US669803A - Dynamo. - Google Patents

Description

No. 669,803. Patentedflar. l2, I901.

C. A. PARSONS &. G. G. STONEY.

DYNAMO.

(Application filed Dec. 15, 1900.) {No Model.)

3 Sheets-Sheet t.

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No. 669,803. Patented Mar. 12, I901.

C. A. PARSONS & G. G. STONEY.

DYNAMU.

(Applicatmn filed Dec. 15, 1900.) {No Model.) 3 Sheets-fiheet 2.

No. 669,803. Patented Mar, 12, mm.

C. A. PARSONS &. G. G/STONEY. DYNAMO.

(Application filed Dec. 15, 1900.) (N0 Mogiel.) 3 Sheets-Sheet 3.

UNITED STATES PATENT OFFICE.

CHARLES ALGERNON PARSONS AND GEORGE GERALD STONEY, OF NEWCASTLE-UPON-TYNE, ENGLAND.

DYNAMO.

SPECIFICATION forming part of Letters Patent No. 669,803, dated March 12, 1901.

Application filed December 15, 1900. Serial No. 40,220. (No model.)

150 all whom, it may concern.-

Be it known that we, CHARLES ALGERNON PARSONS and GEORGE GERALD STONEY, engineers, residing at Heaton Works, Newcastle-upon-Tyne, in the county of Northumberland, England, subjects of the Queen of Great Britain and Ireland, have invented certain new and useful Improvements in Dynamos, (for which we have made application in Great Britain for Letters Patent No. 9,203, hearing date the 18th of May, 1900,) of which the following is a specification.

Our invention relates to the adjustment of the position of the brushes on the commutator of a continnous-current dynamo to meet the changed angular position for minimum sparking according to the change of load on the dynamo, and especially relates to dynamos driven by steam-turbines, but is also applicable to dynamos driven by reciprocating steam or gas engines.

It is found on testing a dynamo with a drum or Gram me wound armature of usual construction and magnetic field that the displacement of the angular position of the brushes for minimum sparking varies approximately as the load or the am peres delivered from the dynamo. We are aware that attempts have been made to effect such an adjustment automatically; but hitherto such attempts have not been satisfactory and have not attained any commercial use. Our present invention, which we have practically tested, overcomes the difficulties which heretofore have pre vented the success of this class of adjustment.

Our invention consists in automatically adjusting the position of the brushes on the commutator of a continuous-current dynamo so as to maintain the brushes in the position of minimum sparking at all loads by means of a piston or diaphragm acted upon directly or indirectly by the steam-pressure of the driving engine or turbine at a point where this pressure varies proportionally to the load on the engine or turbine.

In the accompanying drawings, Figure 1 is a side elevation of the automatic brush-shifting device, showing the method of connection to the brush-rocker and having the cylinder in section to show the internal controllingspring. Fig. 2 is a modification of our invention in which two external controllingsprings are substituted for the internal spring. Fig. 3 shows the apparatus fitted to a dynamo driven by a steam-turbine.

Referring to Fig. 1, a is a cylinder which may be steam-jacketed or thoroughly drained from water by means of a cook or plug fitted at w, or it may be worked more or less full of water, according to the desired degree of quickness or slowness of action. A piston b is fitted steam-tight into the cylinder, and between the piston and the top cover 0 is placed a controlling-spring (Z. Bosses I) and c are cast on the piston and top cover, respectively, so thatin case of the spring failing the brushes will not be put into such a position as to sustain damage themselves or to damage the commutator of the dynamo. Steam is admitted to the under side of the piston by means of pipe 6, which may be connected either to the steanrturbine cylinder or, if used in connection with a reciprocating steam-engine, to the valve-chest under the governor throttle-valve. This pipe may be controlled by means of a small throttle-valve it.

