US1481938A - Electroresponstive device - Google Patents

Description

'Jan. 29, 1924.

O. C. TRAVER ELECTRORESPONSIVE DEVICE Filed April 12 1923 nm wm mrfm w J a 3 m0 M a Tmw s .w H

Patented Jan. 29, 1924.

UNITED STATES OLIVER C. TRAVER, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC PATENT OFFICE.

COMPANY, A CORPORATION OF NEW YORK.

ELECTRORESPONSIVE DEVICE.

Application filed April 12, 1923. Serial No. 631,735.

T all whom it may can earn:

Be it known that I, OLIVER C. TnAvEn, 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 Electroresponsive Devices, of which the following is a specification.

My invention relates to electroresponsive devices and more particularly to relays and similar protective devices operative with a time delay in response toiabnormal circuit conditions such as over-current and the like,

and an object of my invention is to provide an improved time limit electroresponsive device which has inverse time characteristics giving a broad range of operation. My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the single figure of the accompanying drawing, I have illustrated in perspective an embodiment of my invention as applied to the control of suitable circuit interrupting means such as a circuit breaker 1 arranged to control the circuit of an electric power line 2. My invention may comprise an electroresponsive device 3 having an element or armature 4 movable preferably with a time delay in response to current above a predetermined minimum value to release a normally restrained movable operating mem-- her or armature 5 of an electroresponsive device 6. The armature 5 is immovable by an energizing winding or coil 7 for current" therein up to a. predetermined value and is movable into the field of influence of winding 7 for current therein less than this predetermined value by any suitable means which may comprise a differential or planetary gear train 8. This train may be continuously driven by any suitable means such as an induction disk shaded pole motor 9. Restraint of one of the moving members of the gear train 8 is effected in response to movement of the element 4 so that the differential action of the gear train 8 is effective to move the armature 5 into the field of influence of the coil 7. When the armature 5 has been moved to a predetermined position corresponding to a predetermined current in the coil 7 greater than the'current to which the element 4 is responsive, the armature 5 will be moved by the coil 7 to attracted position and may actuate a suitable circuit controlling member 10. With this arrangement, obviously the smaller the current the farther the armature 5 has to be moved to be actuated by the coil 7, and therefore the longer the time required to move the armature 5 .to the pick-up position so that with a differential gear train, a broad range of operation with inverse time characteristics, dependent upon the gear ratio, is assured.

The electroresponsive device 3 has an energizing winding 11 which may be provided with taps for varying the strength thereof and the energizing winding 7 of the electroresponsive device 6 may also be provided with taps for the same purpose. The windings 7 and 11 may be connected in series relation with the power line 2 through the current transformer 12 and may be connected in series relation with each other and the actuating winding 13 of the motor 9. Each of the electroresponsive devices 3 and 6 may therefore be adjusted independently and substantially without interfering with the motor 9. he electroresponsive device 3 may be provided with suitable time delay mechanism 14 herein illustrated as of the bellows type so that with a plurality of relays on the line 2, graduated time limits may be obtained for a selective initial action of each relay.

The electroresponsive device 6 comprises the movable member or armature 5 which is carried on a rod 15 having an enlarged portion 16. The rod 15 may be screwed into the armature 5 so that the position of the armature 5 on the rod 15 and relatively to the winding 7 may be changed to adjust the pick-up point of the armature 5. An enlarged end portion 17 on the rod 15 is arranged when the armature 5 is released to engage and reset for example suitable contact controlling mechanism such as a tog gle 18 connected to the circuit controlling member 10 by a, link 19. Upon movement of .mature independently of the member.

. closin or both as desired. When thecircuit contro ling member 10 engages the contacts 21', the control circuit of the trip coil 22 of the circuit breaker 3 is completed from the control bus 23.

