US2437893A

US2437893A - Electromagnetic operator

Info

Publication number: US2437893A
Application number: US482850A
Authority: US
Inventors: William A Ray
Original assignee: General Controls Co
Current assignee: General Controls Co
Priority date: 1943-04-13
Filing date: 1943-04-13
Publication date: 1948-03-16
Anticipated expiration: 1965-03-16

Description

March 16, 1948. w. A. RAY 2,437,893

ELECTROMAGNETIC OPERATOR Filed April 13, 1943 M/ILL/AM ,4. PAY,

Inventor;

orgy, mains: 'yet"the""structure of alternating current "clectrornagnets'presentssomebomplicati'ons. Ac- *cordingl'y, it has been'proposed to rectify the al- 'ternating current and to-operate'a direct current ensue-magnate the rectified current; A sim- Patented Mar. 16, 1948 ELECTROMAGNETIC OPERATOR William A; Ray,= Glendale, Caliii, assignor to General Controls a corporation Application April 13, 1943, Serial No; 482,850

v 8 Claims. 1

* This invention relates to an 'electromagnet, and

' especially "to onethat is utilized for applying a magnetic force-to movean operator.--Such an op- "erator, forexai'nple, may b'e'usedto control a valve. Electromagnets forsuch purposes are now.

- incomrnon use. "These -electromagnets usually employ a movable plunger orarmature that serves to-applytheforceto ano'perator.

' "It is necessary- -to"piovide an electromagnet ariavingsufiicient'powertomove the-plunger or' armature rapidly t'o-theenergizedposition; yet 1 sucnpower is unnecessary merely to hold the opera'tor in'that position; Once energized, the pow- 'erofthe 'ele'ct'romag'net may be materially rednced-withou't-danger ofr'novement of the plunger or' armature" to-de en'erg'ized position. Allthis iswell'understoodt it is"-'referred to herein because one aspectofth'einvention'relates to the control oi-the'p'ower'of the'electromagnet.

In-such magnets, it"has"been-common, in the pastgto' provide acondenser' in parallel with the coil of the electromagnetfwhen the circuit is v interruptedftlie inductivekick of the coil is abs'oroed bythe condenser,andsparking at the-contacts is materially-reduced.

It is an object or this invention to make it possible ad-obtainthe'advantages of such a condenswhen the electromagnetiis'-d'e=en'ergized. Since tli'e"seconda1'y coil isnot' short'circuiteddurin the'pe'riod when the armature orplun'ger is mov ing' to attracted position, it is-ensured that the initial rush ofcurrent to the elec'tromagnet will notinduce "a""-destructivelyheavy current in the secondarycoil.

- It smother-o jector thisinvention to make it v possible to'use ag'coil to perform-the dual function of supplementing thep'o'werof the electromagnet during'the major portion; of-the' stroke, and of providing the short circuited coil thereafter.

It is advantageous to beable to operate an elecai ne't'fromavailable sources of electrical en such ascommerciar alternating current ple' iorm of re'ctifierfsu'cli as "dry disc type, producesF-a riulsating c went-game there is some likelihood cf'pr'odocing enatter -wh'en': the armature or pl uri'g'r isin attractedposition.

It is another object of thls'inventi'onieto provide an electromagnet-capableof" operating; .on a pulsating current, and that is-'relativelyzfree'iof chatter. This object is zaccomplished by, the short-circuited coil; which hastheefiectrof steadying the fluxthrough the :core.

This invention possesses 1 many other. advantages, and has other objects which may be ,made

more easily apparent from.aconslderation of;one

embodiment of the inventioni For :thislpurpose there is shown a 'form in theidrawingsaccompanying and forming part of thelpresentspecification. The form will n0w=be describeindetail, illustratin the general principles of thezinvention; but it is to-be understoodthatthisfietailed description is not to be taken in a limiting-sense, since the'scope of this invention isbestdefined by the appended claims.

Referring to the drawing,theasinglefigure is a wiring diagram of a circuit,- including anioperator that embodies the invention.

