US1338328A - Ock system - Google Patents

Description

A. F. POOLE.

CILOCK SYSTEM.

APPLICATION FILED um: 18. 1919.

1,338,328. Pa ented 'Apr. 27, 1920.

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TN 5 S: INVENTOR Arf/wr fi Poo/e A- RNE AIR-THUR F. POOLE,

MANUFACTURING COMPANY,

OF CHICAGO, ILLINOIS, ASSIGNOB/ TO A. CORPORATION OF PENNSYLVANIA.

WESTINGHOUSE ELECTRIC 85 CLOCK SYSTEM.

1,338,328. Original application filed September 10,

Specification of Letters Patent.

1917, Serial No. 190,587.

Patented Apr. 27, 1920.

Divided and this application filed June 18, 1919. Serial No. 305,099.

To all wiwm it may concern:

Be it known that I, ARTHUR F. Poona, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Clock Systems, of which the following is a specification, this a plication being a division of application, erial No. 190,587, filed Sept. 10, 1917. V

M invention relates to clock systems and particularly to clock systems that are employed in connection with commercial alternating-current distribution systems.

The object of my invention is to provide means for directly indicating, at a generating station, the deviation of a secondary clock from a master clock that is remotely disposed with respect to the generating station.

In practising my invention, I provide means whereby a remotely-disposed master clock controls the operation of one member of a differential device, means whereby the other member of the differential device is actuated in accordance with the frequency of the system and an indicating device actuated bythe planetary member of the differential device to directly indicate the deviation of the frequency of the system from its correct value.

In the accompanying drawin s, Figure 1 is a perspective and partially iagrammatic view of a clock system embodying my invention, and Fig. 2 is a detail view of a part of the mechanism shown in Fig. 1.

A prime mover 10, here indicated as a reciprocating steam engine (although any prime mover, such as a steam or waterdriven turbine, may be employed) drives a generator 11 of alternating current that supplies power to the line conductors 12 and 13. The speed of the prime mover 10 is governed by the usual governor 14, supplied by a steam pipe 15. A. valve 16 serves to control the flow ofsteam through the pipe 15, and aby-pass 17 is provided with an additional valve 18, by which steam may be admitted to the prime mover 10 independently of the governor If the speed of the prime mover 10 too slow, the valve 18 may be opened, thereby supplying the engine with steam independently of the action of the governor 14. In the event that the prime mover 10 is moving too fast, the valve 16 source 26 of electromotive force,

may be manipulated, thus temporarily reducing the speed of the prime mover 10.

is one of the objects of my invention to synchronize the prime mover 10 with a master clock, to the end that the number of alternations sent out through the conductors 12 and 13 shall average exactly sixty cycles per second over a long period of time. It 18, therefore, necessary to provide some means of indicating directly the difference in time between the alternations sent out by the generator 11 and a master clock. To this end, a master clock, more or less diagrammatically shown at 19, is provided and is equipped with instrumentalities for the closing of an electric circuit at certain predetermined intervals, in the present instance, once per minute. Owing to the vibration in the central or generating station, it is undesirable to have the master clock located in the station, and, therefore, electric means have been provided to synchronize a rotating element with the currents sent out by the master clock, as hereinafter set forth.

The master clock contains the usual escape wheel 20 controlled by pallets 21 that are mounted on an oscillatory shaft 21, upon which is also mounted a fork or crutch member 22 for transmitting power to a pendulum 22. A contact arm 23 is insulated from, and mounted on, the shaft 21 and is adapted to engage a coiiperating contact arm 24' that is mounted on the shaft 25 of the escape wheel 18. The shaft 25 is arranged to rotate once each minute, and, whenever the contact member 24 is in a certain position, the contact arm 23 will be brought into engagement therewith, whereby the circuit will be closed once each minute. The contact arm 23 is connected to one terminal of a the other terminal of which is connected, through a conductor 27, to an electromagnet 28 at the generating station. The other terminal of the electromagnet 28 is connected, through a conductor 29, to the escape-wheel shaft 25. Thus, the electromagnet 28 will be energized once each minute by a momentary current sent over the conductors 27 and 29.

Apparatus for keeping a rotating body at the generating station in synchronism with the action of the magnet 28 and for indicating the excess or defect of the alternations sent out by the generator 11 from the corroot number of sixty alternations per second is provided, as hereinafter set forth. An aluminum disk 31 is mounted on a shaft 30 and is driven by the shadedpoles of an alternating electromagnet 32 that is connected to the conductors 12 and 13 by the conductors 33 and The elcctromagnet is so arranged that the aluminum disk 31 will rotate in the direction of the arrow. A worm 35 is mounted on the shaft 30 and engages a worm wheel 36 that is mounted on a shaft 37, upon which a worm 38 is mounted which engages a worm wheel 89 that is moimted on a shaft 40. The gear ratio between the aluminum disk 81 and the shaft 40 is such that, when the disk is running at its normal rate, the shaft 40 rotates once each minute. A mutilated gear wheel 41 and a second mutilated gear wheel 42 are mounted on the shaft 40. Each of said ear wheels has slightly more than one half of its teeth cut away or omitted, as shown, and they are so disposed on the shaft 40 that the teeth of the gear wheel 41 coincide with the blank space on the gear wheel 42, and vice Versa. A disk 43. having projections 4:4: and 45 thereon, is nioimted on the shaft 46.

