US671715A - System of electrical distribution. - Google Patents

Description

Paten ted Apr. 9, I901.- YOUNG.

No. 67I,7I5.

C. SYSTEM OF ELECTRICAL DISTRIBUTION.

(Application filed Aug. 8, 1899.)

2 Sheets-Sheet I.

(I0 Iodol.)

lNVENTOf? W/T/VESSES M 3m m: NORRIS PETERS cc, PNOTD-LITNO,WASHINGTON, D. c.

No. 67l,7l5. Patented Apr. 9, l90l.

C. I. YOUNG.

SYSTEM OF ELECTRICAL DISTRIBUTION.

(Application filed Aug. 8, 1899.) (No Ilodel.) 2 Sheets-Shaet 2.

WIT/VFSSE'S. //VV/VTOf? a z 7 BY g g 2 ATTORNEY "ruz' NORRIS PETERS co. PNOTO-LIYHQ, WASNINGTON, n, c.

UNITED STATES PATENT OFFICE.

CHARLES I. YOUNG, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE WESTINGHOUSE ELECTRIC 0 MANUFACTURING COMPANY, OF

PENNSYLVANIA.

SYSTEM OF ELECTRICAL DISTRIBUTEON.

SPECIFICATION formingpart of Letters Patent No. 671,715, dated April 9, 1901.

Application filed August 8, 1899.

T0 ctZZ whom, it may concern:

Be it known that I, CHARLES I. YOUNG, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a new and useful Improvement in Systems of Electrical Distribution, (Case No. 844,) of which the following is a specification.

My invention relates to systems of alternating-current electrical distribution; and it has for its object to provide a means for maintaining synchronism between two or more alternating-current generators supplying distributing-mains in parallel.

It has been found in practice that where two or more alternating-current generators are driven by independent engines there is a tendency for the machines to get out of synchronism, particularly if the generators are of large size. Where ordinary engine-governors of either the centrifugal or inertia type are employed, it is found that any tendency or inclination of the generators to get out of synchronism rapidly accentuates until the machines get so far out of step as to render the shutting down of the plant necessary unless the governors are very sluggish in their action. The failure of the governors of the engines to maintain the generators in synchronism when they tend to pull apart seems to be due to the fact that when the separation begins each machine makes an effort to bring the other into step with it, not by a steady pull, but by a succession of jerks, the periodicity of which depends upon the difference between the rate of alternation of the two machines, and these jerks have the opposite effect on the governor of the engine from that which is necessary in order to bring about the desired resu1tthat is to say, the pull upon the machine running at the lower speed is an acceleration which so acts upon the governor as to reduce the speed still further, and the pull upon the more rapidly running machine has the same efiect upon the governor that a slowing down of the machine would have, and hence its action is to still further increase the speed. This effect is especially Serial No. 726,582. (No model.)

marked in governors of the inertia type 011 account of their practically instantaneous response to variations in speed. In order to correct this difficulty, I propose to employ a combination of centrifugal and inertia governors in such manner that the former will tend to maintain the speed of its engine uniform without regard to the other generators and engines of the system and that the inertia-governor will act in opposition to the centrifugal governor and be controlled in its action by the electrical relation between its generator and the other generator or generators of the system.

In the accompanying drawings, Figure 1 is a side elevation of a steam-engine and an alternating-current electric generator directly connected thereto, portions of the supporting apparatus being broken away. Fig. Zis a detailed View of a portion of the inertia-governor. Fig. 3 is a detail sectional view of the portion shown in Fig. 2 and some additional features. Fig. sis a diagram of two-phase distribution-circuits and two generating sets connected thereto in parallel.

