US1810627A - Constant speed control for prime movers - Google Patents

Description

June 16, 1931. R. e. STANDERNICK 1,310,627 I CONSTANT SPEED CONTROL FOR PRIME MOVERS Filed Oct. 19. 1929 Inventor. Re inald G. Sbandehwick l| m His Attorne that disclose Patented June 16, 1931 UNITED STATES- PATENT oFFlca REGINALD G. STANDERWICK, OI MABBLE'HEAD, MASSACHUSETTS, ASSIGNOR TO GEG'ERAL ELECTRIC COMPANY, A CORPORATION 01' NEW YORK cons'rmr srnnn coN'moL iron rnnm uovnns Application fled October 19, 1929. Serial No. 400,983.

being desired that over a period of time the prime mover shall neither gain nor lose in the total number of revolutions which go to make up constant speed.

The ob'ect of my invention is to provide an improve control mechanism whereby constant speed of operation of a prime mover is obtained, and for a consideration of what I believe to be noveland m invention, attention is directed to the following description and the claims appended thereto.

My invention is well adapted for use with turbine driven alternators for holding constant frequency on an alternatin current transmission line, and in the followm specification it is described as applied to t is use. It is to be understood,however, that the invention is not limited thereto necessarily. v

In the drawing, the figure is a diagrammatic view of a speed control mechanism embodying my invention.

According to my invention, I provide a prime mover, such as an elastic fluid turbine, with a governing means which is virtually isocronous, and in connection therewith I provide a correcting mechanism whereby when the prime mover departs a certain number of revolutions in either direction from the integrated number of revolutions which re re-' .is virtua 1y isochronous, but I now prefer to use an arran ement of the general type of in my Patent No. 1,629,318, dated Ma 17, 1927.

I will escribe first the virtually isochronous ggverning means, after which I will descri the application of my speed correctin means thereto. I

eferrin to the drawing, .1 indicates an elastic flui turbine provided with an admission conduit 2 and an exhaust conduit 3. In 7 admission conduit 2 is a valve means 4 which controls the flow of elastic fluid to the turbine. The valve means is connected by a stem 5 to a lever 6, pivoted at one end on a fixed support 6, the arrangement being such that when the lever is raised it lifts valve means 4 to open it, while when the lever is lowered it moves valve means 4 toward closed posi-.

tion. At the free end of lever 6 is a roller 7 which rests on a cam 8 mounted on the cam shaft 9. On cam shaft 9 is a pinion 10 which meshes with a rack 11 on the upper end of a rod 12. The lower end of rod 12 is connected to the piston 13 of a fluid actuated motor the cylinder of which is indicated at 14. 15 is a spring which acts in a direction to move piston 13 down in the cylinder 14. When piston 13 moves downward the cam shaft is turned in a direction to effect movement of valve means 4 toward closed position, while when piston 13 moves upward the cam shaft is turned in a direction to eflt'ect opening movement of valve means 4. Admission of actuating fluid to the fluid actuated motor is controlled by a pilot valve structure comprising a pilot valve casing 16 in which is a valve 17 which controls the flow of actuating fluid through a pipe 18 to the under side of piston 13 and a valve 19 which controls the flow of actuating fluid from beneath piston 13 to a discharge conduit 20, which may leadto any suitable point. The pilot valves 17 and 19 are connected by a stem 21 to a floating lever 22, one end of which is connected by a lever 23 pivoted on a fixed support 24 to rod 12, thereby providin a usual form of follow up connection. he other end of lever'22 is connected by a link i 25 to one end of a floating lever 26. Lever sleeve 28 is located in a pilot valve casing 29,

provided with a port 30 which communicates with the lower end of a cylinder 31 which forms a part of a fluid actuated motor. In cylinder 31 is a piston 32 connected by a stem 33 to lever 26. Piston 32 is biased toward the lower end of cylinder 31 by a spring 34. In pilot valve bushing or sleeve 28 are admissionlfarts and discharge ports which ture.

