This document summarizes a seminar on ultrasonic motors. It discusses the principles and construction of ultrasonic motors. Ultrasonic motors operate using the piezoelectric effect to convert electrical energy to mechanical vibrations. They have advantages over traditional electromagnetic motors like noiseless operation, compact size, and high torque at low speeds. However, they also have disadvantages like high cost and need for high frequency power supplies. Ultrasonic motors find applications in devices like cameras, watches, power windows and actuators.

1. A
Seminar
on
ULTRASONIC MOTORS
By
Y.CHAKRI VENKATA DINESH
(13HM1A0217)
Department of Electrical And Electronics Engineering
Annamacharya Institute of Technology and Sciences
19/01/17 1Dept.of EEE,AITS-KADAPA

2. Contents
 Introduction
 Drawbacks of Electro Magnetic Motors
 Principle of operation
 Construction
 Working
 Characteristic features
 Advantages & Disadvantages
 Applications
 Conclusion
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3. Introduction
A motor is a machine which converts electrical
energy into mechanical energy.
UltraSonic Motors (USMs) are next generation
motors.
The first USM was developed by Russian scientist in
1965
USMs are characterized by the absence of noise
during operation , high accurate speed and position
control etc.,
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4. Drawbacks of Electro Magnetic Motors
 Noisy operation
Less efficiency
High motor temperatures
High cost
Increased size with increase in rating of motor
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5. Principle of operation
USM works on the principle of Converse Piezoelectric
Effect.
(a)When applied DC voltage has same polarity
(b) When applied DC voltage has opposite polarity
(c) When AC voltage is applied
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6. Construction
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7. Piezoelectric Ceramics
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8. Working
When high frequency voltage (>20KHz) is applied
piezoelectric material vibrates.
There are two power transformations involved in
running of USM.
(a)Conversion of Electrical energy into
mechanical vibrational energy by Inverse
Piezoelectric Effect.
(b)Vibrational energy of stator is
transformed into continuous moving
energy of rotor due to frictional interaction
between stator and rotor.
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9. Characteristics of USM
Simple construction
Absence of magnetic action
Low Speed
High Torque
Quick response
Noiseless
Compact
Lightweight
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10. Advantages of USM
Low AC voltage excitation
High torque at low speeds
Short time response
Ultra small size can be easily miniaturized
Dust free
Noiseless operation
High efficiency
High torque/weight ratio
No magnetic interference
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11. Disadvantages of USM
Piezoelectric materials are expensive
Requires high frequency power supply (>20 KHz)
Ultrasonic noise occurs
Due to friction life of motor reduces
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12. Applications
Auto focusing & optical zooming in digital cameras
Automatic wrist watches
Power windows
Roll screen motor for automatic open & close actions
Actuators for VCRs & CD players
 Robotics
Wall clocks
Ultrasonic welding
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13. Conclusion
The above mentioned
advantages and applications concludes scope
of USMs in day - to -day life.
However disadvantages
brings up need for further researches in fields.
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