US3737736A - Electromagnet-controlling system - Google Patents

Electromagnet-controlling system Download PDF

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Publication number
US3737736A
US3737736A US3737736DA US3737736A US 3737736 A US3737736 A US 3737736A US 3737736D A US3737736D A US 3737736DA US 3737736 A US3737736 A US 3737736A
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Prior art keywords
rectifier
condenser
circuit
thyristor
inserted
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
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Inventor
H Stampfli
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Lucifer SA
Parker Hannifin Manufacturing Switzerland SA
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Lucifer SA
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    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03KPULSE TECHNIQUE
    • H03K17/00Electronic switching or gating, i.e. not by contact-making or -braking
    • H03K17/51Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used
    • H03K17/56Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used using semiconductor devices
    • H03K17/72Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used using semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region
    • H03K17/73Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used using semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region for dc voltages or currents
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00Magnets
    • H01F7/06Electromagnets; Actuators including electromagnets
    • H01F7/08Electromagnets; Actuators including electromagnets with armatures
    • H01F7/18Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
    • H01F7/1805Circuit arrangements for holding the operation of electromagnets or for holding the armature in attracted position with reduced energising current
    • H01F7/1833Circuit arrangements for holding the operation of electromagnets or for holding the armature in attracted position with reduced energising current by changing number of parallel-connected turns or windings
    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03KPULSE TECHNIQUE
    • H03K17/00Electronic switching or gating, i.e. not by contact-making or -braking
    • H03K17/51Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used
    • H03K17/56Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used using semiconductor devices
    • H03K17/60Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used using semiconductor devices using bipolar transistors
    • H03K17/64Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used using semiconductor devices using bipolar transistors having inductive loads
    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03KPULSE TECHNIQUE
    • H03K17/00Electronic switching or gating, i.e. not by contact-making or -braking
    • H03K17/51Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used
    • H03K17/56Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used using semiconductor devices
    • H03K17/72Electronic switching or gating, i.e. not by contact-making or -braking characterised by the components used using semiconductor devices having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/20Output circuits, e.g. for controlling currents in command coils
    • F02D2041/2068Output circuits, e.g. for controlling currents in command coils characterised by the circuit design or special circuit elements
    • F02D2041/2079Output circuits, e.g. for controlling currents in command coils characterised by the circuit design or special circuit elements the circuit having several coils acting on the same anchor

Abstract

An arrangement for feeding the power winding of an electromagnet with rectified A.C. by means of a thyristor or triac. The latter is inserted in parallel with a transistor the conducting condition of which is provided by a condenser fed by the rectified A.C. and discharging into the base of the transistor which latter acts then on the electrode controlling the thyristor, to allow the latter to return into its non-conductive condition at the end of an alternation. A maintenance or holding current is provided either through an auxiliary electromagnet winding or through a chopped current feeding the power winding and produced by a pulse generator.

Description

United States Patent 91 Stampfli [54] ELECTROMAGNET-CONTROLLING SYSTEM [75] Inventor: Harald Stampfli,

Geneva, Switzerland Petit-Saconex,

[73] Assignee: Lucifer S. A., Carouge-Geneva,

Switzerland [22] Filed: Apr. 4, 1972 [21] Appl. No.: 240,354

[30] 7 Foreign Application Priority Data Apr. 23, 1971 Switzerland ..'.....59()9/71 June 4,1971 Germany ..P 21 28 651.1

[5 6] References Cited UNITED STATES PATENTS Gieffers ..3 l 7/DIG. 4 Lancles ..3l7/l48.5 B

[111 3,737,736 51 June 5,1973

Primary ExaminerWilliam H. Beha, Jr. Att0rneyEmory L. Groff et a1.

57 ABSTRACT An arrangement for feeding the power winding of an electromagnet with rectified A.C. by means of a thyristor or triac. The latter is inserted in parallel with a transistor the conducting condition of which is pro vided by a condenser fed by the rectified A.C. and discharging into the base of the transistor which latter acts then on the electrode controlling the thyristor, to allow the latter to return into its non-conductive condition at the end of an alternation. A maintenance or holding current is provided either through an auxiliary electromagnet winding or through a chopped current feeding the power winding and produced by a pulse generator.

