US1956279A - Electromagnetic relay construction - Google Patents

Description

April 24, 1934. F. w. GoDsEY, JR

ELECTROMAGNETIC RELAY CONSTRUCTION Filed Aug. 25, 1932 INVENTOR ocse y, ATTORNEYS ze# f Patented Apr. 24, 1934 UNITED STATES PATENTl oFFICE Frank W. Godsey, Jr., signor to The Safety New Haven, Conn., as- Car Heating & Lighting Company, a corporation of New Jersey Application August 25,

14 Claims.

This invention relates to the construction of electromagnetic relays and more particularly to the construction and operation of polarized electromagnetic relays.

One of the objects of this invention is to provide a relay construction of the above-mentioned character which will be simple and inexpensive, compact and rugged, and highly efficient in action. Another object is to provide a polarized electromagnetic relay in which the many and various disadvantages, deficiencies and defects of polarized relay constructions heretofore known may be dependably and reliably overcome in a thoroughly practical, inexpensive and simple Way. Another object is to provide a polarized relay construction of high efficiency. Another object is to provide a construction of the above-mentioned character capable of high sensitivity of action. Another object is to provide a construction of the above-mentioned character in which high sensitivity will be achieved at an erliciency heretofore unknown in electromagnetic relays. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing in which are shown by way of illustration several of the various possible embodiments of my invention,

Figure l is a schematic front elevation of a preferred form of polarized relay construction, certain illustratively related parts being d'agrammatically indicated;

Figure 2 is a horizontal sectional View as seen along the line 2-2 of Figure l;

Figure 3 is a schematic front elevation illustrating another possible form of polarized relay construction, certain illustratively related parts being diagraminatically indicated; and

F. gure 4 is a horizontal sectional View as seen along the line 4--4 of Figure 3.

Similar reference characters refer to similar parteJ throughout the several views of the drawing.

As conducive to a clearer and more ready understanding of certain features of my invention, it might at this point be noted that polarized electromagnetic relays, in which a movable part such as an armature intended to partake of movements the irections of which are deteriff n,

- mined by the direction of current flow through 1932, Serial N0. 630,327

the energizing winding of the relay, as heretofore proposed or met with, are characterized by a number of serious defects and deiiciencies; if such heretofore known relays are at all sensitive, such sensitiveness is achieved at substantial sacrifices involving the use of auxiliary sources of electrical energy for energizing, for example, a polarizing Winding, but the use of such an auxiliary source of energy subjects the construction to dependence upon such auxiliary source and to iiuctuations and variations in the latter, making the standard of operation of the relay unreliable and variable. Attempts to obviate such defects as well as to avoid the sacrifice of eiiiciency that is attendant upon the use of an auxiliary source have centered about utilizing a permanent magnet to achieve the polarization, but here such attempts have resulted in serious impairment of sensitivity, failure to improve appreciably the eiiiciency, and other disadvantages. One of the domina-nt aims of this invention is to provide a polarized electromagnetic relay kin which the many disadvantages, some of which have just been noted, that characterize known practice in polarized relay construction may be reliably and inexpensively eliminated, and in which materially improved standards of sensitiveness, reliablity, and efficiency may be achieved.

Referring now first to Figure l there is generally indicated at l0 a polarized electromagnetic relay construction illustratively related to two circuits, one a controlling circuit and the other a controlled circuit. The controlling circuit may include any device or arrangement, diagrammatically indicated at l1 and which includes any suitable source of electrical energy to which the relay 10 is to respond; the relay 10 is provided with a Winding 12, related to a magnetic circuit to be more clearly described hereinafter, and the Winding 12 is connected by conductors 13-14 to the arrangement or device 11 so that the winding 12 is made responsive to the electrical conditions established by or in the part 11.

