An equipment OEM had installed a new centrifugal dust-collector blower on a line they were building for one of their own clients. The blower — a direct-drive, ~3,000 CMH-class machine on a fabricated base with anti-vibration mounts — was recent, still under warranty, and sat at the client's plant a long way from both the OEM's base and the fan works. The line couldn't be handed over to the end-user until the fan ran smoothly, so the OEM needed the fan manufacturer to step in and clear it fast. We'll call them the Builder.
On first running, the blower showed heavy vibration and what looked like a rotational wobble. Two things were now uncertain and both blocked the project: was it the fan, or the way it had been erected and started up, and could it be brought to an acceptable vibration level on the client's site, not on a test bench? Because the machine was on a base and structural frame the fan-maker hadn't built, the answer had to come from the site as it actually was — remote, freshly erected, with the client's line waiting on acceptance.
The first question was the only one that mattered, and we answered it with measurements, not opinion: was the machine built wrong, or was this a start-up matter? The reading was unambiguous. No manufacturing or design defect was found — the fan itself was on-spec, its duty sitting well inside our capability envelope (2,00,000 CMH, 2,000 mmWC, 400 HP, 600 °C; impeller ≤ 3,000 mm). What the site showed was a textbook commissioning-stage picture: a residual running balance to be trimmed on first run, plus a foundation, mounts and base frame that needed setting for the duty. Every one of those is a commissioning check — the kind that is meant to be caught and corrected before handover, which is exactly what we did.
We started remote: we asked for photographs and running videos and tried to resolve it online. When the root cause couldn't be isolated by mail and phone, we deputed a service engineer to the site rather than guess.
On site, the engineer: - Measured vibration at both bearings (drive and non-drive end) in all three axes — the way to separate a running-balance problem from a mounting problem before touching anything. - Dynamically balanced the rotor in situ — the corrective that moved the numbers, done on the machine as installed. - Re-measured after balancing to prove the result against the standard. - Documented the installation corrections the Builder should make to hold it there — a more rigid foundation (a steel plate and proper bolting under the base channel), correctly-rated (softer) anti-vibration mounts sized to our calculation, and stiffeners added to the base frame — and supplied the replacement mounts as a spare.
Testing language: the on-site figures are vibration measurements taken on site to the ISO 20816-3 method. (No air-performance test was part of this visit — we don't claim one.)
| The constraint | How we handled it |
|---|---|
| A remote, out-of-region site with the client's line waiting on acceptance | Remote photo/video triage first, then a single planned deputation to diagnose and balance in one trip |
| The fan sat on a base and structural frame we hadn't erected | Assessed foundation, mounting and isolation in situ; wrote up the corrections for the Builder's scope and supplied the correct anti-vibration mounts |
| The cause could be the fan or the way it was started up | Measured at both bearings in three axes to rule the machine in or out first — it ruled out, and pointed straight to first-run balance and mounting |
With the fan confirmed sound, the machine was field-balanced in situ and commissioned properly. Vibration on the worst axis fell from ~20 mm/s to about 2.1 mm/s — roughly a 90% reduction — putting every measured point inside ISO 20816-3 Zone A at handover. The complaint was resolved in a single site visit and closed on a signed site report, with the machine still under warranty. The Builder left with a fan proven to the standard on their own line, plus a short list of foundation and mounting corrections to keep it there.
| Parameter | Before | Verified on site | Method |
|---|---|---|---|
| Vibration, worst axis | up to ~20 mm/s | under ~2.1 mm/s | ISO 20816-3 |
| Vibration zone at handover | — | Zone A | ISO 20816-3 |
A vibration on first run doesn't mean a bad fan. More often it's a commissioning-stage matter — running balance, foundation rigidity or mount hardness that hasn't been set for the duty yet — and all of it is checkable on site in a single visit. That's why a commissioning-stage vibration check belongs in every start-up: measure at both bearings, trim the running balance, set the foundation and the mounts, and prove the machine to ISO 20816-3 before the line is handed over. Catch it there and it never becomes a warranty call.
Planning a new line, or fighting vibration on a freshly-installed fan? Ask us for a site-readiness check and an on-site dynamic balance — any make.
— Jitamitra Electro Engineering · Technical Services
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