US1689946A - Electromagnetic relay device - Google Patents

Electromagnetic relay device Download PDF

Info

Publication number
US1689946A
US1689946A US65981A US6598125A US1689946A US 1689946 A US1689946 A US 1689946A US 65981 A US65981 A US 65981A US 6598125 A US6598125 A US 6598125A US 1689946 A US1689946 A US 1689946A
Authority
US
United States
Prior art keywords
armature
permanent magnet
electromagnet
relay
pole
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
US65981A
Inventor
Hudd Alfred Ernest
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Automatic Electric Inc
Original Assignee
Automatic Electric Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Automatic Electric Inc filed Critical Automatic Electric Inc
Application granted granted Critical
Publication of US1689946A publication Critical patent/US1689946A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00Electromagnetic relays
    • H01H51/22Polarised relays
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H50/00Details of electromagnetic relays
    • H01H50/54Contact arrangements
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H51/00Electromagnetic relays
    • H01H51/22Polarised relays
    • H01H51/2272Polarised relays comprising rockable armature, rocking movement around central axis parallel to the main plane of the armature
    • H01H51/2281Contacts rigidly combined with armature

Definitions

  • the positiveness of a polarized relay in its deenergized position used for controlling such vital circuits as are demanded in railway signalling is a very desirable feature.
  • the polarizing field is arranged to operate in such manner as to assist the normal restoring forces in maintaining the relay armature in its normal position on the failure of energizing current.
  • the operating member of the relay is adapted to take up two different positions according to the direction of the exciting current While its armature is adapted to operate always in the same direction irrespective of the direction of the exciting current, magnetic attraction between the operating memher and the armature ensuring the movement of the former'when the latter is attracted.
  • Figs. 1, 2 and 3 show end elevations of a three position polarized relay in its normal and two energized positions respectively, while Fig. 4 shows a side elevationof the same relay.
  • Figb5 shows a side elevation of atwo position polarized relay and'Fig. 6 an end elevation of the same relay.
  • Thf'three posit-io'n polarized relay has a d e-energized position shown in 1, one position when energized. with say positive current shown in Fig.2 and one position when energized withnega'tive current shown in Fig. 3.
  • the two position relay shown in magnet.
  • Figs. 5 and 6 is polarized in such manner that, say positive current or no current will ass1st the normal restoring forces of the relay to maintain it in an inoperative position and that negative current only will operate the relay to close its contacts.
  • the relay comprises a fixed solenoid or helix 3, an armature 1, a swinging contact carrier 5- of non-magnetic material, and a permanent magnet 8.
  • the armature consists of a bar extending through the rectangular opening in the solenoid 3,and is pivoted on a pair of non-magnetic brackets 2, (one shown in Fig. 4) secured to a downwardly extending portion 9 of the pole piece 10.
  • the free end of this armature is formed into an arch com-- prising extensions 4 and 4, as shown in Figs. 13..
  • Fig.4 also shows the extension 4 and indicates, by use of interrupted lines, that part of the armature which extends through the solenoid or helix.
  • the swinging contact carrier 5 is of nonmagnetic material and is pivoted on bearings 6 and 7.
  • the permanent magnet 8 comprising an ordinary steel bar, is traversely fixed by clips 12 and 13 to the carrier 5, so that the north and south poles of the permanent magnet are positioned immediately below the extensions 4 and 4.
  • the armature normally drops by gravity until the extensions 4 and 4 encounter the'north and south poles of the permanent magnet, and the extensions therefore normally hold the carrier in its central position as shown in Fig. 1.
  • ⁇ Vhile the relay is in this position the extensions 4- and 4 serve as a keeper for the permanent
  • the foregoing is the no current condition of the relay.
  • a return magnetic path for the armature 1 is provided by'means of the limb 9 which terminates in a pole piece 10, which completes the magentic circuit through the short-airgap 11 to the top-side of the armature 1.
  • This relay comprises a mounting panel to which are secured two non-magnetic supports 30 and 30. These supports are drilled and serve as bearings for the reduced portions 22 and 23 of core 21 of an electromagnet comprising core 21 and winding 20, as shown in Figs. 5 and 6.
  • pole pieces 24 and 24 are slightly reduced and at these points extends through pole pieces 24 and 24 in fixed relation thereto.
  • pole pieces comprise soft iron bars the ends of which are connected together with non-magnetic contact carriers 32 and 32, respectively.
  • a permanent magnet in the form of a bar 26 which-extends across thebottom end of supports and 30'. Movement in the opposite direction is limited by an armature comprising a soft iron bar 27 fixed to the supports 30 and 30 and lying against the mounting panel.
  • the movable magnetic elements in this case bars 24 and 24, are normally attracted and held in engagement with the north and south poles of the permanent magnet, leaving air-gaps 28 and 29 between I the bars 24 and 24 and the fixed armature 27.
  • the operation of the relay is as follows If direct current is passed through the windmg on the iron core 21 in such a direction as to produce a north pole at 24 and -asouth If, however, a reverse current is passed through the winding, the poles 24 and 24* will become of unlike polarity to the poles of the permanent magnet 26. The mutual attraction existing under this state of affairs prevents any movement of the iron core 21 taking place. The effect of no current or one of incorrect direction is therefore the same and the relay contactsare thus held positively in their normal position in either case.
