Patent GB-190828438-A (GB)
Title: Apparatus for Transmitting Power at a Reduced and Variable Speed by Means of Dynamo Electric Generators and Motors.
Inventor: JOHANNET MAX
Filed: 1908-12-30
Granted: 1909-06-17
Abstract: 28,438. Johannet, M. Feb. 3, [date applied for under Section 91 of Patents &c. Act, 1907]. Distributing. -For transmitting power at a reduced speed from a highspeed turbine to automobiles, railway trains, ships' propellers, &c., a number of generator sets with h both field magnets and armatures capable of revolution are employed on the same or different shafts, and the field magnets of the first are connected mechanically to the armature of the second, and so on ; the current from the first generator-unit is supplied to the second, and so on, while the current from the last serves finally to drive the motor or motors. By these means, wide variations of speedtransmission ratio are secured, while the speed of commutation in none of the machines is exceeded. Specification No. 25,988, A.D. 1906, [Abridgment Class Dynamc-electric generators &c.], is referred to. Fig. 1 shows an arrangement of three generators and a motor u connected together as described so as to transmit power from the turbine a. The four dynamo machines may be connected in series with each other ; or they may be independent. With all the generators in series, the generators act as a single machine, the speed of which is the sum of the slips between the elements of the three generators, and the total slip is shared between the various generators, so that commutation difficulties are eliminated. The successive elements of the dynamos may be grouped concentrically as shown in Fig. 2. The magnets c of the motor u may be arrauged in known manner to form an automatic oscillating switch, and devices of this kind are shown in Fig. 3 applied to the case of a single generator f between the prime-mover and the motor u which drives a ship's propeller. The field magnets q oscillate round their bearings, and the movement is limited by a link x, Fig. 4, attached to a balance beam y oscillating about a pivot z and held at the other end by a spring 2 attached to an adjustable sleeve. The field-magnets winding is divided up, and the various ends are connected to a number of contacts 5 upon the field magnets, on which is held a brush 6. Under the action of the couple of the motor, the spring 2 stretches in accordance with the value of the couple and completes the circuit of the current by one or other of the commutator contacts, and by moving the sleeve, the speed of the motor may be varied. The electric connexions are shown in Fig. 6, in which the generators are shown connected in series. The brush 6 may be provided with a screw adjustment so that the speed of the motor may be varied by adjusting this brush by hand. In a modification, the automatic oscillating switch is provided with additional contacts for varying the number of magnet turns of the generator c, which gives further speed variations ; a reverser may be employed in this case. The invention may be applied to the driving of a distribution generator to give a constant voltage, as shown in Fig. 9. The generator has a main exciting-winding carrying the main current, and an auxiliary winding 21 carrying the. current of the generator-motor combination ; and the movable field magnets of the generator control a switch 23, which acts automatically to put in or out of the circuit the various sections of the auxiliary winding 21 or regulates a resistance.