5 Claims, 2 Drawing Figures ELECTROMAGNET-CONTROLLING SYSTEM The present invention covers an arrangement controlling an electromagnet and adapted to supply upon energization a strong initial current, followed by a weaker maintenance current. Such an arrangement allows in particular the electromagnet to exert a larger initial attraction without exaggeratedly heating its winding, since the maintenance current following the initial current is comparatively weak.

The control arrangement comprises, according to the invention, a Graetz rectifier connected with a supply of AC. and feeding an electromagnet winding in series with a thyristor, the control electrode and the cathode of which are connected with each other through delaying means which become conductive at a predetermined moment following the closing of a control switch.

In the accompanying drawings:

FIGS. 1 and 2 illustrate diagrammatically and by way of example two embodiments of the arrangement forming the object of the invention.

As illustrated in FIG. 1, a rectifier 1 operating on both alternations is connected through a switch S with the terminals a and b fed by a supply of A.C., e.g. the

mains.

The controlled electromagnet includes two windings B, and B the maintenance winding B being fed directly across the terminals and d of the rectifier l. The power winding B, is connected across said output terminals of the rectifier, in series with a resistance R and a transistor T,. Said winding B, is also connected with the negative output terminal d of the rectifier through a thyristor T in series with two diodes D, and D The base of the transistor T, is connected with a condenser C through a Zener diode Z. This condenser C forms with the resistance R, and RC element. The base of the transistor T, is connected with its emitter through a leak resistance R The power winding B, is shunted by a diode D The operation of the arrangement is as follows:

The closing of the switch S obviously energizes the winding B The winding B, is also subjected to a positive voltage since the transistor T, is non-conductive at the start; in fact the control electrode of the thyristor T is practically subjected to the voltage of the positive terminal c of the rectifier, whereas the cathode of said thyristor is substantially at the voltage of the terminal d. The thyristor T is therefore conductive, so that the power winding B, is fed.

The condenser C is loaded gradually through the resistance R, and when itsvoltage reaches the threshold voltage of the Zener diode, said voltage is applied on the base of the transistor T, which becomes conductive.

The control electrode of the thyristor T returns then to the voltage of the terminal b and is therefore negative with reference to the cathode of the thyristor by reason of the drop in voltage by about 2 volts across the diodes D, and D Since the drop in voltage across the transistor T, is about 0.5 V,.the control electrode is biased negatively by about 1.5 V with reference to the cathode of the thyristor T The thyristor is therefore under conditions which make its extinction an easy matter during the next passage through zero of the rectified current fed by the rectifier l.

After extinction of the thyristor T the winding B, is no longer fed and only the maintenance winding B remains operative. It should be remarked that the diode D cuts out all overvoltages in the winding B, during said extinction of the thyristor T Of course, many modifications may be brought to the circuit described and in particular it is possible to re place the Zener diode Z by any other component provided with a threshold voltage beyond which it becomes conductive.

The embodiment illustrated in FIG. 2 distinguishes from the first embodiment through the absence of an auxiliary maintenance winding B for the electromagnet. The circuit feeding the winding B, is identical with that of FIG. 1 except for a resistance R inserted be tween the collector of the transistor T, and the control electrode of the thyristor T In this second embodiment, a pulse generator 2 provides the application to the control electrode of the thyristor T of pulses synchronized with the frequency of the mains and phase-shifted with reference to the latter. Thus, when the transistor T, becomes conductive and prevents consequently the automatic ignition of the thyristor T the latter is rendered conductive during each alternation by the pulses supplied by the generator 2. Thus, there is obtained a chopped current, the average value of which is lower than that of the current obtained at the start. Said chopped current forms the maintenance current for the electromagnet.

