US2669673A - Arc furnace control system - Google Patents

Arc furnace control system Download PDF

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Publication number
US2669673A
US2669673A US333458A US33345853A US2669673A US 2669673 A US2669673 A US 2669673A US 333458 A US333458 A US 333458A US 33345853 A US33345853 A US 33345853A US 2669673 A US2669673 A US 2669673A
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US
United States
Prior art keywords
movable electrode
circuit
current
molten bath
movable
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
US333458A
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English (en)
Inventor
Ralph A Geiselman
Glenn C Biggs
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.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
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 Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US333458A priority Critical patent/US2669673A/en
Priority to JP145554A priority patent/JPS311047B1/ja
Application granted granted Critical
Publication of US2669673A publication Critical patent/US2669673A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/144—Power supplies specially adapted for heating by electric discharge; Automatic control of power, e.g. by positioning of electrodes
    • H05B7/148—Automatic control of power
    • H05B7/152—Automatic control of power by electromechanical means for positioning of electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • ' invention relatesto control systems. and; Particularly, to control systemsfor governing the. operation of movableelectrodesof electric arc. furnaces,
  • Fur ther, lf-thevelectrodesremain.in contact with the, molten; bath, for a .sufiicient, time. to. allow. the: cooling of the bath, the movable electrodesmay freeze to thebath...
  • Inanw are. furnace syst m the. m vablelecrodes are. normally connected 1 to. the source, of power supp y throu h, a. circuit breaker. This; rcuit; breaker. durin th operation of. the are. furnace may be. int rrupt d a plur lity of times. during each hour of operation.
  • Each timev the circuit breaker is interrupted the operator often ectuates the circuit breaker to,theclosedposition" under 1o ad,,tha,t is, when either-the sourceoij power. is. normally. supplying energy to the. moyable electro.des,, or; when a short circuit conditionexists.
  • Theactuation of the ,circuit'break'er to theclosedposition under. load a. plurality of; times. each. hour shortens the. life. of a the circuit. breaker. considerably.
  • An object. ofthisinvention is to provide for, actuating anlelectrodeof an arcfurnacea prev determined, distance from its assmiatedmoltenbath oncethe main power supply to. theelsotrone,
  • Another. object .of this invention is .to provide for lengthening the life .ofvoircuit, interruptingmeans, connected. between a. movable, electrode of. anercfurnaceandits source. of power, by moving the electrode. apredetermined, distance, from the. molten bath, when the flow of "current is interrupted, sothat the, circuit interrupting means. is; not... closeddar. load when... initiating;
  • acontainer I 2 having; disposed therein .amoltenbath .l .4.
  • apluralityof movable. electrodes 16;,18 andlO aredisposedin closeproximityto the uppersur; face of thezmolten bath, 14;
  • themovable electrodes. I .6, 1 Sand 20. are .directly connected to load conductors22; 241 and 26,.re; spectively, which .inturn are connected. to a suit, able source ofpowersupply (not shown) through circuit interruptingmeans 30'.
  • the movable electrodes, I 6 and I8 also. hare associated; therewith fi'exiblecablesfli and 38 resp ctively, and pulleys, 40; and, 42; respectively.
  • theflexible 033318732 maybe wound upon a winding drumi5-2; operated by a reversible electrodemotor 5!.
  • the motor 5'4 comprises a field winding' 56 disposed to' berenergized from any suitable direct? current: source, such. asthe battery 58; andan.
  • armature-winding 60" connected byconductorstl" and' 64' to-be. suppliedwith energy from a main; enerator 56" that is drivenby analternating; current" motor 68. and excited by an exciter generator.
  • the exciter generator I6 is also provided with two control field windings 82 and 84, which are disposed to be so energized as to oppose each other and to cooperate in controlling the excitatiori of the cxciter generator iii.
  • the control winding 84 of the exciter generator Hi responsive to the arc voltage of the movable electrode 20
  • one of the input terminals of a full-wave rectifier 88 is connected to the container i2 and the other input terminal of the rectifier 88 is connected to the movable electrode 20 through an adjustable resistor 90, the function or which will be described hereinafter.
  • the output terminals of the rectifier 83 are connected to the control field winding 8 of the exciter generator Ill.
  • a current transformer 92 is disposed in inductive relationship with the load conductor 25.
  • the current transformer 92 is connected to the input terminals of a full-wave rectifier 94, through normally closed contact members $56 of a control relay 98, the function of which will be described hereinafter.