Referring now to the details of construction, 1 is an engine,which may be of any type desired, that here shown being of the YVestinghouse type. Mounted upon the bed-plate 2,which supports the engine 1, is an alternating-current generator 3,which may also be of any desired or suitable design and capacity. The engine-shaft 4 and the generator-shaft l may be either coupled toget-l1erasindicated,

for example, at 4J or the engine-shaft may be extended and the armature of the generator be mounted directly thereon. The contrifugal governor 5 of the engine may be of the usual or any Well-known type in which weights are thrown out centrifugally by means of an increase in speed, so as to change the position of an eccentric in order to vary the lead of the valve motion. The eccentric-strap is here shown as connected by means of a rod 6 with one arm 7 of a bell-crank lever 8, the other arm 9 of the lever being provided with a curved slot 10, in which is mounted a pin or roller 11 in one end of a rod 11. The other end of the rod 11 is connected, by a pivotal or hinged connection to the valve-ste1n12, the

supply of steam to the engine-cylinders bef tional illustration that a belt-and-pulley coning determined, so far as the centrifugal governor is concerned, by the position of the eccentric, since that determines the degree of movement of the arm 9 of the bell-crank lever 8, as will be readily understood.

Coupled with the centrifugal governor is an inertia-govern or constructedand arranged as follows: Rigid-1y mounted upon the shaft t is a disk or wheel.13, which' may be'of such weight and proportions as to serve to some extent as a l'ly-- wheel,'if desired, As shown, this wheel is provided with a laterally-projecting rim 13 and a laterally-prejecting hubf 13 at one side. On this hub is mounted, so as to turn freely thereon, a bar 1%, having-at its respective'ends weights 1-4: and 14 bar 14: is attached to the wheel 13 by means of coiled springs 15, which tend to hold the bar in the position indicated in Fig. 2 of the drawings. The end of the bar 14: provided with the weight 14 is connected to the wheel 13 by a dash-pot 1b, the cylinder of the dashpot being pivoted to the wheel 13 and the piston-rod to the bar 14, and the construction is such as to insure a slow return of the bar to its normal position whenever it is moved from such position in either direction.

Rigidly mounted upon the bar 14 is a disk 17, provided with two curved slots or guideways 18,projecting in opposite directions from the center. Splined to the shaft a, so as to be readily movable longitudinally, is a disk 19, having a turned-over edge 19", or being otherwise formed, so as to provide a seat for a ring 20, this ring making such a fit in its seat as to remain stationary, while the disk 19 turns with the shaft without any consid erable amount of friction. Pivotally connected to the other side of the disk 19 are two inclined rods or arms 21, the free ends of which project into the curved slots or guideways 18, intermediate guides 22 for these arms being mounted upon the shaft 4.. The ring 20 is connected to a suitable plate or ring 23 by means of arms 24, a snfficient number of these arms being employed to give the required strength and rigidity to the apparatus. Only two are shown in the drawings; but three or four or even more may be employed if found necessary or desirable. If the friction between the disk 19 and the ring 23 causes undue strain upon arms 2a, additional supports or guides 24 may be provided. The ring or plate 23 is connected by means of a horizontal rod 25 or, preferably, by two such rods, one on each side of the shaft 4:, to one end of the lever 26, this lever being pivotally mounted midway of its ends in a suitable bracket 27. The end of this lever opposite that to which the rod 25 is pivoted is pivotally connected to one end of a rod or link 28, the other end of which is movably connected to one arm of a bell-crank lever 29,supported by a bracket The 30. The other arm of tho bell-crank lever 29 is connected to the rod 11 by means of a rod 31.

It willbe readily understood 'without addinection may be employed between each generator and its driving-engine in lieu of the direct connection shown without change in the governor mechanism, provided the enginesliaft is made of sufficient length to accommodate such mechanism.