A bevel gear wheei 46 is mounted on the shaft d0 and constitutes one side of a difierential gear, the center member 47 of which embodies a bevel gear wheel 48.. The gear wheel 48 engages a bevel gear wheel 49 of the same size as the bevel gear wheel 46 and is mounted on a shaft 50. .On the shaft of the motor 51 is a worm 52 that drives a worm gear wheel 53 which is mounted on a shaft 54, upon which is also mounted a worm 55 that drives a worm gear wheel 56 on the shaft 50. The motor 51 is connected, by conductors 57 and 58 to the line conductors or bus bars 12 and 13. The direction of rotation of the synchronous motor 51 is such that the bevel gear wheel 49 turns in the op site direction from the bevel gear wheel 46 and the gear ratio between the synchronous motor 51 and the bevel gear wheel 49 is such that, when the frequency of the alternating current is exactly sixty cycles per second, the gear wheel -19 rotates once per minute. From the gear arrangement described, it is obvious that, if the bevel gear wheel 1-6 turns in one direction at the rate of one rotation per minute and the bevel gear Wheel -19 turns in the opposite direction at the rate of one rotation per minute, the central member 47 of the differential-gear device will remain immovable, but, if the rates of rotation of the gear wheels 46 and 49 are not the same, the central member 47 will be displaced an amount proportional to the difference.

For the purpose of clearly and directly indicating the displacement of the central member -17, agear wheel 51 is mounted on a shaft 52 and is one half the diameter of the gear wheel -17 and in engagement therewith.

A second hand 53, that moves in front of a dial havingsuitable,graduations 54s thereon, is mounted on the t s Well known that, in a differential gear having two side members of equal size, the central member is displaced one half of the algebraic sum of the displacement of the two side members. Consequently, if the ear wheei 49 gets an entire revolution ahead or behind th gear wheel 46, the second hand 53 will turn through an entire revolution, since the gear Wheel 51 is but one half the diameter of the gear wheel 47. Thus, the second hand 53 will indicate directly the departure of the rate of rotation of the synchronous motor 51; that is, the departure of the alternations on the system from the current frequenc y of sixty cycles per second. This, of course, depends upon the assumption that the aluminum disk 31 is kept at a rate of speed that is in synchronism with the impulses of the electric-magnet 28. V

The electromagnet 32 is provided with a magnetic shunt 61 that is adapted to be approached or Withdrawn from the poles of the magnet by a screw 62 on a shaft viously, when the shunt 61 is moved closer to the magnet 32, the magnet wili exercise a diminished torque on the aluminum disk 31, and the speed of said disk will accordingly diminish. On the contrary, if the shunt 61 is withdrawn from the poles of the magnet 32, the magnet will exert an increased torque on the disk 31, and the disk will be accordingly accelerated. In order to maintain the shunt 61 in its proper position, a rectangular framework is provided consisting of a side piece 64, united by a pillar 59 to a side piece 65, said side pieces being pivotally mounted 011 a shaft 66 upon which is mounted a gear wheel 67 that is held in its proper position between the side plates 64 and 65. The gear wheel 67 has connected thereto a bevel gear wheel '68 that engages a bevel gear wheel 69 which is mounted on the shaft 63. The gear wheel 67 engages a wide gear wheel 7-0 that is rotatably mounted between the side plates 64 and 65 on a shaft 71. The gear wheel 70 engages a second spur gear wheel 72 that is similarly mounted on a shaft 73. The arrangement of the gear wheels 70'and 72 is such that the gear wheel 7-2 is adapted to engage the mutilated gear wheel -12, but not the mutilated gear wheel l1. Similariy, the gear wheel 76 is adapted to engage the mutilated gear wheel 41, but not the gear wheel 42. Obviously, if the framework, comprising the plates 64 and 65 and the pillar 59, is permitted to drop, the gear wheel 72 will be first turned to actuate the gear wheel 67 in one direction by reason of its engagement with the teeth of the mutilated gear wheel 42, and, after a vacant portion of said gear wheel 42 has been reached, the gear wheel '10 will be picked up by the teeth on the gear IOU wheel 41 and the gear wheel 67 will be turned an equal amount in the reverse direction. The gear arrangements between the gear wheels 70 and 72 and the screw 62 are such that, when the gear wheel 70 is turned by the gear wheel 41, the shunt 61 is withdrawn from the poles of the magnet 32, thereby accelerating the rate of the disk 31. When the gear wheel 72 is turned by the teeth of the gear wheel 42, the reverse is true. That is, the shunt 61 is moved nearer to the poles of the magnet 32, thereby retarding the motion of the disk 31. The plate 64 is engaged by a latch 75, which is held against a stop 76 bya sprin 77, said latch having an armature 78 attac ed to it that is adapted to be attracted by the electromagnet 28. The plate 64 isnormall' held by the latch in the position shown'in ig. 1, that is, in the position where the gear wheels 70 and 72 are out of engagement with their oo6p crating mutilated gear wheelsj42 and 41. However, once each minute the ma; et 28 attracts the magnet 78, and a spring 9 pulls the framework 64, 65 and 59 into a sition determined b a stop 80,"and either t e 1'- wheel 72 or the gear wheel 70 is engage by its cotiperating mutilated gear wheel. The plate 64 is provided with'an arm'81, that is adapted to be en aged by the projections 44 and '45 on the 'sk 43; Accordingly, the plate 64 is lifted twice during each rotation of the shaft 40. -The'projection 44 maybe taken as determining-by its contact with the arm 81, the zero position of the shaft 40;

