Hi Guys,

I'm having problem with coal crusher at my plant. Since commissioning period, which was 5 years ago, the crusher keeps tripping on high vibration (oddly enough, it has vibration protection). I personally think the tripping for high vib is unnecceary coz that's the nature of a crusher.

However, my management still insist the high vib trip protection is needed by all means and they ask me to consider increase the tripping setpoint (currently it'll trip at 18 mm/sec). But I cant find any reference standard for crusher equipment and the manufacturer (pennsylvannia crusher) didnt give any reply to my emails.

Any of you guys have experience in monitoring crusher that can help me on this? I need to know how high can I increase the vib setpoint. I'd appreciate any advice / comments. Thanks

Mozaid,

My experience with crushing equipment is that there are two general failure modes which may be detected by overall vibration. One is the structural type failure of foundation, structure, hold down bolts, wear and fatigue of internal crushing mechanism etc. The other mode may include bearing wear/failure.
Can you look at spectrums and waveforms on this equipment? If this is just a transmitter with overall vibration calculated, you are limited in what you can detect. I would take baseline readings while the crusher is empty and another set while crushing. This will make it much easier to detect bearing failures. While crushing, the overall noise and vibration levels make it much more difficult to detect bearing failure. Setting the trip level at 200% of the baseline crushing level should allow you enough warning to investigate structural and internal failures. To detect bearing failures while crushing, you would need to do some high pass filtering, like demodulation/peakvue/high frequency bearing analysis techniques employ.
I don't think you will find standards or recommendations for this type of equipment, as the wide variety of equipment and generally high vibration levels would make that difficult.

Good luck!