A DC shunt motor drives a centrifugal pump at a speed of 1000rpm when the terminal voltage and line currents are 200 V and 50 A,respectively. Given the armature resistance, Ra = 0.1 ohm and fieldresistance, Rf =100 ohm. Design a circuit which the speed of themotor can be controlled by using the added resistance method to thearmature circuit and the maximum starting current is 120 A. Next,if the added resistance in the designed circuit above can beadjusted so that the speed is 800 – 900 rpm, analyze the minimumand maximum values of the resistance should be adjusted in thearmature circuit. Then, design a circuit which the terminal voltagecan be adjusted so that a conveyor can be operated at speed 745.46rpm.
