🔍 Key Concepts

• How the generator field in a Ward-Leonard system is powered and controlled • Difference between self-excited DC generators and separately excited DC generators • Why Ward-Leonard drives need wide and smooth speed control of the DC motor

💭 Think About

• Look closely at the illustration: does the generator field get its power from the generator’s own output, or from an external DC source? • Which type of DC generator allows the operator to vary the field current independently of the generator’s armature voltage for fine speed control? • Would a permanent magnet or series field give you the same level of smooth, adjustable control shown in the speed/torque graph?

✅ Before You Answer

• Verify whether the generator field winding is shown connected directly across the generator armature (self-excited) or to a separate DC static power supply (separately excited). • Check that the system requires independent adjustment of field current for speed control over the full range shown in the lower graph. • Eliminate any options that would not allow continuous, smooth variation of generator output by changing only the field current.