US2181283A - Synchronous circuit make and break device - Google Patents

Description

Nov. 2& 1939.

w. E. PALMER 2,181,283

SYNCHRONOUS CIRCUIT MAKE AND BREAK DEVICE Filed Sept. 10, 1937 4 Sheets-Sheet 1 HIIIII Nov. 28, 1939. w. E. PALMER SYNCHRONOUS CIRCUIT MAKE AND BREAK DEVICE 4 Sheets-Sheet 2 Filed Sept. 10, 1937 izaar zfir- Q Z JaZ 11,5- faher Nov; 28, 1939. w. E. PALMER SYNCHRONOUS CIRCUIT MAKE AND BREAK DEVICE 4 Sheets-Sheet 3 Filed Sept. 10, 1937 I IIIIIIIJ Nov. 28, 1939. w. E. PALMER SYNCHRONOUS CIRCUIT MAKE AND BREAK DEVICE Filed Sept. 10,- 1937 4 Sheets-Sheet 4 NON WW Patented Nov. 28, 1939 UNITED STATES PATENT OFFICE amass SYNCHRONOUS CIRCUIT: MAKE DEVICE Walter E. Palmer, Cicero, Ill. v Application September 10, 1937, Serial No. 163,232 11-01mm. (01. 200-91) It is well known that in'maklng and breaking an electric circuit, considerable arcing of the current is occasioned at the make and break points which eventually causesconsiderable damage,

and is objectionable for many reasons. These arcings are occasioned'by reason of the fact that the making and breaking has heretofore been eifected, especially in alternating current, when the current is pulsating or flowing, and the higher the voltage on the line the greater will be the are.

It is one of the objects of the present invention to provide an improved make and break device by means of the use of which an alternating circuit will be made and broken at the neutral point in the sine wave of the current, or when there is no current flowing, and to that end the invention consists in providing an improved circuit make and break device, embodying in its construction a motor operating in synchronism with the current in the line which is to be controlled, whereby the circuit will be made and broken when the.

current value is zero, or between alternations of this current.

To the attainment of these ends and the accomplishment of other new and useful objects as will appear, the invention consists in the features of novelty in substantially the construction, combination and arrangement of the several parts hereinafter more fully described and claimed and shown in the accompanying drawings illustrating Figure 5 is a detail sectional view takenon line 55, Figure 3.

Figure 6 is a view partly in section as taken on line 66, Figure 3, showing in diagram the wiring.

Referring more particularly to the drawings, the numeral l0 designates a shaft which is journaled in suitable bearings suchas in supports ll held in positionin any suitable manner. A drum l2 constructed of any suitable insulating material and having contact plates l3-H recessed into the periphery thereof, is mounted for free movement on the shaft l0.

Adjacent the end of the drum I2 is arranged a disc 16 having a cut away portion I1 and a cut awayportion l8 to forni a shoulder l9. Encompassing the shaft I0 is a coiled spring 20 one end of which rests against a lug 21 on the disc I. and the other end of the spring'rests against a projection 23, which is secured to the end of the drum l2 and is disposed in the space or cut away portion ll of the disc IS. The disc I6 is secured to the shaft ill by a set screw it.

Passing through the shoulder 19 is a screw 24 one end of which contacts the support 23 so that 10 by adjusting the screw 24 a rotary adjustment of the drum relative to the shaft l0 may be obtained.

If desired, .a lock nut 25 may be provided for locking the screw 24 against adjustment.

Carried by a suitable support 26 are contact brushes 21 one for each of the contact plates l3l lon the drum l2 and are disposed to engage the periphery of the drum l2 as well as the contact plates l4. These brushes may be held in 20 position in any suitable manner but preferably by means of upright pins or members 28 which are preferably screw-threaded and are provided with nuts 29 to form binding posts to which one controlled is connected. If desired, one or more springs 3i may be provided which tend to hold the brushes 21 in contact with, the periphery of the drum. These springs contact the support 26 and also an insulating 30 cross-bar member 32 which latter is adjustably secured in position by means 01 bolts 33 as shown more clearly in Figures 1 and 4.

