Ampere's Circuital Law
Mechanical Equivalent of Heat
Trees and Cotrees
PSD or CSDClosely Related Articles
Types of DC Motor
DC Shunt Motor
DC Series Motor
DC Compound Motor
Brushless DC Motors
Working of Motor
Speed Regulation of DC Motor
Speed Control of DC Motor
DC Motor Working
Torque in DC Motor
Construction of DC Motor
Testing of DC Machine
Swinburne Test of DC Machine
Losses in DC Machine
Ward Leonard Method
Armature Reaction in DC Machine
Commutation in DC Machine
Methods of Improving Commutation
Starting Methods for DC Motor
3 Point Starter
4 Point Starter
Compound Wound DC Motor or DC Compound Motor
So the compound wound DC motor reaches a compromise in terms of both this features and has a good combination of proper speed regulation and high starting toque. Though its staring torque is not as high as in case of DC motor, nor is its speed regulation as good as a shunt DC motor. Overall characteristics of DC shunt motor falls somewhere in between these 2 extreme limits.
Types of Compound Wound DC MotorThe compound wound DC motor can further be subdivided into 2 major types on the basis of its field winding connection with respect to the armature winding, and they are:
Long Shunt Compound Wound DC MotorIn case of long shunt compound wound DC motor, the shunt field winding is connected in parallel across the series combination of both the armature and series field coil, as shown in the diagram below.
Voltage and Current Equation of Long Shunt Compound Wound DC MotorLet E and Itotal be the total supply voltage and current supplied to the input terminals of the motor. And Ia, Ise , Ish be the values of current flowing through armature resistance Ra, series winding resistance Rse and shunt winding resistance Rsh respectively. Now we know in shunt motor, And in series motor
Therefore, the current equation of a compound wound DC motor is given by And its voltage equation is,
Short Shunt Compound Wound DC MotorIn case of short shunt compound wound DC motor, the shunt field winding is connected in parallel across the armature winding only. And series field coil is exposed to the entire supply current, before being split up into armature and shunt field current as shown in the diagram below.
Voltage and Current Equation of Short Shunt Compound Wound DC MotorHere also let, E and Itotal be the total supply voltage and current supplied to the input terminals of the motor. And Ia, Ise, Ish be the values of current flowing through armature resistance Ra, series winding resistance Rse and shunt winding resistance Rsh respectively. But from the diagram above we can see, Since the entire supply current flows through the series field winding. And like in the case of a DC shunt motor, Equation (2) and (3) gives the current equation of a short shunt compound wound DC motor. Now for equating the voltage equation, we apply Kirchoff’s law to the circuit and get, But since Thus the final voltage equation can be written as, Apart from the above mentioned classification, a compound wound DC motor can further be sub divided into 2 types depending upon excitation or the nature of compounding. i.e.
Cumulative Compounding of DC MotorA compound wound DC motor is said to be cumulatively compounded when the shunt field flux produced by the shunt winding assists or enhances the effect of main field flux, produced by the series winding.
Differential Compounding of DC MotorSimilarly a compound wound DC motor is said to be deferentially compounded when the flux due to the shunt field winding diminishes the effect of the main series winding. This particular trait is not really desirable, and hence does not find much of a practical application. The net flux produced in this case is lesser than the original flux and hence does not find much of a practical application. The compounding characteristic of the self excited DC motor is shown in the figure below.
Closely Related Articles Types of DC Motor Separately Excited Shunt Series Compound DC MotorShunt Wound DC Motor | DC Shunt MotorSeries Wound DC Motor or DC Series MotorPermanent Magnet DC Motor or PMDC Motor | Working Principle ConstructionBrushless DC MotorsMore Related Articles Electrical Motor | Types Classification and History of MotorWorking of Electric MotorDC Motor or Direct Current MotorSpeed Regulation of DC MotorSpeed Control of DC MotorWorking or Operating Principle of DC MotorTorque Equation of DC MotorConstruction of DC Motor | Yoke Poles Armature Field Winding Commutator Brushes of DC MotorTesting of DC MachineSwinburne Test of DC MachineLosses in DC MachineWard Leonard Method of Speed ControlArmature Reaction in DC MachineCommutation in DC Machine or Commutation in DC Generator or MotorMethods of Improving CommutationStarting Methods to limit Starting Current and Torque of DC Motor3 Point Starter | Working Principle and Construction of Three Point Starter4 Point Starter | Working Principle and Construction of Four Point StarterNew Articles Ampere's Circuital LawMechanical Equivalent of HeatTrees and Cotrees of Electric NetworkDifferentiatorIntegratorPhase Synchronizing Device or Controlled Switching Device