Electrical runout? What are you using?

[Ralph2]

Hello.
We are frequently asked to provide a mechanical and electrical runout report on rotors that come into our shop. We have made a device that works but....... because it looks (is) home made customers are skeptical about its accuracy.
So, what are others using?. Any links to portable equipment? How do you calibrate / prove the calibration? What do you use to rotate the shaft / rotor (lathe, vee blocks, between centers........)?
Thank you for your time
Ralph

 

[dgallagher]

We have a runout detection/documentation kit that will work for you. Typically the shaft is in v-blocks if it can be rotated by hand or in a lathe. We use an eddy probe to observe the shaft and display the runout signal on a digital oscilloscope. An optical sensor observes a once per turn trigger - we like to see 2 to 3 trigger pulses on the run out trace on the scope. We can document by printing the scope display or downloading to the scope meter's software to include in a report. We designed a "Bucking Amplifier" to offset the DC gag voltage of the probe to concentrate the display on the changes around the probe gap.

Link to product information:

http://www.stiweb.com/proddata/cmcp810.htm

Residual magnetism, residual stress concentrations, precipitation hardening (pH steel), non-homogenous metallurgical composition around the circumference of a shaft, can all generate electrical runout readings.

 

[Ralph2]

Thanks David
Will pass the information on to the appropriate people.
Ralph