The armature resistance of a shunt motor is 0.09 2. When connected to a 230-V supply a counter-emf of 222.8 V is developed. Find (a) the armature current; (b) the armature current when the armature is not rotating; (c) counter-emf when the armature current is 100 A.

A shunt-wound DC motor with the field coils and rotor connected in parallel (Figure 1) operates from a 130 V DC power line. The resistance of the field windings, R. is 208 n. The resistance of the rotor, R,, is 4.90 1. When the motor is running, the rotor develops an emf E. The motor draws a current of 4.46 A from the line. Friction losses amount to 45.0 W Part C Compute the emf E. • View Available Hint(s) Tematates Symbols undo redo Tese keyboard shortcuts Help V Submit Part D Compute the rate of development of thermal energy in the field windings. Express your answer in watts. > View Available Hint(s) Templates Symbols undo redo Teset keyboard shortcuts Help Pan,windings = Figure W K 1 of 1 Submit Part E Compute the rate Pin.rotor of development of thermal energy in the rotor. R ER, Express your answer in watts. > View Available Hint(s) Templates Symbols undo redo teset keyboard shortcuts help Pinrotor=

Q1. (A)- A series DC motor runs at 600 r.p.m drawing a current of 52A when connected to 220 V supply. The total resistance of the machine is 0.14 2. Calculate the value of the external resistance to be connected in series with the motor circuit to reduce its speed to 400 r.p.m. Assume the load torque is decreased to half of the previous value. Consider the field flux is proportional to armature current.