Spectrum tolerance
Spectrum tolerance
(OP)
Hi folks,
I'm looking at a spectrum signal of a 3600 rpm spindle. one of the bearing defect frequencies is 2332 hz and 2915 hz according to NSK spec. I got a high peak (about 450mg) at 2337 hz and 2918 hz (about 520mg). Is there a tolerance on those readings? Can I condiser those frequencies as bearing defect frequencies?
Thanks
I'm looking at a spectrum signal of a 3600 rpm spindle. one of the bearing defect frequencies is 2332 hz and 2915 hz according to NSK spec. I got a high peak (about 450mg) at 2337 hz and 2918 hz (about 520mg). Is there a tolerance on those readings? Can I condiser those frequencies as bearing defect frequencies?
Thanks





RE: Spectrum tolerance
Any way, with two discreet frequencies each containing about 0.5 g, whether peak or rms, your overall almost certainly exceeds 1 g. The fact the vibration frequencies are such a good match for fault frequencies is remarkable, and indeed suspicious. Fault frequencies 38 and 48 X rotation are numerically pretty high. Are these double row roller bearings?
Is there any vibration history for this spindle? If the vibration is new, it is suspicous also. A good crash can create inner and outer race defects instantly. I like to check my analyzer is configured correctly for the accelerometer sensitivity, and the mounting method is suitable for these high frequencies too. How does the spindle sound, by maked ear, and also listening with a rod or screwdriver?
RE: Spectrum tolerance
-The future's so bright I gotta wear shades!
RE: Spectrum tolerance
RE: Spectrum tolerance
In fact if you calculate the bearing defect frequencies from the standard equations (using the manufacturers data on contact angle, # rollers/balls etc), it also differs by a few Hertz from the manufacturers quoted frequencies.
In short, you are close enough in my books. What are the chances of something else generating that particular frequency anyway.