US2245391A

US2245391A - Polarized relay

Info

Publication number: US2245391A
Application number: US344901A
Authority: US
Inventors: Jr Emil Dickten
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1940-07-11
Filing date: 1940-07-11
Publication date: 1941-06-10
Anticipated expiration: 1958-06-10

Description

June 10, 1941. E. DICKTEN, JR 2,245,391

POLARIZED RELAY Filed July 11, 1940 /A/l/E/VTOR E. Dic/(MAUR.

y alii@ csa-@ 7' TURA/EV `of inert gas, it is Patented June 10, 1941 2,245,391 POLARIZED RELAY Emil Dickten, Telephone York, N. Y., a corporatie Jr., Totowa, Laboratories, Incorporated, New

n of New York N. J., assignor to Bell Application July 11, 1940, Serial No. 344,901

8 Claims.

This invention relates to electromagnetic devices and more particularly to polarized relays.

It is an object of the present invention to provide a relay structure of the polarized type which has a suitable margin of safety against false operation when ahigh percentage of the operating current is flowing and the relay is at the same time subject to vibration.

It is a further object of the invention to reduce the cost and to increase the utility, durability and the reliability of a polarized relay.

In accordance with the present invention, these objects are attained by the use of saturated iron as a magnetic rectifier tc admit or to impede the iow of magnetic iiux according to its polarity. In its more general aspects the mag- 'netic rectifier is disclosed inV my application Serial No. 344,898, led July 11, 1940. In the present invention the magnetic rectifier has been illustrated as applied to a relay structure of the type disclosed in application Serial No. 198,629, of W. B. Ellwood, filed March 29, 1938. One of the chief advantages of this invention is that it eliminates the complicated mechanical and magnetic structures of the usual polarized relays and enables these to be replaced by three magnetic contact springs and one or two small permanent magnets whereby the magnetic contact springs perform both the magnetic and electrical functions essential to a polarized relay structure. By enclosing the contacts inan evacuated vessel or in a vessel having an atmosphere possible to use a magnetic material such as iron for the contacts or precious metal contacts may be used.

For a more comprehensive understanding of the invention reference may be had to the following detailed description taken in connection with the accompanying drawing in which:

Fig. 1 shows one embodiment of the invention partly in cross-section;

Fig. 2 shows a second embodiment of the invention partly in cross-section; and,

Fig. 3 shows the invention embodied in a relay structure for enabling the closure of its contacts only in response to current of one polarity applied to its operating coil.

Referring first to Fig. 1 of the drawing, I is a glass vessel through one end of which terminals 2 and 3 are sealed and through the other end of which a single terminal 4 is sealed. To the inner end of terminal 2 is welded or otherwise secured, a strip 5 of pure iron which is provided between its free or contact end 6 and its point of attachment to the terminal 2 with a raised portion l. of terminal Similarly secured to the inner end 3 is a second strip 8 of pure iron which is also provided between its free or contact end 9 and its point of attachment to the terminal 3 with a raised portion I0. The raised portions l and I0 extend away from each other approximately into engagement with the inner wall of the vessel I and are joined by a short permanent bar magnet II. 'I'he north pole of magnet II is shown in magnetic engagement with the raised portion 'l of strip 5 and the south pole is conductively but not magnetically separated from the raised portion I0 of strip 8 as indicated at I2 by an insulating cement such as, for example, aluminum oxide. The main portions of the strips 5 and 8 are electrically separated from each other by a low reluctance air gap I3.

Similarly secured to the inner end of terminal l is a flexible strip I 4 of pure iron, the inner end of which lies midway between the contact ends S and 9 of the strips 5 and 8 and normally separated therefrom by air-gaps. The vessel I may contain any suitable inert and non-corrosive gas such as helium, argon or neon or may be evacuated.

'I'he pressure of the enclosed gas may be adjusted before the vessel is sealed to the best operating condition. Surrounding the vessel I is an operating coil I5.

Considering the operation of this relay, the strips 5 and 8 separated as they are by a very low reluctance air-gap I3 serve as a keeper for the permanent magnet II so that a flux density is normally produced in the strips 5 and 8 sufliciently large to operate the iron thereof in the vicinity of the knee of the saturation curve. In this high flux density condition strips 5 and 8 will still have a low reluctance as compared with that of the air-gaps between their contact ends 8 and 9' and the strip i4. The ilux from the permanent magnet may be visualized as leaving the north pole of the magnet entering the strip 5 ilowing across the narrow air-gap I3 to the strip 8 and entering the magnet at its south pole.

