Choosing a portable balancing machine comes down to five questions: what rotors you balance, where you balance them, which standards you must document compliance with, how many measurement channels you need, and how much of the budget should go into the instrument rather than the service contract. This guide walks through each decision, with typical price classes and a pre-purchase checklist. It is written by the engineering team at Vibromera, manufacturer of the Balanset-1A portable balancer, and reflects field experience across fans, crushers, mulchers, centrifuges, driveshafts and turbine rotors in 50+ countries.
Start with the job, not the spec sheet
The first split is field balancing vs workshop balancing. A workshop (pedestal) balancing machine spins the rotor in its own bearings and needs the rotor removed from the machine. A portable field balancer measures vibration and phase on the running machine and calculates correction masses in the rotor’s own bearings — no disassembly, no transport, no re-installation misalignment. If your typical case is an industrial fan, a combine harvester drum, a mulcher rotor, a centrifuge or a pump impeller that would take a day to remove, field balancing is the economical answer. If you balance small armatures in series production, a workshop machine wins.
The six specifications that actually matter
- Measurement channels. Two channels let you balance in two planes simultaneously — the standard case for rotors longer than they are wide. Single-channel instruments force you to measure planes sequentially, doubling run count.
- Phase reference. A laser or optical tachometer is non-negotiable: without a phase mark you get vibration severity but cannot calculate where to place the correction mass.
- Vibration spectrum (FFT). Balancing only helps when unbalance is actually the dominant fault. An instrument with FFT lets you check that the 1x component dominates before you start, and spot misalignment (2x), looseness (harmonics) or bearing defects instead.
- Balancing method. The influence coefficient method with trial weights is the industry standard for field work; check that the instrument stores influence coefficients per machine so repeat jobs need fewer runs.
- Tolerance calculation. The instrument should compute permissible residual unbalance per ISO 21940-11 (former ISO 1940-1) G-grades and tell you pass or fail, not leave you with a bare amplitude number.
- Severity assessment. Zone evaluation per ISO 10816 / ISO 20816 before and after correction documents the result for the customer or the maintenance log.
Standards the instrument must support
For documented industrial work the short list is: ISO 21940-11 (balance tolerances, G-grades), ISO 10816-3 / ISO 20816-3 (vibration severity zones for machines above 15 kW), and for fans specifically ISO 14694 (BV categories). If the vendor cannot say which editions the firmware implements, treat the tolerance readout as decorative.
Price classes on the market
| Class | Typical price | What you get | Where it fits |
|---|---|---|---|
| Smartphone apps + external sensor | under €500 | Severity indication, rough spectrum; usually no phase, no two-plane balancing | Screening, education |
| Portable two-channel balancer | €1,500–6,000 | Two-plane balancing with laser phase reference, FFT spectrum, ISO tolerance check, reporting | Field balancing as a service or in-plant maintenance; the Balanset-1A (€1,975) sits in this class |
| Multichannel analyzer platforms | €10,000–40,000+ | 4–16 channels, route-based condition monitoring, modal analysis options | Vibration departments, monitoring programs |
| Workshop balancing machines | €8,000–100,000+ | Balancing in own bearings to fine grades, series throughput | Manufacturing and overhaul shops |
The practical sweet spot for maintenance teams and balancing contractors is the portable two-channel class: it covers two-plane dynamic balancing of the overwhelming majority of industrial rotors at roughly one tenth of the cost of a workshop machine plus removal downtime.
Ten-point checklist before you buy
- Two measurement channels and simultaneous two-plane balancing.
- Laser/optical tachometer included, with reflective tape supplied.
- FFT spectrum and time waveform, not just overall RMS.
- Tolerance calculation per ISO 21940-11 with G-grade selection.
- Zone assessment per ISO 10816/20816 built in.
- Storage of influence coefficients for repeat machines.
- Report generation (PDF or export) for customer documentation.
- Sensor cables long enough for your largest machine — 4+ meters.
- Vendor support that answers engineering questions, not only RMA tickets.
- Total kit price including sensors, tachometer, scales and case — not a bare unit price.
Frequently asked questions
Can one instrument balance both a small fan and a large crusher rotor?
Yes — field balancing scales with the rotor because correction masses are calculated relative to measured vibration. The same two-channel instrument handles rotors from grams to tonnes; what changes is the trial weight size and the G-grade target.
Do I need a vibration analyzer and a balancer as separate devices?
No. A properly equipped portable balancer is a vibration analyzer with balancing software: the Balanset-1A, for example, works in vibrometer mode with FFT spectrum for diagnostics and switches to guided single-plane or two-plane balancing when unbalance is confirmed.
What accuracy can field balancing achieve?
With a phase-referenced two-channel instrument, residual unbalance within G 1.0–G 2.5 per ISO 21940-11 is routinely achievable on site; workshop machines are only required for finer grades such as G 0.4 gyroscope-class work.
Is a €300 vibration app enough to start a balancing service?
No — without a phase reference you cannot place correction masses, and without two channels dynamic (two-plane) unbalance cannot be separated. Screening apps complement but do not replace a balancer.
Questions about a specific rotor? The Balanset-1A product page lists the full kit contents, and the field balancing guide covers procedure, theory and troubleshooting step by step.