The'brushes 21 are preferably provided with 01'' balls 3!. A spring pressed plunger 36 contacts I with one oi the rollers or ball: 25 and a conical member 31 contacts the other of the rollers or balls 35. This conical -member 31 preferably into the support 26 and held against adjustment by means of a nut or collar 39. The upright 28'forming a part of the binding post preferably passes through a slot 40 so as to permit the brushes 21 to be moved laterally for 45 a limited distance and whenever individual adjustment is necessary or desired. The spring pressed plunger 36 contacting the ball 35 tends to move the brush 21 towards the right in Figure 4, and by adjusting the conical member 31 upwardly the brush 21 will thus be moved to the right. However, when the adjustment to the left in Figure 4 is desired for the brush 21, the conical member 31is forced downwardly and the spring 55 of the terminals 30 of the line which is to be 25 r forms an extension on a screw or bolt 38 threaded inclined faces 34/ into which are (recessed rollers ,35

pressed plunger 35 will yield sufllciently to permit the brush to so move.

Another brush 4| similar to the brush 21 and similarly adjusted also contacts the periphery of the drum l2 and is in position to be engaged by the contact members l4 carried by the drum.

These members M are of such a length that they will span the space between the brushes 21 and 4| when the drum is moving in the direction of the arrow in Figure 4 'at the points where the make and break of the circuit is effected.

To the binding post 42 which is connected to the brush 4| is secured the other terminal 48 of the line or circuit which is to be controlled.

Thus it will be seen that when the drum I2 is rotated clockwise, the contact members l4 will engage or move out of engagement with the brushes 21-4| and thereby open or close the circuit in the controlled line.

The drum l2 by its rotation effects the make and break of the circuit and this drum is rotated intermittently by means of a synchronous motor 44.

To that end there is provided on the shaft 45 of the motor 44 a gear 45 of any suitable type, preferably a spiral gear which meshes with a spiral gear 41 that is mounted upon and rotates. freely about the shaft l8, and mounted upon the shaft l8 adjacent but spaced irom the gear 41 is a disc 48, the disc being secured to the shaft for rotation therewithin any suitable manner such as by means of a set screw 48.

Secured to and projecting laterally from the gear 41 and disposed in the space between the gear 41 and the disc 48 is a collar which rotates with the gear 41 and in a counter-clockwise direction as shown more clearly in Figure 6. This collar 58 is provided with a shoulder 5| for a purpose to be set forth. Carried by the disc 48 is a dog 52 which is pivotally mounted thereto and intermediate its" ends as at 53, and is provided at one extremity with a shoulder 54. A second shoulder 55 is provided on the dog 52 and this shoulder 55 is adapted to be moved into and out of the path of-the rotary movement of the shoulder 5| on the collar 58, so as to lock the disc 48 for rotation with the gear 41 and with it the shaft ID for rotating the drum l2. When the shoulder 55 is moved out of engagement with the shoulder; 5| the disc tatior'i' by means of another dog 55, the operation of which latter will be presently described.

A spring 51 is provided formoving the dog 52 into an operative position with respect to the shoulder 5|. One end of this spring is anchored as at 58 to the dog 52 and at 58 to the disc 48. A stop pin'68 carried by the disc 48 is provided for limiting the movement of the dog 52 about its pivot in a direction to cause the shoulder 55 to disengage or move out of the path of rotation of the shoulder 5| on the collar 58.-

Thus it will be seen that when the dog 52 is in the position shown in Figure 6 the disc 48 will be held against rotation by the dog 55 entering one of the notches or seats 5| in the periphery of the disc 48. In this position of the dog 52 the collar will rotate freely with the gear 41 but the drum l2 will remain still. When, however, the dog 52 is moved into a position that it will contact the shoulder 5|, then the disc 48 will be locked to the shaft H]- for rotation therewith, and as the disc 48 lSjSBGLlI'BdtO the shaft iii of thedrum l2 for rotation therewith, the drum will as correspondingly rotated and the contact points N 011th? necessary to control the adapted, when 48 will be arrested in its rodrum willbe moved into and out of engagement with the respective brushes 4 |-21.