The pulse generator comprises, as well-known per se, a single-junction transistor T fed through a resistance R, and across a Zener diode Z The voltage across the terminals of said diode Z is applied to the base of the transistor T through a resistance R which loads a condenser C Each time the voltage across the terminals of said condenser reaches the threshold value of the transistor T the latter becomes conductive and allows the passage through a resistance R, of a current which produces a voltage pulse which is applied to the control electrode of the thyristor T An important advantage of the circuits described resides in the fact that, whatever the voltage of the mains may be, the voltage to which the transistor T, is subjected never rises above a few volts, since fora voltage of this magnitude, the thyristor T becomes immediately conductive.

It is of course possible to bring numerous modifications to the wiring diagrams described and, in particular, the thyristor T may be replaced by a triac. In such a case, the pulse generator 2 may be provided so as to supply pulses of a negative polarity while the diodes B,v I"

and D may be omitted.

I claim:

1. An electromagnet-controlling system adapted to produce a strong starting current for an electromagnet power winding followed by a weaker holding current comprising a Graetz rectifier, adapted to be fed with A.C., a thyristor circuit including an anode and a cathode inserted in series between the rectifier and the electromagnet power winding and a controlling electrode, and delaying means inserted between said cathode and controlling electrode and adapted to become conductive at a predetermined moment after energization of the rectifier to allow the thyristor circuit to return to its inoperative condition and means feeding a weaker holding current to the electromagnet.

2. A system as claimed in claim 1, wherein the delaying means include a transistor, the emitter-collector circuit of which is inserted in parallel with the thyristor circuit and is connected with the controlling resistance of the latter, a resistance and condenser circuit fed by the rectifier and an element provided with a threshold voltage and operatively connecting said condenser with the transistor base as soon as the condenser voltage has reached a predetermined voltage.

3. A system as claimed in claim 1, wherein the delaying means include a transistor, the emitter-collector circuit of which is inserted in parallel with the thyristor circuit and is connected with the controlling resistance of the latter, a resistance and condenser circuit fed by the rectifier and an element provided with a threshold voltage and operatively connecting said condenser with the transistor base as soon as the condenser voltage has reached a predetermined voltage, and at least one diode inserted between the negative terminal of the rectifier and the cathode of the thyristor circuit and leading the current passing out of the latter towards voltage and operatively connecting said condenser with the transistor base as soon as the condenser voltage has reached a predetermined voltage and wherein the means feeding the holding current include a generator of pulses synchronized with the frequency of the AC. fed to the rectifier and phase-shifted with reference thereto and means for applying said pulses to the thyristor circuit.

Claims (5)

1. An electromagnet-controlling system adapted to produce a strong starting current for an electromagnet power winding followed by a weaker holding current comprising a Graetz rectifier, adaptEd to be fed with A.C., a thyristor circuit including an anode and a cathode inserted in series between the rectifier and the electromagnet power winding and a controlling electrode, and delaying means inserted between said cathode and controlling electrode and adapted to become conductive at a predetermined moment after energization of the rectifier to allow the thyristor circuit to return to its inoperative condition and means feeding a weaker holding current to the electromagnet.
2. A system as claimed in claim 1, wherein the delaying means include a transistor, the emitter-collector circuit of which is inserted in parallel with the thyristor circuit and is connected with the controlling resistance of the latter, a resistance and condenser circuit fed by the rectifier and an element provided with a threshold voltage and operatively connecting said condenser with the transistor base as soon as the condenser voltage has reached a predetermined voltage.
3. A system as claimed in claim 1, wherein the delaying means include a transistor, the emitter-collector circuit of which is inserted in parallel with the thyristor circuit and is connected with the controlling resistance of the latter, a resistance and condenser circuit fed by the rectifier and an element provided with a threshold voltage and operatively connecting said condenser with the transistor base as soon as the condenser voltage has reached a predetermined voltage, and at least one diode inserted between the negative terminal of the rectifier and the cathode of the thyristor circuit and leading the current passing out of the latter towards said negative terminal.
4. A system as claimed in claim 1, wherein the means feeding the holding current include an auxiliary holding winding inserted across the rectifier terminals in parallel with the power winding and thyristor circuit.
5. A system as claimed in claim 1, wherein the delaying means include a transistor, the emitter-collector circuit of which is inserted in parallel with the thyristor circuit and is connected with the controlling resistance of the latter, a resistance and condenser circuit fed by the rectifier and an element provided with a threshold voltage and operatively connecting said condenser with the transistor base as soon as the condenser voltage has reached a predetermined voltage and wherein the means feeding the holding current include a generator of pulses synchronized with the frequency of the A.C. fed to the rectifier and phase-shifted with reference thereto and means for applying said pulses to the thyristor circuit.
US3737736A 1971-04-23 1972-04-04 Electromagnet-controlling system Expired - Lifetime US3737736A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CH590971A CH523583A (en) 1971-04-23 1971-04-23 Device for controlling an electromagnet

