**What is DC Shunt Motor?**

**DC shunt Motors**are also self-excited DC Motor. In an electric circuit, if two components are connected in parallel then it is called a shunt. Similar to this, In shunt, the DC Motor field winding is connected in parallel to the armature winding.

Since field winding and armature windings are connected in parallel then applied voltage is the same for both armature and field winding. The

**connection of Shunt Motors**are shown below

DC Shunt Motor |

###
**DC Shunt Motor Equation (Relation Between Back EMF and Armature Current)**

To study the relation between Back Emf and Armature le consider the simplified circuit diagram given below.

from above-given Circuit diagram

Circuit Diagram For DC Shunt Motor |

**V**=is supply voltage

**I**= Current flowing towards the Motor

**called input current**

**E**

_{b }= is Induced EMF in armature called Back EMF

**I**

_{a}**=is armature Current**

**I**= is field Current called Shunt Current.

_{sh }**R**

_{sh }=is net effective resistance of field winding

**called shunt resistance**

From the above-given Circuit diagram, on applying KCL at node A

then we will find that

**I=I**

_{a}+I_{sh }

for field winding

**V=I**

_{sh}R_{sh}

**V=E**

_{b+}I_{a}R_{a}

###
**Power Equation for DC Shunt Motor**

Power Input to the machine = Mechanical Power Developed +
Loss(Armature loss+ Field Winding Loss)

V=E

_{b+}I_{a}R_{a}---------(1)
On
multiplying By input Current (I) in equation (1)

Then

**VI=E**

_{b}I+I^{2}_{a}R_{a}**+ I**

_{sh}^{2}R_{sh}

**E**

_{b}I= VI - I^{2}_{a}R_{a}**+I**

_{sh}^{2}R_{sh}

Developed
Mechanical Power = Input Power – Power Loss

Developed
Mechanical Power =

**VI – VI**_{sh}–Ia^{2}Ra
Developed
Mechanical Power =

**VI - I**^{2}_{a}R_{a }- I_{sh}^{2}R_{sh}**I**= is armature Loss

^{2}_{a}R_{a}**I**=is field winding loss

_{sh}^{2}R_{sh}###
**Torque Equation of DC Shunt Motor**

Let
Developed Torque is T in N-m and Rotor angular Speed is ω radian per
second

Developed
Mechanical Power = T ω

E

_{b}I_{a}= T ω
T=
E

_{b}I_{a}/ ω
E

_{b }= NPZΦ/60A
After putting the Value E

_{b }of the in above equation, we will get
T = NPZΦI

_{a}/60A ω
As
we know that ω= 2 πN/60

T=
PZΦI

_{a}/A 2 π ---------- (2)
From
above equation (2)

P= No of
Pole,

Z=No of Conductor Coil

Φ = is
Flux per

A= No of Parallel Path

A= No of Parallel Path

I

_{a}= is Armature Current
Out
of these all parameter Z, P, and A are constant for given dimension and rating of
DC Shunt Motor

Hence
after arranging the above equation it may be like this

T
= (PZ/2πA)ΦI

_{a}
If
we will remove PZ/2πA

by a new constant K(say)

Then

T
=
ΦI

_{a}-------(3)
From
equation (3)it is clear that the

**Torque of DC Shunt Motor**is Depend on Magnetic Flux and Armature Current.
And
also, We know that Flux (Φ) also Depend On the Shunt Branch Current

Φ ∝

**I**_{sh}

_{}
if The Supply terminal Voltage is kept Constant then the Current in the Field Winding (

**I**) will_{sh}**Constant then****Φ = Constant**

and then Developed Torque will be the Function of only Armature Current

i.e

T∝ I

_{a}### Characteristics of DC Shunt Motors

The relation between two different quantities is represented by a graph and this graphical representation is called the Characteristics and the relation is called the characteristics equation. The variation of independent quantity and its effect on the dependent quantity is shown on the graph.

**Torgue-Speed**and

**Speed-Armature**characteristics of

**DC shunt**Motors are Similar to Separately excited DC motor and you can look it by clicking here.

###
**Application of DC Shunt Motor**

- Lathe Machines
- Centrifugal Pumps
- Fans, Blowers
- Conveyors, Lifts
- Weaving Machine
- Spinning machines

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