Upon each operation of the dfsc the drum l2, they will move one-half of a revolution, or 180, at which time the dog 52 will be shifted to cause the shoulder 55 to disengage the shoulder 5| and the end of the dog 58 will drop into one of the notches or seats 5| in the periphery of the disc 48 to hold the latter under tension and the end 54 of the dog '52 against a stop shoulder 18 or 18 to be later described.

48 as well as- In order therefore to effect this operation it is operation of the dog 52. In the present exemplification of this invention mechanism is shown for controlling the dog 52 to eflect a making or closing of the circuit which is to be controlled, and also mechanism is shown to effect the breaking of the circuit.

The control mechanisms, however, are arranged at different points in the cycle of operation of the dog.

The dog 55 is pivotally mounted as at 52 and a spring 53 one end of which is anchored to the dog as at 54 and the other end being anchored to a support 55 tends normally to move the end of the dog 55 in a direction to enter one of the seats 5| when the latter is in a position to receive such an end.

An electroresponsive form of a magnet 55 and embodying a coil 51 has co-operating therewith an armature 68 pivotally supported intermediate its ends as at 69, and is provided with a shoulder 18. This shoulder is the armature 68 moves about its pivot in one direction to assume a position in the path of movement of the shoulder 54 of the dog 52 when the disc 48 is rotated, and when the thoulder 54 contacts the shoulder 10 the dog 52 will be rocked about its pivot 53 against the stress of the spring 51 so as to move the shoulder 55 out of engagement with the shoulder 5| and thereby release or unlock the disc 48 with respect to the gear 41 so that although the gear 41 may be further rotated the movement of the disc 48 as well as the drum |2 will be arrested.

At this time the dog" 55 will enter the notch 6| in the disc 48., The parts will remain in this position until the magnetic or electroresponsive device is energized, to attract the armature 58 to swing it about its pivot 58 and thereby move the shoulder 18 out of engagement with the shoulder 54 on the dog 52, allowing the latter under the stress of the spring 51 to assume a position in the path of movement of the shoulder 5| on the collar {ratio again lock the disc 48 and the drum |2 for rotation with the gear 41,

Arranged in proximity to the electroresponsive device 55 is another electroresponsive device 1| embodying a coil 12. Co-operating with this electroresponsive device 12 is an armature 13 which is pivotally supported intermediate its ends as at 14 and provided on one end of the armature 13 is a shoulder or stop 15 with which a shoulder 15 on the end of the armature 68 is adapted to cooperate. A coiled spring 11 is. anchored by one end as at 18 to the end of the armature 68 and is anchored as at 19 to the end 88 of the armature 13.

The shoulder 15aat a predetermined time in the device, assumes a posi- 5 of the shoulder 54 on the dog 52, with the result that the disc 48 and the drum I2 will not be disturbed in their positions even though the magnet 66 were at that instant energized.

However, when the parts are in the position shown in full lines in Figure 6 the energization of the electroresponsive device 66 will cause the armature 68 to swing about its pivot to release the dog 52; this happens when the coil 61 is dc-energized and the spring 11 moves the armature 68 into the position shown in Figure 6.

Should the coil 12 be energized when the shoulder 10 of the armature 68 is in engagement with the shoulder 54 of the dog 52, the shoulder 15 on the armature 13 will'be moved into engagement with the shoulder 16 on the armature 68 and lock the latter in such a position.

Thus it will be seen that when the coil 61 and the coil 12 are both energized, the dog 52 will not be released since the contacting shoulders 15 and 16 respectively of the armatures 13 and 68 will lock the latter against movement. When the dog 56 is moved out of the notch or seat 6| a projecting portion 8I thereof will serve to close a make and break device embodying spring arms 82 and 83 for a purpose to be later described.

