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Sure this forum is also a great source for such information. Thanks pete, nice articles. Anyway, there is still plenty of space in my "library" if someone likes to share nice information :) Books with real life problems would be most intreresting...

Hey. Thanks alot for your efforts pete. Very interesting presentation. I forgot to add that it is variable speed drive(0 to 1500 rpm). I dont have the vibration data now with me, to see exact resonance frequency. I am at home on a sick leave. But yes, it is one clear peak. It seems to...

In what frequency range was your noise/resonance xkHz? My problem is at about 100 to 150 Hz.

Interesting. For how large machines have you done that?

I am now spamming two topics in a row. I have a problem with end shield resonance vibration in an industrial motor. It 4000 HP 1500 rpm machine with newly modified bearing system. I cannot change the excitation source which is however new anti-friction bearing(DGBB) in drive end. Bearings are...

Hi! I would like to learn about troubleshooting. I am mechanical dude so especially vibration, overheating etc. problems are in the area of interest. Can you suggest some online articles, e-books or normal books about this topic?

Hi! I am choosing bearings for 8000HP 750 RPM generator, used directly coupled(flange mounted machine) to diesel engine. Normally flanged sliding bearings are used in this type of machines. Do any of you have any experience about antifriction bearings in these applications? Special...

Thanks pete for your answer. You are encouraging me for more lightweight design which I was hoping to be real. Yet still comments from others are also appreciated. Sorry, I did confuse mode freq and excitation. For sure 2xLF excitation is kept below mode shape - not another way :) Especially...

I am planning to make as accurate vibration model of electrical machine as possible with Ansys Workbench. Since now, I have only been using FEA modal analysis for vibration design. This is my first time to compute vibration responses. I want to include rotor unbalance excitation and...

Thanks for your quick post. In electrical machines there is always heat coming from the rotor shaft to bearing also - might it be the thing why to choose oversize bearings? And in case of inverter driven motors there are insulated bearing housings used - so bearing and also other losses are put...

Thanks Pete for your quick informative post. Actually, the case here is inverter driven 3-phase motor, so life is complicated :) Sorry not mention that in my 1st post. But anyway, you think that 1x supply is not that significant excitation as 2x supply? Resonance would be there but with a...

Hello, I am making a design of a blower. The impeller is rigidly coupled to the motor. Shall I design the system torsional natural frequencies to be above motor supply frequency (60Hz)? What about 2 x supply(120Hz) ? Many thanks! -S

Hello, Motor bearings seems to be almost always 63-series type. Output shaft diameter seems to be dimensioning the bearings as far as I have been making arrangements. When modified lifetimes(Lhmr) of the bearings are considered motor bearings seems to exceeding easily "infinite life" of one...

Hi, I am engineering a 6-pole motor. Now, I am making FEA modal analysis of the stator frame. From literature and experiment I know that in 2 pole machines the stator frame oval shaped modal frequency is kept sub-critical compared to 2 x supply frequency. That is because the 2-pole excitation...