GB709320A - Improvements in or relating to electrical power systems for steel rolling mills - Google Patents

Abstract

709,320. Control of several motors. LUKENS STEEL CO. April 9, 1952 [April 10, 1951], No. 9063/52. Class 38(3) [Also in Group XXXV] Parallel-connected motors 8, 9, for driving the rolls of a plate mill are supplied from compound generators 16 ... 19 provided with armatures a' ... a<SP>4</SP>. The generators also have series-cumulative field windings c<SP>1</SP> ... c<SP>4</SP> and series-differential field windings d<SP>1</SP> ... d<SP>4</SP>, as well as interpole and compensating windings i<SP>1</SP> ... l<SP>4</SP>, the field windings c<SP>1</SP>-d<SP>3</SP>, c<SP>2</SP>-d<SP>1</SP>, c<SP>3</SP>-d<SP>4</SP>, and c<SP>4</SP>-d<SP>2</SP> being interconnected. The generator-polarity is reversed by means of shunt field windings s' ... s<SP>4</SP>. The motors and generators are interconnected in a symmetrical manner, as shown, by means of bus bars 22 ... 31, the object being to establish substantially equal time constants in all the complete circuits through any motor and generator, so tending to reduce commutation difficulties and equalizing the load of the generators at periods of rapid current fluctuation. Thus, the bus bar 24 is connected with the bus bars 22, 23, at points dividing them into portions of substantially equal resistance, and the bus bar 25 is similarly connected to the bus bar 24. Adjustable connections 33 are connected between the bus bars, such as 24, 25, for example, to allow for exact balancing of the resistances of the various branch circuits.