The controlled circuit, which like the controlling circuit above described may be of any desired or suitable character, may, illustratively, include any suitable source of electrical energy indicated at l5, a translating device 16 to be energized or actuated by the source 15 and a fixed contact 17 related to a movable contact 18, these parts being suitably interconnected 'to form a complete electrical circuit as is diagrammatically indicated in Figure 1 so that the circuit of the translating device 16 is opened or closed, dependsoY ing upon Whether the contacts 17-18 are in or out of engagement with each other.

The movable contact 18 is the one that is actuated by the relay 10 and it may be related in any suitable way to be controlled or actuated by the movable part or armature of the relay 10; purely by way of illustration I have shown the contact 18 mounted upon and carried by the armature 19 of the relay 10 so that the position of the armature 19 will control the relation between the contacts 17-18.

The armature 19 forms part of the magnetic circuit with which the relay winding 12 is associated. This magnetic circuit is constructed and related to the winding 12 and to a permanent magnet so that directional changes in the current energizing the winding 12 bring about an actuation and corresponding change in position of the armature 19. For purposes of a more ready understanding of the construction and action of the relay, it might be assumed that the armature 19, pivoted in any suitable way as at 20, is mechanically balanced and that its range of movement about the pivot 20 is between the contact 17 and a stop 21 which may or may not be in the form of another contact or contacts. This armature 19, made of any suitable soft iron, is to be polarized so that changes in the magnetic flux produced by the winding 12 will cause the armature 19 to move from one limit of its range of movement to the other.

To polarize the armature 19 and thus to provide it with a suitable polarizing magnetic ux, I provide a permanent magnet 22 (see also Figure 2) which, however, is peculiarly related to the magnetic circuit of which the armature 19 forms a part. Illustratively the member 22 may take the form of a cylindrical piece of suitable magnet steel, such as cobalt magnet steel and about the member 22 rst relate, in any suitable manner, a soft iron sleeve 23, the parts 22 and 23 being concentric and preferably of identical axial length. The core 22 is permanently magnetized in any suitable manner.

The free or right-hand end of the armature 19 is related to and overlaps one end of this composite unit 22-23, and the magnetic circuit is preferably completed by an L-shaped member 24-25, also of soft iron like the armature 19 and the sleeve 23, the armature 19 being pivoted to the upper end of the vertical aim 25, as at 20, while the horizontal arm 24 extends under and has secured thereto the lower end of the unit 22-23.

The Winding 12 extends about the unit 22-23 and is substantially coaxial therewith.

By way of illustration of an illustrative construction of the parts 22-23, but not by way of limitation thereto, the core 22 of cobalt magnet steel may be given a diameter on the order of one-half inch and a length of three inches; the soft iron sleeve 23, accurately bored out to a diameter slightly less than the outside diameter of the core 22, may have an outside diameter of three-quarters of an inch, is then heated to expand it and thus to receive therein the magnet steel core 22, the subsequent cooling of the sleeve 23 shrinking the latter tightly about the magnet steel core 22 and thus forming a tight and secure physical inter-relation between the two parts. The respective end faces of the parts 22 and 23 are preferably ground of.F to lie in the same respective planes. The resultant combination is then magnetized as by means of a suitably strong electromagnet, the magnet steel core 22 being thus permanently magnetized. I have been able, with such a construction, to achieve a permanent magnetizing force in the magnet steel core 22, which thus becomes a permanent magnet, of an order of magnitude equivalent to approximately thirty to one hundred and fty ampere turns.

Now the permanent magnet or core 22 is of low permeability, and if it alone were to be inserted in the magnetic circuit of the electromagnetic winding of the relay, as has been proposed in prior practice, the inherent low permeability thereof imposes upon the resultant construction the requirement of an electromagnetic winding of a high or large number of ampere turns; that is, the operating winding of the resultant relay must be so large that it will overcome not only the reluctance in the magnetic circuit caused by the air gap in the relay but also the relatively very high reluctance represented by the permanent magnet itself and which is directly in the magnetic circuit of the winding, resulting in a very insensitive relay construction and one which requires relatively large amounts of energy to achieve its operation.