The piston-rod g has attached to its upper end a hand-wheel h' by means of a swiveljoint 2'. This handwheel is fitted with a screw j, passing through its center, for the primary adjustment of the brushes. l/Vhen they have received this, the nut 19 is screwed down and jams the hand-wheel in its position. To the end of this screw is attached a lever 7c by means of an ordinary pin-joint. The other end of this lever is attached also by means of a pin-joint to another lever 11, which is rigidly fixed either to a bar, such as m, specially provided and carried by means of brackets n, cast on the brush-rockers, or it may be connected directly onto the bar 0, which carries the brushes.

In Fig. 2, q and q are external controllingsprings, which are connected to two corners of a triangular frame 0, the other corner of which is connected by a pin-joint to the upper end of the piston-rod g. The screw j in this modification passes through a hole in the side of the triangular frame between the two controlling-springs and is fixed in its position by means of regulatingnuts 3. The screw j is connected, by means of a pin-joint,

to the rigidly-fixed lever Z, Fig. 1.

In operating the device as shown applied to a steam driven dynamo in Fig. 3 the brush-rockers of the dynamo are connected to the piston in cylinder (0. This cylinder is connected by pipe 6 with the main steamsupply pipe of the turbine at a point t between the governor throttle-valve and the turbine. When load is put on the dynamo, the steampressure on the turbine, and therefore at the point it, rises, due to the action of the governors. This pressure is transmitted to the cylinder a by means of the pipe 6, the piston rises, its movement being controlled by an internal springsuch as d or external springs, as q and q, or other means-and the brush-rockers move the brushes around the commutator to the right amount to prevent sparking.

We find that in the Parsons steam-turbines the output in horse-power is proportional to a small fixed quantity, plus a quantity proportional to the steam-pressure acting upon the turbine. The above-described method of connecting the brush-spindles to a piston, &c., secures that the brushes shall be shifted to a corresponding degree. We also find in our present invention that when it is applied to steam-turbines and in connection with their usual method of governing by longer or shorter blasts of steam there is a slight pulsating movement imparted to the piston of the lwushregulator, which keeps the piston free and prevents hunting both mechanically and electrically. By means of the small throttle-valve on the pipe connecting the cylinder of the steam-turbine with that of the brush-regulator these pulsations can be adjusted to any desired degree.

If in place of a steam-turhinea reciprocating engine of any kind be used, the brushregulating cylinder may be connected to the valve-chest under the governor throttle-valve or to theintermediate pipe or receiver or other suitable place where the steam-pressu re varies with the load on the dynamo, and with certain classes of governors reciprocating motion may be obtained, due to the combination of throttling and the pulsating draft of steam entering the cylinder of the reciprocating engine; but the principle is substantially the same.

Instead of a piston a flexible diaphragm or other wellknown method of obtaining movement from steam-pressure may be used.

Instead of directly coupling the cylinder to the steam-turbine orotherenginea hydraulic or compressedair arrangement may be used as an intermediary to transmit the variations of pressure from the one point to the other.

Having now described our invention, what we claim as new, and desire to secure by Letters Patent, is

1. In combination with a continuous-current dynamo an automatic bruslrshifting apparatus consisting of a steam-pressure-actuaied device,connected to the dyname-brushes, and havinga movementdirectly proportional to the load on the dynamo, an engine for driving the dynamo and a steam-supply connection to the said device leading from a point where the steam-pressure used to drive the engine varies with the load on the dynamo, substantially as described.

2. In combination with a continuous-current dynamo, an automatic brush-shitting mechanism consisting of a cylinder, piston, piston-rod, levers connecting said piston-rod to the brush-rockers, the piston being operated against a restraining device by steam, the pressure of which is directly proportional to the load on the dynamo, an engine for driving the dynamo and a steam-supply connection to the cylinder and piston leading from a point where the steam pressure used to drive the engine varies with the load on the dynamo, substantially as described.

In witness whereof we have hereunto set our hands in the presence of witnesses.

CHARLES ALGERNON PARSONS. GEORGE Gllltilhl) ."lONEI.

Witnesses to the signature of Charles Algernon Parsons:

ALBERT E. PARKER, THoRPE P. MARTIN. Witnesses to the signature of George Gerald Stoney:

O'rTo KoNIG, 'l. A. RrrirnnsnAUs.

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