US1485227A - Automatic circuit-breaker attachment for high-tension transmission lines - Google Patents

Automatic circuit-breaker attachment for high-tension transmission lines Download PDF

Info

Publication number
US1485227A
US1485227A US381134A US38113420A US1485227A US 1485227 A US1485227 A US 1485227A US 381134 A US381134 A US 381134A US 38113420 A US38113420 A US 38113420A US 1485227 A US1485227 A US 1485227A
Authority
US
United States
Prior art keywords
hook
clips
line
circuit
conductor
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
US381134A
Inventor
Jr Tomlinson Fort Johnson
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
Priority to US381134A priority Critical patent/US1485227A/en
Application granted granted Critical
Publication of US1485227A publication Critical patent/US1485227A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01HELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10Operating or release mechanisms
    • H01H71/12Automatic release mechanisms with or without manual release
    • H01H71/24Electromagnetic mechanisms
    • H01H71/2472Electromagnetic mechanisms with rotatable armatures

Definitions

  • T 0 all whom it may concern.
  • This invention has reference to automatic circuit breaker attachments for high tension electric installations, and one of its objects is to simplify the installation, thereby greatly reducing its cost though without af- Il fecting its efiiciency.
  • the invention comprises in its broadest aspect, a transformer with bushings of suitable size and construction to receive and support the skeet switches on their upper ends, thus materially reducing the parts, and because of the reduction in parts and the consequent simplification of the installation, correspondingly reducing the first cost thereof.
  • a further object of the invention is to provide an electro-magnetic device for holding the circuit closed, and which is responsive to abnormal currents to cause the rupture of the circuit which may then only be restored by an attendant, the whole operation taking place without any destructive effect upon any part of the circuit as would occur in the case of fusible blow-outs.
  • the skeet head is mounted on and rises from the cap, or cover, of a transformer and is connected to a flexible conductor forming part of the feeding line leading to the transformer.
  • the flexible conductor is so arranged as to be under a normal tendency to draw away from the transformer but is held in position to maintain the circuit by a latch structure released by an electro-magnetic latch responsive to the passage of abnormal currents.
  • the arrangement is such that the break in the circuit, when it occurs, is so extensive as to preclude any liability whatever of the formation of an arc. ⁇ Vhen the circuit is broken it may be restored by the manipulation of the latch of the electro-magnetic structure by an attendant.
  • Fig. 1 is a more or less diagrammatic view of an installation provided with the invention.
  • Fig. 2 is an elevation, on a larger scale than Fig. 1, of the skeet head structure.
  • Fig. 3 is a section on the line 3-3 of Fig. 2.
  • Fig. 4 is a section on the line 44 of Fig. 2.
  • Fig. 5 is a bottom planview of the skeet head structure.
  • Fig. 6 is a detailed view of a manipulating stick for the restoration of the skeet head to normal working conditions.
  • a line conductor 1 and a transformer 2 such as are commonly employed in high tension transmission lines.
  • the line wire 1 is carried to a pole 3 to which it is secured through. an insulating connection 4.
  • the transformer 2 is provided with an overhanging cap or crown 5 provided with a nipple 5. Rising from the nipple there is a post or bushing 6 made up of a series of insulators connected together after the usual custom.
  • the line conductor 1 is provided with a continuation in the form of a flexible conductor 7 made fast to the line 1 by clamps 8 and carried over a pulley 9 mounted on a block 10 fast to the conductor 1. Between the pulley 9 and the clamps 8 the conductor 7 carries a weight 11 hung from another pulley 12.
  • the weight 11 is designed to maintain the con ductor 7 taut and in the event of the flexible conductor loosening at the end remote from the blocks 8 the weight 11 will draw the loosened end of the conductor to the pulley block 10.
  • a hook 13 form ing a contact member for the purpose which will presently appear.
  • the hook 13 has an angle extension 14 of expanding thickness away from the conductor 7.
  • a support in the form of a cap 15 carrying at its upper end a head 16 having a lateral extension 17 terminating in an inverted cup 18 constituting a support or table for a solenoid or electro-magnet 19.
  • the cup 18 near one side thereof is provided with spaced ears 20 and the base 16 has other ears 21.
  • the ears 20 and 21 are alined so as to constitute journal bearings for a rock shaft 22 extending through them.
