Turner Uni-Drive
Custom Gearboxes | Engineering Tools & Resources
Turner Uni-Drive is ready to help you choose a standard industrial gearbox or engineer custom gearboxes with the right calculations and specifications.
Selecting the Right Custom Gearbox
Turner Uni-Drive custom gearboxes and multi-speed transmissions operate across oil fields, food processing, steel production, tube and wire mills, paper mills, mining, construction, textile, automotive, and agriculture sectors around the world.
Our engineering team is available to assist with custom gearboxes, drive sizing, and specifications tailored to your specific application.
Turn to Turner for:
- Positive speed selection with thousands of ratio combinations
- Reversing ratios in all models
- Carburized and ground gearing
- Versatility in shaft location
- Lower cost per output horsepower
- Helical gearing for high HP applications
- Manual, pneumatic or electric shifting
- 2, 3, 4, 6, or 9 speeds in one gearbox
- Proven design and manufacturing methods
Step-by-Step Guide
Gearbox Selection Steps
Follow these eight steps to select the right custom gearboxes from Turner Uni-Drive for your application.
Service Factor
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? Refer to Service Factor Tables for your application service factor.
Ratio Range
Determine the minimum and maximum ratio and the number of intermediate steps required for your application.
Load Characteristics
Constant Horsepower
Select at maximum ratio, output shaft torque equals input shaft torque multiplied by the reduction ratio.
Constant Output Torque
Select at minimum ratio, the multi-speed gearbox functions solely as a speed reducer.
Design Horsepower
Multiply the service factor from Step I by the actual input horsepower required to operate the driven equipment.
Unit Selection
Refer to Quick Selection charts. Use the torque formula to verify capacity:
Torque (in-lbs) = HP × 63,025 ÷ RPMOverhung Load
Calculate the overhung load on input and output shafts. If overhung load capacity is exceeded, an outboard bearing support is recommended.
OHL = HP × 63,025 ÷ (N × R)Shaft Assembly
Refer to shaft configuration diagrams for your transmission model to verify shaft location and assembly requirements.
Ratio Selection
Select specific ratios from the ratio combination charts. Note that certain ratios may require additional transmission speeds. Refer to factory for extended ratio units.
Technical Reference
Procedures for Selecting Ratio Combinations
Use these procedures to select the correct ratio combinations for your custom gearboxes from Turner Uni-Drive.
Model E3
2 Speeds
Select any two ratios shown.
3 Speeds
Select highest speed desired (least reduction or most increase). Skip next three slower speeds. Select two more speeds from any of the remaining slower speeds.
Models 2M, 5M, 10M, 20M, 30M & 50M
2 Speeds
Select any two ratios on the same horizontal or vertical line.
3 Speeds
Select greatest reducing ratio desired. Skip next three ratios to the right. Select two more ratios to the right on the same horizontal line.
4 Speeds
Select any four ratios which form a square or rectangle on the sheet.
6 Speeds
Follow the procedures for a 3-speed unit. Select three ratios in the same three vertical columns on any other single horizontal line.
9 Speeds
Refer to factory for 9-speed ratio combinations.
Models 3M, 6M & 11M
Extended ratio units — refer to factory for all ratio combination selections.
Model 60M
Ratios for the 60M are the same as the 50M. However, the model 60M is available only in 2 and 4 speeds.
Need Assistance?
We are always available to assist with custom gearboxes, ratio selection, and drive sizing. Call us at 816-226-7994 or 816-931-6001 or contact us online.
Technical Reference
Definitions & Formulas
Key terminology and formulas used when engineering custom gearboxes and selecting the right industrial transmission.
Torque
A unit of measure used to represent the twisting or turning effort around an axis. Typically expressed in pound-feet (lb-ft), pound-inches (lb-in), kilogram-meters (kg-m), or Newton-meters (N-m).
Horsepower
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
An abbreviation for Revolutions Per Minute — the number of complete turns a rotating shaft makes in one minute.
Key Formulas
Calculate Torque
Torque (in-lbs) = HP × 63,025 ÷ RPMCalculate Horsepower
HP = Torque × RPM ÷ 63,025Calculate RPM
RPM = HP × 63,025 ÷ Torque (in-lbs)Service Factor
The equivalent power rating must be determined by multiplying the specified transmitted power by the service factor. Service factors represent the relationship between gear unit design power rating and maximum potential transmitted power. Consult the Service Factor Table for your specific application.
Constant HP vs. Constant Torque
Constant Horsepower
Output shaft torque equals input shaft torque multiplied by the reduction ratio, assuming full motor horsepower transfers to the output.
Constant Torque
Output shaft torque requirements match input shaft torque. The multi-speed gearbox functions solely as a speed reducer.
Need Engineering Assistance?
Our engineering team is ready to help design custom gearboxes, assist with drive sizing, and develop specifications for your application.