US1172018A - Electromagnetic indicator. - Google Patents

Description

R. A. FESSENDEN.

ELECTROMAGNETIC INDICATOR.

APPLICATION FILED MAR. 14, 1908.

Patented Feb. 15, 1916.

INVENTOR,

BY M a? A TTORNE Y.

UNITED STATES, 136mm OFFICE.

REGINALD A. FESSENDEN, 0F BRANT BOCK, MASSACHUSETTS, ASSIGNOB, BY MESNE A SSIGNMENTS, TO SAMUEL M. KINTNER, OF PITTSBURGH, PENNSYLVANIA, AND

HALSEY M. Barman, or BLoomEIELn, NEW JERSEY, nnonrvnns.

ELECTROMAGNETTC INDICATOR..

Specification of Letters Patent.

7 Patented Feb. 15, 1916.

Application filed March 14, 1908. Serial No. 421,220.

ing instruments, or means for detecting the character and changes in currents, something after the fashion of galvanometers, and especially adapted f0r-use with alternating currents though of course it. is equally suitable for continuous currents and other electric manifestations by which a field of forceis altered. Its primary Objects are to provide ainore sensitive and reliable indicating instrument, to increase the power of the controlling field and avoid the ill effects of heat in the conductors, and otherwise improve such mechanisms, as well as provide superior means for observing or recording the changes of current, etc. These objects and other advantages to hereinafter appear are attained by means such as illustrated in two forms in. the accom panying drawing, wherein- Figure 1 is a central vertical section of one form of indicator; Fig. 2 is a side elevation'of the indicating part of a modified form of instrument, and Figs. 3 and 4 are sections on the line (3,4) of Fig. 2, showing two positions of the indicating wires.

One of the chief difficulties in obtaining a sensitive indicating instrument of this general type, is that the magnetic field employed is limited because the exciting current is limited owing to the wires becoming heated when they carry heavy currents. I not only obviate this, but also obtain great magnetic concentration and otherwiseimprove the sensitiveness of such instruments by keeping the field conductors cool, which may be done in various Ways as by placing the entire apparatus in a chamber cooled as by liquid air or other refrigerant, or else by making the field conductors hollow and cooling them by contained refrigerating fluid. Also I make the readings more delicate by utilizing the double'efi'ect of two or more moving elements which approach and recede from one another on the passage of currents to be indicated. Thus. in Fig. 1 I provide a loop of a hollow conductor 6,

through which is circulated liquid air or other refrigerant, which has the double ef feet of lowering the resistance to current and also carrying away the heat, whereby very heavy currents may be employed, as for 1nstance, several hundred amperes. A part or all of this field conductor loop 6 is preferably inclosed in vessel 7 which is preferably vacuous and thus removes opposition-to motion of the moving parts, as well as preventing the disturbances of air currents. Also within this chamber 7, and in the field of the conductor loop 6, I provide a fine Wire loop 11, 12, which? may be conveniently kept under regulable tension and is provided with thickened portions 13 in order to increase the visibility or the width of the shadow of the Wires seen through the window 8, and to make them vibrate more definitely. The wire loopmay be balanced and stretched by a pulley 14 attached to a spring 15 and to an armature 16 which is drawn down against the effort of spring 15 by the core 17 of a coil 18, whose strength is regulated by the battery-19 and adjustable resistance 20. Of course any other means for regulating the tension on the wires may be employed and this tension will adjust the natural period of vibration of the indicating wires 11 and 12. It will free to move, the instrument is very sen sitive and easily read. Of course any desired means may be used for recording the motions of the indicating wires.

In the modification shown in Figs. 2,3, 4,

the apparatus is adapted to be placed in a chamber 'cooledby liquid air or other refrigerant in any convenient way; or it may be used bodily in place of the wires 11 and 12 in the apparatus of Fig. 1,replacing the Wires 13' therein. It comprises essentially a field of force such as produced by the magnetiz ing coil 21, and a series of wires or a coil of the wire 22 stretched in the field so as to lie in two parallel planes, as indicated in Figs. 3 and 4. lt is preferable to so mount them on bars 24 that normally the series of wires 23 alternate in position with the series 23*, so that light coming in the direction of the arrow in Fig. 3 is shut 0d by the wires. When a'current passes through the wires 23 however, the cooperation with the magnetic fieldwill cause them to shift position so that they will stand in register and permit light to pass through as indicated in Fig. 4. This efiect can be observed directly by the eye or telescope, or obviously recording means copld be employed such as a traveling photo sensitivesurface 26 on rolls 27 exposed toa portion of the light let through a perforated screen 28. Obviously a tension adjustingmeans, such as illustrated in Fig. 1 could also. be applied to the wires in Fig. 2 or they may be adjusted by screws 25 so as to regulate their natural period of vibration. In ,this

device again, the indication is produced by the cumulative effect of the motion of the indicating wires, which makes the instrument very sensitive in addition to the advantage of using very strong currents for the magnetic field. I

Having thus described my invention and illustrated its use, What ll claim as new and desire to secure by Letters Patent, is the following:

1. An electromagnetic indicator comprising a loop of indicating wire whose members are adapted to be relatively laterally moved by changes in a field of force, and a loop of hollow cooled conducting wire arranged to form a fieldof force, substantially as-described. p

2. A galvanometer comprising a conductor adapted to produce a field of force, two

parallel sets of stretched wires suspended in' said field, and means for observing their movements relative to each other.

3. A galvanometer comprising a conductor adapted to produce a field of force, two parallel sets of stretched wires suspended in said field, and means for observing and recording their movements relative to each other.

A. A galvanometer com-prising a conductor having parallel portions adapted to pro duce a field of force, and plurality of wires stretched in midfield of force and adapted to give an exaggerated indication by mo tions in opposite directions, substantially as described.

5. A galvanometer for high frequency.

suspended in said field and arranged to move laterally in opposite directions, and means to observe variations in the amount of light admitted through the wires when they vibrate. 1

7. A galvanometer comprising a field pro ducer formed of a hollow conductor cooled by liquid therein, and an indicator-having several sets of parallel closely spaced wires mounted in said field, and means for observing the motions of said wires relative to each other, substantially. as described.

In testimony whereof l have hereunto signed my name in the presence of the two subscribed witnesses.

REGINALD A. FESSENDEN.

Witnesses:

A. STEIN, J12, Jnssin E. BENT.

Images