Question

Speed-power characteristic for Ward Leonard speed control method _________________

(a) Will start from origin

(b) Will start from some positive value on power axis

(c) Will start from some positive value on speed axis

(d) Depends on other parameters

I have been asked this question at a job interview.

The query is from Ward Leonard Speed Control Method topic in chapter DC Motors of DC Machines

Answer 1

Correct option is (a) Will start from origin

Easy explanation: Speed power characteristic of DC motor is plotted when, Ward Leonard speed control method is employed. For speed equal to zero, which is less than base speed, we get constant torque but variable power operation. Thus, power will start increasing from origin.