Effect of rotor rectifier on motor performance in slip recovery drives

Despite its simplicity, the static Kramer drive presents a formidable analytical challenge. Rigorous analysis is particularly difficult and there is need for a simpler form of analysis when calculating ratings and steady-state performance. One aspect which is not well documented is the influence of commutation overlap within the rotor rectifier upon motor power factor and peak attainable torque. The paper deals with this point and also shows how system performance can be predicted by largely analytical means, allowing fully for motor resistances, diode voltage drops, and the several possible rectifier overlap modes.