Page 336 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

• Ease of Operation: The operation of the induction motor is very simple because there is no electrical connector
to the rotor that supply power and current are induced by the movement of the transformer performs on the
rotor due to the low resistance of the rotating coils. Induction motors are self-start motors. This can result in
reducing the effort needed for maintenance.

• Speed Variation: The speed variation of the induction motor is nearly constant. The speed typically varies
only by a few percent going from no load to rated load.
• High Starting Torque: The starting torque of the induction motor is very high which makes the motor useful
for operations where the load is applied before the starting of the motor. 3 phase induction motors will have
self-starting torque, unlike synchronous motors. However, single-phase induction motors do not have self-
starting torque and are made to rotate using some auxiliaries.
• Durability: Another major advantage of an induction motor is that it is durable. This makes it the ideal machine
for many uses. This results in the motor running for many years with no cost and maintenance.
All these advantages make induction motor to use in many applications such as industrial, domestic, and in many
applications.

Disadvantages

The disadvantages of induction motor include the following.
• Throughout the light load situation, the power factor is extremely less and it draws a huge current. So, the
copper loss can be high which decreases the efficiency throughout the light load situation.

• The squirrel cage induction motor’s initial torque is not low.
• This is an invariable speed motor and this motor is not applicable where uneven speed needs
• This motor speed control is not easy
• This motor includes a high starting inrush current which will cause a reduction within voltage at the beginning
of time.

Applications

The applications of types of induction motor include the following.
• Lifts
• Cranes
• Hoists

• Large capacity exhaust fans
• Driving lathe machines
• Crushers
• Oil extracting mills

• Textile and etc.
DC Motor

A DC motor is an electric motor that runs on direct current power. In an electric motor, the operation is dependent
upon simple electromagnetism. A current-carrying conductor generates a magnetic field, when this is then placed
in an external magnetic field, it will encounter a force proportional to the current in the conductor and to the
strength of the external magnetic field. It is a device that converts electrical energy to mechanical energy. It works
on the fact that a current-carrying conductor placed in a magnetic field experiences a force that causes it to rotate
with respect to its original position. Practical DC Motor consists of field windings to provide the magnetic flux and
armature which acts as the conductor.

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CITS : E & H - Electronics Mechanic - Lesson 205 - 222