In the present instance-there is shown'an electromagnet I having a core H. The core is diagrammatically illustrated asone having a :pair of arms, provided with the pole pieces 2-x-and 3. These pole piecesco-operate with a movable armature i. The armatured may-be provided with a stem or operating membericonnectedyforexample, to a load to beoperated." The. member 5, for examplamay be thestem of a valve to be. operated by the electromagnet I.

In order to attract the armature-4 and tomeve it into contact with the pole pieces :2 and .3, energizing coils are'provided on thecore II. The core l! thus carries a coil .6,=:arranged-inthe present instance to beoperatedby asource of a1- ternating current toxwhichmains: 25 and'ZG may be connected. However, the electromagnet .l: is arranged for operating oddirectcurrent; and, for that reason, a rectifier'S isincludedvbetween mains 25 and ZG-andthe coil 6. This rectifier 9 may be of a conventional dry disc variety having stacks of discs forming a closed bridge circuit.

The coil 6 may be connected directly to the diagonal points T and 8 oftthevrectifier":bridge; and the mains 25 and-'26 :maybe connected through a switch 12 to the 0therdiagonalpoints i3 and it; The 'magnetomotive force produced by the coil 6 is temporarily augmented-or. supplemented in order to assist int-pulling the armature 4 to the pole-piecesland 3." However, as soon as the armature 4-imoves away from-its unattracted position, thetsupplemental:magnetomotive force is discontinued.

In order to obtain this-'ivresultfzuse. is made of functions:

3 a supplemental coil I 4, placed on core H in assisting relation to the coil 6. With the switch l2 closed and the armature 4 not yet started from its unattracted position, the circuit for coil [4 is completed through the following path: From diagonal point I of the rectifier 9, to the right hand terminal l5 of the coil [4, through the coil I l, left hand terminal l6, connection l'l, contact arm l8, contact I9 carried by the arm l8, stationary contact point 20, and a connection 2%, to the opposite diagonal point B. The arm i8 is shown as eangularly moved in response to the movement of the armature 4, and, for this purpose, may have its left hand end pivoted at 2'! to the stem 5. Thus, when the armature A is in the unattracted position, the arm l8, appropriately pivotally supported on standard 22, is in a position such as to maintain contact between contact points l9 and 20. As soon as the armature A is attracted and moves away from its unattracted position, contacts I 9 and 20 separate,.and coil, M is no longer eiiective to assist or supplement the coil 6.

Accordingly, by this means, a high inrush of electric energy is provided, to ensure that the armature ll will be attracted with a force strong enough to pull it into contact with the poles 2 and 3. When the armature 4 arrives at, or near, the fully attracted position, the magnetomotive force required merely to hold it in that position can be reduced; and this is accomplished by the de-energization of coil I4.

Opening the switch 52 after the electromagnet l has been energized would result in harmful arcing and sparking at the switch contacts. Breaking of a circuit in which there is a heavy inductance, such as the coil 6, is attended with these difiiculties, since the induction of the circuit tends to maintain an arc across the contacts a condenser is obviated. Instead, the arrangement is such that the coil l4, after its temporary energization, is short-circuited to absorb the inductive kick. Short-circuiting of the coil it can be accomplished by the aid of a contact point '23 carried on the lower part of the arm l8, and a co-operatin stationary contact point 24. Thus, when the armature 4 approaches its attracted position,

contact points

23 and 24 engage and the coil M is short-circuited through these two contacts. The complete short-circuit includes the right hand terminal l5 of coil l4,

contacts

24 and 23, arm l8, connection I1, and left hand terminal l8. 2

' This short-circuit persists until the armature 4 begins to drop away from the pole pieces 2 and 3 upon de-energization of the coil 14. Accordingly, when switch i2 is opened, .a substantial part of the inductive kick is absorbed in the coil is.

Since the coil [4 is shorted while the electromagnet l is energized, it serves, as heretofore stated, to reduce the fluctuations of the magnetism in core ll. Coil [4 thus serves three first, temporarily to augment the power of the electromagnet; then to provide a circuit that reduces the self-inductance of the holding coil 5; and, lastly, to smooth out the variations in magnetism in the core ll.

