US2918611A - Electromagnetic relay - Google Patents

Electromagnetic relay Download PDF

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Publication number
US2918611A
US2918611A US737182A US73718258A US2918611A US 2918611 A US2918611 A US 2918611A US 737182 A US737182 A US 737182A US 73718258 A US73718258 A US 73718258A US 2918611 A US2918611 A US 2918611A
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US
United States
Prior art keywords
armature
relay
core
force
branch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US737182A
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English (en)
Inventor
Pettersson Gustaf Adolf
Kornfeldt Paul
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Individual
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Individual
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Filing date
Publication date
Priority to BE538144D priority Critical patent/BE538144A/xx
Priority to DEP14101A priority patent/DE1023823B/de
Priority to FR1131997D priority patent/FR1131997A/fr
Priority claimed from GB1396755A external-priority patent/GB781119A/en
Priority to CH341230D priority patent/CH341230A/fr
Priority to US518872A priority patent/US2858488A/en
Priority claimed from US518872A external-priority patent/US2858488A/en
Priority to US737182A priority patent/US2918611A/en
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US2918611A publication Critical patent/US2918611A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H50/00—Details of electromagnetic relays
    • H01H50/16—Magnetic circuit arrangements

Definitions

  • the present invention relates to electromagnetic switches or relays, and more particularly to electromagnetic relays used in telephone communication systems.
  • Electromagnetic relays play an important part within the field of communication.
  • the great number of components of this kind which for example are used in an automatic telephone station, entails that any fault occurring in these relays in respect of construction or operation is multiplied many times and influences the technical and economical effect of the whole system.
  • Two essential factors to be considered in the construction of relays are the space occupied by a relay and the consumption of current necessary for their operation. If the dimensions of the relays can be reduced, material and space will be saved, whereby the stands, for instance-of telephone stations, can be made smaller and more easily accessible.
  • the consumption of current of the relays can be reduced by eliminating to the greatest possible extent losses, for example due to leakage, and by giving the magnetic field between the magnet core and the armature an optimal shape and strength.
  • all other demands normally made on the functionsvof the relay such as the lifting force of the armature, must of course also be satisfied, including sufficient margins of performance.
  • One of the objects of the present invention is to substitute for the heretofore used trial and error methods a definite rule of calculating the lifting force K of a relay armature as a function of factors determining the. magnitude of the force, such as, for example, the distance between the turning axis of the armature and the point of application of the force on the relay contacts, the ampere turns of the coil or coils, the maximum air gap between the armature and the core and the reluctance of the magnetic circuit.
  • Fig. l is a diagrammatic isometric view of the magnet core and the armature of a conventional flat armature relay, the paths of the lines of force being indicated.
  • Fig. 2 is a diagrammatic elevational sideview of the relay according to Fig. 1-.
  • Figs. 3a and 3b are graphs showing curves representing the lifting force of an armature as a function of the distance (R) of the armature from its turning axis in a practical case, the curve K of Fig. 3a representing the conditions present when the reluctance in the iron circuit is neglected and the curve K representing the con-' ditions when the reluctance of 'the iron circuit is not neglected.
  • Fig. 3b shows the zcro end of curve K, the scale of R being greatly enlarged.
  • Fig. 4 is a graph showing a curve of the lifting force of an armature as a function magnetic material.
  • Fig. 5 is a diagrammatic elevational side view of a relay with a permanent air gap between thearmature and the core.
  • Fig. 7 is a diagrammatic isometric view of core of a novel relay design.
  • Fig. 8 is an isometric view ofa novel armature.
  • Fig. 9 is side view of a core according to Fig. 7 and a magnet an armature according to Fig. 8, which form a relay ac cording to the invention.
  • Fig. 10 is another embodiment of a magnet core.
  • Fig. 11 is the armature for the magnet core according and air respectively.
  • the subsequentcalculation is made in connection with a fiat armature relay according to Fig. 1, in which reference numerals 1 and 2 designate the two branches of a relay structure.
  • This structure is magnetically equivalent to a magnet core with three branches or legs, in which the area of the central branch is twice the area of each of the outer branches.
  • Reference numeral 3 designates the transverse member (the yoke) which in the equivalent circuit c'onnects the branches.
