US1471890A - Protective device - Google Patents

Description

Oct. 23, 1923. 1,471,890

' H. G. FRENCH PROTECTIVE DEVICE Filed Oct. 24 1919 Inventor Henr GFvench, WM

His Attorney.

Patented Oct. 23, 1923.

UNITED STATES 1,471,890 PATENT OFFICE.

HENRY G. FRENCH, 0F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PROTECTIVE DEVICE.

Application filed October 24, 1919. Serial No. 333,018.

To all whom it may concern:

Be it known that I, HENRY G. FRENCH, a citizen of the United States,"residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Protective Devices, of which the following is a specification.

My invention relates to electrical protec tive devices, particularly to relays and has for its object to provide a novel and improved relay device which is operative in response to predetermined abnormal conditions to positively move into circuit c0ntrol-' ling position, which is positively and definitely operative as soon as such abnormal conditions reach a predetermined amount, which is quickly returned to its initial position when such abnormal conditions disappear and which is in other particulars to be more specifically described, an improvement upon other relay devices heretofore known in the art.

The novel features which I believe to be characteristic of my invention will be definitely indicated in the claims appended hereto, while the features of construction and mode of operation will be understood by reference to the following description taken in connection with the accompanying drawings in which:

Fig. 1 shows, in perspective, a relay embodying my invention, Figs. 2 and 3 are perspective views showing modified forms of my invention, and Fig. 4 shows a detail of construction of the device shown in Fig. 2.

In Fig. 1 I have shown my invention applied to a relay of the induction type comprising a rotatable member or armature 1, preferably in the form of a thin flat clrcular disk of suitable non-magnetic conductlng material and an electromagnetic driving or torque producing element 2 adapted to be connected to the circuit to be protected. 'Operatively related to the armature 1 is a retarding or magnetic drag element 3 which is shown as a permanent magnet. The armature 1 is carried by a shaft 4 upon which I, is mounted a contact member 5 adapted to move into and out of engagement with cooperating contacts 6 to control an auxiliary circuit and operate a tri coil or other suit able device. Operative y related to the shaft 4 is a restraining or pring element 7 adapted to exert a counter-torque on said armature and rotate it in a direction opposed to that exerted by the torque or motor element 2.

Normally the force exerted by the counter-torque or restraining element 7 is suffi ient to overcome the torque exerted by the driving or torque producingelement 2 and the armature is thus held in its initial position against a stop 8 or othersuitable means. When, however, due to the occurrence ofan abnormal condition above a predetermined amount on the circuit to be protected, the flux generated by the torque or current re sponsive element 2 is sufficient to exert a driving torque on the armature or rota-table member 1 of an amount necessary to overcome the counter torque exerted by the spring 7, the armature is moved in contact controlling direction and contacts 5 andti brought into engagement. As the armature is rotated in contact controllingdirection,

the tension or countertorque'exerted by the" spring I is increased, requiring a correspondingly increased torque by the motor element 2 to compensate for the increase of opposing or countertorque. If some compensation is not made for the increase in tension of the spring 7, a current just enough to start the armature in contact con trolling direction would not be sufficient to complete the movement of the armature to contact controlling position. Without an increase in current, therefore, the armature would come to rest with the torque and countertorqu'e a proximately balanced. The increase in e ect exerted by the coun tertorque element 7 may be compensated for in several different ways and according to my invent-ion, I show three structures whereby this compensation is made and the armature carried positively into contact controlling position by that torque which is sufficient to overcome the countertorque ele ment and initially move the armature in contact controlling direction. v Having a positive movement of the armature 1 to contact controlling position insures the elimination of so-called floating caused by the armature starting from initial position and coming substantially'to rest or floating at some point intermediate initial and contact controlling position where the countertorqiie is substantially balanced by the driving torque. In this instance, a sudden increase in. the abnormal condition would carry the armature to tripping or contact closing po sition in a c interval which is quicker than desired. due to the smaller path of travel from "ing to tripping position.

There another teature to be overcome in relays of this type and that is a delay in return of the armature and contacts from tripping or contact controlling position to initial position. It is essential that the re lay have a quicl: reset in order to be ready for the next operation. A slow reset would be open to the same disadvantage as the con dition of floating as a second abnormal condition occurring before the armature reaches initial position would carry the contacts to tripping position in a quicker time interval than desired.

