US1286239A - Electrical protective device. - Google Patents

Description

A. W. COPLEY & B. H. SMITH.

ELECTRICAL PROTECTIVE DEViCE.

APPLICATION FILED JUNE 30, I916.

1,286,290 Patented Dec. 3, 1918.

2 SHEETSSHEET 1.

WITNESSES: INVENTORS ATTORNEY A. W. COPL'EY & B. H SMITH.

ELECTRICAL PROTECTIVE DEVICE.

APPLICATION FILED JUNE 30, 1916.

1,286,239. 7 Patented Dec. 3, 1918.

2 SHEETS-SHEET 2- Fig.5.

WITNESSES:

INVENTOR5 Almon M Copley 8 Benjamin H. Smith" ATTORNEY ALMQN' W. COPLEY, F PITTSBURG ENJAMIN H. M1 H, GE TURTLE CREEK,

PENNSYZVANIA, ASSIGNORS T0 WESTINGHOUSE ELECTRIC AND MANUFACTURING CQMPANY, A CORPORATION 0F PENNSYLVANIA.

Application illed June 30, 1916.

T 0 all whom it may concern:

Be it. known that we, Amrou W. Corner, a citizen of the United States, and a resident of Pittsbur h, in the county of Allegheny and State of Pennsylvania, and BENJAMIN H. SMITH, a citizen of the United States, and a resident of Turtle Creek, in the county of Allegheny and State on Pennsylvania, have invented a new and useful Improvement in Electrical Protective Devices, or which the following specification is a continuation in part of copend ing application Serial No. 771,888, tiled June 5, i913,

@ur invention relates to electricai protective devices and particularly to relays. One object of our invention is to provide a time-limit relay having electrical means for obtaining its time-limit functions.

Another object of our invention is to provide a relay of the above indicated character that shali have an inverse time-iimit for all values of current up to a predetermined and a definite time-limit for all. values of curr nt above the predetermined value.

A further object our invention is to provide a relay ofthe above indicated character that shall have means whereby a definite time-limit may be obtained for all values of current at which the device is adapted to operate.

@ur present application is a continuation, in part, of our copending application, Serial No. 771,888, filed June 5, 1913. e

In the carrying out of our invention, we provide a magnetizable core member, an armature, main and auxiliary windings-and a saturable transformer so connected between the two windings that, according to the value or the current at whichit becomes saturated, the torque of the armature may be so regulated that it may be constant for all values of current traversing the main winding, or it may vary substantially as the current traversing the main Winding up to a predetermined value of current and be substantially constant above the predetermined value of current.

the accompanying drawings Figure l is a diagrammatic view oi a relay embodying our invention, and Figs. 2 and 3 are diagrammatic views of modified forms of relays embodying our invention.

Specification of Letters Patent.

Patented Dec. 3, 1918,

Serial no. looses.

A relay 1 is operatively connected to an electric circuit 2 and comprises, in general, a magnetizable core member 3, a rotatable armature i, a main winding 5, a secondary winding '3, auxiliary windings 7 and a saturable transformer 8.,

The armature A- is mounted upon a shaft 9 upon which is also mounted a movable bridging contact member 10 that is adapted to engage two stationary contact members 31 which constitute the terminals of a tripping device (not shown). The inner end of a relatively light spring 12 is operativcly connected to the shaft 9 and its outer end is connected to a stationary member 13. The armature 1- is adapted to turn between the poles of permanent magnets 14 for the purpose of damping or retarding its move; ments. The main winding 5 of the relay It is operatively connected the secondary winding 15 of a current transformer 16, and the secondary winding 6 of the relay 1 is operatively connected to a primary winding 1? of the saturable transformer 8. A secondary winding 18 of the transformer 8 is operatively connected to the auxiliary windings 7 of the relay.