  • the flat armature of the relay has a transverse portion 4 and a longitudinal branch 5. The armature is shown in the non-operative position and forms an angle a with the general plane of the magnet core. 1
  • the path of the lines of force through the relay is indicated by a dashed line extending through the rear part of branch 1, branch 5 of the armature, portion 4 of the armature, a dash and dot line extending through the air gap, and a dashed line extending through branch 2, yoke 3 and again through branch 1.
  • Fig. 6 is a graph showing comparative curves of the lifting force of an armature as a function of the distance.
  • R is the distance between the turning axis and the edge of the armature as shown in Fig. 2.
  • the lifting force K is obtained by dividing the moment M by the distance (R-i-l) between the turning axis of the armature and the lifting stud of the relay. Then the equation will be as follows:
  • the maximum of the force K is found to lie at values for R of about 2-10- meters. This partly is due to the fact that the flux of leakage from the underside of the armature, when the values for R are small, impinges upon the magnet core beyond the turning axis of the armature and thereby gives rise to a moment which is directed against the principal moment, and partly because in practice there always remains a certain air gap (compare the curve K in Fig, 6). When greater values for R are concerned, the two moments cooperate.
  • relay constructions can be improved in different respects. It may for instance be desirable to reduce the amount of material in the iron circuit, when otherwise the values for a, IN, and K are unchanged.
  • the aim may be to reduce the ampere turns IN as much as possible, the above data as to a, K, and the amount of material in
  • weak current systems are involved, the use of material, the permeability, and the lifting force of the lifting studs of the contact spring group are given, as regards the electromagnetic relays which are included in such a system.
  • the electromagnetic relays which are included in such a system.
  • the next problem is how to achieve the desired minimum when using the available quantity of material. Furthermore, space must be left for the winding, and the leakage between the difierent portions of the relay must be kept at a low value.
  • the geometrical quantities occurring in the for mulas set forth above must be chosen so that certain demands as to space are satisfied.
  • a certain amount of material must be added, as shown above, which is needed to comply with the mechanical requirements.
  • the path of the lines of force through the outer branch 1 of the core is concentrated within an area around the turning axis of the armature 4.
  • the portion of the outer branch 1 located in front of this turning axis is magnetically inoperative. Consequently, in regard to the magnetic action the branch need not be longer than about half the length shown, that is, it needs to extend only to the turning axis of the armature.
  • the branches must have a certain length in excess of that necessary for magnetic reasons only.
  • the compromise between the magnetic and the mechanical demands for dimensioning that must be made for practical use has been found to be a length (g) of the outer branches of the core which is at most 80% of the length (e) of the central branch; for certain particularly advantageous practical constructions of the relay 60% are sufficient.
  • the sum of the width of the active branches is greater than half the sum of the Width of the passive branches, and said sum may also be greater than the sum of the height of these branches divided by the number of branches.
  • the Lifting power is in this case 4.55 times greater than in the previous case (425 gms.).
  • the distance (R) between the rear edge and the turning axis of the armature must be made considerably larger than the theoretical value (0.00O75 l()- m.) according to the curve representing K in Fig. 6, for instance 2 lO" rn.
  • the distance (R) between the armature and its turning axis should be not more than at most 60%, for example 50% of the whole length (R-l-L) of the armature.
  • the leakage has been neglected.
  • the factor 0.9 must be placed before y. in the expression for K.
  • a relay core comprising two outer branches 7 and a central leg 6 and a yoke 8 carrying a winding 9.
  • the central leg 6 has a width b and a height h and a length e, whereas the length of each outer branch is g.
  • the width of the yoke is f.
  • armature 10 is shown in Fig. 8, whereby 11 represents the central portion or leg and 12 represents the outer portions or legs of the armature.
  • the relay is shown in side view in Fig. 9 wherein 13 represents a holding means for maintaining the armature 10 against the core. 14 is an adjusting screw and A represents the airgap between the outer left hand ends of parts 6 and 10.
  • Figs. 10 and 11 a relay obtained when modifying the relay of Figs. 7 to 9 in the above suggested manner.
  • An active branch is a branch of the core, no point of which is in magnetic contact with the armature when the latter is in its released position.
  • the force required for the lifting operation of the relay is generated in the air gap between the underside of the branches and the armature.
