What will be the effect of opening of field of a DC shunt motor while motor is running?

What will be the effect of opening of field of a DC shunt motor while motor is running? Explanation: In a DC shunt motor if supply for the field winding is cut down, the speed would dangerously increase in order to maintain the back emf of the motor.

What can happen to a DC shunt motor if the shunt field should open?

In shunt motor if field gets open circuit then back emf will get zero as e=kΦw. Current in armature circuit is directly propotional to voltage so the armature winding will burn . This happens when motor is loaded.

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What will happen if the shunt field winding opened accidentally during the experiment?

Ans: if the shunt field winding of a loaded shunt motor accidentally breaks, the loss of shunt field current would result in stopping of the motor or burn out the armature or fuse.

What will happen if field winding terminal will be open circuited?

“The fact that full field or armature voltage might exist across an open circuited field winding means very little as no current can / will flow through it.” … Hence, now E is forced to the system, and as long as the voltage terminal is on, E is going to be Vt-RaIa.

What will happen when the load on a DC shunt motor is decreased?

As the load increases, to maintain the voltage at a constant value, current decreases, due to which the strength of magnetic field produced by the Internal Winding of DC motor decreases. … When the field current is decreased, the field flux is reduced, and the counter emf decreases. This permits more armature current.

Why is it dangerous to lose the field of a shunt motor?

Now cutting off the field winding is dangerous for shunt dc motor. As for shunt motor, speed is inversely proportional to field current, so cutting off the field winding results in dangerously high speed. Thus motor gets damaged.

What would happen if the field of DC shunt motor is opened * 1 point?

What will be the effect of opening of field of a DC shunt motor while motor is running? Explanation: In a DC shunt motor if supply for the field winding is cut down, the speed would dangerously increase in order to maintain the back emf of the motor.

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What happened to the DC motor if it run without any starter explain in details?

What will happen if DC motor is used without starter? Explanation: It would cause intolerably heavy sparking at the brushes which may destroy the commutator and brush-gear. Sudden development of large torque will cause mechanical shock to the shaft, reducing its life.

Which motor has the poorest speed control?

Which of the following DC motor has the poorest speed control? Explanation: DC series motor at no load condition gives infinite speed ideally. Practically it will damage all the armature circuit.

Which DC motor has maximum self loading property?

Which DC motor has got maximum self-loading property? Explanation: A differentially compound DC motor, flux reduces so sharply at small increase in load at higher values of load.

What will happen if field winding is disconnected accidentally from rotating DC shunt motor?

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. In dc series motor the motor will go to infinite speed (theoretically) as flux is inversely proportional to the speed…

Why starter is used in DC shunt motor?

Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor’s armature winding and restricts the current to an acceptable level.

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Why is field winding resistance high?

Why? The series filed winding is always connected in series with the armature and thus has to carry the armature current which directly gets decided by the load. … 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.

Why DC shunt motor is constant speed?

If the load on the motor increases armature speed reduces and thereby cause a reduction in the back emf. … Hence, a DC shunt motor always maintains a constant speed. Under no load condition, the back emf becomes nearly equal to the applied voltage.

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.

What is the principle of DC shunt motor?

Construction and Working Principle

The working principle of a DC Shunt Motor is, whenever a DC motor is turned ON, then DC flows throughout stator as well as the rotor. This current flow will generate two fields namely pole as well as the armature.

Motorization