The inventor claims 1 1. In an electromagnet,- a magnetic member adapted to be influenced by a magnetomotive force to move from an unattracted position to an attracted position, a coil adapted to be connected to a source of electrical energy, another coil also adapted to be connected to said source, and magnetically coupled in cumulative relation to said first coil and connected to said source in parallel with the first coil, and means operated in response to substantial movement of said member from its unattracted position for successively disconnecting said other coil for parallel arrangement and short-circuiting the said other coil.

. 2. In an electromagnet, a magnetic member adapted to be influenced by a magnetomotive force to move from an unattracted position to an attracted position, a coil adapted to be connected to a source of electrical energy, another coil also adapted to be connected to said source, and magnetically coupled in cumulative relation to said first coil and connected to said source in parallel with the first coil, and means operated in response to substantial movement of said member from its unattracted position for short-oircuiting the said other coil, said short-circuiting means bein arranged to open the circuit of the said other coil when the member moves away from its attracted position.

3. In an electromagnet, a magnetic member adapted to be influenced by a magnetomotive force to move from an unattracted position to an attracted position, a pair of coils in cumulative relation and adapted to be connected to a source of pulsating electrical energy to cause said member to be attracted, and means operated in response to movement of said member from its unattracted position for disconnecting one only of the coils from the source and for thereafter short-circuiting said one coil.

4. In an electromagnet, a magnetic member adapted to be influenced by a magnetomotive force to move from an unattracted position to an attracted position, a pair of coils in cumulative relation and adapted to be connected to a source of pulsating electrical energy to cause said member to be attracted, and means operated in response to movement of said member from its unattracted position for disconnecting one only of the coils from the source and for thereafter short-circuiting said one coil, said means being arranged to'open the short-circuit of said one of the coils when the member moves away from its attracted position.

5. In an electromagnet, a magnetic core, a pair of coils disposed on the core in cumulative relation, a magnetic member co-operating with the core and arranged to be moved from an unattracted to an attracted position, a source of pulsating current for energizing said coils, and a circuit controller operated by movement of said member in response to energization of the coils for de-energizing one only of the coils when said member moves away from its unattracted position, as well as for thereafter short-circuiting said one of the coils.

6. In combination, a full wave rectifier having an input adapted to be connected to a source of alternating current, a first coil adapted to be connected to the output side of the rectifier, a magnetic member movable to an attracted position when said coil is energized, a second coil wound cumulatively with said first coil, and

adapted to be connected to said-rectifier, and

means operated in response to movement of said member toward its attracted position for disconnecting said second coil from the rectifier and 5 for thereafter short-circuiting said second coil.

7. In combination, a full wave rectifier, means for optionally connecting the input of said rectifier to a source of alternating current, an electromagnet including a first coil connected to the output of said rectifier, and a second coil wound in assisting relation to the first coil, a magnetic member adapted to be moved from an unattracted position to an attracted position and to be retained in said attracted position upon energization of said magnet, and means operated in response to movement of said member for connecting said second coil to the output of said rectifier when the member is in its unattracted position and for short-circuiting the second coil when the member is in its attracted position.

8. In combination, an electromagnet having a first coil and a second coil wound in assisting relation, a magnetic member adapted to be influenced by said magnet to move from an unattracted position to an attracted position, switch means for connecting said second coil to a source of electrical energy and means operating in response to movement of said member for shortcircuiting said second coil when said member is in its attracted position.

WILLIAM A. RAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 954,745 Larsen Apr. 12, 1910 1,005,856 Linquist Oct. 17, 1911 1,717,247 Perry June 11, 1929 1,742,367 Nettleton June 11, 1929 1,978,737 Bower et a1 Oct. 30, 1934 1,979,127 Warrick Oct. 30, 1934 2,001,494 Jones May 14, 1935 2,274,013 Swenson Feb. 24, 1942 FOREIGN PAIENTS Number Country Date 284,409 Germany May 21, 1915