I'm looking for links to companies that manufacture Torsional Converters? These are the devices used to condition signals from sensors such as prox probes, encoders, tachometers, etc. when used to measure rotational vibration, torsion or speed variation of rotating equipment and webs.

Many years ago I used a Spectral Dynamics torsional converter (SD-25 380 - no longer available) and another box made in Japan by a company called Minato (now sold under the ATC brand -- but it's expensive). I also know that Caterpillar made one (maybe still makes one) but I can't find any specific information on it.

I've found a (relatively) new USA company offering custom made torsional converters. The company is Copp-Tek, http://www.copp-tek.com/

I'm interested in finding other providers.

The first sentance in my post was not a question. The "?" was a mistake.

"I'm looking for links to companies that manufacture Torsional Converters."

Tony,

If you search for high speed Frequency to Voltage converters you may find one. Hear is a quick link to one product:
http://www.onosokki.co.jp/English/hp_e/products/keisoku/revo/fv1300.htm

I use a Copp-Tek that works well. It has the advantage that the ouput is calibrated into usefull units. I believe that Phil Copp made the unit for Caterpillar.
I also use a strain gage/telemetry system for torque and torsional vibrations.

Walt

Thanks Walt. I remember I did find Ono Sokki in my searches. I need an input frequency range to at least 100k Hz. Ono Sokki only goes up to 20k Hz.

The older Minato had an input frequency to 1M Hz. That model is no longer produced. The new ones go to 100k Hz. as does the Copp-Tek torsional converter.

The nice things about the Copp-Tek torsional converter are it's small size and low price.

Bently Nevada makes the TK-17. PDF at http://www.bently.com/prod/products/datasheets/141581.pdf

John

Thank you again for the replies.

quote:

I use a Copp-Tek that works well.

Walt, will you be so kind and contact me at ibrahim3i(at)yahoo.com? I have a CoppTek but I can not use it. I have tried to get help from Phil but unfortunately despite his many efforts to provide that help, the end result has been a failure.

I am wondering if you can maybe help me get my unit working. The spectra we get are totally meaningless.

Besr Regards
Ibrahim H Caglayan, PhD
Ankara TURKEY

Ibrahim,

You can check the Copp-Tek unit for proper electrical operation with a controlled signal (pulse or square wave) from a function generator. A quick turn back-and-forth of the frequency knob will give a crude frequency modulated signal. I can also generate a modulated signal with DasyLab. Be sure to use your analyzer/counter/tachometer to "see" the fundamental frequency (rpm x # encoder lines) from your encoder output, or you are wasting your time feeding the signal to the torsional converter.

1) The biggest issue is to get a good signal from an encoder. I have had poor/inconsistent results trying the "homemade" optical target approach.
2) The encoder housing/sensor must be free of vibration or it will generate false signal modulation.
3) The encoder must be located along the power train where angular velocity is expected to be high. This is opposite the strain gage approach, since you want a location with high strain that (by definition) has low angular velocity.

Hope this helps,
Walt
w_f_strong [at] msn [dot] com

This message has been edited. Last edited by: Walt Strong,