US1776716A - Prime-mover-generator plant - Google Patents

Description

Sept. 23, 1930. A BEEKMAN 1,776,716

PRIME MOVER GENERATOR PLANT Filed Feb. 25, 1928 luv/cantor:

Royc 7\. Beekman, yM ZZQRJ Patented Sept. 23, 1930 UNITED STATES PATENT OFFICE ROYCE A. BEEKMAN, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL,ELECTRIC COMPANY, A CORPORATION OF NEW YORK IRIME-MOVER-GENERATOR PLANT Applicationfiled February 25, 1928. serial No. 257,055.

My invention relates to prime-mover-generator plants wherein a prime mover constructed and arranged for a given direction of rotation and subject to damagewhcn rotated in the reverseddirection is used to drive a generator which, due to its connection in a power system, is subject to a motoring action with reversed rotation upon failure of its prime mover to supply the necessary torque to drive it as a generator.

An object of my invention is to provide means for preventing such reversal and the consequent damage attending it.

In ship propulsion systems, especially where it has been found desirable to use Diesel engines, it is common practice to provide a plurality of generating units because the smaller engines may be more easily constructed, installed and repaired. Furthermore, such arrangements provide more ecopairing them without incapacitating the ship or unduly slowing up its schedule.-

In the case of direct current systems it has been found desirable to connect several generators in series with one another in order to eliminate or compensate for speed variations of the several prime movers. \Vhen, however, the generators are thus connectedtherc is the possibility that any one of the generators may motor with reversed rotation whenever its prime mover for any reason fails to supply the necessary torque to drive it as a generator. Certain types of prime movers may be constructed for rotation in either d1- rection but are more cheaply constructed for rotation in a given direction. Such is the case of the Diesel engine. In I either case, however,'the prime mover is subject to damage When rotated in a direction .opposlte to the direction in which it is normally arranged to function. i

mover or to permit it to recover and continueto run driving its generator as a generator and supplying power to the system. In this manner I am able to prevent a reversal of the prime mover.

My invention will be better understood from reference to the following description when considered in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. 1 shows a simplified diagram of connections diagrammatically illustrating a system in which my invention has been applied, and Figs. 2 and 3 show details of a switch mechanism which may be used in said system.

Fig. 1 shows a propeller motor 1 provided with a separately excited field 2 and arranged to be supplied with current from generators 3 driven by suitable prime movers 4, such as Diesel. engines; The generators 3 are connected in series with one another and with the propeller motor 1 by conductors 5, 6, 7 and 8. Switching means may be provided in this circuit for shorting out any generator or for disconnecting the motor from the generator, but since such arrangements are already well known and form no part of the present invention the diagram has not been complicated by illustrating them. The se eral generators 3 are provided, with separately excited fields 9 which are connected through conductors 10 and 11 tobuses 12 and 13 which, in turn are connected to a potentiometer 14. This potentiometer 14 is connected across a suitable source of supply 15 by conductors 16 and 17 and is adapted to regulate simultaneously the amount and direction of the exciting current supplied to the several fields of the several generators. In the circuit of each generator field is an adjusting rheostat 18 and a cutout shown as a relay 19. The operating coil of the relay 19 is connected across the source of supply 15 through conductor 20, contacts 21 and contact member 22 of a switch mechanism 23, and conductors 2 1 and Contact member 22 is normally biased against an abutment 26 by a weight or a spring 27 but upon the correct rotation of the prime mover dis moved against the contacts '21 to complete the circuit of the relay l9which then closes and completes the field circuit of the generator 3 driven by the prime mover 1. Motor field 2 is connected acrossthe source of supply 15 by conductors 28 and 29 and its degree of excitation is controlled by'means of a rheostat '30 inserted in series with it.

The switch mechanism .43 may be of any suit-able construction so long as it will maintain its contacts close lwl1en the prime mover with which itis connected rotates in one direction and breaks this connection when the prime mover'slows down. abnormally or its direction of rotation is rev rsed a few de-. grees'. agrammatically illustrated in Figs. 2 and 3.

The construction may be such'as di- Referring to these figures, it will be noted that as there illustrated the switch mechanism comprises two disks 31 and 32 placed in close proximity to one another with their lower portions immersed in a heavy oil 33.

