AC Servo Drives

Mechanisms belonging to the range of motion electronic products, AC servo drives operate on alternate voltage patterns. As electronic amplifiers, they serve to power electric servo motors that similarly operate on alternate voltage pattern.

As special electronic amplifiers they A) monitor control feedback signals received from motors. B) According to feedback signals received they make necessary adjustments. C) They form a part of a dynamical system.

The function of AC servo drives is guided by the ‘control theory’, which is a sub part of Physics and Mathematics. According to this theory, A) A controller, manipulates the input to a system. B) This manipulation is geared to achieving the desired effect on the output. C) Output variables follow a reference of time. A.C servo drives act as controllers or A.C electrical amplifiers.


"Motion theory" also controls the functioning of servo drives. As special electronic mechanisms, they control the velocity of mechanisms. After receiving a command signal from a control system geared to A.C voltage, they amplify such signals and after due amplification, they transmit electric current to a system. Automatically, the electric current transmitted will be proportionate to the received command signal.

The servo motor with an attached velocity sensor does the needful work of reporting the motor’s actual velocity back to servo drive. After a due comparison of motor’s actual velocity with the command velocity, AC servo drives contribute to altering the due voltage frequency. Thus any error in voltage frequency is corrected by A.C servo drives. Usually servo motors rotate at a velocity matching the control signal. Servo motor control ensures the due matching leading to the establishment with proper configuration and tuning- which is a combination of proportional and derivative gain.

A.C servo drives are not only easily available, but they are also compatible with different variety of motors. Use of A.C servo drives has manifold advantages. Forming an integral part of the servo system their additional feedback serves to detect unwanted motion. They usually accurately assess the commanded motion. Moreover they are better adjusted to changing speed, with a better life span; giving effective durability to a system.

Servo drives are generally of two types. 1) Digital servo deals with discreet tracking of signals. 2) Analog deals with continuous tracking of signals.  Servo drives which form an integral part of the servo system have an enormous role to play in industries involved with robotics, automation and any other kind reliant on motion theory.

Servo Drives – Facts and Features

Servo drives have revolutionized the way key industrial applications run today. Digital servo has taken the mechanism of motion control to a new height where it amplifies the signals and makes mechanical output faster and more effective.

Benefits of servo drives -

• Higher and more dynamic response
• Reliable
• Cost effective
• Higher productivity and performance
• Accurate output
• Flexibility that can share technologies across diverse types of machines
• Higher safety and hygiene protocols
• User friendly interface that is easily PC adapted for fluid control
• Comprehensive programmed software for easier manipulation
• Higher feedback and report system makes for stronger output functions
• Super speed internal and external communication system enabled across multiple platforms
• Regular and quick updates of speed, position and current status leading to machine precision
• Reduced errors in tracking
• High precision supply of current while saving energy
• Interface for analog reading to use older machines

Digital servo drives function across servomotors like torque, asynchronous and linear motors and the brushless PM AC motors due to high end modular design. Based on 32- bit 400MHz microprocessor, it can used as effectively as a singular product as in a comprehensive system. It can ease the way your machine performs this providing higher output or aid in the machine design. Effective servo drive functions offer complete digital control and manipulation of brushless servo motors, delivers increased current and velocity leading to high precision performance that is the need of the hour across industries. Multi level interfaces, effective feedback system and superior controllers.

Leading vendors design and offer different kinds of servo drives –

• Servo drives that can control low power application for smaller machines requiring less than 1.5 kw. This effectively reduces design time and commission time, as well as provide layouts and CAD drawings.
• Digital servo drives that can handle multiple applications through single-axis motion control. They have inherent dynamic brakes, velocity observer, tuner and suppression algorithms to provide more cost effective motion control output.
• A multi-axis servo drive can helps in decreasing engineering time by helping effectively in networking, programming and operations. Adds greater flexibility and handles global voltage volume needs.
• Some come with high end safety options and flexible designs that can function on multiple levels and interfaces.
• EtherNet Servo Drives standardize the entire communication network leading to faster commissioning and startups, precise and easier configuration. Allows effective control integration with high speed connectivity.
• Some have troubleshooting options built in them, with automatic capacity of motor recognition.