Synchronized control system

Claim 1

IN A SYSTEM HAVING A VARIABLE SPEED MASTER DRIVE AND A SLAVE DRIVE ADAPTED TO BE COUPLED TO A LOAD AND INCLUDING AN ELECTRO-MAGNETIC COUPLING BETWEEN THE SLAVE AND THE LOAD AND AN ELECTRO-MAGNETIC BRAKE FOR THE SLAVE, THE COUPLING AND THE BRAKE EACH HAVING A CONTROLLED EXCITATION CIRCUIT TO MAINTAIN THE SLAVE OUTPUT IN SYNCHRONISM WITH THE MASTER, THE COMBINATION COMPRISING, MEANS CONDITIONING THE BRAKE EXCITATION CIRCUIT TO CONTINUOUSLY ACTIVATE THE BRAKE, OTHER MEANS OPERATIVE IN RESPONSE TO AND DURING EXCITATION OF THE COUPLING TO DISABLE THE BRAKE EXCITASTION CIRCUIT, INDIVIDUAL MEANS FOR GENERATING A VOLTAGE PROPORTIONAL TO THE OUTPUT SPEED OF EACH DRIVE RESPECTIVELY, MEANS IN SAID COUPLING EXCITATION CIRCUIT FOR COMPARING THE GENERATED VOLTAGES, OTHER MEANS IN SAID COUPLING EXCITATION CIRCUIT FOR ADJUSTING THE EXCITATION OF THE COUPLING IN ACCORDANCE WITH THE COMPARED DIFFERENTIAL VOLTAGE BETWEEN SAID GENERATED VOLTAGES TO PROVIDE A COURSE SPEED MATCHING OF THE DRIVES, A SERVO SYSTEM COACTING BETWEEN THE DRIVES TO PROVIDE A SIGNAL PROPORTIONAL TO MINUTE DIFFERENCES IN SPEED BETWEEN THE DRIVES, MEANS FOR ALGEBRAICALLY ADDING SAID SIGNAL TO THE VOLTAGE GENERATED PROPORTIONAL TO THE OUTPUT SPEED OF THE MASTER DRIVE AND THEREBY SUPERIMPOSE A FINE ADJUSTMENT ON SAID EXCITATTION ADJUSTMENT MEANS TO SYNCHRONIZE THE OUTPUT OF THE SLAVE WITH THE MASTER.