US2200104A - Network relay adjusting device - Google Patents

Description

May 7, 1940. w. K. SONNEMANN NETWORK RELAY ADJUSTING DEVICE Filed Jan. 9. 1937 INVENTOR MY/iam 5027272277027.

WITNESSES: wM/M (9 W NEY Patented May 7, 1940 UNITED STATES PATENT OFFICE NETWORK RELAY ADJUSTING DEVICE of Pennsylvania Application January 9, 1937, Serial No. 119,806

4 Claims.

My invention relates to alternating-current induction type protective devices and particularly to an improved induction-drum network relay of the general type disclosed in U. S. Patent No. 2,013,836, granted September 10, 1935, to John S. Parsons and assigned to Westinghouse Electric & Manufacturing Company.

In the aforesaid Parsons patent, there is disclosed a three-phase induction type power directional relay having its magnetic core arranged as a central group of three symmetrically disposed potential magnets, surrounded by an outer group of three symmetrically disposed current and phasing magnets. The secondary induction element is in the form of a conducting drum, rotatably mounted on the common axis of symmetry of the two groups of magnets, and having its cylindrical portion disposed in the air gaps between the two groups of magnets in order to produce exact quadrature of the potential and current flux, lag loops of copper, or other conducting material, are mounted on the potential magnets. Overvoltage adjustment, for phasing operations, is made by means of a second group of copper lag loops movably mounted in the air gaps betwen the potential magnets and the induction drum.

Although the relay described in the abovementioned Parsons patent is compact in dimensions and provides high torque with satisfactory operating characteristics, it is difficult to manufacture and adjust because of the extreme accuracy required in positioning the current magnets. A displacement of the current magnets of only a few thousandths of an inch from the position of symmetry opposite the potential magnets, produces an undesirable distortion of the relay characteristics because of the effect of the lag loops upon the current magnet flux.

It is an object of my invention to provide a novel network relay of the type indicated above, which will have characteristics substantially free from distortion caused by displacement of the current and phasing magnets.

A further object of my invention is to provide a novel lag adjustment, suitable for application to induction type protective devices which re spond to a second degree electrical quantity, such as power.

Another object of my invention is to provide a novel network relay in which a single lag loop serves to produce quadrature relationship of potential and current flux and also serves as an overvoltage adjuster.

Other objects of my invention willbecome evident from the following detailed description, taken in conjunction with the accompanying drawing, in which Figure 1 is a fragmentary plan view, with parts broken away, showing one element of an induction-drum relay embodying my invention;

Fig. 2 is a sectional View on the line II-II of Fig. 1; and

Fig. 3 is an enlarged plan view of a fastening collar used in the relay element shown in Figs. 1 and 2.

Referring to Figs. 1 and 2 in detail, the relay is provided with a metal base plate I, which serves as support for the magnets and moving parts. A block 2 of steel or other suitable material is secured to the base plate I by means of suitable machine screws 3 and 4, which pass through holes drilled in the base plate I. The hole 5 for the machine screw 4, is of considerably greater diameter than the latter, in order to permit adjustment of the position of the block 2 in a manner to be hereinafter explained.

A fiat circular washer 6 and a lock washer I are provided between the head of the screw 4 and the base plate I for locking the block 2 in any position to which it may be adjusted. A pair of metal pins 8 are secured to the steel block 2, in parallel relationship, near the base plate I. The pins 8 lie on either side of a pin portion 9 of an eccentric member ID. The eccentric member I is preferably machined as a single piece of metal, having a fillister head portion II and a cylindrical bearing surface journaled in the base plate I. The eccentric member I0 is held in rotatable relationship in the base plate I by means of a metal collar I2, an enlarged plan view of which is shown in Fig. 3.

A current and phasing magnet I3 is secured to the block 2 by means of suitable machine screws I4. The current and phasing magnet I3 comprises a C-shaped assembly of laminations I5, of

suitable magnetic material, upon which is mounted a pair of current coils I6 and a pair of phasing coils IT,

The assembly of laminations I is so shaped as to provide an arcuate inner surface substantially concentric with the axis of a shaft I 8, upon which a cup-shaped. aluminum drum I9 is mounted. The drum I9 serves as the relay secondary element and is mechanically connected to suitable contact members (not shown) which serve tocomplete a closing circuit for the network circuit breaker in one position of the drum I9 and to complete a tripping circuit for the breaker upon rotation of the drum I9 in the opposite direction in a well known manner. A spring 20 is provided for biasing the drum l9 in .the closing direction, as indicated by the arrow 2|.

