Patent GB-191014766-A (GB)
Title: Improvements in Combined Speed and Current Regulators for Dynamo-electric Series Machines.
IPC: H02P5/685
Filed: 1910-06-18
Granted: 1911-06-19
Abstract: 14,766. Compagnie de l'Industrie Electrique et Mecanique. May 19, [Convention date]. Regulation, automatic systems and apparatus for.-In a series system, the speed of the motor is controlled by a regulator comprising a centrifugal governor a, Fig. 1, and an electro-magnetic device b excited by the current feeding the motor, the two elements of the regulator being so interconnected that the regulation of the speed can only take place to such an extent that the variation of the current which results from this regulation does not exceed a certain fraction of the normal current. In the arrangement shown in Fig. 11, the motor is controlled by shifting the brushes by means of a servomotor S supplied with oil through a distributor i, Fig. 8. The sleeve of the governor a actuates a lever h, which is pivoted at o and carries a flat spring k, from which is cut out a central tongue, a sliding piece allowing variation of the length of that part of the tongue which is liable to be bent relatively to the spring k. The rod l<10>, to which the primary distributor l is secured, passes through and is secured to the tongue. The upper end of the rod l<10> carries a coil c acted upon by a coil b<1>, the coil c rising when the current increases. When the governor sleeve falls owing to an increase of the load on the motor, the upward movement of the distributor l does not take place until the current in the coils b<1>, c indreases; this increase is brought about by an increase of the generator voltage. The regulator may also be applied to the generator, in which case the centrifugal governor may be dispensed with. In this case, the regulator is provided with an iron plate p, which is normally held against the core b; but, should the current fall below a certain value owing to an accident to the line, the spring r<1> lifts the plate p, thereby raising the distributor and causing the servo-motor to return the brushes of the generator to the polar axis. The pump mechanism by which oil is supplied to the distributor i consists of a small pump d and a large pump c, the two pumps being connected in parallel and driven by the shaft s. The small pump d pumps oil from the casing A into the cylinder g<10>, which has a bushing g<20> in its lower part, in which slides a piston g acted upon by a spring R. From the cylinder g<10>, the oil passes through the pipe g<1> to the space D of the distributor i. The small pump d compensates for losses due to leakage in the distributor i, and maintains a constant pressure in the space D when the apparatus is at rest during the periods of regulation. When the pressure exceeds the normal value, the piston g is raised, and the openings g<2> in the bushing g<20> are uncovered so that oil can flow back into the casing A, thereby temporarily short-circuiting the small pump. The large pump e draws oil from the casing A and forces it through a pipe e<3>, Fig. 3, openings g<4>, g<3>, and a groove in the piston g, back to the casing A, the pump e being thus normally short-circuited by the pump d. Whenever the pressure in the pipe g<1> falls, the piston g covers the openings g<4> so that the pump e forces oil through the valve e<2> into the space D. When the primary distributor l is raised or lowered, oil flows from the space D to one of the spaces f<1>, the other space f<1> at the same time being connected with one of the spaces f<2> communicating with the escape pipe f<5>. The slide valve f, which is continuously rotated, is thus moved in the same direction as the primary distributor l, and connects the space D with one of the spaces E, F connected with the servomotor.