Time: 20:00
Important one liner Torque development of dc motor
- Torque in a DC motor is the rotational force produced by the interaction of armature current and magnetic flux.
- The fundamental torque equation is T = k φ I_a, where k is a construction constant.
- Armature current directly influences the magnitude of developed torque.
- Flux per pole is controlled by the field winding excitation.
- Starting torque can be enhanced by increasing armature current via reduced resistance.
- Diverter resistance in series with field winding boosts starting torque.
- Compensating windings counteract armature reaction to maintain torque under load.
- Interpoles are used to reduce commutation sparking and torque pulsations.
- Series DC motors provide high starting torque but variable speed under load.
- Shunt DC motors deliver more constant speed with moderate starting torque.
- Compound motors combine series and shunt for balanced torque characteristics.
- Back EMF opposes supply voltage and limits armature current with speed increase.
- Reducing armature voltage lowers speed but retains proportional torque characteristics.
- Diverter resistance control allows fine torque adjustment at startup.
- Ward-Leonard drive system offers precise torque and speed control for industrial DC motors.
- Torque ripple caused by armature reaction and commutation irregularities can be minimized by skewing.
- Cogging torque due to slotting effects is reduced by rotor skewing design.
- Excessive armature reaction can distort field flux and decrease torque output.
- Regenerative braking reverses torque to feed energy back to power supply.
- Torque-speed curve of a DC motor is linear under constant flux conditions.
- Practical torque-speed characteristic falls at higher speeds due to losses.
- Friction and windage losses reduce net available torque.
- Brush shift alters neutral plane to improve commutation and torque stability.
- Optimal brush timing reduces sparking and enhances torque production efficiency.
- Temperature rise in windings can affect resistance and torque output stability.
Keywords: Torque development of DC motor, DC motor torque equation, starting torque DC motor, armature reaction, compensating windings, interpoles, diverter resistance, torque-speed characteristic, Ward-Leonard drive, DC motor commutation