US1904539A - Method of and apparatus for gas blast circuit interruption - Google Patents

Description

April 18, 1933. s. RUPPEL 1,904,539

METHOD OF AND APPARATUS FOR GAS BLAST CIRCUIT INTERRUPTION Filed Sept. 24. 1929 ,m lNlTlAl. OPENING BLAsT 20m:

iii Jim I /0 $4 a /5 SWITCH CONTACT mm OPENING IIWO VE'HENT \SWITCH OPENING I MOVEMENT oP i/ igimmr 33 T A 70 \sw/rcn LA CONTACT OPERATOR 4 w sign of the contact structure andswitch parts,

Patented Apr, 18, 1 933 srewaar antenna, or so.

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Application filed September 2 19%, serial Zto. coasts, and in Germany hotelier that,

This invention relates to the control of compressed gasor fluid-blast switches and switches of the aforesaid character.

The control of circuit interrupters of-the fluid-blast type, as gas-blast switches, depends on a number of factors including the interrupting capacity oi the switch, the doand the character of the gas hlast. lln general, it may he said that a comparatively limited separation of the switch contacts hetween which the blast is directed is efl'ectivze,

to cause interruption of the circuit. Rees tablishment' of arcing may he prevented by inter-posing additional dielectric in the circuit, as by iurther lengthening ofthe arc gap or hy the opening of so-called disconnecting switches connected in series in the circuit. In the case where separate disconnecting switches are dispensed with, the additional dielectric may he inserted by lengthening the switch opening stroke.

The current interrupting action of the blast is most effective when the blast bears a certain relationship tothe gap traversed h the blast and the current to be interrupts. in general, the gap is comparatively small,

30 as of the order of a few millimeters when gas at high pressure is used. The contacts, which are separated abruptly, therefore have interposed between the same a compressed gas layer which is 'suflicient to interrupt the 5 current and to prevent reestablishment of arcing. The above relationship, however, is not constant for a given circuit interrupter and may vary under different operating conditions. There is, therefore, a range within 40 which the" gap may vary coincident with the most favorable interrupting conditions.

In accordance with my invention the switch opening movement is eiiected so that the zone or range within which the most 5 favorable blast interrupting action'may be had is traversed slowly and the circuit is incorrupted in the most effective manner,

Further, in accordance with my invention, the switch opening movement is at first cf- 0 fected rapidly and thereafter is retarded within the most effective hlast zone, the completion of the switch opening movement hein at increased speed,

i y invention will he more set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will he pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, Fig. l a partly diagraatic illustration oi operating mechanism for carrying out the method. em-

hodying my invention; Fig. shows another arrangement of operating mechanism, and r 1g. 3 is a sectional view of pneatic oper- As stated in the general description, it is preferable under certain conditions to alter the speed of the switch part which is moved, during the switchin out movement. This can take place in'di erent ways as described by way of example in the following figures. in one such arrangement there is provided a drive shaft or spindle having mounted thereon spur wheels of diflerent sector diameters arranged to engage alternatively" toothed wheelsor gears mounted on the switch actuating shaft so that the speed of rotation of the switch actuating shaft may be varied during the switching out movement with uniform speed of rotation of the drive shaft. In this arrangement, the aforesaid wheels and gears are mounted on the respective shafts. as by means of lock cones,'or any suitahle tree-wheeling arrangement, arran ed so that upon rotation of the drive shaft in the opposite direction for efiectin closing of the switch the shafts are couple by gear wheels ating means for carrying out the above methv transmitting uniform closing movement to l trated. The same applies to the toothed wheel 49 on the spindle 45. The switched-in or closed circuit position is shown in Fig. 1.

