speed control & braking of dc shunt motor

7/29/2019 Speed Control & Braking of DC Shunt Motor

1/28

Presentation on Speed Controland Braking OF DC Shunt

Motor

ByCH KALYANI

13MPE0072


2/28

Speed control of DC Machine

What is speed control

One of the important features ofdc motor is that its speed can becontrolled with relative ease.


3/28

Speed control of DC Machine

We know that the expression ofspeed control dc motor is givenas,

60a a

a a

V I R ANZ P

V I RK

=

=


4/28

Methods of changing Speed

The speed can be controlled by varying

Terminal voltage of the armature V ,

External resistance in armature circuit R

And flux per pole .


5/28

Control Methods

Flux controlmethod

ArmatureVoltagecontrolMethod


6/28

Field Resistance control Method

In this method , speed variation isaccomplished by means of a variableresistance inserted in series with the shunt

field .

An increase in controlling resistancesreduces the field current with a reduction influx and an increase in speed.

This method of speed control is independentof load on the motor.


7/28

Circuit Diagram


8/28

Simulink Diagram


9/28

Simulation Results

Field Control Method

Armature Voltage 240

SNO Field Current Speed

1 0.96 1924

2 1 1848

3 1.043 1772

4 1.091 1695

5 1.143 1619

6 1.2 1542

7 1.263 1466


10/28

Graph


11/28

Simulation Results


Armature Voltage 220

SNO Field Current Speed

1 0.88 1922

2 0.9167 1846

3 0.9665 1770

4 1 1694

5 1.048 1618

6 1.1 1540

7 1.158 1465


12/28

Graph


13/28

Armature Voltage control

In this method of speed control a variablesource of voltage is provided to supply the

power to the armature circuit. Voltage to the

field circuit should be different from thevariable voltage source provided to thearmature.


14/28

Armature Voltage Control


15/28

Simulation Results


Field Current 1.6

SNO Armature Voltage Speed

1 170 820.6

2 180 868

3 190 917.1

4 200 965

5 210 1014

6 220 1062

7 230 1110


16/28

Speed Vs Armature Voltage

Armature Voltage1 180 200 220 240

0

200

400

600

800

1000

1200

1400

Speed1

Speed1


17/28

Simulation Results


Field Current 1.4

SNO Armature Voltage Speed

1 170 894

2 180 947

3 190 1000

4 200 1053

5 210 1105

6 220 1158

7 230 1211

8 240 1263


18/28

Armature Voltage2 180 200 220 240

0

200

400

600

800

1000

1200

1400

Speed 2

Speed 2


19/28

Braking


20/28

Braking of DC shunt motor

Three methods of Braking

Plugging

Regenerative

Dynamic (or) Rheostatic control


21/28

Rheostatic Braking

In armature or rhoestatic control method ofspeed the voltage across the armature isvaried by inserting a variable rhoestatic orresistance called controller resistance in

series with armature circuit.

As the controller resistance is increased, thepotential difference across the armature is

decreased thereby decreasing the armaturespeed.


22/28

Dynamic (or) Rheostatic BrakingCircuit Diagram


23/28

Dynamic braking


24/28

Simulink Result


25/28

Regenerative Braking Circuit


26/28

Regenerative Braking


27/28

Regenerative Braking


28/28

Thank

You

speed control & braking of dc shunt motor

Documents