The composite construction 22-23, however, may, in accordance with my invention, be directly inserted in the magnetic circuit of the electromagnetic winding 12 without incurring such vital disadvantages as have just been noted, because the soft iron sleeve 23 is of high permeability and hence low reluctance and is principally determinative of the permeability of the unit 22-23 insofar as the latter forms part of the magnetic circuit.

The cross-sectional area of the sleeve 23 is proportioned, that is, made large enough, so that the flux from the permanent magnet 22 does not saturate the sleeve 23, and the permanent magnet 22 therefore tends to supply a constant amount of flux through the sleeve 23 and the magnetomotive force available across the ends of the unit is constant within substantially close limits and will not vary unless the soft iron sleeve 23 is saturated by the flux from the permanent magnet core 22.

The magnetomotive force thus made available by the permanent magnet 22 sends a flux across the air gap (see Figure l) through the armature 19, member 25 and member 24, assuming the upper end of the permanent magnet 22 to be the north pole and the lower end thereof to be the south pole; this flux, produced by the abovementioned magnetomotive force which, as already noted above, remains constant within very close limits, is the flux which polarizes the armature 19, and it is with respect to this polarizing iiux that the ux produced by the winding 12 acts to control the position of the armature 19 and hence the relation of the circuit-controlling contacts actuated by the armature.

rPhe effective magnetic circuit in which the winding 12 functions is of relatively high permeability and low reluctance, being, because of features of construction above-mentioned, substantially unaffected by the high reluctance and low permeability of the permanent magnet core 22; the magnetic circuit available to the ux produced by the winding 12 may, for purposes of better understanding certain features of construction and action, be considered as including the high reluctance core 22, the air gap, armature 19, member 25 and member 24, but the low permeability or high reluctance part 22 of this circuit is shunted by the low reluctance or high permeability part 23. The magnetic circuit therefore has a portion thereof made up of two: parallel paths, namely the parts 22 and 23. The flux produced by the winding 12 therefore seeks out and mainly passes through that path of these two parallel paths that is of lower reluctance, and is hardly appreciably affected by the high reluctance path.

Moreover, the cross-sections of the soft iron members 19, 25 and 24 of the magnetic circuit may be suitably proportioned with respect to the cross-section of the soft iron sleeve 23 so as to maintain low reluctance in so much of the magnetic circuit as they constitute.

Accordingly, it requires but a relatively small magnetomotive force or ampere turns produced by the winding 12 to bring about an actuation of the armature 19, and the Winding 12 can cause actuation of the armature 19 in response to comparatively small energizing currents. For example, when the current in the winding 12 reverses and hence when it is desired to change the position of the armature 19 and thus alter the condition of the controlled circuit, the magnitude of current, in the reversed direction, through the winding 12, need be but relatively very small to produce` the flux necessary to coact or react with the polarizing flux in the armature 19 (produced by the permanent magnet 22) to effect the corresponding change in position of the armature 19 itself; the reluctance of the magnetic circuit for the ux produced by such current is consistently relatively small and is free from detrimental effect thereon by the inherent high reluctance of the permanent magnet core 22 itself.

Thus, high sensitiveness is achieved and also high eniciency; neither of these important factors is interfered with by the low permeability of the permanent magnet core while efficiency is not made low because there is no power consumption supplied by an auxiliary source of energy. Also, the many disadvantages arising out of variations in an auxiliary source of energy such as is necessary where the relay is electro-magnetically polarized as in certain heretofore known structures, and thus constancy of standard of operation may be reliably achieved while at the same time avoiding the many inherent disadvantages in heretofore known relays where polarization is achieved by a permanent magnet.

