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 with 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.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
