A CONTROL CIRCUIT FOR USE IN ROTOR-FREQUENCY-DEPENDENT SHORT-CIRCUITING OF ROTOR SERIES RESISTANCE FOR A DRIVE MOTOR

摘要

1. Arrangement for the rotor-frequencydependent short-circuiting of the rotor series resistances of a drive motor, more particularly for lifting devices, by means of a rotor-frequencydependent gate circuit having a frequency-determining device and a converting device (1, 3) and also by means of a desired value presetter (6) and a comparator circuit (10) for producing the short-circuit command, characterised in that the gate circuit, in the open state, releases a fixed reference frequency (reference frequency generator 5) to a counter (4) which in turn transmits the counted periods of the reference frequency via a matrix circuit (Eprom 18) as actual digital rotor frequency value to the comparator circuit (comparator 10), and the desired value presetter (6) is effected digitally by adjustable coding switches (7) to the comparator circuit (10), the short-circuit command of the comparator circuit (comparator 10) being capable of being influenced by a delay circuit (13).