US1576572A - Rheostat - Google Patents

Description

, March 16 1926.

, 1,576,572 P. l. CHANDEYSSON Filed April 18, 19224v I. ckdndqyaon.

005513 l y r f'lH'otneq Y Patnted Mar. 16, 1926.

UNITED STATES vPATENT oFFlcE,

PIERRE I. CHANDIEYSSON, 0F ST. LOUIS, MISSOURI.

RHEOSTAT.

' Application tiled April 18, 1922. Serial N'o. 554,469.

To all '1v/wm t 'may concern:

Be it known that PIERRE I. CHANnm'ssoN, a citizen of the United States of America,

residing at pSt. Louis, in the county of St.-

LouisI and State of Missouri,'has invented certain new and useful Improvements in Rheostats, of which the following is a speci- Iication.

V'lhis invention relates to improvements in rheostats and providesimeans of introducing or cutting out simultaneously, resist-ance into separate or distinct circu1ts.

Certain types of generators, notably low voltage machines, are provided with two commutators for various reasons. These generators are operated sometimes with the armature circuits in parallel, sometimes as three wire machines, and sometimes with the two commutators in series.

When so used, my rheostat permits of the excitation 0f such generator so that each side or each commutator of the armature furnishes exactly one half of the exciting current, and it further gives the advantage that when the generator is so connected, it can be operated either as a three vwire machine or as a two wire machine, with the outside leads eitherin parallel or in series without making any change whatsoever in the shunt connections.

As constructed for commercial purposes preferably in accordance with the following specification,

My rheostat, briefly will consist of two resistances', coiled generallyin one piece, each resistance embodying a plurality ofloops or turns at suitable intervals, which loops are fastened to a series of posts insulated froml their support, the face of the post extending above the face of the support, constltuting a liat surface from which a rubbing contact of suitable material can travel and conduct the current from these surfaces to a suitably disposed conductor, on which the other part of the rubbing contact brush rests. Two such sets of resistance binding posts with their projecting fiat contact surfaces are so mounted that conducting brushes at the opposite extremity of a lever pivoted centrally between them, can be moved thru an arc of about 180, and during its travel, short-circuit simultaneouslyv on both sides the binding posts to which the resistance is attached to the metallic surface to which the current is admitted or from which the current is led away from the apparatus.

In the accompanying drawingswhich. illustrate a preferred embodiment of `my invention,

, Figure l is a plan View of the rheostat;

Figure 2 is a vertical sectional viewof the rheostat with the brush carrying lever moved to a position about 90 spaced fromthat shown in Figure 1; and

Figure 3 is a diagrammatic view of the resistance, illustrating the coils and ,theirl connections with the contacts'.

Referring more particularly to the drawings by numerals of reference, I provide a rheostat casing 2 of metal, said easing being of a dome-shape to provide -therebeneath a recessed portion ,4 wlthin which are housed and protected, the coils of the rheostat to be later described, the flanges of which casing are provided with a suitable number of spaced ears 6' by which the device may be attached to an instrument-board or wherever its service is required.

The crown o r upper face of the domeshaped casing is provided upon each side of -a medium line with a semicircular series of wire to avold uncertain resistance of joints,

embodies a series of coils 16, each of which is formed of a suitable number of convolutions, said coils being provided with inter-connecting portions 18 of U-shape which straddle the extension of the contact shank, and

upon the threaded end 19 of which is applied a nut 20 which clamps or binds the portions 18 securely against the under face of the nut 12 and in good electrical contact therewith.

The current is led into the rheostat thru a connector 22 having a socket 24 into which is inserted the bared end of the conductor, which latter is bound by screws 25, said connector being secured upon the upper face of the casing by a screw 26 also suitably insulated. Said connector is further secured in position thru a bolt 28 which passes thru the inner end thereof and thru the end one of the series of openings 8 in the casing and pin 59. The lever is from which it is insulated by the same plate of insulating material which serves for the several contacts.

The terminal of the last coil is bound to the shank of the contact which is designated at 10, the interconnecting portions between the several coils being connected as has been stated to the shanks of the several contacts until finally the terminal of the rst coil is bound between the nuts 30 and 31 of the bolt 28 which secures the connector 22 on the casing and also serves as the conductor.

Concentric with4v each series of contact 10 andai-ranged inwardly thereof is an arenate electrica-l contact rubbingV plate or strip 34 one end of whicl1 terminates adjacent the last of the contacts and is secured upon the crown or upper face of the casing thru bolts 36 passing thru openings 38 arranged in said casing, said bolts and said Contact strip being insulated by the insulating sheets 14. The strip 34 is preferably formed integral with an outlet connector 40 similar to the inlet connector 22. i

The switch i member which brings into operation the Variable resistance in the circuit in which the rheostat is included comprises a lever 42 having a pair of diametrically opposite arms 44 provided adjacent their ends and upon the lower face of each with a socket 46 Within which is disposed a bridge piece 48 of suitable material, for instance, spring copper leaves, said bridge iece being suitably secured within the socket y such means as an insulated bolt and nut arrangement 50 and insulated from the supporting arm by an insulation sheet 52.

The lever 42 is mounted for oscillation upon a post 54 journalled centrally of the upper face of the-casing in an enlargement y a rotatable element journaled 1n the casing,

thereof and is urged downwardly to maintain the bridge piece 48 in contact with the contact members 10 and 34 by a tension spring 56 coiled around the lower extension ofthe post 54 and seated intermediate the lower facey of the enlargement and 'a cross provided with a knot 60 for operating it. f

It is obvious that the current entering by the terminal connectors 22 passes thru the coils, across the bridge members of the switch lever, back thru the rubbing contact strips and out at the terminals 40.

` It is evident from the description that my rheostat can be lutilized for other purposes than to regulate the current in two parts of the f/ieldfl circuit of a motor or a generator; for instance, the two independent reslstances I claim is 1. A rheostat comprising a4 substantially dome shaped 'casing provided with a plu-- rality of sets` of spaced contacts, anl arcuate contact plate arranged adjacent each set of spaced contacts, a resistance element sup-'- ported in the dome of said casing and connected with certain of the contacts, said` resistance element comprising a vseries of spiral coils with interconnecting loops, said loops adapted to straddle the aforesaid contacts, a rotatable element journaled on the casing, and U-shaped conductors carried thereby and adapted to bridge the spacesbetween the plates and the spaced contacts.

2. A. rheostat comprising a substantially dome shaped casing provided with a, plurality of sets of spaced contacts, an arcuate contact plate arranged adjacent each set of spaced contacts, a resistance element supported in the dome ofsaid casing and connected with certain of the contacts, Said resistance element comprising a series of spiral coils with interconnecting loops, said loops adapted to straddle the' aforesaid contacts,

and having arms extending laterally therefrom, said arms being provided with concaved sockets on their lower sidesv and U- shaped conductors carried in said sockets and adapted to bridge the spaces between the plates and the spaced contacts.

In testimony whereof I aflix my signature.

PIERRE I. CHANDEYSSON.l

Images