Technical library
How balancing works with Balanset-1A
From the first measurement to the verification run: what happens at each stage, why the software asks for exactly these values and how to read its result.
Manual review: 8 September 2026
In short
First you measure the vibration as it is. Then you give the rotor something to respond to: a weight of known mass, first in one plane and then in the other, with a run each time. From the difference between those runs the software works out how many grams to add and at what angle. What remains is to fit the weights and confirm with a verification run that the vibration has dropped.
What the measurement needs
- Two vibration sensors
- Measure vibration at the rotor bearings.
- Laser tachometer
- Reads the reflective mark. From its signal the instrument counts speed and measures vibration phase.
- Unit and software
- The unit takes the signals, the software calculates the weights.
01
Sensors, planes and preparing the machine
Two different places on the machine are involved, and it pays not to confuse them. The sensors go on stationary parts near the bearings: they only listen to vibration and stay there for the whole job. The weights go on the rotor itself, and they are what changes the balance.
A correction plane is a place along the rotor where a weight can be attached securely: the edge of a drum, an impeller disc, a fan shroud. For two-plane balancing, pick two such zones spaced along the length and name them “Plane 1” and “Plane 2” from the start. Those numbers travel through the software, the calculation and the report, so there is no reason to renumber them halfway through.
Time spent inspecting the machine before the first run is rarely wasted. Clean the rotor of caked material, check the bearings, the mounting of the supports and the fasteners. Balancing evens out the distribution of mass; it does not cure play, rubbing or a damaged bearing. On a faulty machine the calculation will still succeed — and the vibration will stay.
Fit sensors and weights only on a stopped machine that cannot start unexpectedly, and put the guards back before every run. That rule applies at every stage that follows.
Sensor — where you measure. It stays in place for the whole job.
Plane — where the weight goes. The software calculates a separate mass and angle for each one.
How this looks on a mulcher
How to mount the sensors and aim the tachometer
Mount each vibration sensor on a rigid, stationary surface next to the bearing — on the bearing housing rather than on a thin cover that rings on its own. Choose the position and direction once: if a sensor shifts between runs, the software ends up comparing measurements that are no longer comparable.
Aim the tachometer at the reflective mark. The instrument counts speed from that mark and ties the vibration phase to it, so without a steady signal there is no calculation: overall vibration is measured without the mark, but that is not enough for balancing. Route the cables well clear of rotating parts.
02
The first measurement: what the meter shows
Before calculating any weights, look at how the machine behaves on its own. Open the Vibration Meter with F5 and let the rotor settle at its working speed.
Take several readings in a row without touching anything. If amplitude and phase stay close from one reading to the next, the data can be trusted and you can move on to the trial runs. A wide spread means something else is changing — usually drifting speed, a varying load or a loosely mounted sensor. It is far easier to find the cause now than after the weights are on.
- Vs Overall vibration
- Every frequency in the measurement band, not just the rotational one.
- Vo / 1× Vibration at rotational frequency
- This is what the calculation uses, together with the phase.
- F Phase, degrees
- The position of the vibration relative to the tachometer mark. It is not the angle for mounting a weight.
- RPM Revolutions per minute
- They show that every run happened at the same speed.
Why only Vo goes into the calculation
Vs is everything the machine produces within the measurement band: imbalance, bearings, gear meshing, neighbouring equipment. Vo is only the component at rotational frequency, and it is Vo, together with the phase, that the calculation uses.
That has a practical consequence. After a successful balancing job Vo drops noticeably while the overall level Vs may stay high — which means other parts of the machine are the main contributors. It works the other way round as well: a large Vo is not proof of imbalance on its own, since misalignment and loose mounting produce a similar picture. So move on to weights once the mechanics are sound and the readings repeat.
03
Trial runs: how the rotor answers a weight
The first measurement only tells you how badly the machine shakes. How this particular rotor responds to added mass is still unknown, and without that the correction cannot be calculated. The trial run is how you find out: you attach a weight of known mass at a known place and see what changed.
The sequence is simple. First a run with the trial weight in plane 1. Then take it off, move it to plane 2 and run again. Mark both positions on the rotor itself, with a marker or paint: you will measure the correction angles from those marks, so they need to survive the whole job.
The table below shows the ordinary case, where the trial weight is removed after each run. For that, leave the “Leave on rotor” checkbox switched off in the software — it exists for weights that genuinely cannot be removed, and then the calculation treats them as part of the rotor.
