T = Fr is the formula for torque, where T is torque, F is force, and r is the effective radius. F = BIl, where B is flux density, I is current, and l is length. By substituting F = BIl into T = Fr, the combined formula for torque is T = BIlr. Another formula for torque is T=60P/2πn, where T is torque, P is power, and n is rotational speed in revolutions per minute. This formula and the previous formulas describe the relationships between torque, force, current, and other factors in motors and generators.