Servo gear reducers and system efficiency

"According to the U.S. Department of Energy, American industries spend more than $30 billion every year on electricity for motor-driven systems. Because nearly 70% of all electricity used in industry is consumed by motor systems, increases in the energy efficiency of existing motor systems should lead to dramatic nationwide energy savings. In fact, the DOE estimates that greater attention to motor system management could reduce energy costs by up to 18 percent, while improving productivity, reliability and profitability.
In the late 1990s, the DOE introduced its Motor Challenge program, a partnership between the government and industry to capture 5 billion kilowatt-hours per year of electricity savings. This translates to about $250 million in energy cost savings and 1.2 million metric tons of carbon emissions reduction per year. A specific goal of the program is to increase the market penetration of energy-efficient industrial electric motor-driven systems by helping industry adopt the systems approach in designing, purchasing, installing, and managing motors, drives, and motor-driven equipment. This approach increases the efficiency of electric motor systems by shifting the focus from individual components and functions to total system performance.
Electricity use on servo systems is a primary concern, and can yield serious savings if designed efficiently. Optimized components allow systems to perform at their best. Gear reducers are components that, if appropriately sized for the application, provide reliability, measurable efficiency and optimal performance.
Gearboxes, or planetary gearheads, are used to reduce speed. They convert input speed (typically provided by an electric motor) into a lower output speed to generate higher torque. In other words, they reduce RPM, turning it into power for use in low-RPM high-torque applications. Gear reducers can be used on electric lifting actuators, electric ball screw actuators and for gearboxes conveyers, among others.
A likely choice for most servo systems, gear reducers are a component which can be sourced individually; however, this should be evaluated with the entire system. Proper analysis of requirements and system specifications can lead to a gear reducer becoming one of the most cost-saving components of the system.
A gearbox that is appropriately sized can generate maximum efficiency from a complete system. To achieve the best sizing, it’s important to consider the following requirements:
1. Choosing a servo-rated gear reducer. Servo-rated standards have been derived from the alpha cycle, the servo testing protocol developed by WITTENSTEIN, one of the leading planetary gearheads manufacturers. This alpha cycle determines the wear behavior under sinusoidal load in relation to running time. These ratings have also been verified by the leading servo motor manufacturers.
2. Using system analysis and servo sizing software. Only through in-depth analysis with software and application requirements can a gear reducer and servo motor be appropriately sized for the application.
Appropriately-sized gearboxes can increase savings directly with time. Energy cost savings for using a servorated gear reducer could approach $100 per axis/per month. This real-world example of cost savings underscores the importance of analyzing system components and using the best tools from the right manufacturers to design an efficient system.
Furthermore, by using the appropriate gearbox for the application, industries may be able to use a smaller motor for the application. This creates even more efficiency, which will add to the energy cost savings. Because optimized components enable complete systems to perform as efficiently as possible, it is important to carefully analyze both the individual parts of the system as well as the system as a whole. Even small efficiency improvements can have dramatic economic, as well as environmental, results.
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Chris Muldowney is the president of Tek-Matic (www.tekmatic.com, Rockford, IL), a supplier and distributor of automation and control products, specializing in gearboxes conveyers, electric ball screw actuators and electric lifting actuators