In this position the movable rod contact 11 of the switch is in engagement with a stationary nozzle-like contact 12 substantially at the restricted portion of said contact. The rod contact is suitably guided for longitudinal reciprocal movement within a gas chamber 13 which is formed by an insulating switch casing 14. The gas chamber 13 is in communication with the nozzle contact 12 and a gas supply conduit 15 so that upon opening of the switch contacts gas under pressure may be directed into the gas chamber so as to exhaust through the nozzle contact 12 and extinguish arcing between the contacts in the manner previously described. The switch actuating lever 48 is suitably connected to the lower end of the contact rod 11 as by a pin and slot connection 48, it being understood that the operative connection between the opening mechanism and the switch is diagrammatic and without reference to the correct proportioning of the corresponding movements of said mechanism and switch.

(1n the switching out, the spindle is rotated clockwise, and through the wheel 49 rotates the wheel of the spindle 46 with it.

The circumferential speed of the spindle 46 is here in proportion to the arc radii greater than that of spindle 45. The contact separating speed for the initial opening movement is diagrammatically indicated in Fig. 1 is therefore high. In the further course of the switch opening movement, the wheels 49 and 50 come out of engagement, and in their place the wheel 52 engages the wheel 51 which causes a reduction of the cir cum'ferential speed of the spindle 46 in proportion to the radii, which is equivalent to a slowing down of the switch opening movement. This opening movement is arranged so as to be in the most favorable blast zone for the reasons above given and is likewise indicated in the drawing. In the latter part of the switching out movement, the wheel 49 again engages with the wheel 50, while the wheel 52 is out of engagement with the wheel 51. The circumferential speed therefore again increases, and the latter or final part of the switching out movement indicated in the drawing is completed at greater speed.

During the switching out process, the wheel 54 driven by the wheel 53 runs loose as indicated. On the switching in the spindle 46 is moved through the wheels 54 and 53, while the wheels 49 and 51 run idly. The switching in process is therefore completed without reduction or alteration of speed.

It will be apparent that the above arrangement may be modified so as to include cams suitably designed so as to effect reduction of the switch opening speed throughout the range of the most effective blast action.

Another arrangement includes an elastic intermediate member, as a spring for example, included in the coupling between the driving and the switch actuating shafts. In this arrangement the switch actuating shaft is first rotated at high speed by the driving shaft until the former abuts a stop member. There is a dwell in the opening movement of the switch shaft at this point, the stop member being subsequently released by continued actuation of the driving shaft so that the switch opening movement ,is completed. During the aforesaid dwell the'driving shaft has stored up energy in the intermediate member of the coupling which is effective, after the release of said stop, to cause final opening movement of the switch at high speed.

In Fig. 2 the switch spindle 46 is actuated by the driving spindle 45, through the spring 58, which together with the slotted rocking link 57 is suspended at the point 64 of the lever 55 and the point of the lever 66. The drive of the switch piece 60 is effected by the lever 55 through the connecting link 59. On switching out or counter-clockwise movement of lever 66 the lever 55 is rotated inthe same direction by the spring 58 until the stop 56 rests on the stop lever 61. The stop lever 1 is carried loosely on the spindle 45 and is held by the spring 63 in the correct position. It has, furthermore, a stop 62. After the lever 55 has been prevented from further movement by the stop 56, the spring 58 is tensioned'so that when the lever 66 has carried the stop lever 61 along with it at 62, the lever 55 now released, is thereby brought suddenly into the end position of the switching out movement. In the switching-in movement the lever 66 carries the lever 55 directly with it through the link 57 The switch piece therefore comes to a stop during the switching out movement after a short time, then moves with increasing speed into the end position. i

The aforesaid arrangements for effecting variable speed opening of the switch by mechanical means may be used for practically every type of fluid-blast switch wherein positive separation of the contacts is elfected. In certain types of pneumatic drives including a piston for effecting closing and opening of the switch by gas pressure a special type of pneumatic control may be used to advantage. For example in a pneumatic pisis not limited tospecificdetails of constructhe switch closing movement may be effectedat substantially constant speed.

In Fig. 3 a pneumatlc arrangement for effecting variable opening s ed of the 5 switch is shown comprising a riving cylinder 5 of a compressed gas gear, in which the piston 6 moves with the switch actuating or piston rod 33. The pipe 67 is in communication with the compressed gas supply for switching out, as is the pipe 72 for switching in. Furthermore, the circulating or by-pass pipe 68 is arranged on the cylinder, the check valve 69 bein mounted within the same.