  • the output terminals of the rectifier 9d are connected to the control field winding 82.v
  • an adjustable resistor Illll is connected across the currenttransformer 92, which adjustable resistor in conjunction with the adjustable resistor 9%) provide the necessary adjustments for obtaining a balance between the control field windings 82 and 3d of the exciter generator 79, when the movable electrode'Zil is disposed a proper distance from the molten bath Id for operating conditions.
  • the movable electrode 20 is maintained in a substantially constant regulated position relative to the molten bath I l.
  • the control field windings 32 and as have an equal and opposite efiect and thus the effects neutralize each other.
  • the movable electrode 25 moves closer to the molten bath ld' than its regulated position, the current fiow through the load conductor 26'increases tothereby increase the output of the current transformer 92, which in' turn increases the current flow through the control field winding 82.
  • the lowering of the movable electrode 20 below its regulated position decreases the arc voltage as applied to the control field winding 84' through the rectifier 88.
  • the flux produced by the field winding 82 is greater in magnitude than the flux produced by the field winding 84.
  • the resultant flux will cause'the exciter generator l0 todevelop a voltage of such polarity as to energize the main generator field winding 74 in a direction to impress a voltage on the motor armature 60, having a polarity to cause the motor 54 to operate in a direction to raise the movable electrode 2!), to thereby return it to its regulated position.
  • the resultant fiux produced by the control field windings 82 and 84 will effect a lowering of the movable electrode 20, to thereby return it to its regulated position.
  • circuit interrupting means 30 is connected between the movable electrodes I6, I8 and 20 and their source of power supply (not shown).
  • the circuit interrupting means 39 comprises a trip device I02, which can either be manually energized by a pushbutton I04, or energized in response to a short circuit condition, to thereby trip the circuit interrupting means 30, and thus disconnect the movable electrodes I5, I8 and 20 from their source of power (not shown).
  • a protective device I06 is disposed to be responsive to the outputs of current transformers I08, III) and I I2, which are disposed in inductive relationship with the load conductors 22, 24 and 28, respectively.
  • normally open contact members I II are disposed to be actuated in response to these output currents of the current transformers I08, III], and II2.
  • a circuit for energizing the trip device I02 extends from a negative terminal I22 of a suitable direct current source (not shown) through the normally open contact members IIS of the protective device I05, an energizing winding II8 of the trip device I92, and auxiliary contact members I20 of the circuit interrupting means 30, to a positive terminal IE3 or the source of direct current (not shown).
  • the circuit interrupting means 30 also controls auxiliary contact members I24 and I25, the function of which will be described here inafter.
  • the control relay 9B in order to initiate the actuation of the movable electrode 20 in a direction away from the molten bath I4 once the. circuit interrupting means 38 has been actuated to the circuit interrupting position, the control relay 9B is provided.
  • the control relay 98 comprises the normally closed contacts and normally open contacts I30, associated with the operating mechanism disposed within the rectangular area 46.
  • the control relay 9! also comprises a corresponding set of contact members I3I and I32 associated with the operating mechanism disposed within the rectangular area 50,
  • an operating coil I48 of the relay 98 is provided.
  • a time delay I42 is provided:
  • the time delay relay M2 comprises an When this occurs, a direct-current circuit is come pletedito; the; operating coil I40 of; then-controli relay; 98,", which circuit, extends fronra positiviterminahlliaofa direct current source ;of energy,
  • the current flow through the control field winding 52 of the exciter generator ii) is such as to effect a raising of the movable elec-- trode above its regulated position, which move ment takes place until the action of the time delay relay I42 stops such movement.
  • the auxiliary contact members I24 of the circuit interrupting means 30 are actuated to the closed position, thereby completing an alternating current circuit to the operating coil I44 of the time delay relay I42.
  • the normally closed contact members I48 of the time delay relay I42 are actuated to the open position, thereby interrupting the direct-current circuit to the operating coil Mt of the control relay $39.
  • the deenergizing of the operating coil I48 causes the normally open contact members I38, I32 and I36 to be actuated to their open position.
  • a pushbutton IE6 is disposed to be actuated to thereby complete an energizing circuit to an energizing winding I58 associated with the circuit interrupting means 38.
