5 Effective Methods to Reduce Electric Motor Starting Current

Reduce Electric Motor Starting Current

1. Direct Start

Direct start is the method where the stator winding of the motor is directly connected to the power supply and started at the rated voltage. This procedure is characterized by high starting torque and short start time.

It is the simplest, most economical, and most reliable way to start. The full-voltage start draws a large current without a significant increase in starting torque. It is convenient and quick to start but requires a larger grid capacity and load. This method is mainly suitable for starting motors below 1W.

2. Series Resistance Start

Series resistance start is a method of reducing voltage during the start process. A resistance is serially connected in the stator winding circuit during startup. As the starting current passes through, a voltage drop occurs across the resistance, reducing the voltage applied to the stator winding, thereby achieving the purpose of reducing the starting current.

3. Autotransformer Start-Up

Utilizing the multiple taps of an autotransformer for voltage reduction can both accommodate the start-up needs of different loads and achieve larger start-up torque. It’s a commonly used method for starting larger capacity motors.

Its greatest advantage is the substantial start-up torque. When the winding tap is at 80%, the start-up torque can reach 64% of that during direct start-up, and the start-up torque can be adjusted via the tap.

4. Star-Delta Reduced Voltage Start-Up

For a squirrel-cage asynchronous motor with a delta-connected stator winding under normal operation, if the stator winding is star-connected during start-up and switched back to delta after start-up, the start-up current can be reduced, mitigating its impact on the power grid. This method is known as star-delta reduced voltage start-up, or simply star-delta start-up.

With the star-delta start-up, the start-up current is only one-third of that during direct start-up with a delta connection. During star-delta start-up, the start-up current is only 2-2.3 times the original. This means that with star-delta start-up, the start-up torque also drops to one-third of that during direct start-up with a delta connection.

It is suitable for no-load or light-load start-up situations. Compared to any other voltage reduction starters, it has the simplest structure and is the most cost-effective.

Besides, the star-delta start-up method has another advantage: when the load is light, the motor can operate under a star connection. At this time, the rated torque can match the load, which can enhance the motor’s efficiency and save power consumption.

5. Variable Frequency Drive Start-Up (Soft Start-Up)

The variable frequency drive is the most technologically advanced, comprehensive, and effective motor control device in the modern motor control field. It adjusts the motor’s speed and torque by altering the frequency of the power grid.

Due to its reliance on power electronics and microcomputer technology, it is costly and requires a high skill level from maintenance technicians.

Therefore, it is mainly used in areas that require speed control and high standards for speed control.

Don't forget, sharing is caring! : )
Shane
Author

Shane

Founder of MachineMFG

As the founder of MachineMFG, I have dedicated over a decade of my career to the metalworking industry. My extensive experience has allowed me to become an expert in the fields of sheet metal fabrication, machining, mechanical engineering, and machine tools for metals. I am constantly thinking, reading, and writing about these subjects, constantly striving to stay at the forefront of my field. Let my knowledge and expertise be an asset to your business.

Up Next

Mastering CAD/CAM: Essential Technologies Explained

Basic Concepts of Computer-Aided Design and Computer-Aided Manufacturing Computer-aided design and computer-aided manufacturing (CAD/CAM) is a comprehensive and technically complex system engineering discipline that incorporates diverse fields such as computer [...]

Virtual Manufacturing Explained: Concepts & Principles

Concept of Virtual Manufacturing Virtual Manufacturing (VM) is the fundamental realization of the actual manufacturing process on a computer. It utilizes computer simulation and virtual reality technologies, supported by high-performance [...]

Understanding Flexible Manufacturing Systems: A Guide

A Flexible Manufacturing System (FMS) typically employs principles of systems engineering and group technology. It connects Computer Numerical Control (CNC) machine tools (processing centers), coordinate measuring machines, material transport systems, [...]

Exploring 4 Cutting-Edge Nanofabrication Techniques

Just as manufacturing technology plays a crucial role in various fields today, nanofabrication technology holds a key position in the realms of nanotechnology. Nanofabrication technology encompasses numerous methods including mechanical [...]

Ultra-Precision Machining: Types and Techniques

Ultra-precision machining refers to precision manufacturing processes that achieve extremely high levels of accuracy and surface quality. Its definition is relative, changing with technological advancements. Currently, this technique can achieve [...]

Exploring High-Speed Cutting: Tech Overview & Application

Cutting machining remains the most prominent method of mechanical processing, holding a significant role in mechanical manufacturing. With the advancement of manufacturing technology, cutting machining technology underwent substantial progress towards [...]

Top 7 New Engineering Materials: What You Need to Know

Advanced materials refer to those recently researched or under development that possess exceptional performance and special functionalities. These materials are of paramount significance to the advancement of science and technology, [...]

Metal Expansion Methods: A Comprehensive Guide

Bulge forming is suitable for various types of blanks, such as deep-drawn cups, cut tubes, and rolled conical weldments. Classification by bulge forming medium Bulge forming methods can be categorized [...]
MachineMFG
Take your business to the next level
Subscribe to our newsletter
The latest news, articles, and resources, sent to your inbox weekly.
© 2024. All rights reserved.

Contact Us

You will get our reply within 24 hours.