Patent GB-190722605-A (GB)
Title: Improvements in Systems of Electric Power-transmission for Driving Ship's Propellers and other Apparatus.
Filed: 1907-10-14
Granted: 1908-05-14
Abstract: 22,605. Siemens Bros. Dynamo Works, [Siemens-Schuckert-Werke]. Oct. 14. Motor control systems.-The armatures of separate motors for driving ships' propellers and for other purposes are connected in series with that of a generator, and the field currents are so adjusted that the speeds of the motors may be altered simultaneously or separately for steering and the like. Fig. 1 shows a circuit in which the motors m<1>, m<2> are connected in series with the turbinedriven generator g, .the three fields n, n<1>, n<2> being separately excited from mains k through rheostats r, r<1>, r<2>. Alternatively, the fields n<1>, n<2> may be energized by separate armatures on the turbine shaft, these being excited through rheostats from the mains. Fig. 3 shows the arrangements for regulating both motors by a single controller z. With the handle on either of the stops d<1>, both motors run in the same direction at a common speed. As the handle is raised, the field current is decreased in one motor, which is thus slowed down, the other one running at maximum speed. Passage from the contact d<5> to c' reverses the rotation of the slowed motor, which speeds up again as the switch is moved towards the contacts c<1>, until the two motors run at full speed in opposite directions with the switch arm vertical. Continued rotation of the switch slows down and reverses in a similar manner the machine which previously ran at a maximum speed. By altering the generator resistance r, the current through both motor armatures may be altered. Fig. 4 shows the arrangements for running on either or both of duplicate generators g<1>, g<2>, the shafts of which drive through clutches b<1>, b<2> their own exciters d<1>, d<2>, and those e<1>, e' of the propelling-motors m<1>, m<2>. With both generators in use, the switches u, u<1>, u<2>, p are placed as shown, and the motors are controlled by means of the exciting-rheostats r', r<2>, the controller z being inoperative. If it be required to shut down, say the turbine t<2>, the clutch b<2> is disengaged, the switch u<2> is turned down, and the switches p, u closed, both motor armatures being thereby connected in series with the generator g<1>, and the controller z being included in the circuit for regulating either of them singly, as in the case of Fig. 3. The exciter e<2> will be driven by the machine d<2>, which takes a motoring-current from the machine d'. Joint regulation is effected by the rheostat r<1>. The controller contains an additional set of resistances so arranged that as resistance o<1>, o<2> ... or c<1>, c<2> ... is added to that motor which is being slowed, resistance i<1>, i<2> ... or f<1>, f<2> ... is cut out of the exciting-circuit of the other motor. With the switch vertically downwards on the left of the stop s, the motors run at equal speeds in the same direction, and, as it is moved in the direction of the arrow, they are successively slowed and reversed as in Fig. 3. Alternating-current machines may be used, the exciters for the generator and motors being carried by the generator shaft and excited from direct-current mains. Joint and separate control of the motors are respectively effected by rheostats in the field circuits of the generator and motor exciters. Fig. 6 shows an arrangement in which the alternating-current generator has two armatures g<1>, g<2>, the field current of the latter being regulated by a rheostat r for joint control of the motors m<1>, m<2>. The two windings a<1>, b<2> supply the motor fields through rheostats r<1>, r<2>, which allow separate control of the motors. For reversing the rotation, a switch u is employed, this being preferably coupled to the rheostat arm r. The invention may also be applied to series motors, in which case the regulation is effected by resistances in parallel with the field coils.