EP0311998A1 - Circuit for the impulse-rate feeding of armoured electromagnets and electromagnets fed by such circuit - Google Patents

Circuit for the impulse-rate feeding of armoured electromagnets and electromagnets fed by such circuit Download PDF

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Publication number
EP0311998A1
EP0311998A1 EP88116901A EP88116901A EP0311998A1 EP 0311998 A1 EP0311998 A1 EP 0311998A1 EP 88116901 A EP88116901 A EP 88116901A EP 88116901 A EP88116901 A EP 88116901A EP 0311998 A1 EP0311998 A1 EP 0311998A1
Authority
EP
European Patent Office
Prior art keywords
current
electromagnet
fed
electromagnets
circuit
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.)
Withdrawn
Application number
EP88116901A
Other languages
German (de)
English (en)
French (fr)
Inventor
Antonio Faccini
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP0311998A1 publication Critical patent/EP0311998A1/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/18—Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
    • H01F7/1805—Circuit arrangements for holding the operation of electromagnets or for holding the armature in attracted position with reduced energising current
    • H01F7/1838—Circuit arrangements for holding the operation of electromagnets or for holding the armature in attracted position with reduced energising current by switching-in or -out impedance

Definitions

  • the invention concerns the realization of a circuit for the impulse-rate feeding of armoured electromagnets and of electromagnets fed by such circuit.
  • the invention is particularly efficient when applied to electromagnets having small and medium traction fields of force.
  • electromagnets are electromechanical devices which are used as driving units in different fields of application, such as automations, armour-­plated doors, actuators, etc.
  • the currently known constructions are electromagnets having a cylindrical mobile core which are usually fed with direct current, or electromagnets fed with alternate current, but they are built with a frame and with a lamellar pack. In both of the just-mentioned constructions, the electromagnet coil is fed at a fixed voltage.
  • each magnet The distinctive and characteristic elements of each magnet are the maximum traction force which the electromagnet can exert in relation to the stroke of its mobile core and the maximum number of driving movements that can be performed within a pre­determined period of time.
  • the current required when the electromagnet is in its closed position is 10 - 15 times lower than the current necessary to move the core during the traction phase.
  • the current is higher when the electromagnet is in its open position, than when the electromagnet is it closed position, since the inductance value is low when the electromagnet is open and high when the electromagnet is closed.
  • the main limit of the direct-current electromagnets consists in the fact that the current passing through the winding is practically constant during the entire operation, that is both during the opening and the closing of the electromagnet.
  • the purpose of the invention is that of obtaining a simply constructed electromagnet with reduced dimensions and high-level operations both concerning the traction capacity and the number of cycles which it can withstand.
  • Another purpose is that of obtaining an electromagnet fed by an alternate-current source, wherein the coil is passed through by high current in the opening phase, so that said electromagnet may develop a considerable traction force and that, at the same time, the current may be reduced to the minimum necessary to maintain the closed position, in order to avoid energy waste and damaging high temperatures which limit its functional performance. That is, the proposed construction should guarantee a high ratio between the traction current and the closing current.
  • Yet another purpose is that of making an electromagnet available, the construction of which is to be considerably simplified both from the mechanical and the electrical point of view, in comparison with electromagnets giving equal performances.
  • an armoured electromagnet which, in accordance with the patent claims, includes a metal, preferably cylindrical, structure, consisting of a cylindrical container, inside which there is an axial opening wherein the mobile core, which is also cylindrical, slides and wherein said coil is characterized in that it is fed by an implulse-rating current with variable intensity supplied by an electronic circuit, fed with alternate current.
  • the terminals of the coil of the electromagnet are connected with the nodes of a diode bridge which is fed through a normally closed electronic switch, connected parallel to a capacitor.
  • the electronic switch which is normally closed represents a short circuit and the bridge is, therefore, fed by all the alternate current. Because of this a rectified and pulsating current will operate in the electromagnet coil; this will be the maximum current and, therefore, the maximum possible traction force of the electromagnet will develop. Since the normally closed electronic switch has a delayed opening, when said switch is run trough by current, it will open after a certain programmable period of time and at the terminals of the diode bridge a reduced voltage will operate due to the voltage drop which will operate in the capacitor placed in parallel to the feeding source of the bridge. The voltage which is reduced at the terminals of the rectifying bridge will cause the coil to be fed at a reduced current.
  • the current drop is also promoted by some special construction expedients concerning the cylindrical geometry of the electromagnet, the choice of a type of iron having a special magnetic permeability and the reduction of the air cores of the yoke between the core and the botton of the external cylindrical housing.
  • the dimensioning of the electromagnet will be dictated by the opening current necessary to develop in the coil a magnetic force exceeding the re-calling force applied to the mobile core. As far as the current keeping the closed position is concerned, it is reduced because of the zero air-­core.
  • electromagnet according to the invention makes the electromagnet according to the invention particularly advantageous when it is used in the robotic field and, in general, in the field of motion-mechanisms, where high performances and minimum dimensions are required.
  • the electromagnet consists of a cylinder-shaped housing made by cutting a normal tube available on the market, into which a coil 2 is inserted. Said coil 2 is anchored on the ring-shaped projection 3 of lid 4 closing one end of the housing. Another lid 5 closes the bottom part of the electromagnet.
  • the mobile core 6 is a solid metal cylinder which is inserted into the central opening of coil 2 and, as can be observed in Fig. 2, it can slide within the space comprised between the bottom of lid 4 and the C-­shaped stroke-stop, indicated with 8, which is connected with housing 1.
  • coil 2 of the electromagnet is fed at the terminals 20 and 21 of the diode-bridge.
  • coil 2 is run through by a rectified pulsating current which is approximately equal to the voltage applied to the terminal 22 and 23 of the diode bridge, devided by the resistance of coil 2 of the electromagnet.
  • the electronic switch 40 will open, and its opening causes a voltage drop at the terminals of capacitor 31.
  • the electronic switch 40 which is normally closed and has a delayed opening, will not be further described, since it is a device known to people who are knowledgeable in this field.
  • the electromagnet according to the invention which, because it is fed with a rectified current, can be made from a tube or, in any case, of a compact iron material, without any need for magnetic lamellar constructions in order to avoid spurious currents due to the circulation of alternate currents.
  • the housing of electromagnet 1 is a tube which can readily be found on the market; it is cut at its ends and closed with two simple, easily manufactured caps.
  • the electronic circuit shown in Fig. 3, adequately miniaturized, is placed in box 9 on top of the electromagnet, so that a compact construction with minimum overall dimensions is obtained.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnets (AREA)
EP88116901A 1987-10-13 1988-10-12 Circuit for the impulse-rate feeding of armoured electromagnets and electromagnets fed by such circuit Withdrawn EP0311998A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT85617/87A IT1222350B (it) 1987-10-13 1987-10-13 Circuito per l'alimentazione in regime impulsivo di elettromagneti corazzati di trazione e trattenuta ed elettromagneti alimentati con tale circuito
IT8561787 1987-10-13

