We are looking at carrying out routine vibration analysis on some floating aerators on a water treatment pond. The motors are quite large (around 150HP) and drive through a reduction gearbox. The motors are moved around the ponds regularly and held inplace with rope. It is not practical pull them to shore to test them (steep sides on ponds) and rowing out to test them is to dangerous/hazardous (chemicals, bacteria very toxic).
In the past we have used permanently mounted accelerometers wired back to the shore. Because of the number of motors it is expensive to install this amount of transducers. We had looked at wireless solutions ie bluetooth transmitters, but again it was not very cost effective.
I was thinking of using a laser vibrometer from the shore (they can measure up to 90 feet without reflective tape)as this is about the same price as the permanent transducer option, but does not have the problems with cable damage and the laser could be used for other dangerous jobs ie working near HV or on rotating shafts etc.
Does anyone have any experiance with laser vibrometers (reccomend a brand etc) or have any other ideas.

Thanks
Bruce

Bruce,

Sounds interesting to use a laser, but what about beam diffraction thru the water spray and aiming accuracy and steadyness over a 90-ft distance? What about a directional microphone? What about motor current analysis? In the case of the laser, I would try before I buy.

Bruce,

The only company I am familiar with is Polytec, Inc in Tustin, California. Their website is: www.polytec.com. These items are quite expensive but would do the job. New wireless (not bluetooth) accelerometers are due to be available next month at a starting price of US$200-400 a point. If you have a lot of points, why not go with electrical signature analysis (ESA). This technology does work, it will show problems with the motor and the load. Don't represent any of the above people but have been using ESA for the past 5 years and have become a believer.

Ken Culverson

Have you considered wireless data transmission? 802.11b works just fine, and a whole lot cheaper thans laser vobrometers......