As illustrative of another mechanical embodiment of certain features of my invention, reference may be made to Figures 3 and 4 in which the controlling and controlled circuits are interrelated by a relay construction which embodies the same pivoted armature 19 as in Figure 1 related to parts which complete the magnetic circuit or circuits as followsz-Thus, the armature 19 may be pivoted as at 20 to the vertical arm 27 of a soft iron frame-like structure 28 which has a bottom or horizontal arm 29 extending to the right from the lower end of the arm 27, whereupon it extends upwardly to form an arm 30 at whose upper end it is then extended toward the rleft to form an arm 31 that terminates underneath the free end of the armature 19, the frame 27 thus forming with the armature 19 a complete magnetic circuit, all of soft iron and hence of high permeability and low reluctance. Fitted and seated between the upper and lower arms 31 and 29 of the frame 28 is a member 32 made of a material similar to the steel of which the core 22 of Figures 1 and 2 is made, and the member 32 is permanently magnetized in any suitable way.

About the vertical arm 30 of the soft iron frame 28 is the winding or coil 12 which will thus be seen to be directly related to the above-described low reluctance magnetic circuit.

low permeability, is shunted by the upper arm 31 of the soft iron frame 28, the vertical arm 30 and the portion 29L of the lower arm 29. The dimensions and cross-sections of the permanent magnet core 32 and its above-mentioned soft iron shunt are so proportioned that the desired magnetomotive force, commensurate with that which is available across the ends of the unit 22-23 of Figures 1 and 2, is available at the ends of the shunted permanent magnet 32; this magnetomotive force permanently polarizes the armature 19, sending a polarizing fiux therethrough in a circuit which, assuming that the north pole of the permanent magnet 32 is its upper end, will be seen to extend across the air gap (with the armature 19 in its uppermost position), through the armature 19, arm 27 of the frame 28, portion 29b of the bottom arm 29, and thence to the lower end of the permanent magnet 32.

Though the permanent magnet core 32 is present in the apparatus, its high reluctance is virtually prevented from interfering with the high efficiency and high sensitiveness of operation of the relay; whatever currents energize the winding 12 (Figure 3) produce an electromotive force or Iiux which has available to it a magnetic circuit of high permeability and hence low reluctance, in spite of the contrary characteristics of the permanent magnet core 32, and this magnetic circuit will be seen to include the parts 39, 29, 27, armature 19, and part 31, all of which may be made of high permeability material. This magnetic circuit will be seen to have a by-pass of low reluctance about the high reluctance core 32 or, stated differently, the flux induced by the winding 12 and flowing along the arm 30 of the frame 28 has available to it two paths, one of which is of high reluctance and the other of which is of low reluctance, and because of the relatively wide divergence or differences in these reluctances, the flux seeks and flows through the reluctance path and is hardly appreciably affected by the high reluctance path in parallel therewith.

The high reluctance path is made up virtually of the permanent magnet core 32 which, however, is shunted or has in parallel with it the low reluctance path made up of the parts 29b and 27, and the armature 19. Thus, the ux produced by the winding 12, regardless of its direction, is made directly to coact or react with the polarized armature 19 and because of the high permeability path thus made available to it, but a small magnetomotive force or flux from the winding 12 is necessary to cause an actuation of the armature 19 and correspondingly a small amount of current or energizing energy in the winding 12 is necessary to bring about the desired operation of the armature 19.

The high permeability parts of the relay con- The permanent magnet core 32, inherently of ITS struction, two possible examples of which are above described, are made of a suitable iron, for example Norway iron or silicon steel, while the permanent magnet core is made of a suitable material adapted to be permanently magnetized,

such as tungsten steel, cobalt steel,` or the like. v/,a

Moreover, the construction lends itself to unique and advantageous control; for example, with a given size of permanent core and a given permanent magnetization thereof, the extent of polarizing action thereof upon the armature 19 may- Y.

be predetermined in advance by suitably proportioning with respect thereto the cross-sections of the high permeability magnetic circuits which are shunted about the permanent magnet. For example, the cross-section of the sleeve 23 of the construction of Figures l and 2 or the crosssection of the shunt circuit formed by the parts 31, 30 and 29a of the construction of Figures 3 and 4 may be made large or small with respect to the strength of the permanent magnet itself according as the polarizing iiuX in the armature 19 is desired to be small or large. These features are of great practical advantage in that, even though certain circumstances of use might dictate a relatively small polarizing flux, a relatively large or strong permanent magnet might nevertheless be employed and thus achieve greater or more lasting permanence than would otherwise be possible.