  • the shaft 22 carries a yoke 23, provided at the end remote from the shaft with a cross bar 24.
  • a pivoted latch member 25 which, in the particular showing of the drawings, is an angle latch member with one end having a notch 26 to engage over and hold the cross bar 24 and, at the other end, provided with a fork 27 straddling a rod 28 extending up into the solenoid 19 and at the lower end terminating in a head 29.
  • the base 16 has an arm 30 risin therefrom and the shaft 22 carries an arm 31 of similar contour but in position opposed to the arm 30.
  • Arms 30 and 31 together constitute fixed or movable clips forming a contact member between which the hook arm 14 may be introduced and held, the two arms 30 and 31 having respective terminal portions 32, 33, each terminating in spring fingers 34 and shaped to embrace the hook extension 14 which is nrovided along its lower edge with projecting beads 35 holding the hook end 14 from ready escape.
  • the two clips 30 and 31 are normally located in embracing relation to the hook end 14 by means of the angle latch member 25 engaging the cross bar 24, but when the solenoid 19 is energized the rod 28, which may be considered as attached to or forming part of the armature of the solenoid.
  • the solenoid 19 is included in the circuit by means of conductors 35?. one mace fast to the rim 17 and the other to a collar 36 on the uppermost element of the insulator (3.
  • the support 15 may be made of insulating material so as to direct the current through the solenoid 11 by way of the conductors 3 so that the solenoid may be in series in th main circuit or may be in shunt therewith.
  • the hook 13 is provided with an eye to facilitate the handling of the hook by means of a rod 37 in turn provided with a hook end 38 adapted to engage the eve 36.
  • an abnormal current passes through the line 1, conductor 7 and to the transformer 2 it also passes through the solenoid 19 which latter is properly proportioned to operate under such abnormal current, thus attracting its armature and bringing the head into engagement with one arm of the latch 25.
  • This releases the yoke 23 and the pull of the hook 18 immediately forces the clip 31 away from the clip 30 and the contact end 1.4 of the hook pulls out under the effect of the weight 11, whereupon the book 13 may rise until stopped by the block 10.
  • the rod 37 may be used in the manner similar to but the reverse of that already described with respect to the restoration of the circuit after having been broken. After the repairs are completed the circuit is restored as before without danger to the workman.
  • An electric circuit breaker for overhead conductors comprising a support adapted to be included in the circuit with the overhead conductor, an electro-magnetic structure carried by the support, an electrically responsive latch structure also included in the circuit, a pair of opposed clips also included in the circuit and under the control of the electrically responsive latch and constituting contact members, and a contact member pendantly supported from the overhead conductors and adapted to be introduced between the pair of clips to be held by them until one of the clips is released on the opening of the latch, and means for pulling the contact member from between the pair of clips when one of the latter is released.
  • a circuit breaker comprising a pair of opposed clips having a normal tendency toward each other and constituting one contact member of the switch, another contact member adapted for introduction between the clips to complete the circuit and pendantly sup ported from the line, a latch for holding the clips together, and electro-magnetic means for actuating the latch and constructed to be responsive to abnormal electric conditions on the line.
  • an electric translating device opposed clips carried by the translating device and having a normal tendency to move one toward the other, a hook-shaped member for introduction between the clips with the clips and hook-shaped member constituting bridging terminals of an electric circuit thus connected to the translating device, a latch having a normal tendency to hold the terminals in the closed position, an electromagnetic means normally inactive to transmitted currents of normal value and responsive to abnormal currents causing the breaking of the circuit. at the terminals.
  • An electric circuit breaker for use in connection with an overhead line conductor comprising a pair of associated clips constituting a terminal of a circuit fed from the line conductor, a hook constituting the other terminal and introducible between the clips, a pendant conductor connected to the main line conductor and to the hook, a gravity member for lifting the hook from between the pair ct clips, a latch for holding the clips in the closed position, and electro-magnetic means responsive to abnormal currents on the line for rel asing the clips to in turn release the hook.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Breakers (AREA)

