) A shunt DC motor has armature winding resistance RA 0.1 and field winding resi
ID: 2266652 • Letter: #
Question
) A shunt DC motor has armature winding resistance RA 0.1 and field winding resistance R 50 . The e magnetization characteristic of the motor at the speed of 1200 rpm is given in the ci below figure 250 23 1,0 150 50 10 20 4043 50 607. 0 90 100 Field cumeet, A Suppose the motor is fed by a DC voltage of Vr-250 V, the rotor is rotating at the speed of nm-1150 rpm, and the rotational losses are Pro 900 W. Under these conditions, calculate a) The starting current of the armature if no additional resistance is used (2 point)Explanation / Answer
Answer:
In a DC motor, the starting current of the armature is given by: I=(V-E) / R
Where, V is the amount of voltage supplied, E is the back emf and R is the armature winding resistance:
When the motor begins to rotate, its speed remains zero and hence E also remains zero (since back emf is directly proportional to speed of the armature).
Initially, E = 0.
I = V / R = 250 / 0.1 = 2500 Amperes
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.