Publications (1)

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US3737736A true US3737736A (en) 1973-06-05

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US3737736A Expired - Lifetime US3737736A (en) 1971-04-23 1972-04-04 Electromagnet-controlling system

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US (1) US3737736A (en)
JP (1) JPS536696B1 (en)
CA (1) CA954931A (en)
DE (1) DE2128651C2 (en)
FR (1) FR2133652B1 (en)
GB (1) GB1383086A (en)
NL (1) NL174006C (en)

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3864608A (en) * 1973-05-21 1975-02-04 Mkc Electronics Corp Combination monostable and astable inductor driver
US4114184A (en) * 1975-09-05 1978-09-12 Lucifer S.A. Control system for an electromagnet
FR2386194A1 (en) * 1977-03-31 1978-10-27 Rca Corp switching circuit has transistors
US4214290A (en) * 1976-03-19 1980-07-22 Sevcon Limited Control circuit for electromagnetically operated contactor
US4227231A (en) * 1978-09-05 1980-10-07 Eaton Corporation Integral relay low voltage retentive means
US4274122A (en) * 1979-06-20 1981-06-16 Eaton Corporation Energizing and quick deenergizing circuit for electromagnetic contactors or the like
US4291358A (en) * 1978-07-06 1981-09-22 Burkert Gmbh Magnetic valve with electronic control
US4333019A (en) * 1980-05-07 1982-06-01 Hans Weigert Silicon controlled rectifier trigger circuit
US4336564A (en) * 1979-04-04 1982-06-22 Exploration Logging, Inc. Solenoid control circuit
US4355619A (en) * 1980-10-01 1982-10-26 The Bendix Corporation Fast response two coil solenoid driver
US4432034A (en) * 1981-09-30 1984-02-14 Spraying Systems Co. Bridge rectifier for selectively providing a full-wave or a half-wave rectified voltage
US4617445A (en) * 1984-09-17 1986-10-14 Erico International Corporation Control circuit and method for stud welding gun lifting solenoid
US4754362A (en) * 1986-03-07 1988-06-28 Eaton Corporation Magnetically latching and current sensitive automatically unlatching switch assembly
US4984123A (en) * 1989-07-17 1991-01-08 Potter & Brumfield, Inc. Latching switching device having current responsive release
US5012401A (en) * 1990-03-19 1991-04-30 Allied-Signal Inc. Switching power supply with foldback current limiting
US5237262A (en) * 1991-10-24 1993-08-17 International Business Machines Corporation Temperature compensated circuit for controlling load current
US5245261A (en) * 1991-10-24 1993-09-14 International Business Machines Corporation Temperature compensated overcurrent and undercurrent detector
US5278483A (en) * 1986-04-19 1994-01-11 Sew-Eurodrive Gmbh & Co. Motor brake with single free wheeling diode connected in parallel with only one partial coil of brake magnet coil
US5281939A (en) * 1993-05-28 1994-01-25 Eaton Corporation Multiple pole solenoid using simultaneously energized AC and DC coils
US5510951A (en) * 1994-08-01 1996-04-23 Eaton Corporation Electronic control for 3-wire DC coils
US5543632A (en) * 1991-10-24 1996-08-06 International Business Machines Corporation Temperature monitoring pilot transistor
EP0726584A1 (en) * 1995-02-09 1996-08-14 Sprecher + Schuh AG Control device for an electromagnet
US5805405A (en) * 1995-10-12 1998-09-08 Schneider Electric Sa Power supply circuit of an excitation coil of an electromagnet
DE19731381A1 (en) * 1997-07-22 1999-01-28 Heinz Leiber Electromagnetic setting device for i.c. engine valve
US6276508B1 (en) * 1999-12-21 2001-08-21 United Parcel Service Of America, Inc. Chute having sortation features

