Working Principle of DC Motor (animation of elementary model)
Summary
TLDRThe script explains the working principle of a DC motor, highlighting its simplicity. It describes the basic construction, including the armature, commutator, and brushes, and the interaction with a magnetic field. The video uses Fleming's left-hand rule to demonstrate how current-carrying conductors experience mechanical force, leading to rotation. It illustrates the process with a model and concludes by emphasizing the continuous rotation due to the changing positions of conductors and the magnetic field's interaction.
Takeaways
- 🔵 The working principle of a DC motor is based on the force experienced by a current-carrying conductor when placed in a magnetic field.
- 🔧 A basic DC motor consists of an armature, which is a current-carrying coil connected to a supply via a commutator and brushes, placed between the North and South poles of a magnet.
- 🔌 In a simple model, a single turn of a conductor is placed between two opposite poles, and when DC is supplied, the conductors experience a force due to the magnetic field.
- ➡️ Fleming's left-hand rule is used to determine the direction of the mechanical force acting on the conductors within the magnetic field.
- 🔃 The rotation of the armature produces a torque, causing the motor to rotate in a clockwise direction.
- 🔄 The commutator and brushes play a crucial role in reversing the current direction as the armature rotates, ensuring continuous rotation.
- 🔩 The motor's rotation continues due to inertia even when the current is momentarily interrupted as the brushes pass between commutator segments.
- 🔁 The process of current reversal and force application repeats as the armature continues to rotate, maintaining the motor's motion.
- 🏗️ In a more complex DC motor, multiple turns of wire are wound on a coil, and there are multiple poles instead of just two, enhancing the motor's efficiency and power.
- 📚 Understanding the working principle of a DC motor involves recognizing the interaction between electric current, magnetic fields, and mechanical motion.
Q & A
What is the basic principle behind the working of a DC motor?
-The basic principle behind the working of a DC motor is that when a current-carrying conductor is placed in a magnetic field, it experiences a mechanical force. This force can be determined using Fleming's left-hand rule.
What are the main components of a DC motor?
-The main components of a DC motor include a current-carrying armature, a commutator with segments, brushes, and a permanent or electromagnet with North and South poles.
How does the commutator play a role in the functioning of a DC motor?
-The commutator in a DC motor helps to periodically reverse the direction of current in the armature coils as the motor rotates. This ensures that the force on the armature is always in the same direction, causing continuous rotation.
What is Fleming's left-hand rule and how is it used in a DC motor?
-Fleming's left-hand rule is used to determine the direction of the force acting on a current-carrying conductor in a magnetic field. In a DC motor, it is applied to find the direction of mechanical force on the armature conductors, which helps in understanding the motor's rotation.
Why does the current direction in the armature change as the motor rotates?
-The current direction in the armature changes due to the action of the commutator as the motor rotates. This change ensures that the mechanical force on the armature continues to act in the same direction, allowing the motor to maintain its rotation.
What happens when the armature reaches a vertical position with respect to the magnetic field?
-When the armature reaches a vertical position with respect to the magnetic field, the conductors are aligned such that they are between the commutator segments, resulting in no current flow and thus no force acting on the conductors.
How does the motor continue to rotate after passing the vertical position?
-Due to the moment of inertia, the motor continues to rotate past the vertical position. As the armature moves into a horizontal position again, the commutator and brushes reestablish current flow in the conductors, which now experience force due to their new positions in the magnetic field.
What is the purpose of having multiple turns in the armature of a DC motor?
-Having multiple turns in the armature of a DC motor increases the total force and torque produced, which enhances the motor's ability to perform mechanical work.
How does the number of poles in a DC motor affect its performance?
-The number of poles in a DC motor influences the motor's speed and torque characteristics. More poles generally result in smoother and slower rotation, while fewer poles can lead to faster but potentially less smooth operation.
What is the role of brushes in a DC motor?
-Brushes in a DC motor make contact with the commutator segments to supply current to the armature coils. They play a crucial role in transferring electrical energy to the motor's rotating components.
Outlines
🔋 Understanding the Working Principle of a DC Motor
The paragraph explains the fundamental working principle of a DC motor. It begins with the basic concept that a current-carrying conductor experiences a force when placed in a magnetic field. The construction of a DC motor is described, highlighting the armature, commutator segments, and brushes. An elementary model is used to illustrate how a single turn of the conductor, when supplied with DC current, experiences mechanical force due to the magnetic field, causing rotation. Fleming's left-hand rule is introduced to determine the direction of this force. The paragraph also describes how the commutator switches the current flow as the armature rotates, ensuring continuous rotation in one direction. The explanation concludes with a demonstration of how the motor's rotation is sustained even when the conductor's position changes relative to the magnetic field.