are contro respectivel b ilot valves and 36, the pilot valves gonnected to a common stem which is in turn connected to a speed vernor 37. Speed vernor 37 is driven m the shaft 38 of e turbine by a suitable worm gearing indicated at 39, the worm gearing drivingnalso a pump 40 which may be the puma w ch supplieslubricant to the turbine an also fluid pressure for actuating the fluid actuated motors, In the resent the ump is shown as being ocated in an oil 41, and as being proylidefil with an'zgimihssifinl imargduit 142 and 1a isc arge ipe w is e tot esuppy pipe 18. sonnected to discharge ilpe 43 is a pressure relief valve 43a of suite e struc- The right-hand end of lever 26 is connected by a rod 44 to the piston 45 of a fluid actuated motor, the cylinder of which is in- 7 moved the flowof actuating fluid any reason the speed dec,

di'cated at 46. 47 is a spring which acts in a direction to bias piston 45 toward'the lower end of cylinder ,46. The flow of actuating fluid to cylinder 46 beneath iston 45 is controlled by a pilot valve 48 aving its stem 49 connected to one end of a lever 50. Lever 50 is pivoted on the lower end of a link 51 and has its other end connected by a link 52 to a rod 53 which is fixed to and extends parallel to lever 26. Link 52 may be adjusted along lever 50 and rod 53 by means of the set screws shown. This forms in substance an adjustable connection between lever 50 and lever 26, which may be positioned at any 'desired point along lever 50 and rod 53, and .as will be noted, rod 53 extends from a point at the left of the pivotal connection between lever 26 and stem 27 to a point beyond the pivotal connection of lever 26 to stem 44.

Pilot valve 48 is so arranged that when past it either to or away from cylinder 46 will be slow as compared to the flow of actuatin fluid in the case of pilot valves 35, 36 an 17, 19. To this end, the passage controlled by pilot valve 48 may be made in the form of a long narrow slot 48a of a-size to give the desired restricted flow.

Actuating fluid for the fluid actuated motors controlled by pilot valves 36 and 48 1s supp necte to the pump dischar pi 43. At 56 is the discharge pe pipe for p' ot valve 48.

The 0 ration of the construction so far describe is as follows 4 Assume that the turbine 1 is operating at the predetermined normal speed, valve means 4 being opened an amount to supplysuflicient elastic fluid to enable the turbine to carry the load 9n it, and the other .parts being in the posit ons shown in the drawing. If now for speed govermovem'ent of lied by pipes 54 and 55, which are confl let port in pilot valves 35 and 36, whereb pilot valve 35 will uncover slightly the port in sleeve 28, thereby admitting fluid throu 11 port 30 to the under side of iston 32. Pmton 32 is then moved upwar turning lever 26 on the upper end of rod 44 as a pivot. The upward movement of lever 26 through link 25 lifts the right-hand end oflever 22 and pilot valves 17 and 19.' The lifting of pilot valve 17 admits actuating fluid to the under side of piston 13 to move it upward in its .cylinder to effect an openin movement of valve'means 4 whereby ad itional elastic fluid will be admitted to the turbine, tending to bring the speed back to normal value. When piston 13 moves upward it lifts the left-hand end of lever 23, thereby lowerin its right hand end and ilot valves 17 an 18 to restore the pilot va ve 17 to its normal positioh, wherein it cuts oil the supply of fluid pressure to cylinder 14, this being a usual ar rangement of follow-u mechanism. When piston 32 moves upwar turning lever 26 on the upper end of rod 44 as a pivot, it lifts link 27 and pilot valve sleeve 28, thereby bringing the admission port in sleeve 28 to a position wherein it is again covered by pilot valve 35, this likewise being a usual form of restoring mechanism.

With the operation so far described, the valve gear would come to a condition of equilibrium at a s ed slightly lower than normal, because 0 the fact that a speed change was necessary on the part of the speed governor in order to raise i 0t valves 35 and 36. The piston 45 and pi ot valve 48 forms what may be termed a s ed correctin device to automatically bring the speed ack to its former value. The operation of this s ed correcting device is as follows: When piston 32 moves upward, turning lever 26 on the upper end of rod 44 as a pivot, through link 52, the lever 50 is turned on link 51 as a ivot, thereby lowering pilot valve 48. The owering of pilot valve 48 uncovers somewhat the u per end of slot 48a and permits actuatingg uid to escape from the under side of piston 45, so that the piston moves downward, turning lever 26 on the upper end of rod 33 as a pivot. This lowers pilot valve bushin 28 so that the inlet port m it is uncovere slightly permitting actuating fluid to 4 somewhat to increase the speed of the tur-' bine, the upward movement of piston 13 at the same time restorin ilot valves'17 and 19 tonormal position. wi the increased speed, speed tgovernor 37 lowers pilot valves 35 and 36 so at ilot valve 35 again covers the inng 28.. The downward movement of-piston 45, at the same time that it ow past pilot valve 35 to cylinder 31, raising Ill ' a spring 65.

moves bushing 28 downward, also turns lever 50 on link 51 as a pivot to restore pilot valve 48 to normal position, wherein it exactly cov-" ers slot 48a thus preventing further movement of piston 45. This restores the speed to normal value.

