Stall torque is the torque of a device at zero rotational speed or the torque load required to bring it to zero. Electric motors, steam engines, and hydrodynamic drives produce stall torque. Torque converters multiply stall torque and have ratios ranging from 1.8:1 to 2.5:1. The formula relating torque, stall torque, and RPM is T=Ts-(NTs/Nf). […]