Assumin the parts to be in the positions shown in *ig. 1, in which the projection 44 is in engagement with the arm 81, and assuming that a momentary current passes through the ma et 28, since the zero position of the sha 40 is determined b the engagement of the projection 44 wi the arm 81, the disk 31 is then inisynchronism with the current from the master clock, and no correction of the speed of the disk 31 is necessary. Accordin ly, the latch will return to its originai position, and,

when the projection 44 is disengaged from the arm 81, the plate 64 will remain in its elevated position. It is to be noted that the projections 44 and 45 are both of a length which will lift the plate 64 somewhat higher than its position when held by the latch 75. Assuming, however, that, when current is sent through the magnet 28, the pro jection 44 has not yet come into contact with the arm 81, a condition corresponding to that in which the disk 31 is turning more slowly than s nchronous speed, when the latch 75 is with rawn from contact with the plate 64, the framework will drop and will brin the gear wheel 72 into engagement wit the teeth of the gear wheel 4-2, and this enga ement will continue until the arm 81 1S ifted by the projection 44.

As before noted, when the gear wheel 72 is turned by the gear wheel 42, the ma etic shunt 61 is withdrawn from the po es of the magnet 32. Consequently, the rate of rotation of the disk 31 will be accelerated. At the next revolution of the shaft 40, if

' an the disk w'ill bestill farther accelerated. It is evident that this accelerating action will continue until the projection 44 had -made contact'with the arm 81 at the time when the current is sent through the magnet 28. Assuming, on the other hand, that,

at the time current is sent through the magnet 28 thepro'jection- 44-is beyond its position a contact with the arm 81, the unlatching of-thei'plate64 will cause engagement between-'the' gear"wheel 41- and the gear wheel'70,'*withthe result that the shunt 61 *win'approach'the' oms of the magnet, and the speed of-the disk 31will be consequently retarded.- It isetidenflthatthis retarding actionwill cohtinue until the projection 44 has brought into registry with the arm 81- at "the'-'time"'-the current is sent through the magnet 28, o'r,'in other words,

with the istry' of the projection 44, the arm 81 wi -be-brought-'1nto synchronism with the current-sent out by the master clock 17: It-'is thus evident that the rate of rotation of the shaft 40, and, co uently the 'rateof rotationpf the attached gear wheel 46, will be maintained in synchronism withcurrents sent out from the master clock 17; Sincethe shaft 40 is kept rotating in synchronism with the time of the master clock and the gear'wheel49 is rotating in sync ronism with the alternations of the generator, it is evident that the second hand 53 will indicate directly the departure between these two quantlties. In other words it will 'indicate directly the departure of the alternating current from its predetermined rate of sixty cycles per second. For thepurpose of keeping track of errors greater than one minute, which corresponds to a complete revolution of the second hand 53, a pinion 82 is mounted on the shaft 52, and engages a gear wheel 83 that is mounted on, a shaft 84, u on which a pinion 85 is also mounted. he pinion 85. engages a gear wheel 86 that is mounted on a shaft 87 upon which is mounted an indicating hand 88. The gear ratio between the shaft 52' and the shaft 87 is one to sixty; Consequently, the hand 88 will indicate the minutes, and suitable graduations 89 are provided to indicate the amount of deviation of the hand 88. In a similar manner, an hour hand 90. that is mounted on a shaft 91, is geared to the shaft 87 in a ratio of one to twenty-four. The hand 90 will indicate even rotations of the hand 88, although, in practice, the hand 90 is probably superfluous.