' One of the disks 31 is free to rotate about its centerwhile the other disk 32 is free to rotate between contacts 21 and abutment 26 against which it is normally biased by the spring 27, previously referred to. The disk 31 which is free to rotate is mechanically connected directly or through the agency of gears to the shaft of the prime movers 4. Usually it will be found desirable to have the disk 31 rotate at a greater speed than the prime mover. When the prime mover is rotated in the correct direction at a proper speed this disk will also be rotating in a corresponding direction and will exert a dragging effect on theother disk 32, due to the viscosity of the oil 33, with the result that the contact member 22 mounted on disk 32 will be moved against the force of the spring 27 into engage ment with contacts 21 whichare shorted thereby. As previously noted above, this completes the circuit of relay 19 which closes and completes the circuit of the field 9 of the generator 3 driven by the prime mover 4. The switch mechanism above briefly described is in accordance with the invention or" George R. Townsendwhose application Serial No. 75,147, tiled Dec. 12, 1925, for rotary switch mechanism, now Patent 1,677,-

008, granted July'lO, 1928, is assigned to the assignee of the present application.

The operation of the system described is as follows: The prlme movers are started and aslong as they rotate in the correct" dlrectlons the switch mechanisms 23 directly completing the circuits of the field coils 9 'otthegenerators 3. Thereafter the degree of excitation of the generators is simul taneously controlled through the potentiometer 14;. Individual adjustments may be made in each tieid circuit-by means of the rheostats 18. The direction of rotation 01 the propeller motor 1 may thus be controlled according to the well known ard Leonard system by means of the potentiometer 1i. Provlslon is also made for controlling the field of the motor 1 by means'of the rheostat 30 so that under various conditions the motor 1 may be properly adjusted forobtaining the best'results. r

If for any reason one of the prime movers i-should slow down abnormally or stall due to the failure of fuel supply or for some "other reason or otherwise lose its propelling torque, its corresponding generator 3 will tend to motor and rotate theprime mover 1 in a direction opposite to that in which it has beenrotating. Howev'en-as soon as this reversal 1s initiated, and by thls D mean that the prime mover has slowed down abnormally or actually reversed a tew-degrees, the switch mechanism23 operates to open the circuit of the relay 19 which upon opening deenergizes the held 9 of the generator 3 which is motoring. This deenergizes the generator 'andprevents it from-motoring further, thus permitting the prime mover either to come to-rest or under certain conditions even to recover and "again supply power tothe system.

It is a-pparent to those skilled in-the art that the proposed arrangement may be modified to meet varyingv requirements without departing from my invention which has been shownand described in connection with a simplified arrangement for thepurpose of clearly illustrating the invention and I, therefore, aim in the appended claims to cover all such changesand modifications as fall within the true spirit and scope of my invention.

What I claim asnew and desire to secure by Letters Patent of the United. States, is: 1. A prime-mover-generaton plant includingagenerator subject to reverse rotation due to motoring action, a primemover for said generator adapted for rotation in a given' direction only, and means mechanically connected to saidprime mover, responsive when the prime mover slows down abnormally and before 1ts speed approacheszero, for deenergizlng said generator :when it :tends -to reverse the direction of rotationof-said prime mover.

2. In a ship propulsion sy-stem, a propeller motor, aplurality of series connected generators for suplying power to said propeller motor, a plurality of prime movers adapted for rotation in a given direction only for independently driving said generators, and means mechanically connected to each of said prime movers for deenergizing its corresponding generator just before its speed approaches zero due to the motoring action of its generator upon a failure of its prime mover.

3. In a ship propulsion system, a propeller motor, a plurality of series connected generators for supplying power to said propeller motor, means for exciting each of said generators, a plurality of prime movers adapted for rotation in a given direction only for independently driving said generators, switching means associated with each of said prime movers for controlling the can citation of the generator driven thereby, means for biasing each of said switching means to the position in which it deenergizes the generator with which it is associ ated, and means connecting each of said switching means to its associated prime mover for overcoming said biasing means during rotation of said prime mover until just before its speed approaches zero due to the motoring action of its connected generator.

In Witness whereof, I have hereunto set my hand this 2%Lth day of February, 1928.

ROYCE A. BEEKMAN.

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