The coil 84 together with a coil or electroresponsive device 85 correspond respectively with the coil or electroresponsive device 61--12 arranged on opposite sides of the mechanisms. The coils B1 12 co-operate to eflect what might be termed the off position while the coils 8485 co-operate to efifect what might be termed the on position. 1

The synchronous motor 44 is provided with an inductive or starting winding 86 and a syn- .chronous winding 81 and on the motor shaft,

and in the circuit of the inductive winding two centrifugal switches 88-89 are provided.

The switch construction which controls the operation of the device embodies an intermediate spring member or finger 90 and spring members 9I-92 on opposite sides of the member 90, and a switch button or knob 93 being provided for the operation of this switch construction. It will be noted that upon the first depression of the button 93 electrical contact will be made between the members 92 and 90 of the switch structure. This connection, as will be later described, starts the motor into operation and locks both the on and oil release mechanisms. A further depression of the button 93, and while the member 92 is in contact with the member 90, will move the member 90 into electrical contact with the member 9I and this will energize the respective electroresponsive devices.

.The motor operates in synchronism with the sine wave or pulsations in the circuit, and one adjustment'may' be efiected by means of the structure shown in Figure 5, that is, by means of the adjustment of the disc l6-with respect to the drum, through the medium of the screw 24 working through the shoulder I9 and against the support 23 carried by the drum I2, the disc I6 being fast on the shaft by means of the screw I5, while a finer individual adjustment may be obtained by the adjustment of the conical elements .or members 31 operating upon the brushes 21, shown more clearly in Figure 4.

r A centrifugal switch 89 operates to automatically cut out the inductive winding 86 from the line after synchronism of the motor with the alternations or pulsations in obtained.

. The centrifugal switch 08 operates to cut out .coils 12 and 85 the line has been the local inductive circuit which would otherwise pass through the' lock coils in series, to-wit: the coils 12 and 85 that would return to the inductive winding and which would complete a secondary circuit that wouldotherwise operate the lock coils 12-85 contrary to the intention of the desired operation.

Obviously the breaker drum I2 may be geared to'obtain any desired degree of ratio of rotation between the motor and the breaker drum.

When the motor is started by depressing the button 93, so as to form an electrical connection between the members 92 and 90 of the manual control switch, both the centrifugal switches or cut outs 88-89 are closed, allowing the current to pass through both the inductive and synchronous windings 86-81. These switches or cut outs 88-89 remain closed until the motor has attained synchronism with the current sine waves or alternations in the supply line of the controlling circuit. .At this time in the cycle .of operation of the device, both of the switches or cut outs 8889 open, thereby cutting ofi current from the inductive winding 86 and lock coils 1285, thus allowing the motor to run on thesynchronous winding only, and simultaneously de-energizing the lock coils.

When the button 93 is depressed so as to move the member 92 into electrical the member 90 the current will flow as follows:

From line 94, to conductor. 95, contact 90, contact 92, conductor 96, conductor 9'5, at which point the current will divide, a portion thereof flowing through the switch 89, inductive winding 86, conductor 98, conductor 99 to the other side of the line I00, thus energizing the inductive winding 86 starting the motor. I

The other portion of the current will flow from the conductor 91 to conductor IOI, through synchronous winding 81 to the line I00, thereby enabling the synchronous winding to control the speed of the motor when such speed has been obtained.

After the current has passed through the switch 89, -a portion thereof will flow through the conductor I05, to coil 12, conductor I04, coil 85, conductor I03, to switch 88, to conductor I02, conductor 99 back to the line I00. This circuit will continue to flow thereby locking the until such time as the motor has attained synchronous speed, when switch 88 automatically opens to cut off this last referredto circuit, thereby releasing the locks 12 and 85.

Then the button 93 is further moved to cause the member 90 of the switch toalso be moved into electrical contact with the member 9I of the .switch. flow from the line 94 through conductor 95, member 90, member 9|, conductor I06, coil 61 out through conductor I01, conductor I08, back to the conductor I00 on the other side of the line, thereby actuating the oil release 61, provided motor has attained synchronous speed, opening switch 88 and releasing lock 12.