l-Vhen a predetermined overload occurs upon the circuit 2, current proportional to the current, that traverses the circuit 2 will traverse the main winding 5 of the relay and this current will induce a voltage in the secondary winding 6 which, by reason of the closed-circuit relation with the winding 17 of the transformer 8, will cause a current to traverse the winding 17. The current traversing the winding 17 will induce a voltage in the winding 18 and this will cause current to traverse the auxiliary windings 7 of the relay. Thus, a shifting fling is set up in the air gun of-the relay 1 that'causes the armature d to turn against the action of the spring 12 to eiiect engagement between the bridging contact member 10 and the stationary contact members 11. The flux that causes the armature to turn may be assumed to be composed of two parts, one substantially proportional to the current traversing the circuit 2 and the other substantially constant by reason oi the partial m'agnetic'saturation of the transformer 8. Thus, the armature iwill develop a torque substantially proportional to the current traversing the lit) Cid

winding 5, under predetermined conditions.

Hqwever. if the transformer 8 is worked winding above t 1e nice o its satuiartioni aevwthe'nga phase-angular relation between the two fluxes is materially reduced and, thus, the torque of the armature i will decrease. Consequently, at a predetermined value of current, depending upon the magnetic saturation of the transformer S, the torque developed by the armature will become substantially constant for all values of current traversing the winding 5. That, -is to say, the time required for the contact member 10 to engage the contact members 11, after,

a predetermined overload traverses the-circuit 2, will vary substantially inversely as the current traversing the circuit 2, up to a predetermined overload,a nd will be substantially constant for all values of overload above the predetermined value.

In Fig. 2 of the drawings, the magnetizable core member 3 is provided with a magnetizable armature 19 that is supported by springs 20. The armature 19 is provided with contact members 21 that are adapted to engage stationary contact members 22 for the purpose of closing the circuit between the winding 6 of the relay 1 and the winding 17 of the transformer 8, under predetermined conditions.

ln Fig. 2 of the drawings, when a predetermined overload occurs upon the circuit 2, sutiicient current will traverse the main winding 5 to move the armature 19 downwardly. Thus, the armature i will not creep or operate until the contact members 21 and 22 are engaged. if the current required to operatethe armature is of such value as to induce sufficient voltage in the winding ii to cause the transformer 8 to be saturated above the knee of its saturation curve, it will be understood that the torque developed by the armature i will be substantially constant. In other words, the armature 19' is provided for the purpose of so controlling the windings of the relay that the contact member 10 will engage the contact members 11 in a definite time, irrespective of the overload traversing the circuit '2.

in Fig. 3 of the drawings, the armature 19 is provided with a contact member 23 that is adapted to be normally held in engagement with a stationary contact member '24 by the spring 20. T he contact members 23 and 24 constitute the separable terminals of a short-circuit connection 25 across the terminals of the winding 17 of the transformer 8.

hen a predetermined overload occurs upon the circuit 2' and the modified, form or our invention shown in Fig. 3 is employed, the armature 19 will be moved downwardly to open the short-circuit connection 25 around the winding 17 to thus permit the winding 18 to energize the auxiliary windnasaase ings 7 which, in connection with the main 5, cause the armature 4 to turn n of a li ht resetting spring (not shown) with a, substantia onstant torque, substantially as set forth with respect to the device shown in Fig. 2 of the drawings.

It will be understood that, if the arma' ture 19 is omitted from the modified forms of our invention, shown in Figs. 2 and 3, the devices will operate in substantially the same manner as the device shown in Fig. l of the drawings. It will be further understood that the time' required for the contact members 10 and 11 to engage may be changed by varying. the size of the core and the number of turns of the windings of the transformer 8 in order that it may become saturated. under predetermined conditions. Thus, the .time of operation of the relay may be either definite under all .con ditions or inverse up to a predetermined value of current and definite for all values of current above the predetermined value.

We do not limit our invention to the particular arrangements illustrated, as it may be variously modified without departing torque to be exerted on the armature for all j values of current traversing the main winding above a predetermined value.

g A. relay comprising a magnetizable core member having a main and an auxiliary winding thereon, an armature, anda reactance device connected between the main and auxiliary windings for causing the armature to develop a constant torque for all values of current traversing the main wind ing above a predetermined value.

