US314891A - Feank j - Google Patents

Description

(No Model.)

2 Sheets-Sheet '1. F. J. SPRAGUE.

ELECTRICAL INDICATOR.

- .NO. 314,891 Patented Mar. 31, 1885.

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v ELECTRICAL INDICATOR. No. 314,891. Patented Mar. 31, 1885.

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York, have invented a new and useful Im- UNITED STATES I PATENT OFFICE.

FRANK J. SPRAGUE, OF NEW YORK, N. Y.

ELECTRICAL INDICATOR.

SPECIFICATION forming part of Letters Patent No. 314,891, dated March 31, 1885.

Application filed January 24, 1884.

To aZZ whom it may concern:

Be it known that I, FRANK J. SPRAGUE, of New York, in the county and State of New proveinent in Electric-Current Indicators, of which the following is a specification.

The object of this invention is to produce an indicator of variations in electric current which shall operate entirely by such variations, and shall not be influenced in any way, or at least to any practical extent, by permanent magnetism. Such indicators, as they have heretofore been made, have employed permanent magnetism in one way or another, either by the use of steel horseshoe-magnets or polarized steel needles; but where permanent magnets are used the instruments are affected by the proximity-of dynamo-electric machines and by terrestrial magnetism.

In my invention I affect the indicating devices entirely by electricity, and I accomplish this by the use of a core partly or wholly inclosed by a conductor which may be part of the circuit the variations of whose current are to be indicated, or part of a circuit which receives current from a separate source, such core being provided with a magnetic movable extension which is in such contiguity to a conductor of the circuit the variations of whose current are to be indicated as to 'be affected when magnetized by variations in the magnetic field surrounding the conductor, due to the current in said conductor, its movements being suitably indicated. The core may be pivoted within the coil and the movable extension attached thereto, so that the whole will move together, and this is perhaps the simplest construction. In this two extensions are preferably employed, one at each end of the core, to give a greater movement; or the core may be stationary and the extension movable independent-1y thereof. An opposing force to the movements caused by the current variations is provided, such force being variable, so that the indicator may be adjusted for the different currents employed in the different situations where it is to be used, the movable extension being adjusted to acertain position for no current, and deflected therefrom to a greater or less extent, according to i (No model.)

the current which passes. This main idea of my invention is susceptible of very many modifications, some of which will be hereinafter set forth.

In the construction of my apparatus which V I especially prefer to employ, asmall portion of the conductor is formed into a coil, and the soft-iron core is placed centrally within said coil and pivoted at its ends. Upon each projecting end of the core is placed an arm at right angles to said core, said arms extending in opposite directions and parallel to the conductor. One of these arms carries a needle or pointer, the end of which travels upon a scale. An adjustable weight or spring is attached to the core, opposing the movement of the indicating-arm. I may employ for this purpose a weight sliding upon an arm suspended from the core. The arms attached to the core are magnetized from said core when current passes in the coil, and therefore tend to place themselves at right angles to the conductor in proximity to which they are. The weight is so adjusted that with no current passing the needle will stand at a certain selected point upon the scale. Then as the current increases the arm will move more toward a right angle with the conductor in a direction dependent on the direction of the current, and as it diminishes in the opposite direction. The extent of these movements is indicated by the needle upon the scale. The scale is preferably graduated in amperes, so that the current flowing at any time is indicated.

My invention is illustrated in the annexed drawings, in which Figure 1 is a front elevation of the preferred apparatus, and Fig. 2 a side elevation and partial section thereof.

The remaining figures are diagrams il1ustrating various modifications.

- Referring first to Figs. 1 and 2, A is a conductor of the circuit the variations of whose current are to be indicated. The conductor is'broken and connected to the indicating apparatus, as shown, and held by set-screws a a. Within the apparatus the current passes through the standard 13, the coil 0, and the are D. The last supports the scale E. The soft-iron core F is placed centrally within the coilCand pivoted at c 0, the screws d d, which support it, being held, one by the standard B, the other by the arm 6, extending from the lower portion of the arc-piece D. The screws d d are insulated from the parts through which they pass. Upon the core F, outside the coil 0, are placed the arms G and G. Arm G carries a needle, H, the end of which travels across the scale E. From the core extends also the arm I, carrying an adjustable weight, which is the milled nut K. This weight furnishes the opposing force for the current, and is adjustable, so that such force may be made to correspond with the currents of greater or less power,which occur in the different situations in which the indicator may be used, the weight being adjusted 'to the proper point for the circuit in question. When current passes in the coil 0, the core F becomes magnetized, and also the arms G G, which form extensions of the core. These magnetized arms are then affected by the current in the conductor formed by the standard B and are D, tending to place themselves at right angles to the conductor, and variations in the current cause an increase or diminution of such tendency. The core turns on its pivots opposed by the weight K. The movements are indicated by the needle upon the scale. It is, of course, not essential to use two arms, one at each end of the core; but it is evident that an increased effect will be produced by this construction.