  • a permanent magnet In an electromagnetic device, a permanent magnet, an electro-magnet, and an armature of said electromagnet influenced by the polarizing field set up by said permanent magnet when said. electromagnet is deenergized and effective when said electromagnet is energized to influence said permanent magnet.
  • a permanent magnet In an electromagnetic device, a permanent magnet, an electromagnet, an armature for said electromagnet normally engaging both poles of said permanent magnet, and a magnetic circuit produced by the energiza tion of said electromagnet effective to cause said armature to break away from one or the other pole of said permanent magnet dependent on the direction of current flow through the said electromagnet.
  • an operating winding in the form of a solenoid, a pole piece for said magnet, and an armature pivoted to one end of said pole piece and extending through said coil into close proximity to the other end of said pole piece.
  • an operating winding in the form of a solenoid a pole piece for said magnet, an armature pivoted to one end of said pole piece and extending through said coil into close proximity to the other end of said pole piece and a perma- 6.
  • winding in the form of a solenoid, a pole piece for said magnet, an'armature pivoted to one end of said pole piece and extending through said winding into close proximity to the other end of said pole piece, and a permanent magnet operated in one manner by said armature when the said winding is energized by current flow through it in one direction andin a difierent manner when the current flow is in the opposite direction.
  • an electromagnet an armature for said electromagnet operated thereby in the same manner irrespective of the direction of current flow through said electromagnet, contacts controlled'by said armature responsive to its actuation by current flow in one direction and other contacts controlled by a like movement of said armature responsive to current flow in the opposite direction.
  • an electromagnet In an electromagnetic device, an electromagnet, an armature thereforoperated in the same manner irrespective of the direction of current flow through said electro magnet, and contact springs normally held in one position by the armature when the electro-magnet is deenergized and means actuated by s'aidarmature to move said contact springs in one oftwo alternative positions when the electro-magnet is energized depending on the direction of current flow through said electromagnet.
  • an operating member carrying a permanent magnet acted upon by said armature to maintain" said operating member in definite relation thereto during the absence of current flow, said permanent magnet being positioned adjacent to one pole of said armature so that due to its magnetic characteristics it assists the normal restoring forces in maintaining the armature in its normal position.
  • a movable member, an electromagnet and associated armature for moving said member in response to current flow through the electromagnet and a permanent magnet in fixed relation to said member normally cooperating with said armature to hold said member in a neutral position while no current is flowing through said electromagnet.
  • a pivoted member having a permanent magnet secured thereto, an electromagnet having an armature normally bridgin the gap between the poles of said magnet, t e relative position of the pivot of said member with respect to that of the armature being such that when no current is flowing through the electromagnet the armature and magnetwill force the member into a neutralposition.
  • an electromagnet In an electromagnetic device, an electromagnet, an armature, a pivotally secured permanent magnet, for the electromagnet permanent magnet, but becoming a north or southpole while current flows, the direction of current flow being effective to cause one pole of said permanent magnet to oppose and the other td strengthen the attraction between the sai'd armature and magnet so that one pole of the permanent magnet follows the movement of the armature while the other assists this ,follow up action by its opposing action 13.
  • an electromagnet In an electromagnetic mechanism, an electromagnet, an armature for said electromagnet, a permanent magnet normally hav ing its poles in contact with said armature, and contact members associated with said permanent magnet influenced by the armature of said electromagnet in amanner dependent on the direction of current flow therethrough.
  • a contact carrier pivoted at its central point, a permanent magnet carried by said contact carrier and lying parallel thereto, an electromagnet associated with said contact carrier, an armature for said electromagnet pivoted in a plane at right angles to the pivot of said carrier and having extensions normally holding said carrier in a central position, said armature being eifective when the electromagnet is energized to disconnect and repel one of the permanent magnet poles and to strengthen and carry with it the other pole of said permanent magnet.
  • an electromagnet for lift- 7 v ing said armature. and a permanent magnet for assisting the restoration of sald armature when the 1nfluence of said electromagnet ceases.
  • a permanent magnet pivotally secured, an electromagnet equipped with an armature having one of its poles normally in engagement with both of the poles of said permanent magnet, and an exciting winding for actuating said armature to cause the same to in turn attract and move with it one pole of the permanent magnet and repel from it the other pole, the pole attracted being directly dependent on the polarity of the said armature.
  • an exciting winding In an electromagnetic machanism, an exciting winding, a neutral armature and a movable permanent magnet actuated b said armature in a manner dependent on t e direction'of current flow through said winding.
  • an electromagnet In an electromagnetic device, an electromagnet, a three position armature, and a two position armature for moving said three position armature to any of its positions.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Electromagnets (AREA)
  • Telephone Set Structure (AREA)