Description

Feb. 26, 1924. I 1,485,227
T. F. JOHNSON, JR
AUTOMATIC CIRCUIT BREAKER ATTACHMENT FOR HIGH TENSION TRANSMISSION LINES Original Filed'm; :13; 1920 2 Sheets-Sheet 1' 330/3 w /9 a 7 I 3 /7 r6 21/ 5 Fgi' [F (/kIZSOIL, Q/I;
' INVENTOR WITNESS ES M BY ' ATTORNEY Feb. 26, 1924. 1,485,227
T. F. JOHNSON, JR
AUTOMATIC CIRCUIT BREAKER ATTACHMENT FOR HIGH TENSION TRANSMISSION LINES Original Filed May 13-. 1920 2$hoets-Sheetf2 i -l I I 35 a I 36 H [3 2/! o f .I
I F36 aw 6.25 3
- ZEJOILMO JT;
INVENTOR WITN ESSES ATTO R N EY Patented Feb. 26, 1924.
UNITED STATES PATENT OFFICE.
TOMLINSON FORT JOHNSON, JR, F ATLANTA, GEORGIA.
Application filed May 13, 1920, Serial No. 381,134. Renewed May 2, 1923.
T 0 all whom it may concern.
Be it known that I, TOMLINSON F. JoHN- soN, Jr., a citizen of the United States, residing at Atlanta, in the county of Fulton and State of Georgia, have invented a new and useful Automatic Circuit-Breaker Attachment for High-Tension Transmission Lines, of which the following is a specification.
This invention has reference to automatic circuit breaker attachments for high tension electric installations, and one of its objects is to simplify the installation, thereby greatly reducing its cost though without af- Il fecting its efiiciency.
Heretofore it has been deemed necessary to mount the circuit breakers or skeet Switches, as they are commercially known, upon supports individual thereto and located some little distance from the transformers forming part of the installation. An in stance of this is disclosed in my application Serial No. 318,026, for an automatic circuit breaker or switch, filed Aug. 16, 1919. I
26 have found that such skeet switches are capable of being mounted directly upon the transformer bushings so that separate supports, other than the transformer bushings, may be eliminated. The invention, there- 30 fore, comprises in its broadest aspect, a transformer with bushings of suitable size and construction to receive and support the skeet switches on their upper ends, thus materially reducing the parts, and because of the reduction in parts and the consequent simplification of the installation, correspondingly reducing the first cost thereof.
A further object of the invention is to provide an electro-magnetic device for holding the circuit closed, and which is responsive to abnormal currents to cause the rupture of the circuit which may then only be restored by an attendant, the whole operation taking place without any destructive effect upon any part of the circuit as would occur in the case of fusible blow-outs.
The invention is susceptible of many different embodiments of which one is shown in the drawings. Another embodiment is disclosed in my companion application, Se-
rial No. 381,135.
In carrying out the invention the skeet head is mounted on and rises from the cap, or cover, of a transformer and is connected to a flexible conductor forming part of the feeding line leading to the transformer. The flexible conductor is so arranged as to be under a normal tendency to draw away from the transformer but is held in position to maintain the circuit by a latch structure released by an electro-magnetic latch responsive to the passage of abnormal currents. The arrangement is such that the break in the circuit, when it occurs, is so extensive as to preclude any liability whatever of the formation of an arc. \Vhen the circuit is broken it may be restored by the manipulation of the latch of the electro-magnetic structure by an attendant.
The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this specification, with the understanding, however, that the invention. is not confined to any strict conformity with the showing in the drawings, but may be changed and modified so long as such changes and modifications mark no material departure from the salient featuresv of the invention as expressed in the appended claims.
In the drawings:
Fig. 1 is a more or less diagrammatic view of an installation provided with the invention.
Fig. 2 is an elevation, on a larger scale than Fig. 1, of the skeet head structure.
Fig. 3 is a section on the line 3-3 of Fig. 2. p
' Fig. 4 is a section on the line 44 of Fig. 2.
Fig. 5 is a bottom planview of the skeet head structure.
Fig. 6 is a detailed view of a manipulating stick for the restoration of the skeet head to normal working conditions.
Referring to the drawings, there is shown a line conductor 1 and a transformer 2 such as are commonly employed in high tension transmission lines. There are usually three line wires 1 and transformers 2 but this does not preclude the use of adilferent number thereof. The line wire 1 is carried to a pole 3 to which it is secured through. an insulating connection 4. The transformer 2 is provided with an overhanging cap or crown 5 provided with a nipple 5. Rising from the nipple there is a post or bushing 6 made up of a series of insulators connected together after the usual custom. The line conductor 1 is provided with a continuation in the form of a flexible conductor 7 made fast to the line 1 by clamps 8 and carried over a pulley 9 mounted on a block 10 fast to the conductor 1. Between the pulley 9 and the clamps 8 the conductor 7 carries a weight 11 hung from another pulley 12. The weight 11 is designed to maintain the con ductor 7 taut and in the event of the flexible conductor loosening at the end remote from the blocks 8 the weight 11 will draw the loosened end of the conductor to the pulley block 10.
At the end of the conductor 7 remote from the block 8 there is secured a hook 13 form ing a contact member for the purpose which will presently appear. The hook 13 has an angle extension 14 of expanding thickness away from the conductor 7.
At the top of the bushing or post 6 there is secured a support in the form of a cap 15 carrying at its upper end a head 16 having a lateral extension 17 terminating in an inverted cup 18 constituting a support or table for a solenoid or electro-magnet 19.
