Variation in speed by ward-Leonard control of DC motors occurs due to variation in
A. Supply voltage.
B. Armature voltage.
C. Field excitaion.
D. Armature current.
Answer: B
Share your understanding of this question with the correct explanation.
The variation in speed by Ward-Leonard control of DC motors occurs due to variation in the armature voltage.
The Ward-Leonard control system is a method used to control the speed of DC motors. It involves the use of a motor-generator set (M-G set) and a rheostat. The M-G set consists of a motor (called the motor generator or MG) and a generator.
In this control system, the speed of the DC motor is adjusted by varying the voltage applied to its armature. The motor generator converts the incoming fixed-voltage and fixed-frequency AC supply to a variable DC voltage. The rheostat, also known as the field regulator, controls the field excitation of the motor generator.
By adjusting the field regulator, the output voltage of the motor generator can be varied. This variable DC voltage is then supplied to the armature of the DC motor. The speed of the motor is directly influenced by the armature voltage.
When the armature voltage is increased, the motor’s speed increases, and when the armature voltage is decreased, the motor’s speed decreases. Therefore, the variation in speed by Ward-Leonard control of DC motors occurs due to variation in the armature voltage. Thus, the correct answer is B: Armature voltage.