For moving the armature 5 into the field\ of influence of the winding 7, I provide a movable member 24 arranged to be moved by the differential gear train 8 and supported in a suitable bearing member 25. The member 24 is arranged to limit the movement of the armature 5 when the winding 7 is deenergized and to permit movement of the 14eror this purpose downward movement of the member 24 may be limited by a pin 26 engaging bearing member 25, while the lower end of the rod 15 is shouldered to abut the upper end of the member 24 and has an end portion of reduced cross-section slidable in a longitudinal recess in the member 24.

The differential gear train 8 comprises a shaft 27, a driving gear 28 mounted thereon and cooperating with a pinion 29 on the shaft 30' f the rotor or disk 31 of the motor 9. The driving gear 28 carries a rotatably mounted shaft 32 to which are rigidly secured planetary gears 33 and 34 arranged to cooperate with sun gears 35 and 36 respectively which are rotatably mounted on the shaft 27. Rigidly secured to the sun gear 35 is a pinion 37 arranged to cooperate with a straight gear or rack 38 on the movable member 24 for movement thereof. In order that the differential action of the gear train may actuate the member 24, there is rigidly secured to the sun gear 36 a detent wheel 39 arranged to be engaged and restrained against movement by a detent-40 which may be secured to a shaft 41 and which is controlled by the armature 4 of the electroresponsive device 3.

In order to lock the plunger 5 against sub stantially instantaneous movement on cur rent above a predetermined value so that selective action may be obtained in conjunction with the time delay mechanism 14 of the electroresponsive device 3, I provide suitable restraining means such as a stop member 42 and a latch 43 cooperating therewith. The stop 42 is secured to a sleeve 44 adjustably positioned on the rod 15 and arranged to allow the rod 15 to turn therein so that the pick-up point of the plunger 5 or posit-ion thereof relatively to the winding 7 may be varied as heretofore. described. The latching member 43 may be loosely mounted on the shaft 41 and arranged for movement by the crank 45 which is rigidly secured to the shaft 41. This arrangement may boa lost motion connection comprising a pin 46 which projects through an opening in an arm of the latch 43, the size of the opening being larger than the size ofthe pin. A spring 47 may be used to bias the latch 43 relatively to the crank 45 to latching position. With this arrangement, the point of the latch 43 may be readily passed by the stop 42 when the plunger 5 returns to the deenergized position.

\ In order simultaneously to control the detent 40 and the latch 43, the crank 45 is connected to the plunger 4 of the electroresponsiverdevice 3. "With this arrangement, it

will be obvious that, when the member 24 is restrained against movement by the latch 43, the differential action of the gear train will result in the rotation of the sun ear 36 and its associated detent wheel 39. Even without the latch 43 in latching position, the downward thrust on the pinion 37 due to the Weight of the parts is sufficient to cause the differential action of the gear train merely to turn the sun gear 36. If, however, the electroresponsive device 3 is energized in response to current above a redetermined value, the latch 43 will be re eased and the detent wheel 39 engaged by the detent 40 and held against movement, so that the differential action of the gear train rotates the sun gear 35 and therefore eifects movement of the member 24 and plunger 5. The rate at which the member 24 will be moved depends of course upon the speed of the driving gear 28 and the relative gear ratios between each of the lanet gears and its respective sungear. n a practical embodiment of my invention, the planet gears 33 and 34 each have the same number of teeth while the sun gear 35 has 100 teeth and the sun gear 36 has 99 teeth. Consequently for one rotation of the driving gear 28, assuming the detent 40 in engagement with the detent wheel 39, the sun gear 35 will be rotated one tooth or one one-hundredth of a turn and therefore the nfovement of the rack 38 will be relatively s ow.

