Calculating Output Torque
In selecting the most suitable Planetary Gearbox for your application, the TAB output torque is the most important variable. Use the equation compendium below to calculate this variable.
Reduction ratio i is used to reduce the relatively high motor speed nM to a lower output speed nAB.
With: i = nM / nAB
Your desired nominal output torque TN is therefore calculated as follows:
TN = TM . i . h / sf
- Reduction ratio i (see table)
- Gear efficiency h is found in data for specific MDrivePlus/rotary motor - gearbox combinations (choose from "Select a Product" menu above).
When calculating the actual output torque TAB, the calculated nominal output torque TN and the operating factor CB should also be taken into account. CB is merely a factor which addresses the different working conditions of a Planetary Gearbox and which is the result of your subjective appraisal. It is therefore only meant as a guide value. We include the following factors in the rough estimation of the operating factor CB: direction of rotation, load (shocks) and daily operating time. Refer to the table below to calculate the approximate operating factor CB.
| Determining
the operating factor CB |
| Direction
of Rotation |
Load
(shocks) |
Daily
operating time |
| |
|
3
hours |
8
hours |
24
hours |
| constant |
low* |
CB =1.0 |
CB =1.1 |
CB
= 1.3
|
| |
medium** |
CB =1.2 |
CB =1.3 |
CB
= 1.5
|
| alternating |
low*** |
CB =1.3 |
CB =1.4 |
CB
= 1.6
|
| |
medium**** |
CB =1.6 |
CB =1.7 |
CB
= 1.9
|
|
|
Definitions
i = Reduction ratio
nM = Motor speed
nAB = Output speed
TN = Nominal output torque
TM = Motor torque (refer to MDrive Speed Torque Curves)
h = Gear efficiency
TAB = Output torque
CB = Operating factor
sf = Safety factor (0.7 of rated torque at rated speed)
|
