Supplement to Comparison of automatic control systems

This analysis deals with the indirect regulator, wherefrom the behavior of the direct regulator is deduced as a limiting case. The prime mover is looked upon as "independent of the load": a change in the adjusting power (to be applied) for the control link (as, for example, in relation to the adjusting path (eta) with pressure valves or the rudder of vessels) does not modify the actions of the prime mover. Mass forces and friction are discounted; "clearance" also is discounted in the transmission links of the regulator.