What are the factors that affect the speed of a DC motor explain how the speed can be controlled above and below base speed?

Thus, the speed of a DC motor can control in three ways: By varying the flux, and by varying the current through field winding. By varying the armature voltage, and the armature resistance. Through the supply voltage.

What is the effect in a DC shunt motor?

When both (the direction of the field as well as that of armature current) are reversed the direction of rotation will not change. So in the case of DC shunt motor, if the supply terminals are interchanged, there is no change in the direction of rotation.

What are the factors on which the speed of a motor depends?

The electric motor speed depends on both the applied voltage and the number of turns of its coil. The more turns the motor has the higher the strength of the rotor magnetic field if the current is maintained constant.

How do you increase the speed of a DC motor?

Thus, the speed of a DC motor can be controlled in three ways:

1. By varying the supply voltage.
2. By varying the flux, and by varying the current through the field winding.
3. By varying the armature voltage, and by varying the armature resistance.

What is speed control of 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.

Why DC motor has higher speed than shunt motor?

In a shunt wound DC motor, the armature (rotor) and field (stator) windings are connected in parallel. The net voltage increase causes the armature current to increase, which increases the motor torque. This additional motor torque increases speed enough to compensate for the slowdown that occurred due to loading.

What will happen to the speed of DC shunt motor when the flux is increased?

In case of DC shunt motor, the flux per pole is considered to be constant, torque increases with the increase of load current. If the load current increases then the armature current also be increased and the speed slightly falls due to increase in voltage drop in armature.

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

In the shunt motor, speed can be controlled by connecting a variable resistor Rc in series with the shunt field winding. In the diagram below resistor, Rc is called the shunt field regulator. Figure: (a) Speed control of a D.C. shunt motor by variation of field flux.

How can the speed of a shunt dc motor be controlled explain in detail?

The speed of a DC motor (N) is equal to: Therefore speed of the 3 types of DC motors – shunt, series and compound – can be controlled by changing the quantities on the right-hand side of the equation above. Hence the speed can be varied by changing: The terminal voltage of the armature, V.

How to control the speed of DC shunt motor by armature voltage control?

The set up for speed control of DC shunt motor by armature voltage control method is shown in the figure. A rheostat is connected in series with armature winding. By varying the value of R we can vary the voltage across the armature. We can use this technique to control motor speed below its rated value.

What are the disadvantages of field rheostat controlled DC shunt motor?

Disadvantages of Field Rheostat Controlled DC Shunt Motor 1 Creeping speeds cannot be obtained. 2 Top speeds only obtained at reduced torque. 3 The speed is maximum at minimum value of flux, which is governed by the demagnetizing effect of armature reaction on the… More

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

Thus the factors affecting the speed of a d.c. motor are, 1. The flux Φ 2. The voltage across the armature 3. The applied voltage V depending upon these factors the various methods of speed control are, 1. Changing the flux Φ by controlling the current through the field winding called flux control methods. 2.

How to adjust the speed of DC series motor by field control?

Speed adjustment of a DC series motor by field control may be done by: This method uses a diverter. Here the field flux can be reduced by shunting a portion of motor current around the series field. Lesser the diverter resistance less is the field current, less flux therefore more speed.