Description

Oct. 30, 1928.
1A. E. HUDD ELECTROMAGNETIC RELAY DEV ICE 2 Sheets-Sheet 2 Filed Oct. 51, 1925 f l I k- A Patented Oct. 30, 1928.
UNITED STATES 1,689,946 PATENT OFFICE.
ALFRED Earn-ism HUDD, or WALLASEY, ENGLAND, AssIGNon, BY MESNE ASSIGN- mmrs, T0 AuromAr c ELECTRIC me, or CHICAGO, ILLINOIS.
ELECTROMAGNETIC RELAY DEVICE.
lpplication filed October 31, 1925, Serial No anism which is adapted to take up in a reli- 'able and positive manner any one of three operating positions according as to whether it is energized positively or negatively or not energized at all. Moreover the arrangements are such that, if for any reason the polarizing field should fail, the electromagnetic mechanism will remain in the neutral position.
The positiveness of a polarized relay in its deenergized position used for controlling such vital circuits as are demanded in railway signalling is a very desirable feature. To this end and according to the present invention the polarizing field is arranged to operate in such manner as to assist the normal restoring forces in maintaining the relay armature in its normal position on the failure of energizing current.
The operating member of the relay is adapted to take up two different positions according to the direction of the exciting current While its armature is adapted to operate always in the same direction irrespective of the direction of the exciting current, magnetic attraction between the operating memher and the armature ensuring the movement of the former'when the latter is attracted.
In order that the invention may be clearly understood and readily carried into efi'ect, a
polarized electromagnetic mechanism or relay in accordance with the invention will now be more fully described with reference to the annexed drawings which show by way of example theinvention applied to two types of relays particularly'suit-a ble for use in railway signalling systems.
In the drawings comprising Figs. 1, 2, 3, 4,
5, and 6, Figs. 1, 2 and 3 show end elevations of a three position polarized relay in its normal and two energized positions respectively, while Fig. 4 shows a side elevationof the same relay. Figb5 shows a side elevation of atwo position polarized relay and'Fig. 6 an end elevation of the same relay.
Thf'three posit-io'n polarized relay has a d e-energized position shown in 1, one position when energized. with say positive current shown in Fig.2 and one position when energized withnega'tive current shown in Fig. 3. The two position relay" shown in magnet.
. 65,981, and in Great Britain August 22, 1925.
Figs. 5 and 6 is polarized in such manner that, say positive current or no current will ass1st the normal restoring forces of the relay to maintain it in an inoperative position and that negative current only will operate the relay to close its contacts.
Referring to Figs. 1, 2, 3, and 4 it will be seen. that the relay comprises a fixed solenoid or helix 3, an armature 1, a swinging contact carrier 5- of non-magnetic material, and a permanent magnet 8. The armature consists of a bar extending through the rectangular opening in the solenoid 3,and is pivoted on a pair of non-magnetic brackets 2, (one shown in Fig. 4) secured to a downwardly extending portion 9 of the pole piece 10. The free end of this armature is formed into an arch com-- prising extensions 4 and 4, as shown in Figs. 13.. Fig.4 also shows the extension 4 and indicates, by use of interrupted lines, that part of the armature which extends through the solenoid or helix.
The swinging contact carrier 5 is of nonmagnetic material and is pivoted on bearings 6 and 7. The permanent magnet 8 comprising an ordinary steel bar, is traversely fixed by clips 12 and 13 to the carrier 5, so that the north and south poles of the permanent magnet are positioned immediately below the extensions 4 and 4. When there is no current flowing through the solenoid the armature normally drops by gravity until the extensions 4 and 4 encounter the'north and south poles of the permanent magnet, and the extensions therefore normally hold the carrier in its central position as shown in Fig. 1. \Vhile the relay is in this position the extensions 4- and 4 serve as a keeper for the permanent The foregoing is the no current condition of the relay.
A return magnetic path for the armature 1 is provided by'means of the limb 9 which terminates in a pole piece 10, which completes the magentic circuit through the short-airgap 11 to the top-side of the armature 1.
When say a positive current is passed through the winding of the solenoid 3 the armature 1 is pulled up toward the pole piece 10,
in so doing however,.it will drag one end ofthe permanent magnet 8 with it, and thus close the contact making fingers 14 on one side of the carrier 5'. The particular end or pole of the permanent magnet 8 which is lifted is determined by the polarity'pr'oduced in the pole extensions 4and 4.
When the current flow through the winding of the solenoid is in one direction the extensions 4 and 4" will be of north polarity. Under these circumstances the south pole of the permanent magnet will remain attracted to extension 4. as illustrated in Fig. 2, and this end of the permanent magnet will follow the upward movement of the extension 4. This upward movement of the south pole of the permanent magnet is assisted by the repelling action between the extension 4 and the north pole of the permanent magnet.
