US2937321A - Current limiting in the windings of electromagnetic devices - Google Patents

Current limiting in the windings of electromagnetic devices Download PDF

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Publication number
US2937321A
US2937321A US671599A US67159957A US2937321A US 2937321 A US2937321 A US 2937321A US 671599 A US671599 A US 671599A US 67159957 A US67159957 A US 67159957A US 2937321 A US2937321 A US 2937321A
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United States
Prior art keywords
current
magnetic amplifier
winding
control
magnetic
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Expired - Lifetime
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US671599A
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English (en)
Inventor
Richard O Decker
Leonhard Werner
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US671599A priority Critical patent/US2937321A/en
Priority to JP3288760U priority patent/JPS3627195Y1/ja
Application granted granted Critical
Publication of US2937321A publication Critical patent/US2937321A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
    • H01H47/22—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil
    • H01H47/34—Energising current supplied by magnetic amplifier

Definitions

  • Our invention relates to an electromagnetic control system, and, more particularly, to a system for limiting the current in the winding, or coil, of an electromagnetic device designed to be energized with alternating current but in use is being supplied with a direct current, or 'at least one having a large direct-current component.
  • the coil of a solenoid operated valve, solenoid actuated clutch designed to be normally operated from a source of alternating current, or the coil of an alternating-current contactor, each represents an impedance highly dependentonthe position of the armature, or other movable part with reference to the other parts of the magnetic circuit involved.
  • a contactor for example, in open conditions the impedance is small, but the impedance increases rapidly as the armature moves from its unactuated position to its fully actuated position. That is, the impedance increases with a decrease of the air gap in the magnetic circuit with the inductance being a maximum when the air gap is closed.
  • alternating-current contactors With the extensive use of magnetic amplifiers in control circuits, having half wave rectified direct current output alternating-current contactors are'at times connected in the output circuit of the magnetic amplifier. If an alternating-current coil is thus energized from a magnetic amplifier, namely, a magnetic amplifier having a half-wave direct-current output, then the coil has to be redesigned, which is impractical, or some other means have to be provided, as current limiting resistors cut in by extra relays or auxiliary contacts on the contactor.
  • One broad object of our invention is the provision of static means for limiting the current in an inductive load when energized with a direct current.
  • Another broad object of our invention is the provision of controlling the output of a magnetic amplifier supplying an inductive load as a function of the impedance of the load.
  • FIG. 1 is a diagrammatic showing of the simplest embodiment of our invention.
  • FIG. 2 is a somewhat more elaborate diagrammatic showing of our invention.
  • a generally conventional alternating-current contactor, ACC is shown connected in the output circuit of a substantially conventional half-wave magnetic amplifier MAI.
  • the magnetic circuit carries the control windings- 9 and 14 and the main winding 2.
  • the main winding 2 is connected in a circuit that may be traced from the lefthand terminal 1 of a suitable source of single-phase alternating current, main winding 2, rectifier 3, poled as indicated, conductor 4, armature actuating winding 5, conductor 6 to the right-hand terminal 7 of the alternatingcurrent supply.
  • the control winding 14 is connected in a circuit from alternating-current terminal 12, rectifier 13, poled as indicated, control winding 14 to the alternating-current terminal 15.
  • the alternating currents supplied to terminals 1 and 7, and 12 and 15 are in phase with instant polarities as shown.
  • the voltage on terminals 12 and 15 may be made variable, may be arranged to have a directcurrent component of a selected value, or be of a direct current character of a selected value.
  • voltage between terminals 12 and 15 is a resetting voltage that is opposed by a control signal.
  • the reason for the current flow in winding 9 during the resetting half cycles is because of the inductive nature of the coil 5.
  • the current in winding 9 thus increases as the contactor pulls in.
  • the winding relation of the control winding 9 with respect to the windings 2 and 14 is such that the ampere turns increase the resetting of the core of the magnetic amplifier MAI. This increased resetting reduces the output of the gating cycles. Since the magnitude of the current in coil 9 is here directly related to the position of the armature with respect to the stationary portion of the magnetic circuit, it is apparent we have provided a reliable, dependable, and self-adjusting current limiting For this during the next half cycle,
  • the contactor ACC is interconnected with a magnetic amplifier MA2 such that the feed-back circuit in parallel with coil 5 includes conductor 8, device 50 when used, control winding 9 on magnetic amplifier MA2, rectifier 11, poled as indicated, to conductor 4.
  • the magnetic 5 amplifier MA2 is also provided with a control winding 33. in the adjustable voltage circuit including negative terminal 31, adjustable resistor 32, control, or bias, winding 33, and conductor 34 to the positive terminal 35.
  • the magnetic amplifier MA3 has main, or output, windings 41, and control windings 42 and 43.
  • Winding 42 is the feedback winding receiving its signal from magnetic amplifier MA2.
  • magnetic amplifier MA3 serves as a preamplifier for magnetic amplifier MAI.
  • the polarities indicated in Fig. 2 for the terminals 12 and 15, I and 7, and I8 and 23, are the instantaneous polarities for the resetting half cycle of magnetic amplifier MA3, for the gating half cycle of poses the effect of the control signal in winding 43.
  • a control signal of sufiicient magnitude resets magnetic amplifier MAS which then does not reset magnetic amplifier MAI and current flows in the output circuit of magnetic amplifier MAI.
  • Magnetic amplifier MA2 may be so biased that it is cut off for all currents in control winding 9 less than a selected value, namely for all current values present as long as the contactor ACC is open. With magnetic amplifier MA2 cut-oft, no feedback signal is fed to magnetic amplifier MA3. When the contactor ACC closes and thus effects a higher inductance of coil 5, heavy current flows in control winding 9.
  • winding relation of winding 9 with respect to windings 22 and 33 is such that the ampere turns decrease the resetting of the core of magnetic amplifier MA2.
  • an inductive load the energization of which is to be controlled, said inductive load in use having a variable impedance
  • a magnetic amplifier having a magnetic circuit and having a main winding and two control windings, all of said windings being interlinked with the magnetic circuit
  • a rectifier a pair of terminals in use energized with single-phase alternating current
  • an inductive load normally in use having the characteristic to rapidly increase its impedance upon energization with alternating current but the impedance of which rises less rapidly if energized with pulsating direct current
  • a magnetic amplifier in use suitably energized and having an output circuit for producing pulsating direct current
  • circuit means for connecting the inductive load to the output circuit of the magnetic amplifier
  • control means responsive to the rise of impedance of the inductive load to decrease the output of the magnetic amplifier as a function of the rise of impedance of the inductive load.
  • an inductive load unit in use upon energization manifesting a rise in impedance, a magnetic amplifier having a magnetic 0 core, a main winding on the core, and rectifier connected to energize the load unit from a suitable source of alternating current, a control winding for the magnetic amplifier so wound on the core to effect operation of the magnetic amplifier so as to energize the load unit, a sec- 5 ond control winding for the magnetic amplifier, said sec- Either method of precedure, as shown in Fig. 1 or Fig. 50
  • the device 50 is shown interconnected with this circuit.
  • the device 50 may be a meter, or signal light indicating whether or not contactor ACC has operated.
  • the device 50 may also constitute control means for effecting operation of other circuitry depending on the operation of contactor ACC.
  • an inductive load unit in use upon energization manifesting a rise in impedance
  • a magnetic amplifier having a main winding and rectifier connected to energize the load unit from a suitable source of alternating current, a control winding .for the magnetic amplifier to effect operation of the magnetic amplifier so as to effect energization of the load unit, a second control winding for the magnetic amplifier and a second rectifier, poled in opposition to the first rectifier, connected in series with the second control winding, said second control winding and second rectifier being connected in parallel with the load unit, the second control winding being so wound with respect to the other windings of the magnetic amplifier to decrease the output of the magnetic amplifier with a rise in impedance of the load unit.
  • an inductive load unit in use, upon initiation of its energization, manifesting a rise in impedance, at first magnetic amplifier having a main winding and rectifier connected in series therewith comprising the output circuit of the magnetic amplifier, said output circuit in use being connected to a suitable source of alternating current and being'connected to energize the load units, said magnetic amplifier having a control winding for selecting the triggering point of the magnetic amplifier, and havljr ing a second control winding for altering the output of the magnetic amplifier, a second magnetic amplifier having a main winding connected in series with a rectifier, the second control winding of the first magnetic amplifier and a suitable source of alternating current, said second magnetic amplifier having a bias winding for selecting its triggering point and having a second control winding and a rectifier connected in series therewith, this second control winding and series connected rectifier being connected in parallel with the load unit with this rectifier being poled in opposition to the pol-ing of the rectifier in series with the

