11.11.2020

In this video we will introduce and describe the new Adash Advanced Balancing module and explain the basic balancing methods.

All of you know the standard balancing procedures. It is one plane balancing with one measurement point, it is two plane balancing with two measurement points. And generally speaking it is all balancing jobs where the number of planes is equal to the number of measurement points.

Now we should discuss a little about balancing procedures. If the rotor is unbalanced, then the heavy spot exists. The real balancing is the procedure when we find the position and weight of that heavy spot and then we remove it. Or we mount the same mass to the opposite position.

Let's begin with example. I want to balance the wide rotor. The rotor and two measurement points. Correctly I should do two plane balancing with two points. But I have an access to the plane 1 only. The plane 2 is for example under some cover and I have not access there. What to do now? I use the advanced balancing procedure. I need to enter two numbers. The number of planes - it is one. Next is the number of points - it is two.

Next steps are the same as for standard balancing. I use two sensors for point A and B. The first run is the initial run. I get the amplitude and phase for each point. Next is the trial run. Again two measured values. Now the result is displayed. It is the final mass weight and angle. But what does it mean?

If I have access to both planes, then I do two trial runs Then I get the two masses for plane 1 and plane 2. The vibrations should decrease theoretically to zero when I mount them. But if I can mount mass just to plane 1, then I get residual vibrations in both points. And this is the key point. I want get the residual vibrations as low as possible. And this is actually what advanced balancing can do.

You can define up to eight planes and up to eight points. For example 1 plane and 4 points. Or one plane and 8 points. Or 4 planes and 8 points, et cetera. The basic reason remains usually the same. I don’t have access to all required planes.

The advanced balancing gives two solutions. It means two sets of final balancing masses. The first is made by L2 norm. By other words it is the least squares method. It means that the sum of residual squares is the lowest possible value.

The second result is made by L infinity norm. The maximum of residual vibrations is the lowest possible value.

Let's show the example. / "example 1 plane and 4 points"/ If I have 1 plane and 4 points, then I have 4 residual vibration values. Now I will overact two results, which I get. The L2 result is 5, 0, 0, 0. The L infinity result is 3, 2, 2, 2. Now it is on me, what result I prefer.

The possible result is also no result. It means, that adding of any masses in any positions will increase the vibrations. But in real life you probably will not get this result. But with special theoretical values it is possible.

For example, I have one plane and two points. The initial run values are: 10 mm per second amplitude and zero degrees angle for both points. The trial run values are 14 mm per second and 45 degrees in point A and 14 mm per second and 315 degrees in point B. In this situation no mass will help you. Try to find out what is the reason. If you want to decrease amplitude in point A, you must turn the mass of plus 90 degrees. Then you get zero vibration on point A but two times higher vibration in point B. When you turn of minus 90 degrees, then you decrease vibration on point B, but you increase vibration in point A.

The advanced balancing gives also the sensitivity information of results. What is it? It means what would be the residual values, when I mount the masses with some error in position or weight.

I use the example again. I have one plane and two points. The result is 100 grams mass weight and 90 degrees angle position. The residual amplitudes are 2 and 3. But I mount the mass with some error. In weight or angle or both. The percentage residual values informs me, what would be the residual amplitudes if I mount the mass with 5%, 10% and 20% error. For example I get 2,1 and 3,2 for 5%. 2,2 and 3,3 for 10% and 2,3 and 3,4 for 20% error. This is low sensitivity. I can mount the mass with error and residual amplitudes does not increase too much. But I can get 5 and 6 for 5%, 10 and 12 for 10% and 20 and 25 for 20% error. It is high sensitivity. I must use accurate weight and accurate angel to achieve the low near amplitudes 2 and 3.