US1671023A - Circuit interrupter - Google Patents

Description

May 22, 1928. Y 1,671,023

J. T. l-'lTzslMMoNsr C IRCUIT INTERRUPTER Filed Jan.16, 1926 Patented May 22, 1928.

UNITED I STATES PATENT OFFICE.

JOHN T. FITZSIMMONS, OF DAYTON, OHIO, ASSIGNOR, yBY MESNE ASSIGNMENTS, TO DELCO-BEMY CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE.

CIRCUIT INTEBBUPTER.

I applic-atm mea January 16, 1926. serial No. 81,756.

ly to increase the' resistance thereof, at,

which time the extra heavy drain on the current source is materially reduced. Thisv drain becomes material in the lighting system for motor busses which are generally provided with a large number of lamps, all used at the same time.

One of the primary objects of the present invention is tov provide a protective or limiting device in circuit with the lamps of the illuminating system or other work devices of a motor vehicle, which, when an abnormal ow or surge of current passes therethrough due to the cold condition of the lamp laments "or to a short-circuit of any of the Work devices, will open the main circuit between the current source and such lamps or work devices and establish a higher-resistance, secondary circuit to such lamps or work devices. This secondary high-resistance circuit is maintained until the resistance of the lamps is built up to a proper value by the warming of the filaments, or until the short-circuit on any of the work devices is removed, at which time the maincircuit will a ain be restored.

Further objects an advantages of the present invention will be apparent from the ollowing description, reference being hadto the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is a diagrammatic, fragmentary view showing the circuit interrupter and its electrical connections with theysource of current and work devices.

Fig. 2 is a detail sectional view showing the core construction and its plunger armaure.

Referring to the drawings, the numeral 2O designates a base of either insulation or non-magnetic material upon which is mounted the circuit interrupter.

The interrupter comprises a field frame 21, of U-shaped construction, having le 22 and 23, and cross-arm 24. The leg 22 has a foot 25 arranged at right angle thereto, said foot having an aperture in which an insulating collar 26 is provided. The foot is secured to the base 20 by means of stud 27, insulating washers 28 and 29 being placed between the foot and base, and foot and stud nut 30, respectively.

By referring' to Fig. 2, the core of the electromagnetis shown comprising a main body portion 31, one end of which is reduced as at 32. This reduced portion 32 extends into an. aperture in the cross-arm 24 of the field frame 21, the edge of said portion 32 extending beyond the outer surface of said cross-arm and is spun or riveted over so that the core is secured rigidly to the field frame.

The aperture in the cross-arm 24 is so positioned that the core lies midway between the two arms 22 and 23. An insulating collar 33 is provided between the cross-arm 24 and the core.

The core has a central, longitudinal passage 34 throughout its entire length, this passage, however,.being of larger diameter in the main body portion 31 than in the reduced portion 32. This variation'in the diameter of the passage forms the shoulder 35. A sleeve 36, of any suitable non-mag netic material, ts snugly around the core portion 31, one end lof said sleeve 36 abutting against the insulating collar 33, while the otherend has a flange 37. An insulating collar 38 fits about the sleeve 36 and rests on the fiangey 37.

The lplunger armature is designated by of the frame and said head. A re uced portion 41 of such a diameter 4that only a small gap is formed between the legs 22 and 23 of the frame and said head. A reduced portion 42 extends into the larger diameter por-v tion ofthe passage 34 in the core so that a sliding fit obtains. A stem 43, extending from the portion 42 and of lesser diameter,

projects through the smaller diameter por- -said spring tending to push 'the armature into engagement with the base 20, as shown in Fig. l1.

On the lcv 23 there is secured a spring arm whic 1 has a portion 46 bent over to lie parallel with the cross-arm 24. On this cross-arm there is provided an insulating block 47 to which is secured a hollow contact member 48 so arrangedfon said field frame 21 that the stem 43 of the armature may pass through said hollow contact member 48 and engage the movable contact meniber 49, carried by the spring arm portion 46, in such a manner that it will normally lie in engagement with said stationary Contact.

An extension 50 to the portion 46 carries the movable member 51 of the auxiliary contacts, the stationary member 52 thereof being secured "to the interrupter and insulated therefrom in any suitable manner. These auxiliary contacts 51 and 52 are always open when the main contacts 48 and 49 are closed,

rushof current is substantially reduced. u

Supposing, for example, all the lights57 are simultaneously introduced into the circuit by the closing of switches 58. initial rushof a substantially heavy current How will leave the battery, flow through The lBy the use of this interrupter, this initial winding 53 across contacts 48 and 49,

gage the contact member 49 and move it out of engagement with its cooperating contact l 48, thus breaking the circuit through winding 53. Now, the iiow of current from the battery will deviate and pass' through the higher resistance winding 54 on its way to the lights, thus substantially reducing the How from the battery while still maintaining the armature in attracted position due to the direction of How through the winding 54.