The switching out proceffiire takes place the pipe 67 into the cylinder behind the piston 6 which moveswith great speed towards the right. By means of the venting pipe 70 with adjusting cock "(1 or equivalent means 0 the right-hand side of the cylinder is at low pressure. For the purpose of retarding the opening speed of the switch in the manner previously described, the piston 6 is by passed after an initial ,high speed opening movement so that the opening force is suddenly reduced. The by-passing takes place, however, only within the range of the most effective blast interrupting action, beyond which the full openingiforce is again applied. 0 After a certain and adjustable distance, the

piston uncovers the gas inlet to the pipe 68 and the compressed gas is admitted by the valve 69 to the right-hand side of the cylinder in front of the piston. The piston speed 5 is rapidly reduced in accordance with the small difierence of res'sure before and behind the piston. s, however, the righthand side of the piston has been exhausted through the adjustable opening 70, the piston 0 6 moves slowly forward until it closes the compressed gas outlet'of pipe 68 so that it is no longer by-passed, and then by the increase of the pressure difierence the switch movement to the end is quicklyinade. The check valve 69 prevents the switching in compressed gas' infront of the piston from'fiow in'g away, the switching in process is there fore completed with the desired alteration of speed. As the travel of the piston may be. 0 made equal to that of the switch, the switch piece isherealso moved with variable speed during theswitching out operation and uniform speed during the switching in process. It should be understood that invention as follows Compressed gas flows throughtion and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art withoutdepa-rting from the spirit of my invention.

What I claim and desire to secure by Letters Patent of the United States of America is 1 1. The method of operating a circuit interrupter of the fluid-blast type which compr ses eflectlng opening movement of the circuit interrupter at an initially high rate and reducing the rate of contact separation through the range within which the inter-,

rupting action of the blast is most efi'ective.

2. The methodof operating a circuit -in-' terrupter ot the gas-blast type which comprlses effect ng quick initial switch opening I movement ofthe circuit interrupter, retarding the speed of contact separation and'contmuin the separation at a reduced rate throug the range within which the interrupting action of the blast is most effective,

and resuming said opening movement at a higher rate.

3. Operating mechanism for circuit interrupters of the gas-blast type including a SWltCll actuating member, comprising means efl'ecting high speed initial openingmovement of said actuating member, means retardin said member and causing a lower rate 0 opening movement within'a predetermined range in the opening stroke, and means effecting continued opening movement of said member at ahigher rate.

4. Operating means for a circuit breaker of the gas blast type comprising a piston for 'efiecting separation of the circuit breaker electrodes, a cylinderwithin which said piston operates, means for admitting gas under pressure at one end of said cylinder for effecting switch closing movement of said piston, means for admitting gas under pressure at the other end of said cylinder for effecting switch opening movement of said piston,

and means for varying the opening speed ofsaid piston including a by-pass for said piston in said cylinder, and a valve for controlling flow of gas through said by-pass so that sai ment.

breaker of the gas blast type comprising a piston for causing separation of the switch electrodes at variable speed, a cylinder within which said piston operates, means for admitting gas under pressure at one end of said cylinder for effecting circuit closing movement of said piston, an adjustable vent at the same end of said piston, means for ad- 'mitting gas under pressure at the other end of saidcylinder for efiecting circuit opening movement of saidpiston, a by-pass for said piston in said cylinder including a valve normally biased to prevent flow of as piston is checked in its opening move-I 5. Operating mechanism for a circuit hrough said by-pass during circuit closing movement of said piston, said piston being checked in its circuit opening movement by said by-pass and said adjustable vent causing continued opening movement of said piston until said piston has covered the exhaust end of said by-pass whereby said opening movement is resumed at normal speed.

In testimony whereof I afiix my signature.

SIGWART RUPPEL.

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