Publications (1)

Publication Number Publication Date
EP0311998A1 true EP0311998A1 (en) 1989-04-19

Family

ID=11329059

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88116901A Withdrawn EP0311998A1 (en) 1987-10-13 1988-10-12 Circuit for the impulse-rate feeding of armoured electromagnets and electromagnets fed by such circuit

Country Status (2)

Country Link
EP (1) EP0311998A1 (it)
IT (1) IT1222350B (it)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111864616B (zh) * 2020-06-22 2022-07-12 深圳供电局有限公司 显示设备控制电路和五防闭锁系统

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2545878A1 (de) * 1975-10-14 1977-04-21 Philips Patentverwaltung Schaltungsvorrichtung zur ansteuerung eines wechselstrombetaetigten magneten mit gleichstrom
GB1476102A (en) * 1974-10-28 1977-06-10 Telemecanique Electrique Supply circuits for electromagnets
JPS5788707A (en) * 1980-11-21 1982-06-02 Mitsubishi Electric Corp Ac electromagnet device
EP0177215A1 (en) * 1984-10-04 1986-04-09 APV Vent-Axia Limited DC solenoid actuator circuit

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1476102A (en) * 1974-10-28 1977-06-10 Telemecanique Electrique Supply circuits for electromagnets
DE2545878A1 (de) * 1975-10-14 1977-04-21 Philips Patentverwaltung Schaltungsvorrichtung zur ansteuerung eines wechselstrombetaetigten magneten mit gleichstrom
JPS5788707A (en) * 1980-11-21 1982-06-02 Mitsubishi Electric Corp Ac electromagnet device
EP0177215A1 (en) * 1984-10-04 1986-04-09 APV Vent-Axia Limited DC solenoid actuator circuit

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, vol. 6, no. 170 (E-128)[1048], 3rd September 1982; & JP-A-57 88 707 (MITSUBISHI DENKI K.K.) 02-06-1982 *

Also Published As

Publication number Publication date
IT8785617A0 (it) 1987-10-13
IT1222350B (it) 1990-09-05

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