How to dynamically balance a rotor in its own bearings with the Balanset-1A

Stage 1: Preparing for balancing

Initial vibration diagnostics (is it really imbalance?)

Before balancing, always take a preliminary measurement in Vibrometer mode (F5):

Fig. 1. The key check: compare the overall vibration (V1s, V2s) with the vibration at the rotational frequency (V1o, V2o)

Diagnostic rule:

• If V1s ≈ V1o → the dominant source of vibration is rotor imbalance, and balancing will be effective
• If V1s ≫ V1o → a significant part of the vibration is caused by other sources (misalignment, bearings, looseness). Balancing alone will not solve the problem

Mechanical inspection (checklist)

Rotor:

• Thoroughly clean every surface, removing dirt, rust and any built-up product
• Check that no components are broken or missing (blades, hammers)
• Make sure there are no loose parts

Bearings:

• Check for excessive play, unusual noises and overheating
• Worn bearings with a lot of play make it impossible to obtain stable readings

Foundation and frame:

• Make sure the unit is mounted on a rigid foundation
• Check that the anchor bolts are tight and there are no cracks
• Eliminate any "soft foot" (where one support does not sit flush against the foundation)

Stage 2: Setting up the Balanset-1A

Mounting the vibration sensors

Fig. 2. Sensor mounting layout: 1, 2 — vibration sensors on the bearings, 3 — laser tachometer, 4 — USB unit, 5 — laptop

Where to mount them:

• On the bearing housings, as close to the bearing as possible
• For the strongest signal — in the direction of maximum vibration (usually horizontal)

Stage 3: Run 0 — initial measurement

Aim: to measure the original vibration level without fitting any weights.

Procedure:

1. Start the machine and bring it up to a stable operating speed
2. Make sure the rotational speed is steady (not fluctuating)
3. In the software, press the "Run #0" button
4. The instrument records the rotational speed, vibration amplitude and phase

Stages 4–5: Run 1 and Run 2 — trial weights

Aim: to establish how the system responds to a known change in mass.

Choosing the trial weight mass

The trial weight must produce a noticeable change in the vibration:

• A 20–30% change in amplitude, OR
• A 20–30° change in phase

Stage 6: Calculating and fitting the correction weights

Based on the vector changes recorded during the trial runs, the software automatically calculates the mass and fitting angle of the correction weight for each plane.

Fixing methods:

• Welding: small metal plates are welded on (the most reliable and durable method)
• Bolted connection: where threaded holes already exist or can be drilled
• Special clamps: for certain types of rotor
• Removing mass: drilling out holes (less preferred)

Stage 7: Run 3 — verification measurement

After fitting the permanent correction weights:

1. Start the machine
2. Press "RunTrim"
3. The software measures the residual vibration
4. Compare it against the tolerance to ISO 1940

Success criteria:

• The vibration has been reduced by a factor of 5–10
• The residual imbalance is within tolerance
• Vibration falls in zone A or B to ISO 10816

Stage 8: Common mistakes and how to avoid them

Mistake 1: balancing a dirty or faulty rotor

The problem: Trying to balance a rotor that has caked-on dirt, worn bearings or play.

The fix: Always check the condition of the machine before balancing. Cleaning and repair come first.

Mistake 2: trial weight too small

The problem: The trial weight is too light and the vibration changes by less than 20%.

The fix: Increase the trial weight by a factor of 1.5–2 and repeat Run 1.

Mistake 3: unstable rotational speed

The problem: The speed "wanders" between runs, or the machine is running close to resonance.

The fix: Fix the speed (e.g. 1500 rpm for all measurements). If the phase "jumps", change the speed by ±10–15% to move out of the resonance zone.