When the current flow is in the reversed direction, the extensions 4 and 4 become of south polarity, and therefore in this case the north pole of the permanent magnet will be lifted by the extension 4 of armature 1.
It will be seen that in this manner the'actual work done to effect the closingof the contact fingers 14 on either side of the relay is performed by the lift of the armature 1 toward the pole piece 10. The selection or determination of which series of contacts 14 requiring to be closed is determined entirely by the polarity of the permanent magnet 8 in its relation to the polarity of the pole extensions 4 and 4*.
Referring now to the two position polarized relay shown in Figs. 5 and 6, it will be seen that in this structure no rocking carrier is required as only'one series of contacts are used to be operated when the relay is deenergized.
This relay comprises a mounting panel to which are secured two non-magnetic supports 30 and 30. These supports are drilled and serve as bearings for the reduced portions 22 and 23 of core 21 of an electromagnet comprising core 21 and winding 20, as shown in Figs. 5 and 6.
Just outside each end of the winding 20 the *core is slightly reduced and at these points extends through pole pieces 24 and 24 in fixed relation thereto. These pole pieces comprise soft iron bars the ends of which are connected together with non-magnetic contact carriers 32 and 32, respectively.
The rotary movement of the pole piece and carrier unit thus constructed is limited in one direction by a permanent magnet in the form of a bar 26 which-extends across thebottom end of supports and 30'. Movement in the opposite direction is limited by an armature comprising a soft iron bar 27 fixed to the supports 30 and 30 and lying against the mounting panel. With this construction, as in the three position relay, the movable magnetic elements, in this case bars 24 and 24, are normally attracted and held in engagement with the north and south poles of the permanent magnet, leaving air-gaps 28 and 29 between I the bars 24 and 24 and the fixed armature 27.
The operation of the relay is as follows If direct current is passed through the windmg on the iron core 21 in such a direction as to produce a north pole at 24 and -asouth If, however, a reverse current is passed through the winding, the poles 24 and 24* will become of unlike polarity to the poles of the permanent magnet 26. The mutual attraction existing under this state of affairs prevents any movement of the iron core 21 taking place. The effect of no current or one of incorrect direction is therefore the same and the relay contactsare thus held positively in their normal position in either case.
What I' claim and desire to protect by Letters Patent is 1. In an electromagnetic mechanism of the polarized type, an operating member adapted to take up two different positions and an armature adapted to operate always in the same direction irrespective of the direction of exciting current to bring about the movement of the-operating member to either of its positions.
2. In an electromagnetic device, a permanent magnet, an electro-magnet, and an armature of said electromagnet influenced by the polarizing field set up by said permanent magnet when said. electromagnet is deenergized and effective when said electromagnet is energized to influence said permanent magnet.
3. In an electromagnetic device, a permanent magnet, an electromagnet, an armature for said electromagnet normally engaging both poles of said permanent magnet, and a magnetic circuit produced by the energiza tion of said electromagnet effective to cause said armature to break away from one or the other pole of said permanent magnet dependent on the direction of current flow through the said electromagnet.
4. In an electromagnetic device, an operating winding in the form of a solenoid, a pole piece for said magnet, and an armature pivoted to one end of said pole piece and extending through said coil into close proximity to the other end of said pole piece.
5. In an electromagnetic device an operating winding in the form of a solenoid, a pole piece for said magnet, an armature pivoted to one end of said pole piece and extending through said coil into close proximity to the other end of said pole piece and a perma- 6. In an electromagnetic device, an operat-,
I In
ing winding in the form of a solenoid, a pole piece for said magnet, an'armature pivoted to one end of said pole piece and extending through said winding into close proximity to the other end of said pole piece, and a permanent magnet operated in one manner by said armature when the said winding is energized by current flow through it in one direction andin a difierent manner when the current flow is in the opposite direction.
7. In an electromagnetic device, an electromagnet, an armature for said electromagnet operated thereby in the same manner irrespective of the direction of current flow through said electromagnet, contacts controlled'by said armature responsive to its actuation by current flow in one direction and other contacts controlled by a like movement of said armature responsive to current flow in the opposite direction.