Assuming the direction of rotation of the motor disk 31 as shown by the arrow thereon, the driving gear 28 rotates inthe direction shown by the arrow thereon and the sun gear 35 will be turned in the same direction when the detent 40 engages the detent wheel v39. The electrorespo lsive device 3 operates with a relatively short time delay and the plunger 5 is slowly moved into the field of influence of the coil 7 by the difierential action of the gear train at a rate dependent upon the reduction factor thereof until a position or pick-up point is reached where the coil is energized sufliciently to move the plunger to contact controlling position; 1 The pick-up position will of courseill) depend upon the current in the coil 7 and the time upon the travel of the plunger 5 necessary to reach this position, so long as the current in the winding 7 is below a predetermined value which is greater than that required to operate the electroresponsive device 3, and less than that which would result in an instantaneous movement of the plunger 5 from its lowest position. Upon the closing of the trip coil circuit by the circuit controlling member 10 and the opening of the circuit breaker 1, the circuit of the power' line 2 is interrupted and therefore the energizing windings 11 and 7 of the electroresponsive devices 3 and 6 and the motor winding 13 are deenergized. The parts of the relay substantially instantaneously resume the position shown in the drawing, since all rotating parts are free to turn without any restramt and the differential action of the gear train does not effect the return of member 24.

With this arrangement, a wide range of operation is assured( For example, in a practical embodiment of my invention, I am able to obtain an inverse time characteristic from 10 minutes time delay at 120 per cent rated load to substantially instantaneous operation at 150 per cent rated load. If at any time the load returns to normal or 100 per cent before the relay operates the parts thereof will return to normal or reset position.

It will be obvious that relays constructed in accordance with my invention may be used for protection against over-current conditions either where protection alone is desired or where it is desired to limit a customers power consumption without interrupting service unless a certain demand is exceeded for a predetermined time.

lVhat I claim as new and desire to secure by Letters Patent of the United States, is:

1. A relay comprising a winding, an armature adapted to be moved by said winding, a movable member for limiting'the movement of said armature when said winding is de energized arranged upon movement in one direction to vary the position of the armature with respect to the winding so that the armature will be attracted at different current values corresponding to different positions of the member, locking means adapted to hold said armature in the position occupied thereby when said winding is deenergized, a motor for moving said member in said direction, and electro-responsive means arranged simultaneously to release said locking means and establish a driving relationship between said motor and said member,

2. A relay comprising a winding, an armature adapted to be moved by said winding, a movable member for limiting the movement of said armature when said winding is deenergized arranged upon movement 1n one direction to vary the position of the armature with respect to the winding so that the armature will be attracted at different current values corresponding to' different positions of the member, locking means adapted to hold said armature in the position occupied thereby when said winding is deenergized. a motor for moving said member in said direction, and electroresponsivc means connected in series with said winding and arranged simultaneously to release said locking means and establish a driving relationship between said motor and said member whereby upon current below a. predetermined value said armature will be actuated by said winding after a time interval dependent upon the operation of said motor to move the member to a position corresponding to the value of the current which will cause said winding to attract the armature.

3. An electroresponsive device comprising an element movabl in response to a predetermined current, an armature, means comprising a differential gear train for moving said armature and arranged to permit movement of the armature independently of the gear train, means controlled by said element operative in response to movement thereof to rest-rain one of the gears of said train whereby the differential action thereof effects movement of said armature, and a winding operative in response to a greater predetermined current to move said armature to attracted position when the member has been moved to a predetermined osition.

4. An electroresponsive evice comprising an element movable in response to a predetermined current, an armature, means arranged to hold said armature stationary and to be released by said element upon movement thereof, means comprising a differential gear train for moving said armature and arranged to permit movement of the armature independently of the gear train, means controlled by said element operative in response to movement thereof to restrain one of the gears of said train whereby the differential action thereof effects movement of said armature and a winding operative in response to a greater predetermined current to move said armature to attracted position when the armature has been moved to a predetermined position.

