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Hi I've been using accelerometers to monitor bearing behavior on a small micro gas turbine. The sensors are mounted on the outer casing perpendicular to the shaft axis to measure vibrations at bearing locations. I'm getting consistent results for measuring the vibration levels at various RPM...

Hi guys I'm trying to implement a phase shift meter in VB.NET between 2 audio signals. I'm using Math.NET cross-correlation functions however they can't calculate the phase shift or lag between the 2 signals as far as I can tell. Can anyone recommend a .NET DSP library that can calculate phase...

Hi all I'm currently balancing micro-turbine rotors using 2 plane balancing method. ISO1940 G2.5 requires a quality balance limit of 0.033mm.gram per bearing location in my case (100,000rpm), which I'm finding near impossible. Is ISO1940 limits a bit of an overkill? The best I can physically...

Hi all I'm currently balancing micro-turbine rotors using 2 plane balancing method. ISO1940 G2.5 requires a quality balance limit of 0.033mm.gram per bearing location in my case (100,000rpm), which I'm finding near impossible. Is ISO1940 limits a bit of an overkill? The best I can physically...

Hi all Can anyone explain the difference between influence coeff vs soft suspension balancing? See video here: https://www.youtube.com/watch?v=KVUcLiuctyE This guy uses soft suspension where he measures rotor dimensions & weights. I thought there was only one method and that was influence...

Hi all I have successfully built a 2 plane balancing machine using the trial weight method. However, it is getting very tedious to run the method again for trimming the balance weights. I would like to build the system that shows the amount of weight I need to trim after each run (without...

Hi All I'm trying to balance a small propeller using a vibration meter. Is there a way I can balance it using trial weight runs and without using phase measurements? Something similar to the 4 run method? I'm trying to avoid the effort of trimming weights constantly to obtain the final...

Hi Can someone explain how dynamic balancing machines determine the "trim weight" required without using trial weights? There is an example in this video http://erbessd-instruments.com/Eng/video.php (2 Planes Balancing of Turbocharger Rotor) that illustrates this. How does the machine...

Hi guys, Does anyone have Python code for calculating vibration magnitude and phase shift using a PC sound card? thanks Mark.

Hi guys, Have been performing the 4 run method for a while now. Works well enough with a vibration meter. The balance weight location works fantastic. However I find that the weight required according to the method is often incorrect (typically lower than required). What am I doing wrong? Is...

Hi guys, I have been experimenting with single and dual plane balancing for a while. I use a simple accelerometer connected to an oscilloscope. I filter the signal using a low pass RC filter which seems to work well. Typically I setup the rotor, sample the signal and then adjust the RC filter...

Hi guys, I was reading an article recently regarding the application of the correction weight when performing a single plane balance. The article stated a rule of thumb, "Always shift the trial weight in the direction opposite the observed shift of the reference mark from the original vibration...

Hi guys, I have been experimenting with a home made single plane balancer. I have used an accelerometer mounted on top of a ducted fan. I use two methods for determining phase shifts between trial runs, 1. A IR sensor which index's a white marker on the fan hub. This signal is superimposed...

Hi guys, Just want to clarify something. I've been running single plane balancing of my small fan units and all is good. Only thing I'm uncertain is the allowable tolerance of the imbalance. I would like to use ISO 1940 as a guide. If I choose G2.5 as my standard, how can I use the "UCW"...

Hi guys, I recently built a circuit that interfaces with a MEMS accelerometer to perform a single plane balance. This was done on an electric motor and fan combination (5" diamater). The circuit interfaces with a CRO and generates a sine wave and also filters any unwanted noise coming from the...

Hi guys, I've been developing a simple dynamic balancer using a MEMS accelerometer and a tacho sensor. I have attached the setup to a rotating disc which is unbalanced by adding a small piece of tape. When I run it up I can see the vibration induced onto the accelerometer which appears as a...