The sequence of operations taking place upon the depression of the, off button 93 are as follows:

Upon bringing the contact members 92 and 90 into engagement the motor is started by the current .flowing through the inductive or starting winding, and simultaneously the lock coils 12 In this position the current willv and 85 are energized to lock the armatures 58 and magnet 61 will be energized tending to pull the armature and shoulder 18 to release the dog 52 to permit the latter to assume a position where it will engage the rotating shoulder 5|; but this is prevented by the locking shoulder 15 held by the energized locking magnet 12. However, as soon as the motor attains synchronous speed, the locking magnets are de-energized by the automatic opening of the centrifugal switches 8889, and the locking shoulder 15 is moved out of engagement with the shoulder 16, thereby allowing the armature 68 to be attracted by the magnet 61 to release the dog 52 into engagement with the rotating shoulder 5|, and thereby impart to the disc 48, and through it to the shaft in, a rotary motion in the direction of the arrow shown in Figure 6.

dotted lines in Figure 4.

Upon the initial movement of the disc' 48, the dog 56 is raised from the notch 6| of the disc 48, and thereby the switch members 82-83 are brought into contact.

As soon as this takes place, the windings of the motor will be maintained in line connection, even though the pressure from the ofl" button 93 is entirely removed, which would cause all of the members 92--90--9| to move out of electrical contact; thus the function of the switch 82-83 is to insure the completion of the cycles of operation initiated by the depression of the ofi key 93.

The motion of the disc 48 continues for onehalf of a revolution, when the shoulder 54 will be engaged by the shoulder -A of the armature lever 68-A, and the dog 52 will be disengaged from the rotating shoulder 5|. At this point the contact 56 will engage the second notch GI and thereby lock the disc in its "off position and simultaneously separate the switch arms 82-433, thus openingthe motor circuit.-

At the completion of these functions, the con-- tact member M will rest opposite and out of en-. gagement with the brushes 21 and 4|, as shown in An examination of Figure 4 indicates that the break in the control circuit can only occur when the point BQon the contact l4 has reached the point B--| on the shoe 21. Otherwise a make, (that is, a completion of thecircuit) can only occur when the point "M" on the contact M has reached the point M-| on the shoe 4|, upon a further rotation of the drum l2 in the same direction, and after the insert M has once passed out of engagement with the shoes 21 and 4|. This involves a time interval between the'moment when the drum I2 is placed in motion and a the instant or instants when the current value is zero.

Another conductor ||I1-A leads from the coil 84 and is connected to the switch member 8|-A- of the on button 9 3--A so that the coil 84 may be energized when the button 83-A is depressed for the actuation of the armature 68-A.

In this position of the parts of the switch and when the motor has attained synchronism with the alternations in the line 94-46, the switch 89 will automatically open, thereby cutting out the starting winding 86 and this will de-energize the coil 12 with the result that the spring 11 will move the armature 13 to the full line position shown in Figure 6. That is, so that the shoulder 15 will be moved to a pos'tion out of engagement with the shoulder 16 on the armature 68. The coil 61 being then energized will attract the armature 68, moving the shoulder 10 out of contac Lwith the shoulder 54 on the dog 52, releasing the latter, allowing the spring 51 to swing the dog 52about its pivot so that the shoulder 55 will engage the shoulder 5| on the collar 50 and thereby lock the disc 48 for rotation with the gear 41.

While the members 92, 90 and 9| of the switch are in electrical contact, current will also flow through the conductor 96, to the switch member 83. As the disc 48 rotates, the dog 56 will be unseated from the notch or seat 6| causing the dog 56 to swing about its pivot 62 against the stress of the spring 63, with the result that the projecting portion 8| on the dog 56 will engage the contact arm 82 and close the switch, by moving the member 82 into engagement with the member 83 so that.the current flowing in through the conductor 96 and switch member-83 will then continue to flow through the switch member 82,

conductor I08, back to the conductor 94 on the other side of the main supply line.

