Torqueloss

Torqueloss is a term used in mechanical and electromechanical engineering to describe the reduction in torque that is transmitted from a rotating source to a load due to losses within the drivetrain and related components. It is defined as the difference between the input torque provided by the motor or prime mover and the output torque delivered to the driven member, and it can be expressed as a torque value in newton-meters or as a percentage of input torque.

Causes of torqueloss are varied and typically include mechanical friction in bearings, gears, and couplings; lubrication and temperature effects that change viscous resistance; gear backlash and misalignment; shaft flex and structural vibration; and windage losses in higher-speed rotors. In electric machines, electrical losses such as copper (I2R) losses, iron losses, and inverter switching losses also reduce the torque available to the load for a given current. These factors can interact, causing torqueloss to depend on speed, load, temperature, and operating conditions.

Measurement and assessment of torqueloss commonly involve comparing input and output torque under controlled conditions using dynamometers and torque sensors. Torqueloss may be reported as a raw torque difference or as a percentage of input torque, and it can vary with speed and load, often forming part of a broader efficiency analysis of a drive system.

Implications of torqueloss include reduced acceleration, lower peak torque at the load, higher heat generation, and decreased overall efficiency. Design and operational strategies to minimize torqueloss focus on improving drivetrain efficiency, such as selecting low-friction bearings and gears, optimizing lubrication and cooling, ensuring proper alignment, controlling thermal rise, and applying efficient motor control techniques in electric drives.

See also: torque, drivetrain efficiency, powertrain, torque ripple, mechanical efficiency.