e 8. In an electromagnetic device, an electromagnet, an armature thereforoperated in the same manner irrespective of the direction of current flow through said electro magnet, and contact springs normally held in one position by the armature when the electro-magnet is deenergized and means actuated by s'aidarmature to move said contact springs in one oftwo alternative positions when the electro-magnet is energized depending on the direction of current flow through said electromagnet.
9. In an electromagneticmechanism of the polarized type, 'an armature, an operating member carrying a permanent magnet acted upon by said armature to maintain" said operating member in definite relation thereto during the absence of current flow, said permanent magnet being positioned adjacent to one pole of said armature so that due to its magnetic characteristics it assists the normal restoring forces in maintaining the armature in its normal position. 10. In a three position electromagnetic device, a movable member, an electromagnet and associated armature for moving said member in response to current flow through the electromagnet and a permanent magnet in fixed relation to said member normally cooperating with said armature to hold said member in a neutral position while no current is flowing through said electromagnet.
11. In an electromagnetic device, a pivoted member having a permanent magnet secured thereto, an electromagnet having an armature normally bridgin the gap between the poles of said magnet, t e relative position of the pivot of said member with respect to that of the armature being such that when no current is flowing through the electromagnet the armature and magnetwill force the member into a neutralposition.
'12. In an electromagnetic device, an electromagnet, an armature, a pivotally secured permanent magnet, for the electromagnet permanent magnet, but becoming a north or southpole while current flows, the direction of current flow being effective to cause one pole of said permanent magnet to oppose and the other td strengthen the attraction between the sai'd armature and magnet so that one pole of the permanent magnet follows the movement of the armature while the other assists this ,follow up action by its opposing action 13. In an electromagnetic mechanism, an electromagnet, an armature for said electromagnet, a permanent magnet normally hav ing its poles in contact with said armature, and contact members associated with said permanent magnet influenced by the armature of said electromagnet in amanner dependent on the direction of current flow therethrough.
14. In an electromagnetic device, a contact carrier pivoted at its central point, a permanent magnet carried by said contact carrier and lying parallel thereto, an electromagnet associated with said contact carrier, an armature for said electromagnet pivoted in a plane at right angles to the pivot of said carrier and having extensions normally holding said carrier in a central position, said armature being eifective when the electromagnet is energized to disconnect and repel one of the permanent magnet poles and to strengthen and carry with it the other pole of said permanent magnet.
15. In an electromagnetic mechanism of the lOS armature therefore, an electromagnet for lift- 7 v ing said armature. and a permanent magnet for assisting the restoration of sald armature when the 1nfluence of said electromagnet ceases.
18.7In an' electromagnetic mechanism, a
h contact carrying element, an armature, an
electromagnet effective when energized to attract said arma-ture into the same definite relation to said electromagnet irrespective of the direction of current flow through said electro-';-
magnet,'and means associated with said carrier and armature for causing said armature to move said'carrienina direction dependent on the direction of current flow through said electromagnet. a 19. In a polarized relay, a permanent magnet pivotally secured, an electromagnet equipped with an armature having one of its poles normally in engagement with both of the poles of said permanent magnet, and an exciting winding for actuating said armature to cause the same to in turn attract and move with it one pole of the permanent magnet and repel from it the other pole, the pole attracted being directly dependent on the polarity of the said armature. g 20. In an electromagnetic machanism, an exciting winding, a neutral armature and a movable permanent magnet actuated b said armature in a manner dependent on t e direction'of current flow through said winding. 21. In an electromagnetic device, a perma nent magnet, an e'lectromagnet, an armature for said electromagnet permanently magnetically attracted and held in contact with said permanent magnet, and electro mechanical means efiective upon energization of said electromagnet to move said armature in a definite direction irrespective of the direction of current flow and to bring about a movement of said permanent magnet in a direction depending on the direction of current flow.
22. In an electromagnetic device, an electromagnet, a three position armature, and a two position armature for moving said three position armature to any of its positions.
In testimony whereof I affix my signature.
ALFRED ERNEST HUDD.
US65981A 1924-11-22 1925-10-31 Electromagnetic relay device Expired - Lifetime US1689946A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB28000/24A GB251317A (en) 1924-11-22 1924-11-22 Improvements in or relating to electromagnetic mechanisms

