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You may want to look at thread384-39286. Can I have a star too?

I almost forgot the last part to normalize the window: w = w / (a0+a1+a2+a3+a4) Regards, Troy

I'm sorry, but WIM32's formula looks a little strange. There should be a pi and no exponents. Also, the initial constant should be close to unity. For the P201 window I have: a0=0.999028 a1=2*0.925752 a2=2*0.351960 a3=0 a4=0 w = a0 - a1*cos(2*pi*t/T) + a2*cos(4*pi*t/T) - a3*cos(6*pi*t/T)...

vanstoja - Those are good references. Blevins also has a good book on flow induced vibration and vortex shedding. hfzmm - We have performed several field investigations of large heat exchangers. Tests we have used include impact tests of the tubes while the unit is down, strain gages inside...

Skip, The engine/generator sets I was telling you about ran at 1800 RPM. To confirm if your vibration is strictly due to unbalance or if a lateral critical speed may be involved, I would suggest performing an unloaded speed sweep. The amplitude of the 1x vibration should change with the...

dshiel, Have your operating conditions changed in the last month? Is the motor variable speed? Are you running at a different point on the pump curve? Has the consistency of the process fluid changed? When you check the motor current, is it pulling more amps than before?

The motor driven mud pump system that I was telling you about also uses Kevlar belts. I've heard that this type of belt is very strong and can actually be tightened to the point of bending the shaft before the belt will break. If you feel that the belt was not overly tight, then another...

I have tested several planetary gear systems and have found the following book to be very helpful. The Gear Analysis Handbook By James I. Taylor

Skip, Anyway you look at it, the vibration levels that you measured on the generator bearing are too high. A few years ago, I did extensive vibration testing of several diesel engine generator sets. The single bearing generators had high vibrations for several reasons: 1. The overhung...

I recently performed a field test on a motor driven mud pump system. At certain speeds within the operating range, the belts experience a lot of slapping. From the strain gage telemetry system on the motor shaft it was determined to be a torsional resonance. Does you problem occur at a...

A strain gage telemetry system can be used to evaluate actual transmitted and dynamic torque in a shaft. A full bridge arrangement (4 gages) can measure torsional strain while negating strains due to bending, axial and temperature effects. The voltage signal proportional to strain can be...

Poor engine maintenance and cylinder misfire can definitely create torsional vibration problems. In fact, I'm giving a short course on how to avoid torsional vibration problems in reciprocating equipment at the GMRC next month. If you are interested, you may download our paper at...