Which of the following is true regarding speed of DC shunt motor when load is increased?

Explanation: As the load is increased, speed of the DC motor will reduce slightly, the change is so negligible that in many cases it is assumed that speed of the DC motor remains constant. Hence, characteristic is also called as shunt characteristic.

How the speed of the DC shunt motor can be increased?

How speed of the DC shunt motor can be increased? … Decreasing armature current will help in increasing speed for DC shunt motor. Since load current is addition of armature current and field current we’ll get less armature current for more field current.

Why the speed of a DC shunt motor decreases as the load increases?

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. This results in a decreased interaction of the two magnetic fields and thus Decrease in Speed of motor is observed.

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Does the speed of a shunt motor increase or decrease when the armature current increases?

When the armature voltage and current are both increased, the motor speeds up. In a shunt motor, speed is usually controlled by a rheostat connected in series with the field windings, as shown in figure 2-8. When the resistance of the rheostat is increased, the current through the field winding is decreased.

When the speed of a DC shunt motor increases its armature current?

Complete answer:

From the equation. (3) we can say, speed is inversely proportional to armature current. Thus, when the speed of the dc motor is increased, the armature current will decrease.

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.

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 are the factors affecting the speed of a DC shunt motor?

The above equation shows that the speed depends upon the supply voltage V, the armature circuit resistance Ra, and the field flux Ф, which is produced by the field current. In practice, the variation of these three factors is used for speed control.

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When load is removed which motor will run at highest speed?

1 Answer. When load is removed, series motor will run at the highest speed.

How do you control the speed of a DC shunt motor?

The speed of DC shunt motor can be varied by varying the field current. As we increase the resistance R of the rheostat, the field current Ish decreases. So the flux φ decreases. This results in increasing the speed of the motor.

How does current affect motor speed?

The current through the motor times the resistance of the motor creates a small voltage that must be subtracted from the applied voltage. As the load and current increase, this IR drop also increases causing the motor to lose a little speed.

Why DC shunt motor is started on no load?

For DC shunt motor the field resistance is high and armature resistance is low so the variation of flux is very less when rated voltage is applied to the motor and motor speed does not exceeds rated speed at no load. So we can start the DC shunt motor with no load.

How do you increase the speed of a shunt motor?

Adding more resistance in series with the field winding will increase the speed as it decreases the flux. In shunt motors, as field current is relatively very small, Ish2R loss is small. Therefore, this method is quite efficient.

What the speed of DC motor is increased?

The speed of a dc motor is changed by changing the current in the field or by changing the current in the armature. When the field current is decreased, the field flux is reduced, and the counter emf decreases. This permits more armature current. Therefore, the motor speeds up.

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Why does current increase when DC motor is increased?

Why does armature current increase when load on the DC motor increase? When the load increases the motor slows down. This reduces the counter EMF. This allows a higher current to flow.

What is the speed of dc motor?

DC controls adjust speed by varying the voltage sent to the motor (this differs from AC motor controls which adjust the line frequency to the motor). Typical no load or synchronous speeds for an AC fractional horsepower motor are 1800 or 3600 rpm, and 1000-5000 rpm for DC fractional hp motors.