Direct-Current-Compound
EEE
DC compound machine efficiently combines the characteristics of series and shunt DC machines for improved performance under varying load conditions.
Key Points:
Field Windings:
Shunt Winding: Connected in parallel with the armature; provides nearly constant magnetic flux.
Series Winding: Connected in series with the load; flux varies with load current.
Purpose of Compounding:
Combines the benefits of shunt (stable voltage) and series (high starting torque) machines.
Helps maintain nearly constant voltage under varying loads in generators.
Provides better torque characteristics in motors.
Types of DC Compound Machines:
Short Shunt Compound: Shunt winding connected only across the armature.
Long Shunt Compound: Shunt winding connected across both the armature and series winding.
Cumulative Compound: Series and shunt flux aid each other; voltage rises slightly with load.
Differential Compound: Series flux opposes shunt flux; voltage drops with load.
Applications:
DC Compound Generators: Power supply where load varies, e.g., workshops, elevators.
DC Compound Motors: Machines requiring high starting torque and stable speed, e.g., cranes, presses.