GB191411159A - Improvements in and relating to Dynamo Electric Machines. - Google Patents

Abstract

11,159. Fiorani, T. May 29, 1913, [Convention date]. Void. [Published under Section 91 of the Act.] Exciting. - Constant voltage is obtained from a variable - speed continuous-current machine D, Fig. 1, by including in its exciting-circuit a motor M running at constant torque or speed. The motor is shuntexcited at a and its armature is in series with the field coil S of the machine D, the motor being driven by an auxiliary dynamo D', which is coupled mechanically to the dynamo D and is excited by permanent magnets, an independent source of constant voltage, or by a winding b connected across the machine D under regulation. It is shown in the Specification that this arrangement gives constant voltage across P N independently of speed variation, and a polarity which is independent of the direction of rotation. The two machines D, D' may be combined into one, as shown in Figs. 2 and 3. In the four-pole form shown in Fig. 2, a winding b is shunted across the main circuit P N and the motor armature M is in series with the exciting-coil S. Compensating-coils C, C' are used in series with both brush pairs. In the form shown in Fig. 3, independent pairs of poles P<1> P<2>, P<3> P<4> are excited by coils shunted across the brushes 1, 3. The centre point A of these coils is connected through the motor armature M to the centre point K of the motor field coil, which is connected across the brushes 1, 3. The point K is also connected to a pair of short-circuited brushes 2, 4 on the machine D. At starting, the dynamo D is excited by permanent magnets or an independent constant voltage supply, such as a battery B, producing pairs of north and south poles at P', P<3> and P', P<4> respectively. Superposed on this magnetizing-current is one producing pairs of north and south poles at P<1>, P<4> and P<2>, P<3> respectively. It is shown in the Specification that constant voltage and polarity result, as in the case of Fig. 1.