US1925994A - Apparatus for interrupting alternating power circuits - Google Patents

Description

Sept. 5, 1933. CHESNUT 1,925,994

APPARATUS FOR INTERRUPTING ALTERNATING POWER CIRCUITS Filed Feb. 23, 1929 Patented Sept. 5, 1933 APPARATUS FOR INTERBUPTING ALTER- NATING POWER CIRCUITS Frank T. Chesnut, Trenton, N. 1., assignor to Ajax Electrothermic Corporation, Ajax Park, N. J., a corporation of New Jersey Application February 23, 1929. Serial No. 342,282

6 Claims.

My invention relates to disconnection of alternating current power circuits.

The main purpose of my invention is to provide for opening a-plurality of alternating current power circuits one at a time through the same disconnecting mechanism.

A further purpose' is to provide for throwing a resonated reactance in parallel with the current supplies for alternating current power circuits, one circuit at a time, then opening the supply to the particular circuit with which the resonated reactance is in parallel and subsequently opening the circuit through the resonated reactance and repeating the operation with the same resonated reactance for the other circuits as they require disconnection.

Further purposes will appear in the specification and in the claims.

I have illustrated my invention purely diagrammatically and by one form only, selecting a form which is practical, efficient and thoroughly reliable and which at the same time well illustrates the principles of my invention.

Figure 1 shows diagrammatically a plurality of power circuits with disconnecting means adapted to be efiective, one at a time, with any of them.

Figure 2 shows operation of diagrammatic circuits from a distant point.

The generator 9 is intended to be typical of the different types of alternating current sources of supply available and is not intended to be restrictedto the normal rotary generator of commerce.

This generator is shown in Figure 1 as supplying alternating current to a number of power circuits having diflerent characteristics, to indicate that the application of my invention is independent of the character of circuit interrupted. In one of these circuits a resistance load 10 is shown. In a second an inductive load 11 appears, with resistance 10 separately shown but intended to include the resistance inherent to the inductive load aswell as any outside resistance which may exist in the circuit. In the third connection a'resonant circuit is supplied, comprising an inductance 11 and capacity 12. All of these circuits are connected across current supply lines 13 and 14 through suitable switches. A wave trap is used which is capable of operation with any of the circuits. I have illustrated one such trap comprising a resonated circuit having capacity .15 and inductance 16.

The wave trap is adapted to be connected between one of the lines, such as line 14, and the load, in parallel with the normal connection of this load with the line so that the same wave trap may be used to parallel the normal connections between any of the loads and the line.

The character of switch or switches by which the wave trap and the normal connection .of the load with any line are placed in parallel, one at a time, for any of the loads, and

by which the connections are subsequently opened, is not important, provided that it is ing the required function; and switch will, therefore,

capable of performthe character of be determined upon the basis of the simplicity, reliability and convenience of the switch as distinguished from any supposed novelty in the switch types of switches are itself. Two such shown. One is intended to represent a spring contactor but for convenience of illustration is shown as provided with knives movable laterally across the contacts.

The loads are shown in Figure 1 as through with the line normally contacts 18 and conductors 19.

switch arm 1'7 with its contact connected switch arms 1'7,

Each switch arm 1'7 is electrically connected with a switch arm 20 which is adapted to engage or break contact with a contact 21 without opening the engagement of 18. A third contact 22 provides convenient resting place for arm 1'7 when its engagement with contact 18 is broken.

The wave trap is connected between line 14 and the several contacts 21, one for each circuit to be opened.

In operation the current for the loads normally passes through switches 1'7, 1'7

and 1'7 and their connections 19. To interrupt the circuit supplying any of the loads,

such as that through switch 17', the wave trap is connected in parallel with the corresponding connection switch 20' against contact 21.

through connection 19 can then opening switch 1'7 tion of this switch. This 19, as by closing The current be interrupted by as shown in the dotted posiis permissible because the condenser of the wave trap will take up the surge which would otherwise cause arcing,

will be distributed in the trouble at the switch.

this surging current wave trap instead of causing The current through the wave interrupted by opening the arc. This interruption of to or from the wave trap can and trap can then be switch 20' without any the circuit connection take place at is opened it can be turned dotted position of t a load a ain in its normal circuit the corresponding switch 17, 17' or 1'7 is closed.

It is convenient but by no means necessary to couple the switches 17 and 20, 17' and 20', 1'7 and 20 respectively so as to permit independent movement between them throughout a limited rangeof separation and to require that the two switches shall move together when the limit of separation has been exceeded. The separation should be sufficient to permit the two switches to engage contacts 18 and 21, 18' and 21, etc. at the same time, carrying switch 17 with switch 20, for example, in counter-clockwise movement in Figure 1 after the limit of movement has been reached, and closing switch 20 against switch 17, for example, with clockwise movement in the figure so that but one switch need be operated in each direction. During this last (restoring) movement of the switch arms, switch 20 will momentarily close the circuit through the ,wave trap unless the circuit meantime be interrupted at some other point.

