Page 344 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

LESSON 223 - 236 : AC Drives

Objectives

At the end of this lesson you shall be able to
• state the various steps involved in the condition of AC drives
• state the advantages & disadvantages of AC drives.
AC Drive

An AC drive is a device used to control the speed of an AC motor that control loads ranging from pumps and fans
to complex machines. An AC drive may control other aspects of an application as well, but that depends on the
capabilities of the drive and how it is applied.
AC drives function by converting a constant AC frequency and voltage into a variable frequency and voltage.
There are many types of AC drives, but this course focuses on low voltage (less than 1000 VAC) AC drives used
with three-phase induction motors, the most common pairing used in industrial applications.
The importance of controlling speed varies with the application, but, for many applications, speed control is
critical because it affects many other aspects of a manufacturing process. Many processes require multiple AC
drives functioning independently or in coordination. AC drives are also used in non-manufacturing applications,
but the basic principles of operation are the same.

Advantage of AC Drives
Lower Energy Costs
• Less Usage
• Reduce Demand
• Improved Power factor
Reduced Maintenance
• Mechanical stress
• Shock loads
• Reduced cavitation
Improved Process control
• Speed control
• Flow control
• Pressure control
• Temperature control
• Acceleration control

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