When the coil l5 is energized, electromagnetic lines of force are caused to ow into the core of the coll, some of which tend to flow in strip 5 and some of which tend to flow in strip 8, and then across the air-gaps to the strip I4, thence out of the core of the coil or, reversely, dependent upon the polarity of the current by which the coil I5 is energized.

if the direction of the ux due to current in the coil I5 is pictured as entering the core of the coil by the strips 5 and 8 and as leaving by the strip I4, the coil flux opposes the permanent magnet flux in the strip 5 and the ux density in this strip is therefore decreased whereby flux readily ows across the air-gap between the contact end 6 of strip 5 and the strip I4 and therefore the vstrip I4 becomes attracted into engagement with the contact end 6 of strip 5. At the same time in the strip 8, the coil flux aids the permanent magnet flux but, since this strip is already almost or entirely saturated due to the permanent magnet flux, the increase in flux in this strip will be slight or nil and practically no flux will iiow across the air-gap between the contact end 9 of this strip and strip I4 and therefore there will be no force tending to hold strip I4 from engagement with strip 5. The engagement between strips 5 and I4 electrically connects terminals 2 and 4.

A current of the opposite polarity through the coil I5, will cause iiux to ow in the reverse direction through the strips 5 and 8 and in this case, since the coil flux in strip 8 opposes the permanent magnet flux therein and the coil ux in strip 5 aids the permanent magnet flux therein, the strip I4 will be attracted into electrical engagement with the contact end 9 of strip 8 thereby interconnecting terminals 3 and 4.

Fig. 2 illustrates a modified form of lthe invention in which the vessel 2|, terminals 22, 23 and 24, flexible strip 34 and coil 35 may be iden- .tical with .the similar parts of Fig. 1. Welded or otherwise secured Ito the inner end of terminal 22 is a flexible strip 25 of pure iron which is provided between its free or contact end 26 and its Apoint of attachment to the terminal 22 with a, recessed portion 21. Similarly secured 4to the inner end of terminal 23 is a flexible strip 28 of pure iron which is provided between its free or contact end 29 and its point of attachment to the terminal 23 with a recessed portion 30. The contact ends 26 and 29 of the

strips

25 and 28 are positioned on either side of the end of strip 34 and are separated therefrom by air-gaps. A permanent bar magnet 3l is secured to the outer face of strip 25 in bridge of the recessed portion 21 thereof, whereby only the polar ends of the magnet are in engagement with the strip 25 and the recessed portion 21 thereby serves as a keeper for the magnet 3I. A `second permanent bar magnet 32 is secured to the outer face of strip 28 in bridge of the recessed portion 30 thereof whereby only the polar ends of the magnet are in engagement with the strip 28 and the recessed portion 30 thereby serves as a keeper for the magnet 32. The flux from magnet 3I may be visualized as leaving the north pole thereof flowing through the strip 25 toward the attached end thereof and entering the south pole of said magnet, and the flux from magnet 32 may be visualized as leaving the north pole thereof, flowing through the strip 28 toward the contact end 29 thereof and entering the south pole of such magnet.

-Considering the operation of this modifled form of relay, when the coll 3-5 is energized, electromagnetic lines of force are causedrto ow into the core of the coil, some of which tend to ow in the strip 25 and some of which tend to flow in the strip 28 and across the air-gaps to the strip 34, thence out of the core of the coil or, reversely, dependent upon the polarity of the current by which the coil is energized.

If the direction of the iiux due to current in 'the coil 35 is pictured as entering the core of 'the coil by the

strips

25 and 28 and as leaving by the strip 34, the coil ux opposes the permanent magnet ux owing from magnet 3l through strip 25 and .the flux density in this strip is therefore decreased whereby flux read` ily flows across the air-gap between the contact end 26 of such strip and strip 34 and therefore strips 25 and 34 become attracted into engagement. At the same time in the strip 28, the coil flux aids the flux for magnet 32 but, since this strip is already almost or entirely saturated due to the ux from magnet 32, the increase in flux in this strip will be slight or nil and practically no flux will flow across the air-gap between the contact end 29 of strip 28 and the strip 34 and therefore there will be no force tending to hold strip 34 from engagement with strip 25. The engagement between

strips

25 and 34 electrically connects terminals 22 and 24.

A current of the opposite polarity through the coil 35 will cause -ux to flow in the reverse direction through the

strips

25 and 28 and in this case, since the coil flux in the strip 28 opposes the flux from the permanent magnet 32 and the coil ux in strip 25 aids .the flux from the .permanent magnet 3|, the

strips

28 and 34 will be attracted into engagement thereby interconnecting terminals 23 and 24.

