Speed reducers are equipment designed to change rotational speed from an input shaft into a lower output speed. This shift is accomplished when the motor sends power to the reducer’s input shaft, where it then converts said power into a lower output speed, so that the reducer can transfer it to the connected load through the output shaft. Speed reducers service various devices, and they are offered with a variety of specific loads and torque capacities, though they are all made from strong, durable metals like steel.

Sometimes, more general speed reducers are referred to interchangeably, though they are different. Such types include: gear reducers, gear drives, gear boxes, gear heads and gearmotors. Gear reducers handle heavy shock loads and minimize total power and machine size. They offer the advantages of low consumption and a light weight, coupled with a steady startup and heavy transmission torque.

Gear drives, on the other hand, increase the torque of a variable speed power source or glean a variable output speed from a constant speed power source. They do so by, with the help of gear ratios, changing the direction, torque and speed of rotating shafts. (Gear ratios represent the relation between a gearmotor input speed and a gear head output speed.) Gear boxes, which contain input and output shafts, plus a set of gears, only offer the service of lowering motor speed; Motor speed is lowered through a decrease in output speed and an increase in torque.

Finally, gearmotors work in conjunction with gear boxes or gear heads to increase or decrease motor speed. They acquire access to this speed by turning the electrical energy of either an AC motor or a DC motor, and turning into mechanical energy. Read More…

Leading Manufacturers

DieQua Corporation

Bloomingdale, IL | 630-980-1133

Boston Gear

Charlotte, NC | 888-999-9860

Dietz Electric Co., Inc.

Milwaukee, WI | 800-466-6398

Andantex USA, Inc.

Wanamassa, NJ | 800-713-6170

Harmonic Drive, LLC

Peabody, MA | 800-921-3332

In addition to generalized motors, speed reducers are available to meet a variety of specialized needs. Specialized speed reducers include: shaft mounted speed reducers, cyclo reducers, planetary gearboxes, inline gear reducers, right angle gear boxes, variable speed reducers, worm boxes and right angle gear boxes. Shaft mounted speed reducers are mounted directly onto the drive shaft and for that reason, as well as the fact that they’re compact, they do not require a foundation or coupling. Cyclo reducers, as their name suggests, slow input shaft speed by a chosen ratio using rolling elements, specifically a circular disc that rotates off center.

Planetary gearboxes get their name from their composition; they consist of a sun gear, planet gears and a ring and a ring gear. By revolving around the sun gear, different planet gears can produce a variety of reduction rates; their goal is to lower the torque or speed of a rotating input shaft. Inline gear reducers decrease incoming speed, direction or torque of larger systems, with the goal of helping other system parts handle its power and operate well. They influence the input shaft using gear ratios that are aligned along the centerline of the input shaft, or, to put it another way, they align the output shaft with the input shaft. Variable speed reducers, or drives, control the rotational speed and conserve the energy of electric motors.

Depending on the application, variable speed reducers can be mechanical, hydraulic, electronic or electromechanical. Also they may work with direct current (DC) or alternating current (AC) motors, though most often they work with the latter. Compactly designed worm boxes, used in applications requiring low horsepower, maintain high shock tolerance and high gear ratios. Finally, right angle gear boxes are impressive speed reducers that have up to 98% efficiency levels. The “right angle” in their name refers to the position of the input shafts, which are perpendicular to the output shafts. Right angle boxes are commonly found in glass cutting equipment and printing presses.

While speed reducers are utilized by a several industries, the most common industries in which they have applications are: aerospace, automotive, material handling, construction, food and beverage processing, recreation, oil and gas and textiles. Specific applications they serve include: conveyors, pumps, printing presses, compressors, automation equipment, generators and robotic, metallurgy, mine and construction machinery. These industries use speed reducers for many reasons. Their many benefits include: performance improvement, minimal energy loss, increased equipment lifespan, speed optimization and flexible configuration options. Also, newer speed reducers require less fuel or electricity to work, furthering efficiency even more. As reduction ratios continue to reach new heights and designs become more complex, manufacturers are meeting new goals and creating greater power capacities.

Additional Reading…

What you Need to Consider when Buying Speed Reducers

Speed reducers are a mechanical device found in the housing of almost all-mechanical equipment, since they are important components that give operators ability to regulate the output based on different needs. However, unlike what name suggests, they carry on two functions, including reducing rotational speed from the source into more manageable speeds, and with the concerted efforts of the gears, they simultaneously increase torque, so output can be used for mending, milling, and many other processes.

Speed reducers have application in an array of industries, which range from sophisticated robotics to conventional bottling and beverage industry. They are everywhere; however, selection for a particular job needs careful consideration. In this article, we are discussing a number of parameters, so you understand what you need to look into while buying one.

As there are a number of speed reducers it is evident, the application is what dictates which type of speed reducer will satisfy your needs. Basically, there are two designs, inline and right angle, although, different types of gearing are used for speed reducers—

Once you know the application, the next step is looking into the specifications, including mounting position, efficiency, torque, horsepower, speed, and service factor. Among them, the most important factors are torque and service factor.


You need to know how much torque is needed for a machine to work optimally. For application in simple machines, determining torque is easy; however, if you do not have the handbook for a machine it can get difficult. You need to consider many factors, such as coefficient of friction, gravity, inertia as well as acceleration and deceleration. If it is too much of a task you may need the help of an engineer to figure out the right torque. Alternatively, you can deduce the torque by noting the ampere of the motor from which horsepower can be calculated. Further, with the use of relationship between horsepower and torque, you can deduce the torque required.

Service Factor

A motor does not perform uniformly, over time its performance goes down, and if the motor is run above its overload capacity, it can break down. Therefore, to protect speed reducers, they come with service factor inscribed on them, which is a measure of overload capacity a reducer can operate at over a period without being damaged. The service factor usually is a number, for instance, 1.15, which means the speed reducer can manage 15 percent of overload than the rated capacity, without aberrations and anything above that amount will damage it. When making a decision regarding the service factor, you need to consider a number of things, including load characteristics, power sources, starts and stops, and length of workdays. To put it simply, if you put a heavier load than what service factor says, the life of the gearbox goes down. Therefore, it is important that for different purposes, appropriate service factor must be chosen, or your speed reducer will fall apart soon.



Speed Reducer Informational Video