to the apparatus with which the galvanometer cooperates.

My invention is not limited to the specific details illustrated as it may be variously modified without departing from the spirit and scope of the invention, as set forth in the appended claims.

I claim as my invention:

1. A galvanometer for an oscillograph comprising an energizing coil, a core member therefor, three pairs of pole members disposed in series between the poles of the core member, and insulating means for separating said pairs of pole -members from each other.

2. A galvanometer for an oscillograph comprising a magnetizable core member, a plurality of pairs of pole pieces disposed between the poles of the core member and havmg an air gap between the poles of each pair, and insulating means between the said pairs of pole pieces.

3. A galvanometer for an oscillograph comprising a magnetizable core member, a plurality of pairs of pole pieces disposed between the poles of the core member and having an air gap of relatively small crosssectional area between the poles of each pair and of large cross-sectional area between the said pairs of pole pieces, and means for effectively insulating the pairs of pole pieces from each other.

ll. A galvanometer for an oscillograph comprislng an energizing coil, a core member therefor, a plurality of pairs of pole pieces disposed between the poles of the core member and having an air gap of relatively small cross-sectional area between the poles of each pair, said pole pieces having air gaps of relatively large cross-sectional areas between the several pairs and between the poles of the core member and the outer ends of the end pairs.

5. The combination with a magnetizable structure constituting a continuous unin terrupted flux path and energizing means therefor, of a plurality of pairs of pole members disposed in series in said iiux path and insulated from each other.

6. The combination with a magnetizable oke structure constituting a continuous uninterrupted flux path, of a plurality of pairs of pole members disposed in series between the legs of the yoke and insulated from each other.

7. A galvanometer comprising two magnetizable members disposed in the flux path of the galvanometer and having adjacent surfaces extending transversely to said path, and a body of insulating material surrounding, and disposed between said members adjacent to said surfaces.

8. An instrument comprising a magnetizable core member, a pair of pole members disposed in series magnetic-fiuX-path relation thereto, means disposed in the air gap of said pole members for (3o-operation with the fiux field therebetween and a body of insulating material constituting a partition between one of said pole members and said core member.

In testimony whereof, I have hereunto subscribed my name this 14th day of May 1925.

JOSEPH W. LEGG.