Why field flux is constant in DC shunt motor?
The voltage across both windings remains the same. Thus we put this value of armature current Ia to get general voltage equation of a DC shunt motor. Thus the field flux remains more or less constant, and for this reason, a shunt wound DC motor is called a constant flux motor.
Why DC shunt motor is called constant flux or constant speed motor?
Since torque is proportional to armature current, torque also increases. Finally, this increased torque allows the motor to increase its speed and compensate for the slowdown due to loading. Hence, a DC shunt motor is able to self-regulate its speed, and can be referred to as a constant speed motor.
What is the effect of constant flux in operating of DC shunt motor?
Since in case of a dc shunt motor the flux per pole φ is considered to be constant, therefore, torque increases with the increase in load current following linear law, i.e., torque-armature current characteristic is a straight line passing through origin O (Fig. 1.15).
Why the shunt field winding have more resistance than the series field winding?
Hence as the current through series field winding is high, in order to keep voltage drop across it to a small value, its resistance is very low. On the other hand, the shunt field winding is directly connected across the rated supply voltage hence to limit current through it, resistance is very high.
Which is the constant speed motor?
A DC motor can be referred to as a constant speed motor because it can self- regulate its speed.
What will be the effect of armature reaction in performance of DC shunt motor?
Armature reaction weakens the main flux. In case of a dc generator, weakening of the main flux reduces the generated voltage. Armature reaction distorts the main flux, hence the position of M.N.A. gets shifted (M.N.A. is perpendicular to the flux lines of main field flux).
What will happen if shunt field resistance is too large?
Answer: n d.c shunt motor if field winding supply is removed the motor back emf will drop to zero, hence the armature will draw more current to make up the emf. this results in blowing up of fuse.
Which winding has large number of turns shunt or series?
1. Which winding has large number of turns? Explanation: The shunt field winding is provided with a large number (hundreds or even thousands) of turns of thin wire and is excited from a voltage source.
What are the advantages of DC shunt motor?
Advantages of Dc shunt motor:
- The power supply of the DC motor is any way cheap.
- Shunt would motor able to runs at a predetermined speed.
- The speed of a dc shunt motor is sufficiently constant.
- Direct current machines can use for heavy industrial applications where the torque and speed wider range.