to electricpete: Big thanks for answers! I´ll check the linked article in next possible occasion. The mechanical resonance is of course one possibility. The damping of this kind of structure (steel) is low causing a sharp peak (hign amplitude & not much spread in frequency). However impact tests...
to waross: I have learned term beating so that it is the penomenon where frequencies close to each other interact. Typical examples are belt driven fan where pulleys have close diameters and motor & fan have close rotation speeds - or - two machines with nearly same speed sitting in the...
Hello all. Comments & answers:
to waross:
- There is vibration at 4,2 Hz frequency. Amplitude is 0,13 mm/s, rms and measured at the stator core.
- Saliet poles = yes
- Air gap issue = fully possible. Probably the air gap is not measured for a loooong time (=meaning a few decades)
- Reverse...
Thanks for answers!
Comments (sorry, first time here so can not use all fancy stuff what the page offers :))
to crshears: Probably it does not matter and have been there for a long time. Just want to know the reason for the excitation.
to bacon4life: Sorry, wont open for me either. tried now...
Hi.
I measured a bit strange stator vibrations at one hydro power unit. It is a 125 rpm vertical Francis turbine (~24 m head) directly connected to the generator. There were totally four accelerometers installed radially at the stator frame and all measurement locations indicated similar...