Fig 3 shows the invention applied to a relay for enabling the conta-cts thereof to be closed only when the operating coil is energized by current of a predetermined polarity. Essentially the relay is of the same general construction as that disclosed in Fig. 2 with the exception that one of the flexible strips and associated permanent magnet have been omitted. Considering the operation of .the rel-ay of Fig. 3, if the coil 55 is energized by current of such polarity as to cause a flow of flux into its core through the strip 45 across the air-gap between the con-tact end 46 of such strip into strip 54, and then-ce out of the core of the coil, the ux through strip 45 will oppose the flux set up therethrough by magnet 5I and consequently flux will ow across the airgap to strip 54 thereby causing the strips 45 and I54 to 4be attracted into engagement to interconnect terminals 42 and 44. If on the other hand the current flowing through coil 55 is reversed, thereby tending to cause flux to flow into the core of the coil through strip 54 across the airgap and thence out of the core of the -coil through strip 45, the coil flux through strip 45 will aid the permanent magnet flux and consequently insuiiicient flux will flow across the air-gap to cause the attraction of

strips

45 and 54 into engagement.

What is claimed is:

1. In a circuit controlling device, a gas-tight Vessel, a contact spring of magnetic material, a permanent magnet in bridge of a portion thereof, a second Contact spring of magnetic material, said contact springs being enclosed in said vessel, and a coil outside said vessel operative to cause the engagementof the contacts of said -springs only in response to its energization by current of one polarity.

2. In'a circuit controlling device, a gas-tight vessel, a rst contact spring of magnetic material having a recessed portion therein, a permanent magnet secured to said spring in bridge of said recessed portion, a second contact spring of magnetic material, said contact springs being enclosed in said vessel, and a coil outside said vessel operative to cause the engagement of the contacts of said springs only in response to its energization by current of one polarity.

3. In a circuit controlling device. a gas-tight vessel, a Iterminal sealed through each end of said Vessel, a rst contact spring of magnetic material secured to one of said terminals and having a recessed portion therein, a permanent bar magnet having its polar ends secured to said spring and positioned in bridge of said recessed portion, a second contact spring of magnetic material secured to the other of said terminals, said contact springs being enclosed in said vessel with their free ends superimposed, and a coil surrounding said vessel operative to cause the engagement of the contacts of said springs only in response to its energization by current of one polarity.

4. In a circuit controlling device, a gas-'tight vessel, a pair of spaced contact springs of magnetic material, each having a permanent magnet in bridge of a portion thereof, a third contact spring of magnetic material interposed between said spaced contact springs, said contact springs all being enclosed in said vessel, and a coil outside said vessel operative to cause the engagement of the contact of said third contact spring with the contact of one or .the other of said spaced contact springs in response to its energization by currents of opposite polarity.

5. In a circuit controlling device, a gas-tight vessel, a pair of spaced contact springs of magnetic material, each having a recessed portion therein', a permanent magnet secured to each contact spring in bridge of the recessed portion thereof, a third contact spring of magnetic material interposed between said spaced contact springs, said contact springs all being enclosed in said vessel, and a coil outside said vessel operative to cause the engagement of the contact of said third contact spring with the contact of one or the other of said spaced contact springs in response to its energization by currents of opposite polarity.

6. In a circuit controlling device, a gas-tight vessel, a pair of terminals sealed through one end of said vessel, a third terminal sealed through the other end of said vessel, a pair of spaced contact springs of magnetic material secured respectively to said pair of terminals, each of said contact springs having a recessed portion, a permanent bar magnet having its polar ends secured to one of said Contact springs and positioned in bridge of the recessed portion thereof, a second permanent bar magnet having its polar ends secured to the other of said contact springs and positioned in bridge of the recessed portion thereof, said magnets being oppositely poled with respect to the free ends of said springs, a third contact spring of magnetic material secured to said third terminal with its free end interposed between the free ends of said spaced contact springs, and a coil surrounding said vessel operative to cause the engagement of the contact of said third spring with the contact of one or the other of said spaced contact springs in response to its energization by currents of opposite polarity.

7. In a circuit controlling device, a gas-tight vessel, a pair of spaced contact springs of magnetio material, magnetic means for normally magnetically saturating portions of said springs, a third contact spring of magnetic material interposed between said spaced contact springs, said contact springs and said magnetic means being enclosed in said vessel, and a coil outside said vessel operative to cause the engagement of the contact of said third contact spring with the contact of one or the other of said spaced contact springs in response to its energization by currents of opposite polarity.

8. In a circuit controlling device, a gas-tight vessel, a pair of terminals sealed through one end of said vessel, a third terminal sealed through the other end of said vessel, a pair of spaced contact springs of magnetic material secured respectively to said pair of terminals and separated from each other near their points of support by a low reluctance air-ga a permanent magnet insulatedly bridged between said springs neax` their free ends for normally magnetically saturating those portions of said springs extending between the poles of said magnet and said low reluctance air-gap, a third contact spring of magnetic material secured to said third terminal with its free end interposed between the free ends of said spaced springs, and a coil outside said vessel operative to cause the engagement of the contact of said third contact spring with the contact of one or the other of said spaced contact springs in response to its energization by currents of opposite polarity.

EMIL DICKTEN, Ja..