US2665396A

US2665396A - Circuit breaker

Info

Publication number: US2665396A
Application number: US254609A
Authority: US
Inventors: William J Weinfurt
Original assignee: McGraw Electric Co
Current assignee: McGraw Electric Co
Priority date: 1951-11-02
Filing date: 1951-11-02
Publication date: 1954-01-05
Anticipated expiration: 1971-01-05

Description

W. J. WEINFURT CIRCUIT BREAKER Filed Nov. 2, 1951 INVEN 0R.

Patented Jan. 5, 1954 UNITED STATES PATENT OFFICE 2,665,396 CIRCUIT BREAKER William J.

Weinfurt, Wa to McGraw Electric Co uwatosa, Wis., asslgnor mpany, Milwaukee, Wis.,

a corporation of Delaware Application November Z, 1951, Serial No.

4 Claims.

This invention relates to circuit interrupters and is particularly directed to a circuit interrupter in which the combined action of an overload responsive circuit interrupter and electron discharge devices, such as those normally known as ignitrons, are employed.

Objects of this invention are to provide a ciriiow at the first current zero.

A specific feature of the invention is to provide means associated with the contacts for utilizing' the separable contacts.

Further objects are to provide a circuit interrupter in which the contacts are arranged to open at an extremely rapid rate, which is preferably a half cycle,

and are adapted to be engaged by the contact portions B and l of the movable contacts I and 2 reu 9. Further, the auxiliary contacts IU and II are so arranged that they will remain in engagement with the contact portions 6 and 'I of the movable contacts during the initial portion stroke of the movable contacts.

It is to be tacts I of the opening contacts are energized by means of an over center spring I3 connected to one of the contacts and to a rock arm I4. This rock arm is adapted to be sarily Within less than a half a cycle under the influence of the spring I3.

The rock arm I4 is adapted to be operated by The terminals I9 and 20 are adapted to be connected in the line so as to place the circuit interrupter in series in the line. A pair of ignitrons ignitron 22 and the cathode are connected to the terminal I9. understood that the

cathodes

24 and 26 of the of current now so that one or the other of; the

ignitrons always provides a low resistance shunt path across the contacts whenthe contacts startto open.

It will be seen that continued motion of the lmovable contacts l and 2 to their final dotted line position will cause complete deenergization of the ignitor circuits of both ignitrons so that the ignitrons will cease to function and the current ow will therebyT be interrupted.

However, during the time that the rst portion of the motion of the movable contacts l and 2 occurs, the proper ignitor will immediately come into operation to provide a bypass directly across the contacts thereby providing a low resistance current path between the inner end of the solenoid I6 and the terminal I9 thus preventing arcing at the contacts. Upon further opening motion of the contacts, it will be seen that the auxiliary contacts l and ll are disconnected from the movable contacts l and 2 and consequently the ignitrons will be rendered nonconductive.

The full lines showing of the movable contacts is in their closed position, the movable contacts however have been shown in dotted lines at their final open position and in a partially open position.

It will be seen that a very simple type of circuit interrupter has been provided in which ignitrons are bridged across the separable contacts and are so arranged that one or the other immediately comes into operation during the initial portion of the opening stroke of the circuit interx rupter.

Further it will be seen that theabove results are accomplished without the expensive equipment and without the use of any auxiliary equipment whatsoever as the voltage drop across resistors is employed for energizing the ignitor circuit.

It is to be noted that the ignitrons are preferably so designed as to have short time high current carrying capacity and high inverse peak voltage characteristics.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

claim:

l. A circuit interrupter comprising switch means arranged for connection in a load circuit, overload responsive means for operating said switch means, a pair of ignitrons connected in a reverse manner across said switch means and including ignitors, and normally inactive auxiliary circuits including resistors bridged across the ignitor and cathode of the respective ignitrons and arranged to produce a voltage drop when 4 placed in the load circuit, said switch means including means for placing said resistors in the the load circuit when said switch means is partially opened.

2. A circuit interruptor comprising switch means, overload responsive means for operating said switch means, a pair of ignitrons each including an anode, a cathode and an ignitor, said ignitrons being connected in a reverse manner across said switch means, a resistor for each ignitron connected in shunt between the cathode and ignitor of the respective ignitron, said switch means being connected in the load circuit of said circuit interrupter and including contact means normally snorting said resistors when said switch means is closed and auxiliary contact means for placing said resistors in said load circuit when said switch means is partially opened, whereby kthe load current will pass through said resistors for a brief period during the initial portion of the opening motion of said switch means.

3. A circuit interrupter comprising switch means, overload responsive means for operating Isaid switch means, a pair of ignitrons each including an anode, a cathode and ignitor, said switch means including a pair of stationary main contacts and a pair of stationary auxiliary contacts arranged adjacent said main contacts and a pair of electrically connected movable contacts each normally in engagement with a main contact and an auxiliary Contact, said auxiliary contacts being arranged to remain in engagement with said movable contacts for an instant after said movable contacts have leit said main contacts during the initial portion of the opening stroke of said movable contacts, said ignitrons being connected in a reverse manner across 'said switch means, and a resistor for each ignitron bridging the ignitor and the cathode and connected between the main and the auxiliary con tacts.

4. A repeating circuit interrupter comprising switch means, overload responsive means for operating said switch means, a pair of ignitrons each including an anode, a cathode and ignitor, said switch means including a pair of stationary main contacts and a pair of stationary auxiliary contacts arranged adjacent said main contacts and a pair of electrically connected movable contacts each normally in engagement with a main contact and an auxiliary Contact, said auxiliary contacts being arranged to remain in engagement with said movable contacts for an instant 4after said movable contacts have left said main contacts during the initial portion of the opening stroke of said movable contacts, said ignitrons being connected in a reverse manner across said switch means, a resistor for each ignitron bridging the ignitor and the cathode and connected between the main and the auxiliary contacts, and means biasing said movable contacts towards closed position.

WILLIAM J. WEINFURT.

References Cited in the file of this patent UNITED STATES P LENTS Number Name Date 1,0l6,'086 Kraus Dec. 3, 1912 1,902,958 Jackson Mar. 28, 1933 2,215,804 West Sept. 24, 1940