Opening of contacts 48 and'49 will close and are always closed when the latter vare ;the auxiliary . contacts 51 and 52. However,

opened by the armature.

Three windings 53, 54 and 55 are carried by the core. Winding 53 is of low resistance and has its one end connected to the main stationary contact 48, while its other end is in circuit connection with the source of current, shown to 4be abattery 56. Winding 54 is wound in the same direction as 53, but is of greater resistance 'than said Winding 53. One of its ends is grounded on the le 22, or any other suitable portion of the fiel frame 21, while its other end is connected to the source of current 56. Thus, the wind-. ing 54 is connecte-d in parallel with winding 53 and in shunt with the contacts48 and 49. The winding 55 is, wound reversely to the windings 53 and 54, and is of,k lesser resistance than the winding 54 but greater than the `winding'53. Its one end is connected to the auxiliary stationary contact member 52, while the opposite end thereofl is grounded to. connect with the ground of the battery 56.

Work devices shown as lights 57 are adapted to be connected to the interrupter foot 25 by means of switches 58. .On ymotor vehicles, lights having tungsten filaments are most commonly used.' It is well-known that tungsten, when cold, offers very little resist ance to -current How, soy that when a `tungsten filament light is first connected in circuit, a great rush of current will at first occur, this current flow being reduced as the filament in the light warms up. Where a great y number of such lights are turned on, quite a bit of electrical energy -is uselessly expended l before the filaments are warmed sufficiently to oer a normal resistance to the current flow. a Y

i as the resistance of the Work circuit is much less than the resistance of Winding 55, which is now connected in series with winding 54, the current will continue to flowthrough the work circuit until the filaments of the lights have become sufficiently warm to offer substantially the same resistance as winding 55. When this occurs, part of they current will `dev`iate and flow from the winding 54,l

through frame 21, spring arm 45 and its portions 46 and 50 across contacts 5l and 52 through winding 55 back, to the battery via the ground connections. l Winding 55 being reversed to Winding 54, it will destroy the effect of winding 54 and permit -the spring 44 to return the armature to its normal,"inoperativc position on the base 20. This closes contacts 48 and 49 andrestores' 'the circuit through the low-resistance win'd-v mits an excessive fiowof current through the ,Winding 53, this winding -fwill energize the core 31 sothat the armature 40 will be moved to opent-contacts 48and 49 as described. The,

winding 54 being connected in' parallel with winding 53, will maintain the armature in -the. contact-opening position as long as the TheI 'short-circuit is permitted to exist.

shortlcircuit being of lesser resistance than the reverse winding 55, a substantial current flow through said Winding will thus be preeluded and, therefore, no opposing effect will obtain against the holding effect of the windlng 54. rHowever,\as soon as the short-circuit is removed,the resistance of the circuit will be restored to normal, causing a deviation of part of the current iow from said circuit, through the circuit including the i'everse winding, thereby bringing into operation the demagnetizing effect' of said winding and thus restoring the low-resistance circuit through winding 53 by the return of the armature and consequent closing of contacts 48 and 49.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is `as-ollows:

1. A protective device for circuits including work devices, comprising in combination, a solenoid magnet provided with a pair. of normally-closed Icontacts and a hollow core containing a plunger armature, said core having a plurality ,of windings wound about it, one of said windings being adapted to open the contacts when the resistance of the work circuit is reduced below alininimum allowable value, another winding being adapted to hold said contacts open while such low resista-nce is maintained in the work circuit, the third winding being provided for counteracting said holding winding and pei'- mitting the contacts to close when theJresistance in the work circuit is again restored tol its minimum allowable value.

2. A protective device for circuits including work devices, comprising in combination, a solenoid magnet provided with a pairv of normally-closed contacts and a hollow core including a plunger armature, said core having a plurality 'of windings wound about it, one of which is adapted to open the contacts when the resista-nce of the work circuit is reduced below a minimum allowable value, another being adapted to hold said contacts open while such low resistance is maintained in the work circuit, the third winding being adapted to be brought into circuit by the opening of the vcontacts for counteracting said holding winding and'permitting the contacts to close when the resistance in the work circuit is again restored to its minimum allowable value.

8. A protective device for circuits including work devices, comprising in combination, a solenoid magnet having a pair of normally-closed main contacts; a pair of normally-open, auxiliary contacts andl three windings about a common core, one winding being adapted to open the main contacts' and to close the auxiliary'contactswhen lthe resistanceof the work circuit is reduced below a minimum allowable value, the second winding being provided for holding the main contacts openJ and the auxiliary contacts closed j-while the resist-ance in the work circuit is maintained at'a value below the mum allowable value; and the third winding in circuit with the auxiliary contact for counteracting said holding means and permitting the main contacts to be closed when the resistance, in the work circuit is again restored to its minimum' allowable value.