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US671599A 1957-07-12 1957-07-12 Current limiting in the windings of electromagnetic devices Expired - Lifetime US2937321A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US671599A US2937321A (en) 1957-07-12 1957-07-12 Current limiting in the windings of electromagnetic devices
JP3288760U JPS3627195Y1 (enrdf_load_stackoverflow) 1957-07-12 1960-01-01

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US671599A US2937321A (en) 1957-07-12 1957-07-12 Current limiting in the windings of electromagnetic devices

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US2937321A true US2937321A (en) 1960-05-17

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US (1) US2937321A (enrdf_load_stackoverflow)
JP (1) JPS3627195Y1 (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3078396A (en) * 1959-04-30 1963-02-19 Walker O S Co Inc Demagnetizing apparatus
US3084310A (en) * 1959-12-14 1963-04-02 Square D Co Control circuit
US3189796A (en) * 1961-11-14 1965-06-15 Westinghouse Electric Corp Apparatus for suppressing transients during switching
US3258654A (en) * 1966-06-28 Electrical current sensing means

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2518865A (en) * 1939-07-08 1950-08-15 Illinois Testing Laboratories Saturable reactor controlling circuits
US2706764A (en) * 1952-03-20 1955-04-19 Western Electric Co Control circuits
US2747109A (en) * 1953-09-04 1956-05-22 North American Aviation Inc Magnetic flip-flop
US2816260A (en) * 1956-07-31 1957-12-10 Donald G Scorgie Regulated d. c. power supply
US2849662A (en) * 1956-04-24 1958-08-26 Gen Electric Static inverse time overvoltage device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2518865A (en) * 1939-07-08 1950-08-15 Illinois Testing Laboratories Saturable reactor controlling circuits
US2706764A (en) * 1952-03-20 1955-04-19 Western Electric Co Control circuits
US2747109A (en) * 1953-09-04 1956-05-22 North American Aviation Inc Magnetic flip-flop
US2849662A (en) * 1956-04-24 1958-08-26 Gen Electric Static inverse time overvoltage device
US2816260A (en) * 1956-07-31 1957-12-10 Donald G Scorgie Regulated d. c. power supply

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3258654A (en) * 1966-06-28 Electrical current sensing means
US3078396A (en) * 1959-04-30 1963-02-19 Walker O S Co Inc Demagnetizing apparatus
US3084310A (en) * 1959-12-14 1963-04-02 Square D Co Control circuit
US3189796A (en) * 1961-11-14 1965-06-15 Westinghouse Electric Corp Apparatus for suppressing transients during switching

Also Published As

Publication number Publication date
JPS3627195Y1 (enrdf_load_stackoverflow) 1961-10-17

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