The cup 18 near one side thereof is provided with spaced ears 20 and the base 16 has other ears 21. The ears 20 and 21 are alined so as to constitute journal bearings for a rock shaft 22 extending through them. .Vithin the cup-like support 18 the shaft 22 carries a yoke 23, provided at the end remote from the shaft with a cross bar 24. Also within the support 18 there is mounted a pivoted latch member 25 which, in the particular showing of the drawings, is an angle latch member with one end having a notch 26 to engage over and hold the cross bar 24 and, at the other end, provided with a fork 27 straddling a rod 28 extending up into the solenoid 19 and at the lower end terminating in a head 29.
The base 16 has an arm 30 risin therefrom and the shaft 22 carries an arm 31 of similar contour but in position opposed to the arm 30. Arms 30 and 31 together constitute fixed or movable clips forming a contact member between which the hook arm 14 may be introduced and held, the two arms 30 and 31 having respective terminal portions 32, 33, each terminating in spring fingers 34 and shaped to embrace the hook extension 14 which is nrovided along its lower edge with projecting beads 35 holding the hook end 14 from ready escape. The two clips 30 and 31 are normally located in embracing relation to the hook end 14 by means of the angle latch member 25 engaging the cross bar 24, but when the solenoid 19 is energized the rod 28, which may be considered as attached to or forming part of the armature of the solenoid. immediately rises and hitting the latch 25 throws it out of holding relation to the cross bar 24, thus allowing the bar 24 and parts controlled thereby to rise with the result that the arm 31 moves away from the hook end 14, as shown in dotted lines, Figure 3, because the pull of the latter by the weight 11 is sufficient to produce such action.
In the absence of the hook end 14 the ends 32 and 33 of the clips 30 and 31 come to gether but when the hook end 14 is placed between the ends 32 and the said cues are forced up against their normal ten ency to engage and therefore make 9 good contact with the hook end 14.
The solenoid 19 is included in the circuit by means of conductors 35?. one mace fast to the rim 17 and the other to a collar 36 on the uppermost element of the insulator (3. The support 15 may be made of insulating material so as to direct the current through the solenoid 11 by way of the conductors 3 so that the solenoid may be in series in th main circuit or may be in shunt therewith.
The hook 13 is provided with an eye to facilitate the handling of the hook by means of a rod 37 in turn provided with a hook end 38 adapted to engage the eve 36.
hen an abnormal current passes through the line 1, conductor 7 and to the transformer 2 it also passes through the solenoid 19 which latter is properly proportioned to operate under such abnormal current, thus attracting its armature and bringing the head into engagement with one arm of the latch 25. This releases the yoke 23 and the pull of the hook 18 immediately forces the clip 31 away from the clip 30 and the contact end 1.4 of the hook pulls out under the effect of the weight 11, whereupon the book 13 may rise until stopped by the block 10. This produces a wide gap between the line 1 and the transformer 2 and this gap is beyond the capability of the line current to bridge. whereupon the circuit becomes broken and so remains until an attendant. by aid of the rod 37 may engage the hook 13 through the eye 36 and pulls the hook downwardly against the action of the weight 11 until it may be introduced between the clips and 31.
While the invention is designed primarily for the automatic breaking of the circuit on the passage of an abnormally high or heavy current, there are occasions when it is desired to break the circuit purposely with normal current on the line. as for instance, when it is desired to make repairs without danger to workmen. Under such circumstances. the rod 37 may be used in the manner similar to but the reverse of that already described with respect to the restoration of the circuit after having been broken. After the repairs are completed the circuit is restored as before without danger to the workman.
No claim is made in this application for the combination, in an electric circuit breaker for overhead transmission lines, of a contact member adapted to be pendently carried from and electrically connected to the overhead conductor, with the supporting means for said contact member extensible beyond its normal position, a second contact member with which the first con tact member when in extended position is adapted to make engagement, and means for releasing the engagement between the contact members, said means being responsive to the passage of an abnormal current, as this subject matter is claimed in an application for patent filed by me on August 16, 1919, Serial No. 318,026. This application is a continuation in part of an application filed by me on February 26, 1920, Serial No. 361,526.
What is claimed is:
1. In a high tension electric installation, the combination with a transformer, of circuit-breaking apparatus mounted on and solely carried by a bushing belonging to the transformer outfit, and comprising connecting elements which are adapted to be automatically disengaged.
2. The combination with a transformer and a bushing carried thereby, of an automatic circuit breaker mounted on the bushing and provided with means for coupling the circuit breaker to a line wire.
3. In a high tension electric installation, the combination with a transformer having a cap, of a bushing rising from the cap and connected thereto, an automatic switch connected to the top of the bushing, a line conductor, and a flexible conductor connected to the said switch and to the line conductor.
4. In a high tension electric installation, the combination with a transformer having a cap provided with a nipple, of a bushing rising from the cap and connected to the nipple, an automatic cut-out switch, and means for securing the switch to the top of the bushing.
5. The combination with a transformer having an upstanding bushing formed of a series of insulators connected together, of a line conductor, a branch conductor, an automatic switch mounted on the upper end of the bushing and adapted to be engaged by the branch conductor.
