About the Author
A mechanical engineer by trade, Scott Dow has been working in the vibration world for over 25 years. During that time, he has worked extensively as a field analyst and as a trainer, teaching formal classes and also mentoring clients individually and in small groups. During the mid-90s, Scott developed an innovative training method based on recreating interesting and educational case studies he had encountered. Students would receive the actual data to analyze and were free to request any field tests they thought would help them diagnose the problem. Originally called InterActive Training when it was introduced, the cases have recently been updated and the classes are now being offered by Mobius as Analyst Flight School.
Scott currently owns his own business, CBM Consultants. When he is not conducting classes, he continues to mentor both individuals and small groups with either on-site or remote support for database setup, building analysis skills, field testing and more.
The enveloped signals are impact signals,is fundamental frequency harmonics also observed in demodulation spectrum?
Yes – anything that can cause impact-type events. Rotating looseness would be have a 1x fundamental on the demod as would a rub (impact). 2x line frequency is also often observed and is related to winding movement. Gears, hydraulics, reciprocating equipment – anything with a high level of jerk (rate of change of acceleration) can generate peaks on the demod spectrum at the related forcing frequency.