Torque Loss Calculator - Calculator Academy

Calculate torque loss, output torque and efficiency from input torque, power and RPM, or estimate wheel torque from drivetrain ratio.

Torque Loss Formula

TL = AT - ST

Variables:

TL is the Torque Loss (N-m)
AT is the armature torque (N-m)
ST is the shaft torque (N-m)

To calculate Torque Loss, subtract the shaft torque from the armature torque at the same shaft speed under steady, non-generating operation. Select the task for the known pair; do not leave an arbitrary field blank. Power/RPM tasks use T = P ÷ (2π × RPM/60) at a common speed. The drivetrain task instead uses output torque = engine torque × overall ratio × efficiency; its torque loss is referred to the output shaft. The retained FWD/RWD/AWD percentages are illustrative assumptions, not measured or universal losses. Zero input makes inferred efficiency undefined.

How to Calculate Torque Loss?

The following steps outline how to calculate the Torque Loss.

First, determine the armature torque (N-m).
Next, determine the shaft torque (N-m).
Next, gather the formula from above = TL = AT – ST.
Finally, calculate the Torque Loss.
After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem :

Use the following variables as an example problem to test your knowledge.

armature torque (N-m) = 200

shaft torque (N-m) = 100. Thus TL = 200 − 100 = 100 N-m; at a common shaft speed, efficiency is 50%.

FAQs

What is Torque Loss and why is it important?

Torque Loss refers to the difference between the torque generated by the armature and the torque transmitted to the shaft. It’s important because it represents the efficiency loss in mechanical systems, affecting the overall performance of machines such as motors and engines.

How can Torque Loss affect the performance of a machine?

Torque Loss can lead to reduced efficiency in machine performance. Higher torque losses mean that a greater amount of the energy supplied to the machine is not being effectively converted into useful work, leading to increased energy consumption and potentially higher operating costs.

What are common causes of Torque Loss in mechanical systems?

Common causes of steady torque loss include friction, misalignment and other dissipative resistance. Inertial torque during acceleration is outside this steady-state model. Proper maintenance and design optimization can help minimize these losses.

Can Torque Loss be completely eliminated in a mechanical system?

While it’s nearly impossible to completely eliminate Torque Loss in a mechanical system due to inherent inefficiencies, it can be significantly reduced through careful design, precision engineering, and regular maintenance of the system’s components.