Ward Leonard Control System:
This system is used where very sensitive speed control of motor is required (eg electric excavators, elevators etc.) The arrangement of this system is as required in the figure below .
M₂ is the motor whose speed control is required. M₁ may be any motor AC or DC motor with constant speed. G is the generator directly coupled to M₁
♣️ In this method the output from the generator G is fed to the armature of the motor. M₂ whose speed is to be controlled.
♣️The output voltage of the generator G can be varied from zero to its maximum value, and hence the armature voltage of the motor M₂ is varied very smoothly.
♣️Hence very smooth speed control of motor can be obtained by this method
Advantages:
♣️Full forward and reverse speed can be achieved.
♣️A wide range of speed control is possible
♣️Short time overload capacity is large
♣️The armature current of the motor is smooth.
Disadvantages:
♣️High initial cost
♣️The overall efficiency is low, less than 80%
♣️Costly foundation and a large amount of space is required
♣️The drive produces noise
♣️It requires frequent maintenance.