4. A protective device for circuits including work devices, comprising in combination, a solenoid magnet having a hollow core surrounded by a main electromagnet winding, aI secondary electiomagnet winding and a counteracting winding, said coi'e having a plunger armature therein and supporting a pair of normally-closed contacts; the main electromagnet winding being adapted to open the contacts when the resistance in the work circuit is reduced below a minimum allowable value, the secondary electromagnetic winding being provided for maintaining the contacts open while said resistance in the work circuit is maintained at the said low value; and the counteracting electromagnetic winding for destroying the eiiect of the secondary electromagnetic winding and permitting the contacts to close when the resistance in the work circuit is again restored to its minimum allowable value.

5. A protective circuit interrupting device `:for ciicuits including work devices, comprising in combination, an electromagnet of the solenoid type including a core having a plunger armature; a pair of normally-closed contacts adapted to be opened by said armature; a pair of auxiliary contacts noi'- mally open, one of said contacts being operatively connected to one of the normallyclosed contacts; a main winding oii/the core, 011e end of which yis connected to one ofthe normally-closed contacts; a secondary winding of comparatively higher resistance than the main winding, connected in shunt with the .normally-closed contacts; and a third lwinding of lesser resistance than the secondary winding and connected in series therewith but wound in opposition to the aforementioned two windings, one end of said winding being connected to one of the normally-open contacts.

6. A protective circuit interrupting device for circuits including work devices, comprising in combination, an armature; a pair of normally-closed contacts; a main winding for operating the armature to open said contacts when the resistance in thework circuit is reduced below 'a minimum allowable value; a secondary winding of comparatively higher resistance than the main winding,

.wound in the same direction as said main winding and connected in parallel therewith, said secondary winding being adapted to maint-ain the armature in its attracted, contact opening position while the resistance in the work circuit is maintained at' its aforementioned lois7 value; and a counteracting :winding of lesser resistance than the sec- /ondary winding and connected in series with the secondary winding, but wound in opposition thereto, 'said counteracting winding being ineiective to counteract the secondary winding while the resistance in the work circuit is maintained below its minimum allowable value.

7. A protective circuit interrupting device for circuits including work devices, comprising in combination, an armature; a pair of normally-closed contacts; a lnain winding for operating the armature to o en said contacts when the resistance in t e work circuit is reduced below a minimum allowable value; a secondary windin of comparative- 1y higher resistance than the main winding, wound in the same direction as said main winding and connected in parallel therewith,

vsaid secondary winding being adaptedto maintain the armature 1n its attracted contact-opening position while the resistance in the work circuit is maintained at its aforementioned low value; and a counteracting winding of lesser resistance than the secondary winding and connected in series but wound in opposition to' said secondary winding, said counteracting winding becoming effective to destroy the effect of the second-4 ary winding when the resistance in the work circuit is substantially equal to the resis'tance of said counteracting winding. i

8. A protective circuit lnterrupting device for circuits including work devices, comprising in combination, an armature; a pair of normally-closed contacts; a main winding for operating the armature to open said contacts when the resistance in the work circuit is reduced below a minimum allowable value; a secondary winding of comparatively higher resistance than the main winding, wound in the same direction as said main winding and connected in parallel therewith, said secondary winding being adapted to maintain the armature in its attracted contact-opening position while the resistance in the work circuit is maintained at its aforementioned low value; and acounteracting winding of lesser resistance than the secondary winding and connected in series but wound in opposition to said secondary winding, said counteracting winding being ineffective to counteract the secondary winding while theresistance in the work circuit is of .comparatively lesser value than the resistance in the counteracting winding.

9. A protective circuit interrupting device for circuits including work devices, comprising in combination, an electromagnet of the solenoid type including a core having a plunger armature; a pair of main contacts 1nclud1ng a stationary contact, and a movable,contact supported by a spring arm and normally in engagement with the stationary contact, said movable contact being adapted to be moved out of engagement with the stationary contact by the plunger armature; a main winding on the magnet core, one end fof said winding being connected to the main stationary contact; an auxiliary pair of contacts includinga stationary member, and a movable contact member carried by the spring arm' of the main contacts so that said auxiliary contacts will be open when the main contacts are closed; a secondary winding on the core, of higher resistance than the main winding, and connected in shunt with the main contacts, said secondary winding being adapted to maintain the armature in attracted, main-contact-opening position after a current tlow in excess of the maximum allowable value has passed through lthe main winding and energized the core to attract the armature, said excessive current fiow being due to the resistance in the work circuit falling below its minimum allowable value; and a counteracting winding wound on the core reversely to said other two windings and brought into series connection with the secondary winding by the closing of the auxiliary contacts, said winding being eective to counteract the secondary winding and release the armature to permit the main. contacts to close onlyy when resistance in the work circuit substantially equals-the resistance of the counteracting winding.

"In testimony whereof I hereto aix my signature.

JOHN T. FITZSIMMNS.

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