Thus it will be seen that by pressing the button 93 the motor will first be started on the inductive or starting winding 86, and the coil 12 will be energized to move the armature 13 to a position that the armature 68 will be locked against movement about its pivot 69, and the dog 52 will be maintained in a position that the disc 48 will remain idle but the motor will continue to run.

When the motor has attained synchronism with the pulsations in the main line, and upon a further depression of the button 93 so as to cause the members 92, '90 and 9| to be all in electrical contact, current will fiow through coil 61 to energize it with the result that the armature 68 will be attracted and the shoulder 10 will be moved out of engagement with the shoulder 54 to release the dog 52 to cause the disc 48 to be locked with the gear. The disc will then rotate and the dog 56 will move the contact members 82-43 into engagement, thereby closing the circuit causing the motor to continue to run until the disc has assumed the position that another one of the seats 6| will be positioned to receive the dog 56. Just previous to this movement of the dog 56 the coil 61 becomes deenergized, and the spring 11 will move the armature 68-A on the opposite side of the line into a position that the shoulder 54 of the dog 52 will engage a shoulder 1IJ- -A on the armature 68-A, so that the'dog 52 will be shifted to release the disc 48 with respect to the gear 41. .Just at this time one of the seats or recesses 6| will be'in a position to receive the v dog 56.

It is of course to be understood that to perform the opposite operation, that is, what might be termed the on position, the other button 93-A which controls the coils 84 and 85 must be operated, when the same sequence culminating in the operation of the ing coil.

The coils 61-84 are respectively locked by the on actuatcoils 12 and 85 until the motor attains synchroof events occur,"

' be termed the on or switch.

ensues -82-'83 is provided for the purpose of maintaining the motor in operation until the full throw of the drum [2 has occurred, regardless of whether either of theswltch buttons 83-A is closed or open.

Obviously the device may be geared for the desired ratio of rotation between the motor 44' and the drum I2.

It is thought that the operation will be clearly understood from the foregoing, but briefly stated, it is as follows:

In Figure 4 the circuit breaker is shown in what might be termed a closed position, and the operation of the device will be described in connection with the left hand portion of the wiring diagram shown in Figure Gembodying the-coils 61 and I2.

To open the controlled switch, the left hand button 83 is depressed until the member 82 comes into contact with the intermediate member 88. This allows the current to flow from the controlling circuit through the motor winding and the coils 1284 in parallel back to the other side of the line.

'The motor starts on'the inductive or starting winding 88, and when synchronous speed has been obtained, the coils 12-85 are de-energized through the opening of the centrifugal switches 88-88, .thus allowing the actuating mechanism to operate, which occurs upon the movement of the intermediate member 80 of the switch into electrical 'contact with the'member M of @the It-will be seen that the member 8| of the switch is connected with the coils 81, which latter when energized attracts the armature 88, allowing the shoulder 55 on the dog 52 to engage the shoulder 5| on the collar 80. The collar 58 then turns with the revolution of the motor 44, being fastened to the gear 41 for rotation therewith and which gear 41 is on the motor-shaft. Thus when the shoulder 55 of the dog 52 engages the shoulder 5i on the collar 50, the dog 52 together with the disc '48 on which it is mounted is revolved in a counter-clockwise direction for one-half turn until the shoulder 54 on the dog 52 engages the shoulder Hi-A on the armature.

88A that is controlled by the coil 84, as shown in Figure 6. The engagement of the shoulder 54 with the shoulder HJA will swing the dog 52 about its pivot 53 against the stress of the spring 5-! to cause the shoulder 55 to move out of engagement with the shoulder ll on the collar 88.