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2290009B1 (en) * 1974-10-28 1979-08-03 Telemecanique Electrique
DE2922777C2 (en) * 1979-06-05 1984-08-09 Otto Heuss Gmbh & Co.Kg Herstellung Von Orgelteilen, 6302 Lich, De
JPS5824878U (en) * 1981-08-12 1983-02-17
DE3240114A1 (en) * 1981-12-09 1983-06-16 Black & Decker Inc A control circuit for an electromagnetically operated power tool, in particular tacker
GB2143696B (en) * 1983-07-18 1987-05-28 Pt Components Inc Operating coil control system
WO1991015865A1 (en) * 1990-04-05 1991-10-17 Merit-Werk Merten & Co. Kg Hinged-armature relay, especially for motor vehicles
GB2300306B (en) * 1995-04-25 2000-02-09 Pectel Control Systems Ltd Fluid injector systems
DE19645323A1 (en) * 1996-11-04 1998-05-07 Teves Gmbh Alfred Circuit for adapting the flow of a valve driver of the necessary current for operation of the valve
DE19948489A1 (en) * 1999-10-07 2001-04-12 Heinz Leiber Electromagnetic actuator device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3116441A (en) * 1960-02-19 1963-12-31 Itt Circuit for maintaining a load energized at decreased power following energization
US3274452A (en) * 1963-03-12 1966-09-20 Barnes & Reinecke Inc Degausser
US3457464A (en) * 1967-02-15 1969-07-22 Gen Time Corp Electronic timer circuits providing switching at multiple intervals
US3555367A (en) * 1968-06-07 1971-01-12 Westinghouse Electric Corp Off delay timer and internally generated auxiliary direct current voltage source for a controlled rectifier alternating current switch for use therein
US3577040A (en) * 1968-09-26 1971-05-04 Pneumo Dynamics Corp Solenoid control circuit

Family Cites Families (2)

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Publication number Priority date Publication date Assignee Title
DE1270152B (en) * 1964-09-11 1968-06-12 Siemens Ag Means for shortening the switch an inductive load
BE756904A (en) * 1969-10-24 1971-03-01 Lucifer Sa Device for controlling an electromagnet

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3116441A (en) * 1960-02-19 1963-12-31 Itt Circuit for maintaining a load energized at decreased power following energization
US3274452A (en) * 1963-03-12 1966-09-20 Barnes & Reinecke Inc Degausser
US3457464A (en) * 1967-02-15 1969-07-22 Gen Time Corp Electronic timer circuits providing switching at multiple intervals
US3555367A (en) * 1968-06-07 1971-01-12 Westinghouse Electric Corp Off delay timer and internally generated auxiliary direct current voltage source for a controlled rectifier alternating current switch for use therein
US3577040A (en) * 1968-09-26 1971-05-04 Pneumo Dynamics Corp Solenoid control circuit