Publications (1)

Publication Number Publication Date
US1689946A true US1689946A (en) 1928-10-30

Family

ID=10268655

Family Applications (1)

Application Number Title Priority Date Filing Date
US65981A Expired - Lifetime US1689946A (en) 1924-11-22 1925-10-31 Electromagnetic relay device

Country Status (2)

Country Link
US (1) US1689946A (en)
GB (3) GB195824A (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE968610C (en) * 1943-06-27 1958-03-13 Siemens Ag Glass-metal fusion
NL131442C (en) * 1959-11-07
US4570138A (en) * 1983-01-31 1986-02-11 Matsushita Electric Works, Ltd. Balanced armature type relay

Also Published As

Publication number Publication date
GB251317A (en) 1926-04-22
GB252649A (en) 1926-05-25
GB195824A (en) 1923-04-12

Similar Documents

Publication Publication Date Title
US3001049A (en) Magnetic latch
US2245391A (en) Polarized relay
US1606164A (en) Circuit-controlling device
US1837188A (en) Polarized switch
US1689946A (en) Electromagnetic relay device
US2483658A (en) Polarized electromagnetic relay
US2203888A (en) Electrical relay
US2881365A (en) Neutral relay
US1426993A (en) Closed-circuit relay
US1716357A (en) Electromagnetic relay
US1822496A (en) Electrical relay
US2140604A (en) Electrical relay
US2486086A (en) Relay
US1792318A (en) Electromagnetic apparatus
US2336782A (en) Electrical polar neutral relay
US1638098A (en) Relay
US1427368A (en) Circuit interrupter
US2817796A (en) Polarised relays
US1427369A (en) Circuit interrupter
US1959562A (en) Electrical relay
US2345490A (en) Electrical relay
US2373202A (en) Electric instrument relay
US2180288A (en) Electromagnet
US2421998A (en) Electrical circuit controlling device
US3452253A (en) Electromagnetic actuator having a pair of electromagnets with an armature movable between them