Once every so often, the attendant at the central station will glance at the dial in front of which are the hands 53, 88 and 90, and will note the amount of deviation of the current from the true time. He will then, by manipulating the speed of the prime mover through the valves 16 and 18, bring the hands back to their respective zero points. It is evident that the direction of displacement of the hands will denote whether the current is fast or slow, and the attendant will manipulate the valves 16 and 18 accordingly.

It will be reco nized that the central station apparatus erein described is, in some respects, similar to that described by me in a certain copending application, in which there is a continuously rotating element at the central station kept in synchronism with impulses from a master clock. However, my herein described plan has some advanta es in that there may be an occasional failure of the electric impulse sent out by the master clock 17 without effecting the synchronism of the rotating element. It is only in the event that the rotatin element gets in error to the amount of a alf period that it will not be brought into synchronism. In my herein described arrangement, it is evident that, if the currents from the master clock cease, the retating element is moving at approximately the proper rate, since it has been automatically regulated. It may, therefore, be trusted to run for some fifteen. minutes without an current at all from the master clock. This characteristic does not obtain in the device described in my copending application.

It will be noted that, when the disk 3i is corrected, in the event of its moving slower than the normal rate, the correction is proportional to the error. On the other hand, if the disk 31 is corrected for moving at a faster rate, the correction is inversely pro portional to the error. This characteristic will result in the moving element, in the event of its becoming fast, being at once regulated to run slow and then its speed will be increased until it again reaches a condition of synchronisni. If it were worth while, it is of course possibleto make the correction on the fast side proportional to the error. However, the error inany event will be small, since the synchronizing periods are only one minute long, and, there fore, refinement of this kind is not necessary.

My invention is not limited to the particular form of clock mechanisms illustrated, as

be variously modified without dothe spirit and scope of the set forth in the appended it may parting from invention, as claims.

I claim as my invention:

1. In a clock system, the combination with a central station, an alternating-current generator thereat supplying light and power through line conductors extending therefrom, and a series of secondary clocks, including a synchronous motor, at the subb rs stations connected to said conductors, of means tor changing the speed oi said generator, a master clock and an indicator t the rentral station having a hand for indicating directly the dc .rture of the alternations s nt out b sai central station from the time ind ca e y said master clock, whereby the attendant may be informed of the taper d1rect1on to manipulate said speed changing means to bun said generator into synchrom m with'sai master clock- 2. In aclock system, the OQID-PlflfllllOXl with a master clock, a c ntral station including an alte nating qurrenti gcnemtor, has condoctors OQRBWWPKSBA. master clock with said central stationa where y he lo k may be locatedat a place free from the dist rbon of sai can ra station, means f mg out a periodic current over said lin conductor and means at the central station responsive to saidline currents, of an. ind cater controlled by said generator and said current-respanswe means, wherehy the depar-tare of the alternations of. said generator from synchromsm with said periodlc curren may be. determined.

3. In a clock system, the combination with a central station, an alternating-current generator thcreat capable of sup lying current for 1i ht and power, line con uctors extending t erefrom, and a series of secondary clocks, including asynchronous motor, at the subscrihers station connected to said conductors, of means tor changing the speed of said generator, a master clock and an indicator at the central station, said indicator having a hand indicating dire tly the departure of the alternations of said generator from the time indicated by said master clock whereby the attendant may be informed o the roper direction to. manipulate the spec changing means in order to bring said generator into synchronism with said master clock.

4. In a clock system, the combination with a master clock, a central station including an alternating-current generator adapted to supply commercial light and power to subscribers substations, and line conductors connectin said master clock to said central station, w ierebythe clock may be located at a place free from the disturbance of said central station, of means controlled by said master clock for sending out a periodic current over said conductors, means at the central station responsive to said line currents, and an indicator controlled by said generator and said current-responsive means, whereby the departure of the alternations of said generator from synchronism with said periodic current may be determined.

5. The combination with a source of alternating-current for supplying light and power and a master clock, of means actuated in accordance With the alternations 0 the source of current for indicating time, and means for indicating directly the departure of the time indicated by said means from the master clock.

6. In a clock system, the combination with an alternating-current generator for supplying light and power, and a master clock, of

an indicating device, and means for causing the indicating devlce to be actuated in accordance With difference in the alternations of the generator and the indications of the master clock.

7. In a clock system, the combination with a commercial alternatingaiurrent generator, a synchronous motor clock connected thereto and a master clock, of means connected between the clocks for indicating directly the deviation of the clocks from each other to facilitate regulating the frequency of the generator to cl'l'ect synchronous operation of the clocks.

In testimony whereof, I have hereunto subscribed my name this 12 day of June 1919.

ARTHUR F. POOLE.

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