5. An inverse time limit relay comprising an element movable with a time delay in response to a predetermined current, an en ergizing winding, anarmature immovable by said winding for current. therein up to a predetermined value greater than the value of the current to which said element is responsive, means comprising a normally energized differential reducing gear train for moving said armature into the field of influence of said winding, means for restra none of the members of said gear train whereby the differential action thereof is effective to move said armature into the field of in fluence of said winding so that the armature is moved to attracted position in a time substantially inversely proportional to current in the winding up to said greater predetermined value 6. An inverse time limit relay comprising an element movable in response to a predetermined current. an energizing winding, an armature normally restrained from movement and immovable by said winding for current therein up to a predetermined value greater than the value to which said element is responsive, means comprising a dliierential gear train for moving said armature into the field of influence of said winding and means controlled by said element for releasing saidarmature and restraining one of the gears of said train whereby the differential action thereof efi'ects movement of the armature into the field of influence of said winding so that the armature is moved to attracted position in a time substantially inversely proportional to current in the winding up to said greater predetermined value.

7. An inverse time limit relay comprising an energizing winding, an element movable thereby with a time .delay in res use to a predetermined current in the win ing, another energizing winding connected in series with said first winding, an armature normally restrained from movement and immovable by said other winding for current therein up to a predetermined value greater than the value to which said element is responsive, means controlled by said element operative in response to movement thereof to release said armature, means comprising a diflerential gear train for moving said armature into the field of influence of its energizing winding and arranged to permit movement of the armature independently or the gear train, a motor for driving said gear train having an actuating winding connected in series relation with said energizing windings, a detent controlled by said element operative in response to movement thereof to restrain one of the gears of said train whereby the differential action thereof is eiiective to move said armature into the field of influence of its energizing winding so that the armature is moved to attracted position in a time substantially inversely proportional to current in the winding up to said greater predetermined value.

8. A relay comprising a Winding, an armature ada ted to be moved b said winding, a mova le member for imiting the armature Wlll be attracted at movement 01': said armaturewhen said winds mg 18 deenerg'ized arranged to permit movement of the armature in one direction independently of the member and to move'the armature in said direction to vary the posttion thereof with respect to the winding so that the armature will be attracted at different current values corresponding to different positions of the member, locking means adapted to hold said armature in the position occupiedthereby when said winding is deenergized, an electric motor for moving said member in said direction comprising an actuating winding connected in series relation with said relay winding, and electroresponsive means connected in series relation with said motor winding and said relay winding operative in response to current above a predetermined value simultaneously to release said locking means and establlsh a driving relationship between said motor and said member whereby upon current below a predetermined value said armature will be actuated by said windin after a time interval substantially inverse y proportional to the current.

9. A relay comprising a winding, an armature ada ted to be moved by said winding, a move le member for limiting the movement of said armature in one direction when said winding is deenergized arranged to permit movement of the armature in the opposite direction independently of the member and to move the armature in said opposite direction to vary the position thereof with respect to the winding so that the armature will be attracted at different current values corresponding to difierent positions of the member, electroresponsive means for moving said member comprising a driving gear and planetary gears movable thereby, sun gears engaged by said planetary gears, the gear ratlos between said planetary and sun gears being difi'erent, a driving connection whereby one of said. sun gears may move said movable member, and relay means operative in response to a predetermined current to restrain another of said sun gears from rotating.

10. A relay comprising a winding, an armature adapted to be moved by said winding, a movable member for limiting the movement of said armature in onedirection when said winding is deenergized arranged to permit movement of the armature in the opposite direction independently of the member and to move the armature in said opposite direction to vary the position thereof with res set to the windin so that the ifi'erent current values corresponding to different positions of the member,-electroresponsive means for moving said member comprisin a driving gear and planetary ears movalfi'e thereby, sun gearsengage by said planetary gears, the gear ratios between said planetary tion'occupied thereby when said winding is and sun gears being different, a driving condeenergized, and means for controlling said nection whereby one of said sun gears may holding means and said detent means. 1 move said movable member, detent means In witness whereof, I have hereunto set adapted to be operated to prevent another my hand this 11th day of April, 1923.

of said sun gears from rotating, means adapted to hold said armature in the posi- OLIVER C. TRAVER.

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