Have any of you used one of these sonic tensioning meters on belts? If so, what are your opinions? We have good practices on belts, but still have numerous problems with belts from over or under tensioning.

All comments appreciated.

Stan,

I have used one of these to tune a cogged tooth belt that is very prone to flying off the pulleys with great success.

Danny have you used this on any other belt or just on timing belts? I have been thinking about trying to get on due to issues on our I.D. fans we realy have no good way to get proper tension other the old calibrated hand method.

In addition to the "old calibrated hand method" there are these belt tension methods:

1) Force-Deflection method using a hand-held spring gage and ruler
2) Belt Elongation method using a tape measure
3) Constant belt tension by a weight or spring force device on motor support
4) Natural Frequency method using a "Sonic Meter" or equal

I don't own a sonic meter, but have used the equivilent method with a vibraiton analyzer and either tiny accelerometer or microphone. Here are a few issues with belt tensioning in general that I have encountered:

1) Inadequate belt tension requirement based on application (numerical values are too vague or inaccurate based on actual speed and torque)
2) Belt tension and sheave alignment are performed individually and not together, so an alignment change can affect belt tension.
3) Plant operators do not allow machine shut down once or twice after new belt installation for retension as new belts stretch.
4) Belt natural frequency is excited and causes high vibrations and premature belt and sheave wear. Belt frequency can be changed by changing tension, belt span, and belt weight. The actual natural frequencies of the tight span and slack span are quite different from what is measured under static conditions with machine off.

I also use an ultrasound meter to detect belt wear, slip and sheave misalignment.

Walt

Jim,

No, I have only used it on one timiing belt drive. If the client that purchased it could have obtained the proper tuned frequency, we could have recalibrated an electronic guitar tuner for his purposes (since this is his only belt drive). For this drive it should fall between c and c# in octave 0. (btw, I'm attaching a chart of the frequency of musical notes if anyone is interested.)

The versatility of the device was wasted on this unit, but given the high dollar business that they are in, the $500 or so was easily absorbed.

Frequency_of_musical_notes.doc (40 Kb, 18 downloads)

Danny,

Once you know (or calculate) the frequency, you could have used your vibration analyzer to set the timing belt tension. You could hum if you like while strumming the Timing Belt!!

Walt

That's the real beauty of the device- it has all the information needed to make the calculations for you. Plug in your data and it tells you what frequency to tune to.

A washtub, kazoo, drun, cymbols and a few other things and I could be a one man band, but I would have to play pretty loud. 7000 hp engine at about 10000 rpm.

Danny,

Where is the timing belt on this 10,000 rpm 7000 hp engine? Are we talking top fuel dragster? I assume the engine will be off when trying to tension belt by any method!!

Walt