In either position, that is, whether the circuit make and-break device on position, the dog 88 will engage in one of the seats or recesses II in the'disc 48 for the purpose of holding thedrum in such position. The dog 58 also acts to hold the points 54 and 10, or 54 and '|0A according to the position of the disc 48, under tension, that is, the end of the dog 52 will be held firmly against the stop 10 or ID-A. The tension of the spring 83 is preferably greater than the tension of the spring- 51, for the reason that the spring 51 would otherwise overcome the tension of spring 88 and tend to rotate the dog 82 about its pivot 53; which action would force the disc 48 to rotate in a. counter-clockwise direction, which is not desired. Such counter-clockwise rotation would result in the spring 81 drawing or positioning the dog I! so that the shoulder 88 would comis at rest in what might" tact II, and thereby cause another rotation fol the disc 48 in a clockwise direction, which is not desirable at that particular time in i the cycle of operation of the disc.

cycle of opera- 5 and all of the coils Upon completion of the OH tion, the drum 1! will stop will become de-energized.

To perform the opposite operation from that which is, performed by the structure shown on the left hand side of Figure 6, and to employ the 10 coils 84-85, all that is necessary is to depress the other button 83-A or what might be termed the on button, when the same sequence of events occurs, as with the operation of the button 93, culminating in the o ration or activity of the 15 coils 84-85. v

If desired, a suitable closure or cover i119 may be provided for the entire mechanism, and \this cover maybe held in position or supported in any desired or suitable manner.

While the preferred form of the invention has been herein shown and described, it is to be understood that various changes may be made in the details of construction, and in the combination and arrangement of the various parts, within the scope of the claims, without departing from the spirit or this invention.

What is claimed as new is:

1. A rotary circuit make and break device, a synchronous motor connected with an alternating current circuit and from which motor said make and break device is normally disconnected, means embodying a shlftable connecting element for connecting said make and break device with the motor for rotation therewith, means operating automatically to shift said element to lock the make and break device and the moimr for operation in unison in a manner thatat the instant of the make or break the current value is zero, means also operating automatically, and at 4 a different point in the. cycle of rotation of the make and break device, to shift said element to unlock the make and break device from the motor, and means operating to maintain the motor in operation until the full throw of the make and break device has occurred. g

2. A rotary circuit make and break device, asynchronous motor connected with an alternating current circuit ,nd from which motor said make and break device is normally disconnected, means embodying a shiftable connecting element for connecting said make and break device with the motonmeans operating automatically to shift said element to lock the make and break device and'the motor for operation in unison in a manner that at the instant of the make or break the current value is zero, means also operating automatically, and at a different point in the cycle of rotation of the make and break device,

to shift said element to unlock the make and break device from the motor, and means operating to maintain the motor in operation until the full throw of the make and break device has oc-- curred, the last recited means embodyinga supplemental circuit make and break device, responsive in its operation to the operation of a por-' tion of. the connecting means between the motor and the first recited make and break device.

3. A rotary make and break device, a motor connected to an alternating current and nor- 70 mally disconnected from said make and break device, connecting means for connecting the motor and make and break device for operation in electroresponsive means for rendering the means for rendering the said connecting means inactive, means for controllingthe operation of the electroresponsive means, means operating automatically to cut out the starting winding of the motor when the motor operates in synchronism with the alternating current wave, and means operating automatically to interrupt any local circuit which might be established through and between said electroresponsive means and troresponsive devices for causing said pivotally mounted element to become active in a manner that at the instant of the make or break the current value in said circuit is zero, and means whereby said electroresponsive devices may be controlled.

5. In combination, a rotary electric circuit make and break device, a synchronous motor connected to an alternating current circuit and from which motor said make and'break device is normally disconnected, a shouldered element connected with the motor for rotation therewith, an intermittently rotatable element connected with the make and break device, a pivotally mounted element carried by said rotatable element and movable into and out of active engagement with said shouldered element to lock said make and break device for rotation with said rotatable ele-- ment, electroresponsive devices for causing'said' 'pivotally mounted element to become active in a manner that at the instant of the make or break the current value in said circuit is zero, and electroresponsive devices for causing the said pivotally mounted element to become inactive.