- The operation of the governing mechanism is as follows, it'being understood that the speed regulation of each machine should depend mainly on its centrifugal governor and that consequently the apparatus should be so adjusted .with a view to normal conditions that the pin-or roller 11 in the end of the arm :11 shouldnormally be at about the middle point ofthe curved slotlO of the arm 9. Assuming', also, for'the purpose of .the present description that there are two engines and two generators, as indicated in Fig. at, if the machine's-start to get out of synchrouism there is a succession of jerks forward on the slower weight 14 of the inertia-governor to move in the opposite direction relatively to the wheel 13, thus moving the ends of the arms 21, which are in the guide-slots 18, toward theshaft and through the connecting-rods and levers raising the pin in the curved slot 10, thus increasing the lead of the valve motion and speeding up the engine. On the other hand, the jerk backward on the faster machine will through its governing means acting oppositely lower the pin 11 in the slot 10, and thus decrease the lead'of the valve motion and reduce the speed of the engine. As soon as the jerks stop the inertia-governors tend to move back to their normal positions slowly on account of the dash-pots.

The inertia-governor should be made as light as is consistent with the, proper control of itsmech anism, since it is intended to take care of slight variations in speed and tendencies to get out of synchronism as soon as such tendencies appear, the main work of regula tion being taken care of by the centrifugal governors. This arrangement is also extremely useful in case of sudden short circuits, since the inertia-governor will in such cases instantly reduce the lead of the valve motion.

Instead of combining the inertia and centrifugal governors, as shown, so that they act conjointly upon the valve-gear, the centrifugal governor might be employed to operate a throttle-valve, if desired, though I regard the arrangement shown and described as preferable in most cases.

It will be understood that the invention is adapted and intended for use in connection 90 machine and corresponding jerks backward on the faster machine.- Assn mingthat the ro-- with any number of either single-phase or polyphase generators connected in parallel to distribution-circuits and that it is not dependent upon any specific type of engine or generator.

While I have shown and described the invention in connection with steam-engines, I do not thereby intend to exclude engines operated by gas, com pressedair, or other source of energy.

I desire it to be further understood that my invention is not limited to the specific mechanism shown and described, the details set forth being intended merely as illustrative of any operative mechanism for effecting the cooperation of an inertia and centrifugal governor to secure the results specified.

I claim as my invention 1. The combination with an electric generator and an engine for driving the same, of a centrifugal governor for the engine and an independent inertia-governor for controlling the action of the centrifugal governor.

2. The combination with a plurality of engines and a plurality of electric generators connected in parallel to distributing-conductors and respectively driven by said engines, of a centrifugal governor and an independent inertia-governor for each engine acting in opposition to maintain the generators in synchronous operation.

3. The combination with a plurality of electric generators connected in parallel to distrib uting-conductors and a plurality of engines severally driving said generators, of a governing mechanism comprising an inertia element acting to increase the speed of the engine when its shaft receives a sudden impulse in the direction of its motion and to decrease the speed of the engine when its shaft receives a sudden impulse in the opposite direction, and an independent centrifugal element acting to decrease the engine speed When it becomes too high and to increase it when it becomes too low. I

4. The combination with aplurality of alternating-current electric generators connected in parallel to distributing-mains and a plural ity of engines severally driving said generators, of a centrifugal governor and an independent inertia-governor for each engine, the latter serving to so modify the action of the former as to maintain the generators in substantial synchronism.

5. The combination with an electric generator and an engine for driving the same having a centrifugal governor, of an independent inertia-governor connected to the valve-gear and serving to red nce the lead of the valves to a minimum in case of an electrical short circuit.

6. The combination with a plurality of electrical generators connected in parallel to distributing-mains, of a plurality of engines for severally driving the same, each of which has a centrifugal governor for regulating its speed independently of the others and an independentin ertia-governor for regulating its speed in accordance with the electrical rela tions of the several generators.

7. The combination with a plurality of electric generators connected in parallel to distrilduting-mains, of a plurality of engines for severally driving the same, each of which has a centrifugal governor for regulating its valve motion and an independent inertia-governor for modifying the action of the centrifugal governor as the corresponding generator tends to deviate from synchronism with the other generator or generators of the system.

In testimony whereof I have hereunto subscribed my name this 28th day of July, 1899.

CHARLES I. YOUNG.

Vitnesses:

ROBT. B. FLETCHER, A. SAUNDERS MORRIS.

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