In the diagram switches 17, 17' and 17 are shorter than switches 20, 20', 20 so as to avoid engagement of these switches with the contacts 21, 21, 21

In Figure 2 I have applied the invention to parallel operation of a number of specific devices in the same art, here a plurality of tuned furnace inductor circuits having inductors 11 and condensers 12 each, each furnace supply circuit of which can be interrupted by the wave trap mechanism common to all.

In order to indicate that the character of switch is not controlling I have illustrated different switch mechanism in Figure 2 from that in Figure 1. Figure 2 shows pairs of contactor blades 23 and 24, one pair for each load circuit. The contactor fingers are spaced by insulating material 25 and, until the electromagnets are energized, are spring retracted by any suitable spring 26.

The contactor blades are electromagnetically operated in any suitable way as by electromagnets 27 whose coils receive current from a line 28 through appropriate individual switches 29.

The blades engage contacts 30 and 31 which are so spaced and proportioned that in the position of the blades dotted at 23', 24 both blades are closed against their contacts while in the position 23 24 the blade 24 is closed against its contact and the blade 23 is open.

When electromagnetically controlled, the load circuit is connected to the line uninterruptedly through the contact 31, blade 24 and connection 32, but when it is desired to open any circuit, deenergization of the electromagnet 2'? permits the spring 26 to shift both blades to the left to the position shown in solid lines.

Starting with the switch position shown in solid lines at the left in Figure 1 when the proper electromagnet is energized the switch will move in clockwise direction and will, in passing, momentarily include the wave trap in the circuit during its movement to the final position in which the load is connected to the line. This momentary connection takes place while knife 23 is passing over contact 30 and is not objectionable. When knife 24 engages contact 31 a part of the load circuit is placed in parallel with the wave trap circuit, and this condition continues until knife 23 leaves contact 30 and breaks this wave trap connection. The load circuit path through switch knife 24 and connection 32 is then the only load circuit path to the line at this point. This is the switch position for furnace operation.

When the coil of the electromagnet is deenergized, either through failure of current or by opening the appropriate switch, the blades 23 and 24 are retracted by the spring, moving in counter-clockwise direction. By this movement a wave trap similar to that in Figure 1 is first introduced in parallel with a portion of the load circuit which passes through the switch and connection 32, and the circuit through connection 32 is then opened while the wave trap is still connected to receive and to distribute within the trap the surge of current due to the opening of the main circuit. The circuit through the wave trap is then opened and the switch comes to rest in the position shown in Figure 2.

As will be seen the automatic control of the succession of contacts made in opening and closing the blades 23 and 24 ensures the proper order of these contacts and fully protects against accidental or erroneous connection of the circuits. Electromagnetic control of the several devices permits thorough and reliable control of the circuits at a distance so as not only to open and close the circuits but to ensure inclusion of the wave trap in parallel with the portion of the circuit to be interrupted up to the time of interruption of the main circuit.

It will be evident that I have provided mechanism common to any number of circuits to be interrupted which will open these circuits without substantial arcing.

It will be evident that whether a split switch or independent switches, or a multipolar switch be used the function is the same of throwing the common wave trap into parallel with the circuit to be interrupted, maintaining the connection through the wave trap while the current path to the load through the paralleled circuit is interrupted and subsequently interrupting the wave trap circuit.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such in so far as they fall within the reasonable spirit and scope of my invention.

Having thus described my invention what I claim as new and desire to Patent is:-

1. A plurality of alternating current power circuits in combination with a wave trap circuit containing means common for each of the circuits for interrupting each of the circuits and 13 means respectively for connecting the wave trap circuit in parallel with a part of any circuit, for subsequently opening the part of the circuit so paralleled and for finally opening the circuit through the wave trap.

2. A plurality of alternating current power circuits, in combination with a wave trap circuit for interrupting each of the power circuits and means respectively for connecting the wave trap circuit in parallel with a part of any circuit, and for subsequently opening the part of the circuit so paralleled.

3. An alternating current power circuit, a switch in said circuit, a wave trap connected to parallel the part of the power circuit containing said switch, a switch in the connection to the wave trap, circuit connections between the two switches whereby, beginning with the switch in the power circuit closed, the wave trap circuit is closed and the power circuit is subsequently 5 secure by Lett 125,

nating current power circuits, a circuit loop having two parallel branches, an inductance in one branch, a capacity in the other branch, means for connecting the circuit loop in parallel with a portion of any one of the power circuits which is to be broken, means for breaking the paralleled portion of the power circuit to which the loop is connected and means for subsequently disconnecting said power circuit from said loop.

6. In an electrical system, a plurality of alternating current circuits, a switch in each circuit, a shunting circuit having a resonant loop, means for shunting any one of the switches by the shunting circuit and means for removing the shunt from said oneswitch after the switch has been opened.

FRANK T. CHEN'UT.

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