🔄 Advanced DC Motor Construction and Operation
This paragraph extends the discussion to more complex DC motors, moving beyond the single-turn elementary model. It mentions that actual DC motors have multiple turns on a major coil and multiple poles instead of just two. The paragraph suggests that the same principles of force and rotation apply, but on a larger scale with more intricate construction. The video script ends with a call to action for viewers to subscribe, like, and comment, indicating that the content is intended to be educational and engaging.
Mindmap
Keywords
💡DC Motor
💡Armature
💡Commutator
💡Magnetic Field
💡Fleming's Left Hand Rule
💡Torque
💡Inertia
💡Conductor
💡Poles
💡Rotation
💡Electrical Supply
Highlights
The working principle of a DC motor is based on the force experienced by a current-carrying conductor in a magnetic field.
A basic DC motor consists of an armature, commutator segments, and brushes, placed between the poles of a magnet.
In a simple model, a single turn of a conductor is placed between two opposite poles of a magnet.
The direction of mechanical force on the conductors can be determined using Fleming's left-hand rule.
When current flows through the conductors, they experience a mechanical force due to the magnetic field.
The forces on the conductors produce a torque that causes the armature to rotate.
The commutator and brushes ensure that the current direction changes as the armature rotates, maintaining the torque.
The rotation continues due to inertia when the conductors are momentarily not under the influence of the magnetic field.
As the armature rotates, the position of the conductors changes, altering the direction of the force acting on them.
Fleming's left-hand rule is applied again to determine the new direction of the mechanical force as the armature continues to rotate.
The continuous rotation of the armature is due to the alternating forces acting on the conductors near the poles.
In a real DC motor, multiple turns of wire are wound on the armature, and there are multiple poles.
The principle of rotation in a DC motor is the same as in the elementary model, but with more complexity.
The video explains the continuous rotation of a DC motor through the interaction of magnetic fields and electric current.
The video concludes by summarizing the key points and encourages viewers to subscribe, like, and comment.
Transcripts
working principle of DC motor working
principle of DC motor is very simple we
can see that when the current conductor
is placed in magnetic field it
experience some force in particularly
direction the very basic construction of
a DC motor contains a current carrying
armature which is connected to the
supply and through commutator segments
and brushes the armature is placed
between North and South Pole of a
permanent or an electromagnet in
elementary model one single turn of
conductor is placed between two opposite
poles if we start to supply DC via
commutator system current will start to
flow as we see positive terminal of a
battery is connected to left conductor
of a turn and negative terminal is
connected to right conductor of a turn
as we see in model North Pole of the
magnet is placed near left side and
South Pole is placed near right side of
the turn current and left-side flows
inward and current and right side flows
outward
as we see conductor is carrying current
and they placed in magnetic field both
of them experienced a mechanical force
acted on them direction of mechanical
force can be easily determined by
applying Fleming's left hand rule to do
this spread out your left thumb
forefinger and second finger so they are
all at 90 degrees to one another
[Music]
with that if the forefinger is a line a
long direction of magnetic field from
North Pole to the South Pole and second
finger is a line a long direction of the
current and left-side conductor then
thumb indicates direction of mechanical
force similarly if the forefinger is a
line a long direction of magnetic field
from North Pole to the South Pole and
second finger is a line a long direction
of the current and right-side conductor
then thumb indicates direction of
mechanical force due to this upward and
downward force is on the turn one torque
is produced when turn rotates on
clockwise direction as shown
[Music]
after rotation of the turn turn comes to
vertical position in respect of the
magnetic field at this position there is
no current in conductor because turn
conductor and brushes rest between two
calm mutators
[Music]
hence there is no force acting on
conductor by due to moment of inertia
turn continue to rotate and comes
horizontal again position of conductor
has been changed here that means
conductor which was previously in left
position comes to right position and
which was previously in right position
comes to left position at that position
we can determine mechanical force with
applying Fleming's left hand rule let's
do that to do this spread out your left
thumb forefinger and second finger so
they are all at 90 degrees to one to
another so if forefinger is a line in
direction of magnetic field that is from
North Pole to South Pole and second
fingers aligned in direction of a
current in the left-side conductor then
thumb indicates direction of mechanical
force this is clearly upward here
so if forefinger is a line in direction
of magnetic field that is from North
Pole to South Pole and second fingers
aligned in direction of the current in
the right-side conductor then fome
indicates direction of mechanical force
this is clearly downward here do this
upward and downward forces turn tends to
rotate in clockwise direction from that
explanation we can come to conclusion
that here in this model we can see that
whichever conductor comes near South
Pole experience upward mechanical force
and near north pole downward mechanical
force and do this continuously forces
mechanical turn rotate even if battery
is not connected particularly DC motor
rotates had the same principle like this
elementary model instead of single turn
and DC motor we have mountain turns on
major coil and instead of two poles
there is number of pole
installed I hope that you liked it
please subscribe like and leave comment
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