What sits on the rotor in each run
Trial weight Calculated weight
| Run | What we do | Pl. 1 | Pl. 2 |
|---|---|---|---|
| 0 | Initial measurement | No trial weight | No trial weight |
| 1 | Testing plane 1 | Trial weight | No trial weight |
| 2 | Testing plane 2 | No trial weight | Trial weight |
| T | Checking the result | Calculated weight | Calculated weight |
The same runs in photographs and in the software →
What makes a good trial weight
Weigh the trial weight and measure the distance from the axis of rotation to its centre — that distance is the mounting radius. Enter the mass in grams and the radius in millimetres: the software uses both to express the result in units of unbalance.
The point of the trial weight is to produce a clear response. The manual gives a target: the amplitude should change by at least 20% or the phase by at least 30°. Too light a weight changes almost nothing, and the influence coefficients come out imprecise.
There is no universal mass. What a heavy crusher drum barely notices can be far too much for a light impeller. Judge it by the rotor, the running speed and how securely the weight can be attached.
04
The result: mass and angle
After the two trial runs the software returns a pair of numbers for each plane: a mass and an angle. The mass says how many grams to add, the angle says where on the circumference of the rotor to put them.
The critical part is where the angle is measured from. Zero is the position where the trial weight sat in that same plane, and the angle is counted in the direction of rotation. The tachometer mark will not do: the instrument needs it to measure phase, and it usually does not coincide with the origin for the correction angle. This is the single most common reason a correctly calculated weight ends up in the wrong place.
The easiest way to check yourself is the polar diagram — the “Show Polar” button, or “Show Polar Graph” in the classic form. It shows the mass and angle for both planes at once and carries an arrow for the direction of rotation, so a quarter-turn error is much easier to spot there than in a column of figures.
Example: how to lay off 90°
0° — the trial-weight position. The weight itself is already off; only the mark on the rotor remains.
90° — a quarter turn in the direction of rotation. The rotor in this example turns clockwise, so the place we need is on the right.
The diagram explains the angle only: take the mass from the calculation for that plane.
If the radius or the correction method changes
The calculation is tied to the radius you entered. When the weight has to go closer to the axis or further out, recalculate the mass within the same plane: new mass = calculated mass × old radius ÷ new radius. Closer to the centre means a heavier weight, further out means a lighter one.
The “Add” mode shows where to put metal; the “Remove” mode shows where to take it away, by drilling for example. Those are opposite points on the circle, so read the angle again after switching modes.
A result in percent instead of grams means the trial mass has not been entered and the software is working in fractions of it. The “Mirror” checkbox helps when you look at the rotor from the opposite side: it reverses the direction in which angles are counted, and it is worth checking against the rotation arrow on the diagram.
05
The verification run: what you achieved
Remove the trial weights, secure the calculated ones and start the machine once more. The software calls this run “Run T — trim”.
The conditions have to match the earlier runs: the same speed, the same load. Otherwise there is nothing to compare — if the initial reading was taken off-load and the verification under load, the difference shows the change of regime rather than the effect of the weights.
Compare Vo on both channels first: that is the direct answer to whether there is less imbalance. Then look at the overall level Vs. How far the vibration has to come down is set by the machine documentation or the tolerance agreed with the customer; there is no single figure that fits every machine, so it is worth establishing the acceptance criterion in advance.
Before the weights — Run 0The initial Vo readings on channels one and two.
After the weights — Run TThe same channels at the same speed, with new Vo values.
If one more correction is needed
After the verification run the software may propose an additional mass. It is calculated with the weights you have already installed taken into account, so there is no need to remove them: add what is shown and repeat Run T. Step by step this removes the remainder that almost always appears because of imprecise placement.
Residual unbalance in g·mm and vibration in mm/s are different quantities. If you set a tolerance for unbalance, compare it against unbalance.
06
The report and saved coefficients
A report is not a formality. Six months later, at the next service visit, it answers what was already done to this machine and which values to start from.
Record the machine and rotor, the speed, the readings before and after, and the mass and angle for each plane. Photographs of the sensor positions and the weight locations are worth ten lines of description: they show how to repeat the measurement under the same conditions.
Save the finished report as PDF or HTML. Note the tolerance the work was accepted against and the date alongside it — together with the photographs that makes a complete history of the machine.
When saved coefficients are useful
Influence coefficients describe how the rotor responds to a weight. The software keeps them in the archive, and on a repeat job for the same machine the trial runs can be skipped: an initial run, the correction and a verification are enough.
That holds as long as the setup has not changed — the same sensor positions, the same planes, the same radius. If the bearings were replaced, a sensor was moved or the rotor was overhauled, determine the coefficients again. The verification run is done in every case.
Field checklist
Check the items during the job. These marks stay only on this page and are not sent or saved.
Machine / rotor: __________________ Date: ______________ Operator: __________________
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