Patent GB-459858-A (GB)
Title: Improvements in or relating to dynamo electric plant
IPC: H02P9/36
Filed: 1935-07-15
Abstract: 459,858. Dynamo-electric machines. PESTARINI, G. M., Societa San Giorgio, Genoa, Italy. July 15, 1935, No. 20138. Convention date, July 13, 1934. [Class 35] Exciting ; rotary transformers.-The field 3 of a main dynamo-electric machine 1 is adjusted in accordance with a desired electrical or mechanical characteristic of the machine or of the circuit connected therewith by controlling in accordance with the characteristic the ampere-turns of the stator winding 4 of an exciter metadyne 2 of which the primary brushes a, c are short-circuited or closed through a stator winding of the metadyne and the secondary brushes d, b are connected to the field winding of the main machine so that the field winding is supplied with current of a value depending on the ampere-turns of the metadyne stator winding having its axis in the same direction as the commutating axis of the secondary brushes. The winding 4, referred to as a variator winding will be controlled by a regulating device operated in accordance with the required characteristic and the machine 2 functions as quick-response amplifier. Instead of being short-circuited, the brushes a, c may be closed through a stator winding inducing between these brushes an electromotive force opposing the primary current. Commutating poles may be provided. In the application of the invention to a trolley line or third rail metadyne traction equipment, Fig. 7 the main machine 1 is a metadyne transformer supplying traction motors 15, 16. If the secondary current I2 is required to be a function of the voltage Vab or Vcd across either motor in accordance with the curve of Fig. 8, the stator winding 3 is supplied with a current following a similar curve. A dynamo 12 driven synchronously with the main machine is differentially excited at 14, 13 with the line voltage and the secondary voltage Vbd, but instead of feeding the winding 3 direct, the output of this dynamo supplies the variator winding 4 of the metadyne exciter 2. A diesel-electric traction system is described similar to that described in Specification 430,009 with the feature than an exciter metadyne is interposed between the main metadyne and the regulator dvnamo. The armature current of a main machine may be controlled by the provision on the exciter metadyne of an opposing winding 19, Fig. 13, carrying the main current I. The current I will adjust itself so that the ampereturns of the winding 19 compensate those of the winding 4 except for the small amount necessary to create the current in the field 3. This current may be provided for by a winding 20 connected across the terminals of the main machine or by a winding connected across the secondary brushes of the exciter. With this arrangement, the current I will be proportional to the ampere-turns of the winding 4. Instead of the winding 19, an opposing series winding may be placed on the main machine. Fig. 16 shows an arrangement of a dynamo 1 driven by a diesel or other engine, the output of which is to be kept constant over at least a portion of the range. A regulator dynamo 23 mounted on the same shaft as the main machine supplies a variator winding 24 during that part of the operating range in which constant output is required. For the extreme ends of the range, the winding 24 is inoperative to avoid excessive values of current and voltage. Additional variator windings such as 20, Fig. 13 or its alternative referred to above may be provided on the exciter metadyne. Specifications 399,351, 400,416, [Group XXXVII], and 404,734 also are referred to. The Specification as open to inspection under Sect. 91 comprises also the following. The primary brushes of the exciter metadyne may be connected to a constant voltage source. In the arrangement shown in Fig. 20 (Cancelled), the metadyne is replaced by a Kraemer dynamo 26 having a shunt winding 22, a series winding 27 and a separately excited winding 4 which acts similarly to the variator winding 4 described above. This subject-matter does not appear in the Specification as accepted.