1,185,503. Running alternators in parallel. P. R. PEROTIN, J. E. TROTTIER, and J. M. NEUFVILLE. 8 June, 1967 [8 June, 1966; 13 Aug., 1966], No.26501/67. Heading H2H. An arrangement ensuring proportional division of load and reactive k.v.a. among dissimilar parallel connected alternators comprises a variable impedance consisting of a transformer ab the primary winding being inserted in series with the A.C. input to each field winding rectifier, e.g. R1 secondary winding being variably shunted by an impedance Zr for example a transductor controlled in correspondence to busbar voltage through a rectifier R2. Compounding may be effected by an additional current winding C. Oscillations due to variations in load may be minimized by coils S. The output of impedance Zr may be shunted by a switch (not shown) which if closed when large asynchronous motors are started direct on line assists in alternator voltage recovery. The switch may be opened by a time switch coupled to the starting equipment of the motors.