In the case of an increase in the speed of the turbine, an operation similar to that just described takes place except in the opposite direction.

Each position of pilot valve bushing 28 corresponds to a certain definite turbine speed and as will be clear from a consideration of the drawing and the operation of the device as just described, pilot valve 48 covers slot 48a only for one definite position of bushing 28. It follows, therefore, that the corrector comprising piston 45 and pilot valve 48 will always restore the governor mechanism to the same speed after each change in speed.- By making the corrector so that it lags definitely behind the primary governor 37, any hunting of the governing mechanism is avoided. Upon change in load, primary governor 37 first responds to effect quickly an adjustment of the valve means 4 after which the speed corrector functions to bring the speed back to the desired normal value.

The foregoing constant speed operation holds good providing the connecting link 52 is in line with the pivot point between lever 26 and stem 27, as shown in the drawing. However, in some instances a definite change in speed between no load and full load may be desirable and this may be obtained by adjusting link 52 along rod 53 and lever 50. As stated, if the link 52 is located as shown in the drawing, the corrector is effective to maintain constant speed, that is, to correct entirely for the inherent width of regulation of the governor. On the other hand, if link 52 is moved to a position where it is in line with the pivot point between stem 44 and lever 26, then the action of the correctorbe comes zero-because lever 26 moves about the end of stem 44 as a pivot when it is moved by piston 32. By positioning link 52 at points between these two extremes any desired degree of correction may be obtained. And b moving link 52 toward the left from the position shown in the drawing an over correction, i. e., a correction in a negative direction maiyebe obtained.

ferring now to the correcting mechanism, link 51 is connected to one arm of the bell crank lever 60, pivoted on a fixed support 61. The other arm is connected by-a rod 62 to the vertical arm of an inverted T- shaped lever 63, pivoted on a fixed support 64, and held normally in vertical position by Connected to the horizontal arms of lever 63are the plungers of two solenoids, the windings of which are indicated at 66 and 67. These two solenoids may be termed respectively the fast solenoid (marked noid winding 66 is energized toturn threearm lever 63 in an anti-clockwise direction, thereby through hell crank lever 60 and link 51 raising pilot valve 48 so as to permit actuating fluid to enter beneath piston 45;causing the piston to move upward slightly and thereby decreasing slightly the speed of the turbine after the manner already described, and when solenoid winding 67 is energized, three-arm lever 63 is moved in a clockwise direction, thereby effecting a'movement of pilot valve 48 in a direction to cause the speed of the turbine to be increased somewhat.

Solenoid windings 66 and 67 are connected to brushes 68 and 69, which engage conducting slip rings 7 O and 71 on a rotating commutator 72. Commutator 72 is provided also with slip rings 73 and 74, with which brushes 7 5 and 76 engage, and with five contact segments 77, 78, 7 9, 80 and 81. Contact segment 77 which may be termed the normal contact segment (marked N) is connected to slip ring 74. Contactsegments 78 and 79 which may be termed the resetting segments are connected to slip ring 73. Contact segment 80 which may be termed the fast contact segment (marked F) is connected to slip ring 70. Contact segment 81 which may be termed the slow contact segment (marked S) is connected to slip ring 71. The commutator is driven by a synchronous motor 82, the connection being through suitable reducing gears, whereby the commutator will be driven at the desired constant speed as hereafter pointed out. nous motor 82 is connected to the bus bars 83, to which also is connected by conductors 84 the alternating current generator 85 driven by turbine 1. Synchronous motor 82 is thus rotated at a speed corresponding to the speed of turbine 1. The field winding for the synchronous motor is connected to a source of direct current comprising conductors 86 and 87.

At 88 is indicated the pendulum of a master clock of any suitable type. Pendulum 88 is provided with an opening 89, so located that each time the pendulum reaches the middle of its arc of swing it permits light from a suitable light source 90 to impinge on a photo-electric cell 91, which is connected through a suitable ower amplifier 92 to an electroma et 93. lectromagnet 93 is provided witan armature 94 having at its one end a contact 95 adapted to enga e with the segments 77, 7 8 79, 80, and 81. spring 96 normally holds contact 95 away from engagement with the commutator. Each time pendulum 88 swings between li hting source 90 and photo-electric cell 91, lig t from light source 90 passes throu h opening 89 and im- Synchroand a slow relay 101 (marked ducing momentarily an increase of current in the photo-electric cell circuit, which increase is amplified by the power amplifier 92 to a value suflicient to cause electroma net 93 to move armature 94 downward and ring contact 95 into engagement with commutator 72. It will be seen that the contact 95 will be actuated each time the pendulum swings past its center. Associated with the commutator brushes and the solenoid windings 66 and 67 is wir'in including a normal relay 96 (markedil) having contacts 97 and 98, a fast relay 99 (marked F) having? contacts 100,

having contacts 102. The wiring arrangement and the function of the relays will now be described in detail in connection with the operation of the mechanism.

