We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is Adjustable Speed Drive?

By T. L. Childree
Updated May 17, 2024
Our promise to you
About Mechanics is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At About Mechanics, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

Adjustable speed drive is a term used to describe any type of energy transmission device that allows manual or automatic adjustment of its fixed operating speed to control a process or conserve energy. The fixed speed of an adjustable speed drive motor can be increased or decreased according to the type of application for which the device is being used. Adjustable speed drive devices can be electrical or non-electrical. Non-electrical drives may be either mechanical or hydraulic. Electrically powered drives may use direct current, eddy current, or alternating current.

Electric motors operate at a fixed speed governed by the number of internal windings contained in them. Adjusting the speed of a motor using multiple sets of windings would be cumbersome and expensive. A separate motor speed control mechanism is typically required to cause a fixed speed motor to run at varying speeds. This type of speed control mechanism is commonly known as an adjustable speed drive. These drive mechanisms were originally intended for use in process control, but are also utilized frequently to conserve energy.

An adjustable speed drive aids in process control by providing a different operational speed for each process performed. This mechanism also offers smoother motor operation along with acceleration and torque control. Adjustable speed drives can be used to conserve energy by decreasing the fan speed in heating, ventilation, and air conditioning systems. During heating cycles, the reduced fan speed provides improved circulation of warm air throughout a room. Improved air circulation reduces the number of heating cycles required by the system and reduces energy consumption.

Adjustable speed drives can take many different forms including mechanical, hydraulic, and electrical. Mechanical drives may be a variable pitch, belt, and pulley design or a traction type, metal roller system. Hydraulic methods typically take the form of a hydrostatic or hydrodynamic drive. Hydrostatic drives adjust speed through the use of fluid-powered pumps and motors. Hydrodynamic drives change motor speed by means of an impeller-driven input shaft and a rotor-driven output shaft.

An electrically powered adjustable speed drive may utilize either direct, eddy, or alternating current. Direct current drives adjust motor speed by changing its field current or armature voltage. Eddy current drives utilize a device known as an eddy current clutch to regulate a fixed speed motor. Alternating current drives operate by either decreasing the motor’s applied voltage or increasing its winding resistance. Both alternating and eddy current drives are generally considered to be an inefficient adjustable speed drive mechanism.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Discussion Comments

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.