6. A rotary electric circuit make and break device, a synchronous motor connected to an alternating current circuit and from which motor said make and break device is normally disconnected, a shouldered element connected with the motor for rotation therewith, an intermittently rotatable element connected with the make and break-device, a pivotally mounted element calried by said rotatable element and movable into and out of active engagement with said shouldered element to lock said make and break device for rotation with said rotatable element, electroresponsive. devices for causing said pivotally mounted element to become active in a manner that at the instant .of the make or break the current value in said circuit is zero, means whereby said electroresponsive devices may be controlled, and means for arresting said rotatable element against overthrow when the said piv- ,otally mounted element is rendered inactive.-

7. A rotary electric circuit make and .break device, a synchronous motor connected to an alternating current circuit and from which motor said make and break device is normally disconnected, a shouldered element connected with the motor for rotation therewith, an intermittently rotatable element connected with the make and break device, a pivotally mounted element car ried by said rotatable element and movable into .the contact will move out and out of active engagement with said shouldered element to lock said make and break device ior rotation with said rotatable element, electroresponsive devices for causing said pivotally mounted element to become active in a manner that. at the instant of the make or break the current value in said circuit is zero, means operable at will for-rendering the electroresponsive devices active and inactive, means for arresting the said rotatable element against overthrow when said pivotally mounted element is rendered inactive, and means whereby the said arresting,

means will operate at .a predetermined time in the cycle ofoperation of said rotatable element, to maintain the motor in operation until a full throw 0! the make and break device has occurred.

8. In a make and break device, a synchronous motor, connected to an alternating current circuit, a-rotatable contact carrying element normally disconnected from said motor, a rotatable dog carrying element connected with said contact carrying element for rotation therewith, means connected with the motor and with which means the dog co-operates to lock said element for rotation with the motor, electroresponsive devices, armatures individual to the electroresponsive devices and controlled thereby, means carried by the armatures to be moved into interlocking relation whereby one armature will be locked against operation, the last said means also adapted to be moved out of interlocking relation topermit one of the armatures to be engaged by said dog to move the latter out of the position in which it would look the contact carrying element for rotation with the motor, and means whereby said armatures will be actuatedto render said dog active and inactive in a manner that at the instant of the make or break the value of the current. in the line is zero. 7

9. A device of the character described embodying a synchronous motor-connected to an alternating current, a rotatable member separate from the motor, a contact carried by said memher, a, pair of brushes co-operating with said contact, said brushes spaced from each other in the direction of rotation of said contact and for a distance less than the length of said contact,

and means operating automatically to connect said member with the motor, in a manner that of engagement with one of the brushes to break the circuit, and into engagement with the-other brush to make the circuit at the instant or instants when the current value is zero.

10. A rotatable electric circuit make and break device for controlling the circuit of a synchronous motor connected to an alternating current circuit, said device embodying a shouldered element connected with the motor for rotation therewith, an intermittently rotatable element connected with the make and break device, a locking element mounted upon and movable with and with respect to the last said element, electroresponsive means for shifting said locking element with respect to its support and into en'- ga'gement with said shouldered element in a mannet that at the instant of the make and break the current value will be zero, and electroresponsive means for moving said locking element out of active relation with respect to said shouldered element.

11. A- rotatable electric circuit make and break,

device for controlling the circuit of a synchronous motor connected to an alternating current cir cult, said device embodying a shouldered element means for connected with the motor for rotation'therewith, an intermittently rotatable element connected with the make and break device, a locking elemmtmoun d upon and movable with and with respect to the last said element. eleotroresponsive said locking. element with respect to its support and into engagement with said shouldered element in a manner that at the instantotthemakeandbreakthecurrent value 10 will be m, electroreeponsive means for moving 7. said locking element out of active relation with respect to said shouldered element, and means for maintaining the motor in operation until a full throw of the make and break device has occurred, the last recited means embodying a supplemental circuit make and break device rendered activeby the engagement therewith of the said locking element when the latter is shifted out of engagement with said shouldered element.

WALTER E. PALMER.

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