6. An electric circuit breaker for overhead conductors, comprising a support adapted to be included in the circuit with the overhead conductor, an electro-magnetic structure carried by the support, an electrically responsive latch structure also included in the circuit, a pair of opposed clips also included in the circuit and under the control of the electrically responsive latch and constituting contact members, and a contact member pendantly supported from the overhead conductors and adapted to be introduced between the pair of clips to be held by them until one of the clips is released on the opening of the latch, and means for pulling the contact member from between the pair of clips when one of the latter is released.
7. In an electric transmission line provided with an overhead line conductor and with a transformer below the line conductor, normally locked separable clips carried by the transformer, electrically operated means for controlling the lock to permit the separation of the clips and responsive to abnormal electric conditions on the line, and a hook-shaped member electrically connected to and dependent from the line and movable into position between the clips to be held thereby and complete the circuit, whereby on the passage of an abnormal current the clips are unlocked and the hook is released for escape from the clips.
8. In an electric transmission line provided with an overhead conductor and with a transformer below the line conductor, normally locked separable clips carried by the transformer, electrically operated means for controlling the lock to permit the separation of the clips and responsive to abnormal electric conditions on the line, and a hookshaped member electrically connected to and dependent from the line and movable into position between the clips to be held thereby and completing the circuit, whereby on the passage of an abnormal electric current the clips are unlocked and the hook is released for escape from the clips, said hook having an electric conductor carrying it and electrically connected to the line including means tending to lift the hook away from the clips.
9. In a high tension transmission line a circuit breaker, comprising a pair of opposed clips having a normal tendency toward each other and constituting one contact member of the switch, another contact member adapted for introduction between the clips to complete the circuit and pendantly sup ported from the line, a latch for holding the clips together, and electro-magnetic means for actuating the latch and constructed to be responsive to abnormal electric conditions on the line.
10. In an overhead electric transmission system, an electric translating device, opposed clips carried by the translating device and having a normal tendency to move one toward the other, a hook-shaped member for introduction between the clips with the clips and hook-shaped member constituting bridging terminals of an electric circuit thus connected to the translating device, a latch having a normal tendency to hold the terminals in the closed position, an electromagnetic means normally inactive to transmitted currents of normal value and responsive to abnormal currents causing the breaking of the circuit. at the terminals.
11. An electric circuit breaker for use in connection with an overhead line conductor comprising a pair of associated clips constituting a terminal of a circuit fed from the line conductor, a hook constituting the other terminal and introducible between the clips, a pendant conductor connected to the main line conductor and to the hook, a gravity member for lifting the hook from between the pair ct clips, a latch for holding the clips in the closed position, and electro-magnetic means responsive to abnormal currents on the line for rel asing the clips to in turn release the hook.
19. lhe combination with a transformer surmounted by cap and having a bushing rising therefrom, of ahook-shaped contact member, a "flexible conductor connected to a line, and suspending the hook-shaped contact member, another contact member mounted on the bushing adapted to receive and hold the hook-shaped cont-act member, and means for maintaining the hook-shaped member, under tension, whereby, when the hook-shaped member is released from the other contact member the contact members are separated beyond arcing distance.
13. In a high tension electric installation, the combination with a transformer provided With a cap, a bushing surmounting the cap, a device carried by the bushing and constituting one member of a circuit breaker, a flexible conductor connected to the line and suspending the other member of the circuit breaker, electro --mag1'ietically controlled means normally holding the two members oi the circuit breaker together, and constraining means for the flexible conductor ogerative to Withdraw that member of the circuit breaker connected to the flexible c011- ductor from the other member of the circuit breaker to a distance out of close proximity to the transformer.
14. In a high tension electric installation, the combination With transformer, of a bushing rising therefrom and carried there by, a cap on the bushing, a two-part cutout switch on the cap With one member of the switch fast to the cap, a flexible conductor fast at one end to the other member of the switch and the other end of the flexible conductor fast to a line wire, and means for imparting to the flexible conductor a normal tendency to separate the two members of the switch beyond arcing or accidental touching distance.
In testimony that I claim the foregoing as my own, I have hereunto attired my signature.
TOMLINSON FORT JOHNSON, J R.
US381134A 1920-05-13 1920-05-13 Automatic circuit-breaker attachment for high-tension transmission lines Expired - Lifetime US1485227A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US381134A US1485227A (en) 1920-05-13 1920-05-13 Automatic circuit-breaker attachment for high-tension transmission lines

