Gear reducers are used throughout the world in a variety of applications. Gear reducers reduce speed and increase torque. Gear reducers are sometimes called speed reducers, gear drives or gearboxes. There are different types of gear reducer designs. The most common is referred to as a parallel shaft where the input shaft is parallel to the output shaft. This style is the type that Casey Equipment generally sells. There are also right angle gear reducers where the input shaft is at a right angle to the output shaft and concentric gear reducers where the input and output shafts are on the same centerline of the reducer. Casey Equipment also carries a few of these designs. When searching for a used gear reducer, focus on the reduction ratio of the gearing since it is a fixed value that does not change for a particular reducer. Other factors such as horsepower, input speed and service factor are proportional so their relationship can vary between different applications of the same reducer. For example, an 18:1 speed reducer rated at 100HP with an input speed of 1800 RPM will have a 100 RPM output speed. This same reducer is capable of being driven by a 200HP speed reducer at 900 RPM. A second consideration when selecting a gear reducer is the service factor. The service factor is determined by several sub factors such as hours of operation, number of starts and stops, type of equipment driving the reducer and degree of impact loading. AGMA lists recommended service factors for different applications. The service factor of a reducer is simply the ratio of the connected horsepower to the reducer rated horsepower at a service factor of 1.0. For example, a 100HP gear reducer with a service factor of 2.0 can be used in an application requiring a service factor of 1.5 with a 300HP driver. When a reducer application requires a higher input speed than the rated speed, the manufacturer should be consulted to determine if the application is within the thermal horsepower capabilities of the reducer. If you do not see equipment matching your specific requirements, please send Casey Equipment an inquiry and we will help you locate a gear reducer for your application.