Page 125 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

Servo motor
A servo motor is a rotory actuator that allows for precise control of angular position. It consists of a motor coupled
to a sensor for position feedback. It also requires a servo drive to complete the system. The drive uses the
feedback sensor to precisely control the rotory position of the motor. Servo motors are mainly used on angular or
linear position and for specific velocity and acceleration.

Working of servo motor
A servo motor has a system called closed loop control. This system includes a comparator and a feedback path
its like a setup that constantly check and adjusts the motor to keep it in the right place. The comparator is an
important part of the servo motor. It carefully checks where the motor is right now and compares it to where
its supposed to be. If there is difference, it signals that there’s an error, signal the motor to make the necessay
adjustment to get to the correct position.

Servo motors are commonly controlled using a method called Pulse Width Modulation (PWM). This technique
requires the transmission of an electrical signal containing pulses of different lengths to the motor. This pulses
have a width that varies 1 to 2 mill seconds, and they are send repeately at a rate of 50 times per seconds to the
servo motor. The adjustment of the pulse with serves as a means to effectively control the position of the rotating
shaft in the servo motor.
Types of servo motors
i D.C. servo motor

ii A.C. servo motor
Application of servo motors
1 CNC machines: Sevo motors are used in CNC machine. They control the movement of cutting tools
2 Industrial Automation: They are used in conveyors, packing machines printing presses.
3 Robotics: Servo motor are used in robot arms, grippers and joints to achive accurate positionly and smooth
position. This enables robots to perform tasks with pricision such as assembly, welding & material handling.
4 Aerospace and defence: Servo motors are used in aircraft control surfaces, missile guidance sytsem and
unmanned aerial vehicle.
5 Electronics : Servo motor are commonly used in electronic devices as cameras, DVD playes & home
automation systems.
6 Renewable energy: Servo motors are used in solar tracking system to adjust the position of solar panels.
Optimising their orientation to sub for increased energy capture.

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CITS : Power - Electrician & Wireman - Lesson 70-75