It will thus be seen that there has been provided in this invention a relay construction in which the various objects hereinabove mentioned, together with many thoroughly practical advantages are successfully achieved. It will be seen that the construction is compact and inexpensive, is highly sensitive and is of high eihciency, and is well adapted to meet the varying conditions of practical use, particularly such conditions where but a small amount of electrical energy is available in the controlling circuit for energization of the relay.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the accompanying drawing, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In construction of the character described, in combination, means made up of three parts of high permeability and arranged substantially in the form of a U, one of said parts being in the form of a movable armature, and the three parts forming part of a magnetic circuit; a permanent magnet core inherently of 10W permeability substantially closing the U formed by said parts, for permanently polarizing the armature part thereof hollow means of magnetic material of high permeability surrounding said core and extending lengthwise thereof and forming a magnetic shunt about said core for by-passing some of the ilux of the latter; and a control winding about said last-mentioned means, said control winding having thereby a complete magnetic circuit of high permeability, whereby the iiux produced by said winding avoids having to be forced through said low permeability core.

2. In construction of the character described, in combination, means made up of three parts of high permeability and arranged substantially in the form of a U, one of said parts being in the form of a movable armature, and the three parts forming part of a magnetic circuit; a permanent magnet core inherently of low permeability substantially closing the U formed by said parts, for permanently polarizing the armatiue part thereof; hollow means of magnetic material of high permeability surrounding said core and forming a magnetic shunt about said core for by-passing some of the of the latter and extending lengthwise of said core to a sufficient extent to substantially close the U formed by said firstmentioned three parts to form with the latter a complete magnetic circuit which thus is of high permeability; and a control winding related to said complete magnetic circuit for sending therethrough a flux the direction of which changes with directional changes of current energizing said winding, said control winding having thereby a complete magnetic circuit of high permeability, whereby the iiux produced by said winding avoids having to be forced through said low permeability core.

3. In construction of the character described, in combination, means made up of three parts of high permeability and arranged substantially in the form of a U, one of said parts being in the form of a movable armature, and the three parts forming part of a magnetic circuit; a permanent magnet core inherently of low permeability substantially closing the U formed by said parts, for permanently polarizing the armature part thereof a sleeve made of a magnetic material of high permeability and surrounding said core and forming with said first-mentioned three parts a complete magnetic circuit of high permeability; and a control winding related to said high permeability magnetic circuit for creating therein a flux whose direction changes with directional changes in current energizing said Winding.

4. In construction of the character described, in combination, means made up of three parts of high permeability and arranged substantially in the form of a U, one of said parts being in the form of a movable armature, and the three parts forming part of a magnetic circuit; a permanent magnet core inherently of low permeability substantially closing the U formed by said parts, for permanently polarizing the armature part thereof; a sleeve made of a magnetic material of high permeability and surrounding said core and forming with said nist-mentioned three parts a complete magnetic circuit of high permeability; and a control winding about said sleeve connected to a circuit in which the direction of current flow changes, for sending through said high permeability magnetic circuit a iiux directionally responsive to directional changes in the current energizing said winding.

5. In construction of the character described,

in combination, a relay having a movable armature and a permanent magnet core for passing through said armature a polarizing flux, said core being inherently of high reluctance; a control winding for producing a ilux through said armature in a direction depending upon the direction of current flow through the winding; and means forming a low reluctance path for the flux produced by said winding, said means and said core being related in parallel whereby the iiux from said winding is by-passed around said high reluctance core, whereby said electro-responsive means need be less powerful than would otherwise be the case.

