Torque
Torque, abbreviated as \(\tau\) (Greek symbol tau) or T, also called moment of force, is a rotational moment. It is a measure of how much twisting is applied to a fastener. The units used to measure torque are in the form of force times length. Usually measured in newton-metres (Nm) if metric units are used or pounds feet (lb-ft) when imperial units are used.
Torque formulas
\(\large{ \tau = r \; F \; sin \; \theta }\) | |
\(\large{ \tau = l \; F }\) | |
\(\large{ \tau = d \; F }\) | |
\(\large{ \tau = I \; \alpha }\) | |
\(\large{ \tau = \frac{ 5252\; HP }{ s } }\) | (engine horsepower) |
Where:
\(\large{ \tau }\) (Greek symbol tau) = torque
\(\large{ \theta }\) (Greek symbol theta) = angle
\(\large{ \alpha }\) (Greek symbol alpha) = angular acceleration
\(\large{ d }\) = diplacement
\(\large{ F }\) = force
\(\large{ HP }\) = horsepower
\(\large{ l }\) = length, moment arm
\(\large{ I }\) = moment of inertia
\(\large{ P }\) = power
\(\large{ r }\) = radius
\(\large{ s }\) = speed (rpm)
Breakaway Torque
The torque necessary to put into reverse rotation a bolt that has not been tightened.
Breakloose Torque
The torque required to effect reverse rotation when a pre-stressed threaded assembly is loosened.