I overcome all these objections by a structure which consists of a. means to automatieally increase the effect exerted by the motor element on the armature or one of its torque producin components to increase its torque to compensate for the increase in countertorque exerted by the spring or countertorque element 7. In Fig. 1 this compensating means consists of a metallic or conducting member 9 preferably of a thin copper strip of a ring or close circuited configuration supported intermediate the upper portion of the motor element 2 and the armature 1 which in this figure is shown in a position intermediate initial and contact controlling positions for more clearly illustrating the features of construction of the relay. This member 9 is carried upon a suitable bearing device 10 and is movable into and out of the field produced by the driving element in response to the rotation of the armature. This function may be accomplished by several structures, and by way of example, l have shown a gear wheel 11 carried by the shaft & and adapted to move the flux member 9 through a gear segment 12. With the armature 1 in normal or initial position, the flux or close circuited member 9 is termediate the pole tips of the upper portion of the torque element 2 and the armature 1 so that the magnetic flux passe. through the central opening of the flux member 9.

hen the efi'ectof the motor element 2 predominates and the countertorque element is overcome initially to move the armature in contact closi 5: direction the rotation oi": the shaft e and wheel 11 moves the segment 12 ant gradually moves the close circuited member 9 across the field of the motor element 2. As the flu ember 9 thus moves across and out of the field ot the motor element, the tlux member 9 acts a secondary or short circuited windir ant varies the distribution and phase reiat of the fluxes of the motor element 2. This resu ts in an increase the effective tlnr: cutting the armature which gradually increases the torque exerted on the armature by the niiotor element 2 to compensate for the increasing countertorque of the spring T. That current therefore through the motor element necessary initially to overcome the conntertorque of spring '7 and start the armature rotating in contact closing direo tion is suflicient positively to carry the armature to contact closing position. Should. however, the current tall slightly below normal, the countcrtorque oil the spring 7 pie dominates and starts to rotate the armature to initial position. returning at the same time the flux member 9 to initia position and decreasing the torque exerted by the motor element. This results in a decrc of drix 'i torque with the consequent quick return of the armature and contacts to initial position.

In Fig. 2 is shown a slightly niod form of structure for coinpens ng for the increase of countertorque. In this scheme the motor element 2 comprises an an ry winding 12- which is wound opposed to the main winding 13 and which is controlled through a flexible connection by contac s l and 15. These contacts are carried by a insulating support 16 which adjustabl to position the contacts in the path of travel of the moving contact 5. The contacts it and 15 may be nornally open or closed but in the construction shown in l the contacts are normally open and held in the open position by the contact 5 which in initial position engages the lower end of contact Contact 15 extends below contact it for this purpose and terms a stop for the movaldo contact. Both contacts are cart l As norniaiy the ellect ot' the countertorque ele ment 7 predominates, the contact 5 is heh 'o cng remont with contact 15 and this LUlliilt'l, held out of er ugement with its cooperatina contact it. he circuit of auxiliary wind ing 12 is therefore mainta 'si'hen the More th ot the motor elemen abnormal conditions, above a predetermined amount, the torque exe i the motor ele menton the armature iovercome the con and the contact 5 i re to engage the operat The initial impulse tact 5 releases auxi which nux set up by the windings 1'? in portion of the motor element 2 Flt) an increase in torque is exerted on the armature by the motor element which is sufficient to compensate for the increase in countertorque exerted by spring 7. The armature 1 and contact 5 is positively carried into contact closing position without the objectionable feature of floating. A positive pick up of the armature is also obtained, that is the initial impulse necessary to start the armature into operation is suilicicnt to positively move the armature to complete its path of movement. This scheme also operates on the principle of shifting the phase angle between the fluxes of the motor element whereby the torque exerted thereby is increased to compensate for the increase in countertorque.

