Horsepower is a unit of power equal to 33,000 foot-pounds per minute or the rate of work required to raise 33,000 pounds one foot in one minute.

RPM is an abbreviation for revolutions per minute

Torque (in pound-inches) = HP x 63,025 / RPM

Example: 20 HP at 900 RPM = 20 x 63,025 / 900 = 1,400 pound-inches torque

HP = Torque (in pound-inches) x RPM / 63,025

Example: 1,600 pound-inches at 300 RPM = 1,600 x 300 / 63,025 = 7.6 HP

Typically, we assist all our customers in selecting a gearbox for their specific application. Following are the steps we follow and the information we will ask for. If you would like our assistance, please feel free to contact us.

Step 1:

Detail your application. How many hours will it operate each day? What are the characteristics of the driven load? The nature of the prime mover?

Step2:

Figure the maximum ratio you need. The minimum and the number of intermediate steps.

Step 3:

If you need CONSTANT HORSEPOWER at all speeds, select your unit at the maximum desired ratio. In this case, all ratios will have rating capacity greater than the design input HP.

If you need CONSTANT OUTPUT TORQUE at all speeds, select your unit at the minimum desired ratio. In this case, design input HP may exceed the HP rating capacity at the lower speeds.

Step 4:

Determine output torque using the formula HP x 63025 / RPM. Horsepower is the specified transmitted power modified by the service factor. RPM is determined in step 3 by applying the appropriate ratio to the driver RPM.

Step 5:

Select your unit based on output horsepower rating and desired ratio.

Note: Due to the large number of possible ratio combinations for each unit size, it is not practical to list them. Please contact Turner Uni-Drive for answers regarding specific ratios.

Extracted from ANSI/AGMA 6010-F97, Standard for Spur, Helical, Herringbone and Bevel Enclosed Drives, with the permission of the publisher, the American Gear manufacturers Association, 1500 King Street, Suite 201, Alexandria, Virginia 22314

We are anxious to assist you in determining an adequate service factor for your application. Tables are available to provide guidance in determining service factors, or they may be determined by an analytical method. Important factors to consider if using the analytical method include operational characteristics, system conditions and any special considerations.