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i have an electric motor that's submerged in water/glycol. after 1000 hrs of testing, i noticed two regions of corrosion or pitting 180 degrees from eachother. the corrion only effects the ends of the magnetic region of the rotor (see attached sketch). does anyone know what may have caused...

after 1000 hours of testing an electric motor runnig in water/glycol i noticed two large areas of corrosion on the rotor. The two areas of corrsion were located at each end of the magnetic portion of the rotor. The corrosion did not wrap around the circuference of the rotor which makes me...

The attached images show vibration with respect to time. the data was taken from X and Y accelerometers attached to the bearing housing. after looking closely at the data, i now feel that the 210 Hz peaks are not caused by whirl. Im thinking that maybe the impact force excited a rigid body...

Greg, thanks for the input. So whirl can only occur at the rotor's bending mode frquency? can any of the rigid body modes induce whirl? the rotor's bending mode is at 500 Hz

I'm fairly new at rotordynamics and I'm having some trouble interpreting some test data. i would appreciate some input. We're working on a motor that runs on magnetic bearings. The mag bearings lost power during a test and the rotor dropped onto a set of auxiliary ball bearings while spinning...

sketch attachedhttp://files.engineering.com/getfile.aspx?folder=2d8ee3e9-8c44-4722-89a1-bf94568e2da5&file=sketch.JPG

Thank you for the feedback. its not a homework assignment. I work for a company that designs large electric motors for surface and subsea applications. for the last 2 years I've worked on design and analysis of the rotating components in the surface motors (no water pressure). I'm being moved...

Good afternoon, I'm having some trouble understanding how parts will behave when submerged under 3,000 psi of water pressure. One case in particular - if there's a annular disk and hub assembly (both steel) with an interference fit of 2,000 psi. so my question is: even though the...

Thanks everyone for the input. My intent was, as zdas04 mentioned, to operating the gearbox in its intended direction and speed... except i will be driving the low speed output shaft. Internally, the thrust loads will be in the same direction. The only difference will be that the tooth...

Mike, What would i be looking for in the oil sample? The company that manufactured this gearbox was acquired by a company in Germany. The design is 12 years old and the new company is not familiar with the design intent of this gearbox. They prefer not to advise on running the gearbox as an...

I'm looking to purchase a used 4,000 hp gearbox with a single stage helical gears. It was designed to be a speed reducer but I'd like to run it as a speed increaser. Gear ratio - 14:1 low speed shaft - 1,800 rpm high speed shaft - 25,200 rpm the gearbox is single direction. Can i run...

thanks guys, I'll check them out.

I'm looking for a gearbox for a 4000 HP motor. Does anyone have any suggested vendors that i can work with? Preferably, I'd love to find a used gearbox that can handle this power. I'd appreciate any info on suppliers that may carry used boxes. Thanks and best regards, nick

I'm curious as to how the strength of an annealed 8inch round bar made of Inconel 625 varies from center to O.D. Is it possible that the strength (and hardness) is much higher the further you go out in radius? if so, by how much? Material cert shows that the material was tested to have a yield...

Hello, I'm working on a motor enclosure design for a large electric motor. Originally it was designed as a one-piece solid cast part. I've been instructed to make a machined design instead. my plan is to take the original cast design and break it up into sections which would be welded...

Thought some of you would be interested in an update on the situation.... I took the advice of many of you and demanded more time to do a proper in-depth analysis. I even showed my bosses this thread and it freaked them out too see so many comments of how risky this application is. Thanks for...

dheng - the analysis actually was done before the parts were ordered. i looked throw the analysis and the approach looks accurate. The analysis calls out for heat treated inconel 718 to a yield strength of 120 ksi min. The problem was that the designer forgot to add the heat treat spec to the...

i just realized something... if there's any plastic deformation, it would only occur at the center hub where the stresses exceed the yield limits. The radial and hoop stresses reduce at higher radii so i'm definitely over estimating the amount of deformation because not the entire disk reaches...

Mintjulep, that's interesting; i hadnt visualized it that way. that failure mode makes a lot of sense. rb1957, yes the problem area is in the hub. I have calculated that the radial stress goes from about 28 ksi down to 14 ksi while the hoop stress starts at 49ksi and rises to about 69 ksi...

Tmoose - no holes other than the center bore. Greg - i agree... i'm gonna request some more time.