Slave current control system for a plurality of electric motors coupled to a common load

Claim 1

In a motor control system for a plurality of direct currenT motor means each provided with a separate power supply, and all coupled to a common load whereby all motors must rotate at the same speed; the combination for causing the currents through all motors means to be equal as well as the output torques thereof, comprising: means for producing a feedback signal which varies as a function of the speed of only one of said motor means, and for comparing said feedback signal with a reference signal to control the speed of said one motor, means for sensing the current flowing through said one motor means and for producing a master signal proportional thereto, means for sensing the currents flowing through the remaining said motor means and for producing slave signals proportional to the currents through the respective remaining said motor means, and means for comparing each of said slave signals with said master signal to produce error signals for varying the currents through the respective remaining motor means, when the slave and control signals for a respective motor means are not equal, until the currents through all motor means are equal and said error signals are reduced to zero.