For purposes of description, it is assumed that the generator supplies 60-cycle alternating current to bus bars 83, and that it is desired to hold the turbine speed substantially constant and to correct for any increase or decrease in total revolutions so that over a period of time there will be no de arture from the correct total number of revo utions. For this operating condition, synchronous motor 82 will be connected to commutator 72 in a manner such that the commutator makes one complete revolution each second, and the master clock pendulum will be of a character such that it beats seconds. With this arrangement, electromagnet 93 will be energized each second and will move contact into engagement with the commutator each second. If the commutator is set so that the normal contact segment 77 is over contact 95, when the opening in pendulum 88 passes between the llght source and the photo-electric cell, it will be seen that if commutator 72 makes exactly one revolution per second, then electromagnet 93 will be energized at a time such as to bring contact 95 into engagement with contact segment 77. When contact 95 engages contact segment 77, a circuit is closed as follows: line wire 87, conductor- 103, contact 95, contact segment 77 slip ring 74, brush 76, conductor 104, conductor 105, winding of relay 96, resistance 106 and conductor 107 to line wire 86. This causes electromagnet 96 to be energized and up its armature, which then bridges con ts 97, closing'a holding circuit for the winding of relay 96 as follows: line wire 87, conductor 108, contacts 97, the winding of relay 96, resistance 106, conductor 107.to line wire 86. At the same time, a branch circuit is closed by way of conductor through a lamp 109 and conductor 110 to line wire 86. Relay 96 thus remains energized and lamp 109, which may be a green lamp, burns continuously. As the mechanism continues to operate, contact 95 will be brought each second into engagement with contact segment 77 but since relay 96 is held energized no change in the mechanism ick which would be due to an increase in the speed of turbine 1. When this occurs commutator 72 will be rotated slightly more than one complete revolution per second, and after .a predetermined gain in fractional revolutions contact 95 will engage contact segment 78. When this occurs a circuit is closed as follows: line wire 87 conductor 103, contact 95, contact segment 78, slip ring 73, brush 75, conductor 111, resistance 106 and conductor 107 to line wire 86. This shunts the winding of relay 96, whereupon it releases its armature which drops into engagement with and bridges contacts 98. This opens the circuit of lamp 109, which now ceases to burn. If now, the system continues still to gain, then some time later contact 95 will engage con tact segment 80, closing a circuit as follows: line wire 87, conductor 103, contact 95, contact segment 80, slip ring 70, brush 68, conductor 112, conductor 113, solenoid winding 66, conductor 114, conductor 115, contacts 98 and conductor 116 to line wire 86. Energization of solenoid winding 66 will move three-arm lever 63 in a direction to decrease slightly the speed of turbine 1 after the manner already described. At the same time the circuit just described is closed, there is closed also a circuit through winding of solenoid 99 as follows: line wire 87, conductor 103, contact 95, contact segment 80, slip ring 70, brush 68, conductor 112, conductor 113, conductor 117, winding of solenoid 99, conductor 118, conductor 119, conductor 115, contacts 98 and conductor 116 to line wire 86. This energizes the windin of solenoid 99 which operates to bridge its contacts 100, thereby closin a holdlng circuit/ for the winding as fo ows: line wire 87, conductor 108, contacts 100, winding of solenoid 99, conductor 118, conductor 119, conductor 115, contacts 98 and conductor 116 to line wire 86. The bridging of the contacts of solenoid 99 closes also a holding circuit for winding 66,

which may be traced as follows: line wire 87 conductor 108, contacts 100, conductor 113, solenoid winding 66, conductor 114, conductor 115, contacts 98 and conductor 116 to line wire 86. It will thus be seen that solenoid windin 66 now remains energized independently 0 contact 95 and contact segment 80. At this time there is closed also a branch circuit through a red lam 120, which may be traced as follows: line wire 87 conductor 108, contacts 100, conductor 113, lamp 120, conductor 119, conductor 115, contacts 98 and conductor 116 to line wire 86. The valve III III

gear for the turbine is now set to cause the turbine to operate at a slightly lower speed and, it will continue to so rate, losing gradually the revolutions which have been gained. As the gained turbine revolutions are lost, commutator 72 will make slightly less than one com lete revolution in each sec- 0nd, and eventual y will be brought to a position such that contact 95 will engage contact segment 77. During this time it engages contact se ent 78 but this has no operative efiect; Vifiiiin contact 95 again engages contact 77 the circuit first described through the winding of rela{% will be again closed, thereby operating t e relay to open contacts 98 and to close contacts 97. The opening of contacts 98 opens the circuit through solenoid winding 66, thereby permitting three-arm lever 63 to return to its normal position and manner already described to cause it to bridge I time red lamp 121 burns.