I will describe in detail the various modifications illustrated by the remaining figures. In Fig. 3 the two arms G G extend in the same direction from the core F, and the conductor beyond the coil 0 is extended so that both arms are in proximity to it. The same effect is produced as already described.

In Fig. 4 the magnetization is produced by a shunt, f f, while the deflection is caused by the main conductor directly. The shunt may have such resistance as to permit any desired proportion of the current to pass in the coil.

In Fig. 5 the core is magnetized by a separate circuit, 9 g, from a battery or other source of electricity. This furnishes a constant magnetization, while when the coil is in the line or shunt the magnetization of the core and needle-arm is increased and decreased by the current variations, so that such variations produce a double effect upon the needle. In such a case the original graduation of the scale is of course made to conform with this effect.

In Fig. 6 one conductor, A, of the circuit is wound around the core, and the extensions of the core are in proximity to both the conductors A A, so that it is acted upon by both.

In Fig. 7 two conductors are wound into the coil and in opposite directions, so that a double magnetizing effect or a differential effeet is produced, according to the direction of the current.

Fig. 8 also illustrates a form giving either a differential or a cumulative action, the two conductors being wound in the same direction.

Fig. 9 shows a stationary core, with the movable needle-arm G detached from it, and

magnetized from it by induction. In Fig. 10 also the core is stationary, the needle-arm G being pivoted upon it.

In Fig. 11 the detached arm G extendslongitudinally, instead of at right angles, from the core, tending to move to a right angle with the conductor, as before.

Figs. 12, 13, 14, and 15 show other ways of producing the opposing force. In Fig. 12 an adjustable spring, L, is attached to an arm extending from the core.

In Fig. 13 the weight K is suspended by a cord, M, passing over a pulley, N. In this case the weight is constant, instead of varying with the movement of the core, as would be the case in the previously-described forms.

In Fig. 14 the adjustable weight is suspended from a pulley eccentric to the core, and is adjusted by adjusting the eccentric on its shaft, or by adding weights.

In Fig. 15 two equal adjustable eccentrics are employed, each supporting a weight.

It is evident that each of the different mechanical arrangements shown may be employed in connection with any of the various circuit arrangements.

WVhile I have described and prefer to use a core whose magnetism is due entirely to the current passing around it, yet it is evident that a core permanently magnetized to a certain extent and intensified by the current might be used without departing from the spirit of my invention; and I consider this practically the equivalent of the preferred construction. 7

IVhat I claim is 1. In an electrical indicator the combination of a coil forming part of a circuit, a core magnetized from said coil, and a movable arm or needle magnetized from-said core and placed in proximity to a conductor of the circuit the variations of whose current are to be indicated, substantially as set forth.

2. In an electrical indicator, the combination of a coil forming part of a circuit, a movable core magnetized from said coil, and a magnetic extension attached to said core and placed in proximity to a conductor of the circuit, substantially as set forth.

3. In an electrical indicator, the combination of a coil forming part of a circuit, amovable core magnetized thereby, and two magnetic extensions of said core, both affected by the current in the conductor, substantially as set forth.

4. The combination, with the coil, the movable core magnetized thereby, and the one or more extensions in proximity to the conductor, of an adj ustable weight or spring attached to said core and opposing the movement of said extension or extensions, substantially as setforth.

5. The combination, with the coil, of the core pivoted at its ends centrally within said coil, the one or more magnetic extensions of IIO said core situated in such proximity to a con- This specification signed and witnessed this ductor of the circuit the variations of whose 22d day of January, 1884.

current are to be indicated as to be affected by variations in the magnetic field surround- FRANK SPRAGUE' 5 ing such conductor, and the scale indicating Witnesses:

the movements of said extensions, substan- H. W. SEELY,

tialiy as set forth. 0. F. HARRINGTON.

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