The document describes a DC shunt motor. A DC shunt motor has a shunt field winding with many turns of thin wire connected in parallel with the armature. This keeps the flux produced by the field winding constant, resulting in a constant speed characteristic for the DC shunt motor. The motor torque is directly proportional to the armature current. Common applications of DC shunt motors include fans, pumps, lathe machines and other machine tools due to their constant speed performance.

1. DC SHUNT MOTOR
BY,
R.Prabhu
132912
4/7/2015 Prabhu Mike 1

2. DC SHUNT MOTOR
4/7/2015 Prabhu Mike 2

3. DC Motors
• Construction very similar to a DC generator
• The dc machine can operate both as a generator and a motor.
• When the dc machine operates as a motor, the input to the
machine is electrical power and the output is mechanical power.
• In fact, the dc machine is used more as a motor.
• DC motors can provide a wide range of accurate speed and torque
control.
• Principle of operation – when a current-carrying conductor is placed
in magnetic field, it experiences a mechanical force., F = Bli
Eg. Gas turbine,
diesel engine,
electrical motor
4/7/2015 Prabhu Mike 3

4. DC Motors
• • Separately Excited Motors
• Field and armature windings are either connected
separately.
• Self Excited Motors
• Shunt Motors
• Field and armature windings are connected in
parallel.
• • Series Motors
• Field and armature windings are connected in series.
• • Compound Motors
• Has both shunt and series field so it combines
features of series and shunt motors.
4/7/2015 Prabhu Mike 4

5. Shunt Excited DC Machine
Shunt motor
Armature
RA
Shunt Field Coil
4/7/2015 Prabhu Mike 5

6. DC SHUNT MOTOR
-> In the DC shunt motor, the shunt field winding has
more number of turns with less cross-sectional
area.Rsh is the field winding resistance.
-> Ra is the armature resistance. The value of
armature resistance is very small
-> The input voltage V is equal to the voltage across
the armature and field winding.
-> IL is the line current drawn from the supply. The
line
Current is divided into two paths, one through the
field winding and other through the armature.
4/7/2015 Prabhu Mike 6

7. IL = Ia + Ish
where,
Ia = Armature current
Ish = Shunt field current
Ish = V / Rsh
In shunt motor, flux produced by field winding is
proportional to the field current Ish.
i.e., φ α Ish.
Since the input voltage is constant , the flux is also
constant. Therefore, DC shunt motor is called a constant
speed motor
4/7/2015 Prabhu Mike 7

8. CHARACTERISTICS OF DC SHUNT MOTOR
Since Ish and φ are nearly costant, It is the mechanical characteristics of
N=K(V – IaRa) where K is a constant. Shunt motor
4/7/2015 Prabhu Mike 8

9. It also called the
electrical characteristics.
The DC shunt motor
torque is directly
proportional to flux and
armature current.
T α φ Ia
Φ is constant,
T α Ia
4/7/2015 Prabhu Mike 9

10. Applications:
•Blowers and fans
•Centrifugal and reciprocating pumps
•Lathe machines
•Machine tools
•Milling machines
•Drilling machines
4/7/2015 Prabhu Mike 10

11. THANK YOU
4/7/2015 Prabhu Mike 11