6. In construction of the character described, in combination, a relay having means of magnetic material of relatively high permeability and a permanent magnet core that is inherently of relatively low permeability forming With said means a complete magnetic circuit, Whereby said means is polarized by flux from said permanent magnet core; electro-responsive means for producing a magnetic ux in said rst-mentioned means for coaction with said iiux from said permanent magnet core; and means of relatively high permeability for shunting the flux produced by said electro-responsive means around the said relatively low permeability permanent magnet core, whereby said electro-responsive means need be less powerful than would otherwise be the case.

7. In construction of the character described, in combination, a relay having means of magnetic material of relatively high permeability and a permanent magnet core that is inherently of relatively low permeability forming with said means a complete magnetic circuit, Whereby said means is polarized by iiux from said permanent magnet core; electro-responsive means for producing a magnetic ilux in said first-mentioned means for coaction with said ilux from said permanent magnet core; and means for reducing the energizing current of said electro-responsive means necessary for operation of the relay and comprising means of relatively high permeability so related to said magnetic circuit and said electro-responsive means that the reluctance of the path through which said ux produced by said electro-responsive means passes is less than the reluctance of said magnetic circuit.

8. In construction of the character described, in combination, means of relatively low reluctance forming a complete magnetic circuit and provided with electro-responsive means for inducing in said circuit amagnetic flux; and a permanent magnet core for permanently polarizing said magnetic circuit, said core being embedded in a portion of said low reluctance means and being thereby positioned so that the high reluctance path formed by said core is shunted by at least part of said relatively low reluctance magnetic circuit.

9. In construction of the character described, in combination, means of relatively low reluctance forming a complete magnetic circuit and provided with electro-responsive means for inducing in said circuit a magnetic flux; and a permanent magnet core means for permanently polarizing said magnetic circuit, one of said magnetic means being substantially embedded in the other whereby said core means is positioned so that the high reluctance path formed by said core means is shunted by a plurality of portions of said relatively low reluctance magnetic circuit, whereby the high reluctance of said permanent magnet core has but an inappreciable effect upon the reluctance of said magnetic circuit.

10. In construction of the character described,

in combination, an armature of magnetic material, a permanent magnet core inherently of relatively high reluctance for inducing in said armature a polarizing flux, a winding for inducing a flux in said armature for coaction with said polarizing fiux, and means of relatively low reluctance coacting with said Winding and said armature for by-passing the flux induced by said Winding around said relatively high reluctance core, at least a portion of said means lying lengthwise along said core in the direction of the passage of flux therethrough.

1l. In construction of the character described, in combination, means of magnetic material forming magnetic circuits and comprising two substantially parallel but spaced means of relatively high permeability having three members substantially bridged thereacross, thereby to form a plurality of individual magnetic circuits in shunt relation to each other, one of said members being in the form of a permanent magnet core of relatively low permeability and the remaining two members being of relatively high permeability, one of said members being substantially in the form of a tube and another of said members passing through the tube, and a Winding about one of said relatively high permeability members.

12. In construction of the character described, in combination, a polarized relay having a winding, an armature, and a permanent magnet core for inducing in said armature a polarizing flux, said core being inherently of relatively low permeability; and means of relatively high permeability shunting the flux induced by said winding around said relatively low permeability core, said winding extending about both said core and said means.

13. In construction of the character described, in combination, a permanent magnet member and a low reluctance shunt member therefor, one of said members being in the form of substantially a tube and the other of said members being accommodated within said tube.

14. In construction of the character described, in combination, a permanent magnet member and a low reluctance shunt member therefor, said shunt member being in the form substantially of a sleeve shrunk onto the permanent magnet member.

FRANK W. GODSEY, JR.

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