Generator shaft voltage measurement

[jmomic]

Generator rotor shaft is grounded on the turbine side. To test this grounding and also the status of the bearing we are checking the induced shaft voltage on the other end. The good values are 0.5 to 1 VAC. I am looking for signal conditioner or something to connect this measurement into the dcs which accepts only standard industrial inputs like 4-20mA, 0-10VDC etc.

Thanks for help

 

[esee135]

Try a Weidmuller anything to anything converter. The older version (not the pc connect setup version) is fast when you swept sine them into the kHz range. They also have a crazy amount of voltage isolation I believe they are orange and gray, not the new black and red.

http://catalog.weidmueller.com/proc...=5D937065BDECDF86AF27B94A71B61B50?productId=(

[8540310000]%29&page=Product

That may not be the exact model, but they had a true anything to anything (0-10, 4-20, 0-20, name it, it had it, in or out) converter, and it had a switch on the side to select the speed range. Ultra fast, and nice.

You could be 0-10V input, and just zero and span it to spread to 0-10 or 4-20 for your range.

 

[byrdj]

It has been a long time since I went to take a CE shaft voltage, but I recall using a scope to look for arcing peaks in the traces. I also remember VAC much higher

as far as "meter" reading, I took those at the TE to verify ground was effective. TGs with limited access to turbine area had a simple galvonic movement in CR with a pnematic piston putting a carbon brush on the TE shaft for weekly checks