A potential magnet 22 is mounted within the drum it, in a position to cooperate with the current and phasing magnet l3. The potential magnet 22 is of substantially E-shape, having a central salient pole 23, upon which a potential coil 24 is mounted. The magnetic circuit of the potential magnet 22 is partially completed by two return branches 25. The outer surfaces of the salient pole 23 and return branches 25 are substantially arcuate in form and concentric with the axis of the shaft 8.

The free ends of the C-shaped assembly l5 serve as polar projections to produce a rotating field, in cooperation with the salient pole 23, and the assembly l5 as a whole serves as a magnetic member to complete the magnetic circuit of the potential magnet 22.

The inner arcuate surface of the current and phasing magnet i3 is recessed to receive a lag loop 265, of suitable conducting material such as copper, shown as comprising two O-shaped laminations encompassing part of both open branches of the C-shaped assembly !5. The lag loop 26 is substantially symmetrically disposed with reference to the salient pole 23 of the potential magnet 22.

Although only one relay element, consisting of one potential magnet 22 and one current and phasing magnet It, has been shown, it will be understood that the complete relay includes three such elements, disposed in symmetrical relationship about the axis of shaft l8. Various parts of a network relay, themselves well known in the art, but not necessary to an understanding of the invention, have for simplicity been omitted. Examples of such parts are the relay casing, the connection block used for establishing external connections to the relay parts, and the reverse power adjusting spring, which is used to provide an adjustable torque opposing operation of the relay movable assembly to tripping position. Such parts are illustrated and described in various prior art publications such as the United States patent to John S. Parsons, No. 1,893,179, issued January 1933, and assigned to the Westinghouse Electric 8; Manufacturing Company.

The operation of the apparatus shown in Figs. 1 and 2 may be set forth as follows: Referring to Fig. 1, it will be noted that the iron parts of the current and phasing magnet l3 and the potential magnet 22 provide a divided magnetic circuit for the potential flux which traverses the salient pole .23. If the C-shaped assembly I?) is symmetrically disposed with reference to the potential magnet 22, as shown, the magnetic circuit is symmetrically divided so that the magnetic effects produced on one side of the magnetic circuit are duplicated on the other side.

Considering one-half of the magnetic circuit, such as the right hand half, part of the magnetic flux generated in the salient pole 2-? follows a magnetic path interlinking the lag loop 26 and traversing the induction drum l9, as indicated by the broken line 2?. Another part of the flux produced by the salient pole 23 traverses the induction drum l9 but follows a leakage path clear of the lag loop 26, as indicated by the broken line 28.

As the flux which interlinks the lag loop 25 is lagged in phase because of the wellknown action of a shading coil, the equivalent of a shaded-pole induction motor is present, and torque is produced because of the action of the potential magnet 22 alone, even though the current and phasing magnet l3 is deenergized. The torque produced on the right side of the magnetic circuit in this way is balanced by an equal and opposite torque produced on the left side of the magnetic circuit.

However, if the entire current and phasing magnet I3 is rotated slightly in the clockwise direction as seen in Fig. 1 about the machine screw 3 as a pivot, the air gaps in the right side of the magnetic circuit are reduced in length, whereas the corresponding air gaps in the left side of the magnetic circuit remain of approximately their original length. Because of the reduction of air gap length on the right side of the magnetic circuit, the various flux components on the right side are increased in magnitude, and the torque produced by the right side of the magnetic circuit predominates. An unbalanced torque is accordingly produced, and the induction drum would turn if its motion were unopposed.

The direction of the unbalanced torque produced in this way depends upon the relative impedance phase angle of the electric circuit of the lag loop 26 as compared with effective impedance phase angle of the eddy current secondary circuit in the induction drum Hi. I have found that for a network relay of the type described, with the lag loop 26 designed to produce a watt characteristic during directional operation, the unbalanced torque tends to rotate the drum l9 from the side having the longer air gap toward the side having the shorter air gap.