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3864608A (en) * 1973-05-21 1975-02-04 Mkc Electronics Corp Combination monostable and astable inductor driver
US4114184A (en) * 1975-09-05 1978-09-12 Lucifer S.A. Control system for an electromagnet
US4214290A (en) * 1976-03-19 1980-07-22 Sevcon Limited Control circuit for electromagnetically operated contactor
FR2386194A1 (en) * 1977-03-31 1978-10-27 Rca Corp switching circuit has transistors
US4291358A (en) * 1978-07-06 1981-09-22 Burkert Gmbh Magnetic valve with electronic control
US4227231A (en) * 1978-09-05 1980-10-07 Eaton Corporation Integral relay low voltage retentive means
US4336564A (en) * 1979-04-04 1982-06-22 Exploration Logging, Inc. Solenoid control circuit
US4274122A (en) * 1979-06-20 1981-06-16 Eaton Corporation Energizing and quick deenergizing circuit for electromagnetic contactors or the like
US4333019A (en) * 1980-05-07 1982-06-01 Hans Weigert Silicon controlled rectifier trigger circuit
US4355619A (en) * 1980-10-01 1982-10-26 The Bendix Corporation Fast response two coil solenoid driver
US4432034A (en) * 1981-09-30 1984-02-14 Spraying Systems Co. Bridge rectifier for selectively providing a full-wave or a half-wave rectified voltage
US4617445A (en) * 1984-09-17 1986-10-14 Erico International Corporation Control circuit and method for stud welding gun lifting solenoid
US4754362A (en) * 1986-03-07 1988-06-28 Eaton Corporation Magnetically latching and current sensitive automatically unlatching switch assembly
US5278483A (en) * 1986-04-19 1994-01-11 Sew-Eurodrive Gmbh & Co. Motor brake with single free wheeling diode connected in parallel with only one partial coil of brake magnet coil
US4984123A (en) * 1989-07-17 1991-01-08 Potter & Brumfield, Inc. Latching switching device having current responsive release
US5012401A (en) * 1990-03-19 1991-04-30 Allied-Signal Inc. Switching power supply with foldback current limiting
US5237262A (en) * 1991-10-24 1993-08-17 International Business Machines Corporation Temperature compensated circuit for controlling load current
US5245261A (en) * 1991-10-24 1993-09-14 International Business Machines Corporation Temperature compensated overcurrent and undercurrent detector
US5543632A (en) * 1991-10-24 1996-08-06 International Business Machines Corporation Temperature monitoring pilot transistor
US5281939A (en) * 1993-05-28 1994-01-25 Eaton Corporation Multiple pole solenoid using simultaneously energized AC and DC coils
US5359309A (en) * 1993-05-28 1994-10-25 Eaton Corporation Multiple pole solenoid using simultaneously energized AC and DC coils
US5510951A (en) * 1994-08-01 1996-04-23 Eaton Corporation Electronic control for 3-wire DC coils
EP0726584A1 (en) * 1995-02-09 1996-08-14 Sprecher + Schuh AG Control device for an electromagnet
US5781396A (en) * 1995-02-09 1998-07-14 Allen-Bradley Company, Inc. Arrangement for the control of an electromagnet
US5805405A (en) * 1995-10-12 1998-09-08 Schneider Electric Sa Power supply circuit of an excitation coil of an electromagnet
DE19731381A1 (en) * 1997-07-22 1999-01-28 Heinz Leiber Electromagnetic setting device for i.c. engine valve
US6276508B1 (en) * 1999-12-21 2001-08-21 United Parcel Service Of America, Inc. Chute having sortation features

Also Published As

Publication number Publication date Type
NL174006B (en) 1983-11-01 application
NL174006C (en) 1984-04-02 grant
FR2133652B1 (en) 1977-09-02 grant
DE2128651C2 (en) 1984-01-12 grant
GB1383086A (en) 1975-02-05 application
FR2133652A1 (en) 1972-12-01 application
JPS536696B1 (en) 1978-03-10 grant
DE2128651A1 (en) 1972-11-02 application
CA954931A (en) 1974-09-17 grant
NL7205253A (en) 1972-10-25 application
CA954931A1 (en) grant

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