In Fig. 3 is shown a modified compensating structure which consists in providing on the permanent drag magnets 3, extension pole tips 18 which are adjustably supported thereon. Cooperating with the pole tips 18 is an armature 19 mounted between the pole tips and rotatable in response to the shaft 4. The armature 1.9 is preferably mounted on the shaft 4 and is cam shaped in configuration. The relation of pole tips 18 and armature 19 is such that normally with the contact 5 in its initial position against the stop 8, a large air gap exists between the armature 19 and each pole tip. As the armature 1. is rotated in response to the predominating effect of the driving torque, the rotation of shaft 4 rotates the armature 19 relative to the pole tips so that the gap between the armature 19 and each pole tip gradually decreases thus permitting more and more flux to traverse the armature 19 and hence exert a stronger and stronger torque on the armature 19 to rotate the shaft 4 and armature 1 in contact closing direction. Theincrease in effective torque by the armature 19 and pole tips 18 added to the torque exerted by the motor element 2 is suflicient to compensate for the increase in countertorque exerted by spring 7, hen the torque of the motor element falls off, the torque exerted on armature 1.9 likewise falls off so that the armature 1 is quickly re turned to initial position.

lVhat I claim as new and desire to secure by Letters Patent of the United States is 1. An induction relay comprising a rotatable armature, contacts controlled by the movement thereof, restraining means normally holding said armature in initial position, a motor element adapted to exert a torque on said armature tending to turn the same to contact controlling position opera tive in response to current in excess of a predetermined amount of overcome said restraining means, and means operative in response to a movement of said armature in contact controlling direction for varying the phase relations of the fluxes of said motor element whereby the torque of the same is increased to compensate for the increase in restraining effect of said restraining means.

2. An induction relay comprising a rotatably mounted circular disk, contacts controlled by the movement thereof, restraining means for holding said disk in initial position, electromagnetic torque-producing means inductively associated with said'disk operative in response to a current above a predetermined amount to overcome said restraining means and start said disk moving in contact controlling direction, and means affecting the torque exerted by said torque producing element whereby the current required to cause said torque producing means initial y to overcome said restraining means is suiiicient to complete the movement of said disk to contact controlling position.

An induction relay comprising a rotatable armature, contacts controlled by the movement thereof, an electromagnetic torque-producing element inductively associated with said armature and adapted to exert a torque thereon tending to turn the same in contact controlling direction, countertorque restraining means tending to turn said armature in the opposite direction normally effected to overcome the torque of said electromagnetic element and hold said armature in initial position, and a close cireuited member movable by said armature across the field of said electromagnetic element to vary the phase relations of the fluxes thereof whereby upon movement of said armature the torque of said electromagnetic element is varied in accordance with the variation in torque of said countertorque restraining means.

An induction relay comprising a, rotatable armature, contacts controlled by the movement thereof, restraining means normally holding said armature in initial position, a motor element adapted to exert a torque on said armature tending to turn the same to contact controlling position operative in response to a current in excess of a predetermined amount to overcome said restraining means, and means operative in response to the rotation of said armature for varying the phase relations of the fluxes of said motor element whereby the torque of the same is increased upon movement of said armature towards contact controlling position and decreased upon movement thereof towards the initial position.

5. An induction relay comprising aro tatably mounted disk, contacts controlled by the movement thereof, an electromagnetic element inductively associated with said disk and adapted to exert a torque thereon tending to move the same to conta t controlling position, restraining means arranged to exert a countertorque on said disk normally effective to hold the same in werceme 33 said ele:

to currents predetermined value, tort circulted member and nlem'tie thereby t said electromagnetiupon mo. ment of said controlling position the areress the V 7 i .31 IP'J v erement 1.1L. 0 ask tor-:11 1' rque of th used i "eunterze 6. Arnris n r0- eone11 electr0- eseeieted t a torque '0 Contact ztrohi arranged to exert a Jenner? L u disk normally sufficient to overeome the toreue exerted by lhereeh ten sitien, the torque exerted overcome by the torque ectic element when en- ;hove a predetermined said d e-1: towards contact on, nd rotatnhl r meuntet'l genetic element and hetd the (t e 4; lnelnhnf movable zurr= 3$ the "T011 zefnetie element beee and said disk 1t 0 t saie armature aid electromagnetic dz'nninete and said hit is (reused to pre positive] mo -red to eentu t controlllng position 111 responee to any cmfrent eh. predetermined amount) In WltfiPFS whereof. I have hereunto set my hand this 2 rd day of October. 1919.

HENRY G. FRENCH.

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