The unbalanced torque produced by the potential magnet 22 alone, in the manner described above, is used to overcome the bias of the spring 29 and provide a bias tending to prevent rotation of the drum I9 in the closing direction, as indicated by the arrow 2|.

As the salient potential pole 23 is angularly displaced from the open ends of the C-shaped assembly I5, operating torque proportional to the vector product of current in the potential coil 24 and current in either the current coils l6 or the phasing coils I1, is produced in the usual manner. It will be understood that the current coils 16 are connected in such relative direction as to produce additive magnetomotive forces acting around the C-shaped core, and the phasing coils are similarly connected.

In order to adjust the magnitude of unbal anced torque produced by the potential magnet 22 alone, the machine screw 4 is rotated to re lease the block 2, and the eccentric member ID is then turned by means of a screw driver, until the desired value of torque is produced. machine screw 4 is then tightened to maintain the adjustment.

I do not intend that the present invention shall be restricted to the specific structural details, arrangement of parts or circuit connections herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In an alternating-current power-responsive network protective device, a rotatable drum having a conducting skirt portion, a potential magnet within said drum, said potential magnet hav- The ing a salient pole adjacent said skirt portion, a

current magnet outside of said drum, said cur rent magnet having a pair of polar projections erence to said salient pole along the periphery of said skirt portion, a short-circuited coil mounted on said current magnet in a position to divide the effective pole area of each of said polar projections into two parts and to enclose one of said parts for each of said polar projections, and means for angularly adjusting said current mag net to bring one of said polar projections into closer proximity to said skirt portion than the other of said polar projections. r

2. In an alternating current relay, a rotatable armature, an electromagnet having a salient pole disposed on one side of said armature, a magnetic member having a short-circuited coil thereon and mounted on the other side of said armature, said electromagnet and magnetic member and the air gap between them through which the armature moves constituting a divided substantially symmetrical magnetic circuit having a common branch in said salient pole, a lagged return branch traversing said armature and said magnetic member through said short-circuited coil, and a leakage return branch traversing said armature and said magnetic member external to said short-circuited coil, and means for adjusting the position of said magnetic member with respect to said salient pole to alter the effective air-gap length of one division of each of said divided branches, said magnetic member being an integral structure angularly movable as a unit with respect to the axis of said salient pole.

3. In an alternating-current induction-type device, a movable conducting armature, an electromagnet having a salient pole on one side of said armature, a magnetic member on the other side of said armature having a pair of salient projections symmetrically disposed with respect to said salient pole and located along the line of movement of said armature, said electromagnet and magnetic member being proportional to define a divided magnetic circuit through said armature with branches each including one of said salient projections, means for lagging part of the flux of both of said magnetic branches comprising a short-circuited coil mounted on said magnetic member substantially opposite said salient pole, said short-circuited coil being positioned to divide the effective pole area of each of said salient projections into two parts disposed in sequential relationship along the path of movement of said armature and to enclose the part, individual to each of said salient projections, closest to the axis of said salient pole, and means for adjustably moving said magnetic member as a unit angularly with respect to the adjacent surface of said armature to increase the effective air-gap length of one of said magnetic branch circuits with respect to the other.

4. In an alternating-current induction-type device, a rotatable drum having a conducting skirtportion, an electromagnet including a salient'pole on one side of said skirt portion, a magnetic member having a pair of salient projections on the other side of said skirt portion, said salient projections being substantially symmetrically disposed with respect to said salient.

pole along the periphery of said skirt portion and spaced therefrom to define an eifective airgap through which said armature may rotate, said electromagnet and magnetic member being proportional to define a divided magnetic circuit through said armature with branches each including one of said salient projections, means for lagging part of the flux of both of said magnetic branches comprising a short-circuited coil mounted on said salient projections substantially opposite said salient pole, said shortcircuited coil being positioned to divide the effective pole area of each of said salient projections into two parts disposed in sequential relationship along the path of movement of said skirt portion, and to enclose the part, individual to each of said salient projections, closest to the axis of said salient pole, and means for adjustably moving said magnetic member as a unit angularly with respect to the adjacent surface of said armature to increase the effective air-gap length of one of said magnetic branch circuits with respect to the other.

WILLIAM K. SONNEMANN.

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