3. A motor comprising a .magnetizable core member-having a main and an auxiliary winding thereon, an armature and means connected in circult with the said auxiliary winding to cooperate with the main winting to cause the armature to develop a substantially constanttorque when current in excess of a predetermined value traverses the main winding. Y

i. A relay comprising a magnetizable core member having a main and an auxiliary winding thereon, an armature and electrical means connected in circuit with the said auxiliary winding to cooperate with the main winding to cause the armature to develop a substantially constant torque when the current traversing the main winding exceeds a predetermined value.

5. A relay comprising a magnetizable core ire QUE

member having a main and an auxiliary winding thereon. an armature and means interposed in the circuit oi the said auxiliary winding that cooperates with the said main Winding to cause the armature to develop a substantially constant torque when the cur rent. traversing the main winding exceeds a prtaletermined value.

(3. A. relay comprising a magnetizable core member having a main and an auxiliary winding thereon. an armature and a reactor interposed in the circuit of the said auxiliary winding that cooperates with the main wincling to -ause the armature to develop a substantially constant torque when the current traversing the main winding exceeds a predetermined value.

7. 3i relay comprisinga magnetizable core member having a main winding. an auxiliary winding and a secondary winding thereon. and a normally magnetically saturated transformer having two windings thereon, one of the transformer windings being connected in circuit with the auxiliary winding and the. other transformer winding being connected in circuit with the said secondary windin S. A relay comprising an armature, a main winding. an auxiliary winding. and a transformer associated with the said windings and adapted to become magnetic-ally saturated when a predetermined current traverses the main winding to cause the armature to develop a substantially constant torque for all values oi current in the main winding above the predetermined value;

9. A relay comprising a maguetizable core member having a main and an auxiliary winding thereon. an armature, a magnet-i- -ally saturable transformer interposed between the said main winding and the said auxiliary winding and means dependent upon the current traversing the main winding for controlling the circuit of the auxiliary winding.

10. A relay comprising a magnetizable core member having a main and an auxiliary winding thereon, an armature, meansconnected in circuit with the said auxiliary winding to coope ate with the main winding to cause the armature to develop a substantially constant torque when the current in the main winding exceeds a predetermined value. and means dependent upon the current traversing the main winding for controlling the circuit of the auxiliary winding.

11. A relay comprising an armature, a magnetizable core member. a main winding and an auxiliary winding disposed on the core member, and a transformer interposed between the main and auxiliary windings and adapted to become saturated under predetermined conditions to cause the armature to develop a substantially constant torque under these predetermined conditions.

12. L relay comprising an armature. a main winding. an auxiliary winding. and means connected between the said windings whereby a substantially constant. torque is exerted upon the armature when the current traversing the main winding exceeds a predetermined value.

13. A relay comprising an armature. a main .vinding. an auxiliary winding. and means operatively connected between the auxiliary and main windings whereby a substantially constant torque is exerted upon the armature when the current traver ing the main winding exceeds a predetermined value.

ll. )1 relay for an electric circuit comprising an armature. windings therefor and means connected between the windings for causing the armature to develop a torque that varies substantially directly as the current traversing the circuit up to apredetermined value of current and a substantially definite torque above the predetermined value of current.

15. Si relay comprising an armature, a.

main winding. an auxiliary winding and means operatively connected between the said windings whereby a torque is exerted on the armature that varies directly as the current traversing the main winding up to a predetermined value and a substantially constant torque is exerted upon the armature above. the predetern'iined value of current.

16. A relay for an electric circuit comprising a magnetizable core member having two cooperating windings thereon. an armature. and means connected between the two windings whereby a torque is exerted on the armature. in accordance with the current traversing the circuit up to a predetermined value and a constant torque is exerted thereon for all values of current traversing the circuit above the predetermined value of current.

17. A. relay comprising a magnetizable core member having a main and an auxiliary winding thereon. an armature and electrical means connected in circuit with the said auxiliary winding for causing a constant torque to be exerted on the armature for all values of current traversing the main winding above a predetermined value.

In testimony whereof. we have hereunto subscribed our names this 29th day of June. 1916.

ALBION Vv'.-COPLEY. BENLXMIN H. SMITH.

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