  • the apparatus embodying the teachings of this invention has several advantages. For instance, the length of life of the circuit interrupting means 30 is greatly increased. Further, the material of the movable electrodes I6, I8 and 20 cannot ipossibly contaminateithesmolten: bath; a oncerthezcircuit interrupting-means 30;. actu-y ated:tovthezopenzposition. Inaddition bypracr ticing this invention the movable 4 electrodes I 5&1, l8, and Zilcannot: freeze to themolten; bath; Ms, once ithasicooled sufiiciently, v
  • an arc furnace control system for controlling the positioning of a movable electrode with respect to a molten bath in which the arc receives energy from a source of power
  • the combination comprising, circuit interrupting means connected between the source of power and the movable electrode, a motor for moving the movable electrode with respect to the molten bath, means responsive to the current flow through the movable electrode for actuating the circuit interrupting means to the open position, control means including a control relay responsive to the opening of the circuit interrupting means for so energizing the motor as to actuate the movable electrode in a direction away from the molten bath whereby the material of the electrode cannot contaminate the molten bath, and a time delay relay also responsive to the opening of the circuit interrupting means for deenergizing the control relay once the motor has actuated the movable electrode a predetermined distance from the molten bath to thereby stop the movement of the movable electrode.
  • circuit interrupting means connected between the source of power and the movable electrode, a motor for moving the electrode with respect to the molten bath, a generator for supplying power to the motor, a control winding for the generator, a full-wave rectifier having input and output terminals, the output terminals being connected to the control winding, a source of alternating current, circuit means including a control relay for connecting the source of alternating current to the input terminals of the rectifier; the control relay being responsive to the opening of the circuit interrupting means to thereby connect the source of alternating current to the input terminals of the rectifier to thus so energize the motor as to actuate the movable elecrode in a direction away from the molten bath whereby the material of the movable electrode cannot contaminate the molten bath, and a timedelay relay also responsive to the
  • circuit interrupting means connected between the source of power and the movable electrode, a motor for moving the electrode with respect to the molten bath, a generator for supplying power to the motor, a control winding for the generator, a full-wave rectifier having input and output terminals, the output termi- 8 nals being connected to the control Winding, a source of alternating current, circuit means including a control relay for connecting the source of alternating-current to the input terminals of the rectifier, manual trip means for actuating the circuit interrupting mean to the open position, the control relay being responsive to the opening of the circuit interrupting means to thereby connect the source of alternating current to the input terminals of the rectifier to thus so energize the motor as to actuate the movable electrode in a direction away from the molten bath whereby the combination' comprising, circuit interrupting means connected between the source of power and the movable electrode, a motor for moving the electrode with respect to the molten bath, a generator for supplying power to the motor, a control winding for

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Discharge Heating (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
US333458A 1953-01-27 1953-01-27 Arc furnace control system Expired - Lifetime US2669673A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US333458A US2669673A (en) 1953-01-27 1953-01-27 Arc furnace control system
JP145554A JPS311047B1 (enrdf_load_stackoverflow) 1953-01-27 1954-01-26

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US333458A US2669673A (en) 1953-01-27 1953-01-27 Arc furnace control system

Publications (1)

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US2669673A true US2669673A (en) 1954-02-16

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Family Applications (1)

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US333458A Expired - Lifetime US2669673A (en) 1953-01-27 1953-01-27 Arc furnace control system

Country Status (2)

Country Link
US (1) US2669673A (enrdf_load_stackoverflow)
JP (1) JPS311047B1 (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3217205A (en) * 1962-06-07 1965-11-09 Pullman Inc Electric furnace electrode position control

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3217205A (en) * 1962-06-07 1965-11-09 Pullman Inc Electric furnace electrode position control

Also Published As

Publication number Publication date
JPS311047B1 (enrdf_load_stackoverflow) 1956-02-15

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