  • An outer branch or passive branch is a branch of the core, which is in permanent magnetic contact with those parts of the armature which constitute the turning axis of the armature. Owing to this contact, a magnetic short circuit occurs and no part of the flux theoretically passes through the air gap between the underside of the passive branch and the armature.
  • reference numeral 15 designates the active branch and 16 designates the passive branch.
  • the coil winding is designated by 17.
  • FIG. 11 an armature 18 is shown, R being the distance between the armature and its turning axis, while L is the active length of the armature.
  • FIG. 12 A symmetrical relay built in accordance with the same principle is shown in Fig. 12.
  • the relay of Fig. 12 is developed from the one according to Fig. 10 by dividing the active branch into two halves, each having a width of [7/2, b being the total width of the active branches. The two halves are situated on both sides of the passive branch.
  • the total width (b/2+b/2) of the active branches is in an approximate relationship to the height it such as 7 to 1.
  • the reference numeral 19 designates the passive branch of a core, and 20 designates the active branches.
  • the coil windings encompassing the passive branch 19 are designated by 21.
  • Fig. 13 shows an associated armature 22.
  • a magnetic relay circuit comprising a relay coil, a magnet core having an active branch and two passive branches, said active branch being disposed symmetrically in relation to the passive branches, a pivotally mounted armature having a main portion and at least one arm portion, said armature forming a variable airgap with the active branch of the core, the length of the arm portion of the armature, the length of the main portion of the armature, the distance between the pivot axis of the 11 I armature and the point of contact of the outer forces acting 'upon the armature, the airgap, the permeability of the magnetic material used in the magnetic circuit, the cross-sectional area of the core at a right angle to the direction of the magnetic lines of force and the width of the core being correlated in accordance with the equation:
  • R is the length of the arm portion of the armature, L the length of the main portion of the armature, (R+l) the distance between the pivot axis of the armature and the point of attack of the outer force acting upon the armature, 5 the maximum airgap between the armature and the core, a the permeability of the magnetic material, A; the cross-sectional area of the core at right angles to the direction of the magnetic lines of force, b the width of the core, and (D+L half the length of the path of the lines of force in the magnetic material for selectively providing a maximum lifting force of the armature for a given number of ampere turns of the coil and a minimum number of ampere turns for a given lifting force respectively.
  • a magnetic relay circuit according to claim 1 wherein said core has a transverse portion and a longitudinal portion disposed at a rightangle thereto, said longitudinal portion constituting the active branch of the core, the total width (1) of the transverse portion of the core being at least equal to the length (e) of the longitudinal portion of the core.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Electromagnets (AREA)
US737182A 1955-02-19 1958-03-27 Electromagnetic relay Expired - Lifetime US2918611A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
BE538144D BE538144A (fr) 1955-02-19
DEP14101A DE1023823B (de) 1955-02-19 1955-05-12 Elektromagnetisches Relais
FR1131997D FR1131997A (fr) 1955-02-19 1955-05-12 Relais électro-magnétiques
CH341230D CH341230A (fr) 1955-02-19 1955-05-13 Relais électromagnétique
US518872A US2858488A (en) 1955-02-19 1955-06-29 Electromagnetic relay
US737182A US2918611A (en) 1955-02-19 1958-03-27 Electromagnetic relay

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
SE2858488X 1955-02-19
GB1396755A GB781119A (en) 1955-05-13 1955-05-13 Improvements in or relating to electro-magnetic relays
US518872A US2858488A (en) 1955-02-19 1955-06-29 Electromagnetic relay
US737182A US2918611A (en) 1955-02-19 1958-03-27 Electromagnetic relay

Publications (1)

Publication Number Publication Date
US2918611A true US2918611A (en) 1959-12-22

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US737182A Expired - Lifetime US2918611A (en) 1955-02-19 1958-03-27 Electromagnetic relay

Country Status (4)

Country Link
US (1) US2918611A (fr)
BE (1) BE538144A (fr)
CH (1) CH341230A (fr)
FR (1) FR1131997A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4514711A (en) * 1983-07-30 1985-04-30 Matsushita Electric Works, Ltd. AC Drive electromagnetic relay

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT387376B (de) * 1986-02-21 1989-01-10 Leopold Makovec Anordnung zur behandlung von wasser

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4514711A (en) * 1983-07-30 1985-04-30 Matsushita Electric Works, Ltd. AC Drive electromagnetic relay

Also Published As

Publication number Publication date
CH341230A (fr) 1959-09-30
BE538144A (fr)
FR1131997A (fr) 1957-03-04

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