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US381134A US1485227A (en) 1920-05-13 1920-05-13 Automatic circuit-breaker attachment for high-tension transmission lines

Publications (1)

Publication Number Publication Date
US1485227A true US1485227A (en) 1924-02-26

Family

ID=23503821

Family Applications (1)

Application Number Title Priority Date Filing Date
US381134A Expired - Lifetime US1485227A (en) 1920-05-13 1920-05-13 Automatic circuit-breaker attachment for high-tension transmission lines

Country Status (1)

Country Link
US (1) US1485227A (en)

Similar Documents

Publication Publication Date Title
US1393344A (en) Method of and means for switching
US2314693A (en) Electric circuit interrupter
US2621271A (en) Switch construction
US2671142A (en) Circuit interrupter construction
US1485227A (en) Automatic circuit-breaker attachment for high-tension transmission lines
US2400850A (en) Multiple circuit interrupter
US2630508A (en) Circuit interrupter
US2734964A (en) Circuit interrupters
US2347851A (en) Fuse device
US2735911A (en) Circuit interrupter
US2597134A (en) Circuit interrupter
US2617908A (en) Flip-open disconnecting switch
US1232458A (en) Ignition-switch.
US710056A (en) Automatic circuit-breaker.
US975419A (en) Electric-circuit switch.
US2757259A (en) Electrical circuit breaker
US2589024A (en) Motor control system and switch
US2158638A (en) Fuse construction
US1306638A (en) Circuit controlling device
USRE14881E (en) Overload circuit-breaking apparatus
US2532259A (en) Electric circuit interrupter
US532537A (en) Harry p
US1854031A (en) Protective arrangement
US1102728A (en) High-tension switch.
US646688A (en) Device for shifting electric current from one conductor to another.