. The 3.3. A 15-hp, 160-V, 1000-rpm shunt dc motor with compensating windings has an armature resistance of 0.416 ). Its shunt -field resistance is adjustable between 25 to 100 shunt-field winding has 750 turns. The magnetization curve data at rated speed is shown. a) For field-current speed control, find the minimum and maximum motor speeds in rpm (must have 2 digits after the decimal point) when the motor consumes 6000 W of power. [4 points] b) At 4800 W of input power, design an automatic starter circuit for this shunt dc motor with RF set at 40. The maximum starting current is limited to 300% of IA and the starting resistor stage is to be cut out when IA falls to its consumed value. Find the number of stages of the starting resistance and their associated values. What is the value of IA immediately after all starting resistors are cut out? [4 points] c) Now the motor is reconnected as a separately excited dc motor with VA connected to a variable dc source of 100 V to 200 V, and VF = 160 V. However, its compensating windings fails resulting in armature reaction demagnetization umf of 150 At. At the same input power as that of part a), find the minimum and maximum motor speeds if both methods of speed control (VA and IF) are used. Explain the conditions of VA, IF and RF when these speeds occur. [4 points] I EA (V) 230 240 250 260 268 275 281 IF (A) 1.0 5.0 6.0 7.0 2.0 3.0 4.0 . The 3.3. A 15-hp, 160-V, 1000-rpm shunt dc motor with compensating windings has an armature resistance of 0.416 ). Its shunt -field resistance is adjustable between 25 to 100 shunt-field winding has 750 turns. The magnetization curve data at rated speed is shown. a) For field-current speed control, find the minimum and maximum motor speeds in rpm (must have 2 digits after the decimal point) when the motor consumes 6000 W of power. [4 points] b) At 4800 W of input power, design an automatic starter circuit for this shunt dc motor with RF set at 40. The maximum starting current is limited to 300% of IA and the starting resistor stage is to be cut out when IA falls to its consumed value. Find the number of stages of the starting resistance and their associated values. What is the value of IA immediately after all starting resistors are cut out? [4 points] c) Now the motor is reconnected as a separately excited dc motor with VA connected to a variable dc source of 100 V to 200 V, and VF = 160 V. However, its compensating windings fails resulting in armature reaction demagnetization umf of 150 At. At the same input power as that of part a), find the minimum and maximum motor speeds if both methods of speed control (VA and IF) are used. Explain the conditions of VA, IF and RF when these speeds occur. [4 points] I EA (V) 230 240 250 260 268 275 281 IF (A) 1.0 5.0 6.0 7.0 2.0 3.0 4.0