contacts 98. Then following this, when contact 95 engages contact segment 81 it energizes the slow rela 101, which operates after the manner alrea y described in connection with fast relay 99, except that the slow solenoid winding 67 is now energized to effect operation of the valve gear in a direction to increase the speed of the turbine, whereby the lost revolutions will be regained. At this The mechanism will be reset after the manner already described when contact 95 again engages normal contact segment 77.

In accordance with the rovisions of the patent statute,I have descrlbed the principle of operation of my invention, together with the apparatus which I now consider to re resent the best embodiment thereof, but I e sire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is 1. The combination with a prime mover having governing means for regulating it, whereby it operates at substantia ly constant speed, of a master control means, means operated in synchronism with the prime mover, means for comparing the operationof the master control means with the operation of said synchronously operated means, said com paring means comprising a .source of light, alight sensitive cell periodically excited by said source of light and a relay periodically actuated by said light sensitive cell, and

means for adjusting said governing means to temporarily change the speed of rotation of the prime mover when the prime mover either gains or loses a predetermined number of revolutions as compared to said master control means.

2. The combination with a prime mover having governing means for regulating it, whereby it operates at substantially constant speed, an alternating current generator driven by said prime mover, and a power line connected to said generator, of a master control means, means operated in synchronism with the frequency of the power line, means for comparing the operation of said master control means with said synchronously operatcd means, said compa ing means com? prising a source of light, a light sensitive cell periodically excited by said source of light and a relay periodically actuated by said light sensitive cell, and means for adjusting said governing means to temporarily change the speed of rotation of the prime mover when the prime mover either gains or loses a predetermined number of revolutions as compared to said master control means.

3. The combination with a prime mover having governing means for regulating it whereby it operates at substantially constant speed, of a master clock, means operated in synchronism with the prime mover, means for comparing the' operation of the master clock with the operation of said means, said comparing means comprising a source of light, a light sensitive cell periodically ex cited by said source of light and a relay periodically actuated by said light sensitive cell, and means for adjusting said governing means to temporarily change the speed of rotation of the prime mover when the prime mover either gains or loses a predetermined number of revolutions as compared to said clock. v

4. The combination with a prime mover having a governing means and correcting means for rendering said governin means substantially isochronous, of means or moving said correcting means to increase or decrease the speed of'the prime mover whereever the prime mover loses or gains a redetermined number of revolutions and or restoring said correctin means to normal position when the pre etermined number of revolutions has been gained or lost.

5. The combination with a prime mover having a governing means and correcting means for rendering said governing means substantially isochronous, of electromagnetic means for movin said correcting means to increase the spec of the prime mover, electromagnetic means for moving said correcting means to decrease the speed of the prime mover, circuits for said electromagnetic means, means for closing said circuits when the prime mover loses or gains a predator'- niined nunlilber of revolugionsi and means lfgr e ectmg' teopenmg' o sai circuitsw n the redetermmed number of revolutions have n gained or lost.

6. The combination with a prime mover havin governing means for re ating it whereiy it operates at substantia y constant of a commutator having contact segm ments, means for rotating sai commutator at.a speed which bears a definite relation to the. speed of the rime mover, a contact, means whereby sai contact engages certain contact so cute in case the rune mover 1 5 loses or game a determined num rof revolutions, and means whereby when said contact engages certain contact segments said governing means is adjusted to cause the prime mover to gain or lose said predetermined a number of revolutions.

.7. The combination with a prime mover having governing means for re ating it where y it operates at substantia y constant speed, an alternating current generator 35 driven by said prime mover, and a power line connected to said generator, of a master control means, a commutator having contact segments, means for rotatin said commutator in synchronism with the quency of the no power line, a contact, means operated b said master control means for brin g sai contact into engagement with sai commutator, said contact engaging one of said segments in case the prime mover loses. or gains a pre- :5 determined number of revolutions, and means whereby when said contactenga a segment, said governing means is a justed to cause the rims mover to gain or lose said predetermined number of revolutions. Q In witnem whereof, I have hereunto set my hand this seventeenth day of October, 1929.

REGINALD G. STAN DERWICK. 1

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