General kinematics and force arithmetic
Cooling Tower Fan Kinematics Calculator
Calculate shaft frequency, blade-pass frequency and blade-tip speed. Optional inputs add force from a supplied residual unbalance, tip-clearance ratio and descriptive frequency separation.
Calculated quantities
These are general kinematic, geometric and rotating-force equations; they are not formulas mandated by ISO. With U in g·mm, 1 g·mm=10−6 kg·m, so the force result is in newtons.
ISO 14694:2003/Amd 1:2010 covers industrial-fan balance/vibration specifications within stated power/application limits and excludes foundation/installation effects and effects on personnel, equipment or processes. It is under revision. ISO 14695:2003/Cor 1:2009 describes fan-vibration measurement and does not itself give interpretation criteria.
ISO 21940-11:2016 с Amd 1:2022 establishes procedures/tolerances for rotors with rigid behaviour and excludes flexible rotors. This page therefore does not choose G6.3, allocate permissible unbalance to planes or assert that a cooling-tower fan is rigid.
No risk classification: frequency proximity alone is not proof of resonance, and tip speed or clearance ratio alone is not proof of safe blade stress/contact margin. Use manufacturer limits, modal/operational testing, damping and operating-envelope review.
