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Dear Forums members,

I am balancing a  turbine rotor( HP side journal cladding work done) after completion of above repair activity, we have done re burnishing on the both journal area, electrical run out is within limit, gausse value is up to one, mechanical run out is also found ok.

Low speed balancing done @900 rpm, unbalance brought as per API 612 standard.

Initial shaft vibration (unfiltered) are 16/28 on LP side and 27/27 on HP side.

We have taken full high speed run up to over speed also , the shaft vibration are touching max. 30 micron through out the run and pedestal vibrations are less than 1.0 mm/sec. 

We have rechecked the electrical run out, guasse value also again every thing found OK.

We have interchanged the probes also, but no change.

The shaft vibrations limit is 25.4 microns.

Can anyone analyze the problem and suggest the solution.

Ravishanker

 

 

 

 

 

 

Original Post

The consistent values from slow roll to high speed indicate glitch/electrical mechanical run out on probe track areas.

Hope you have checked the run out on probe areas with respect to the bearing journals.

Can yo share the type of cladding repair that has been carried out?

Normally after repair of Bearing journals, a clean fine cut and burnishing is preferred on probe track area with respect to the bearing journals.

Presume that no cladding has been done on probe track area.

 

 

Dear Forum members,

We have once again checked the mechanical runout and taper on journal area are within 10 microns but ERO is 17 microns on both sides and even guasse value is less than one on both burnishing area.

in journal area we observed some guasse value and this is also brought less than one.

We have once again loaded the rotor in the vacuum tunnel with B & k non contact probes fixed at burnishing area.

Initial shaft vibration readings are 21/29 microns at LP side and 35/35 microns at HP side.There is no change in shaft vibrations at Low speed run.

Later we have changed to shinkawa instrumentation with non contact probes.

Here we observed, 25/20 microns at LP side and 23/25 microns at HP side, looks better values and we have increased the speed up Mcs  (15/15 microns at  LP side and 18/18 microns at HP side and found shaft vibrations are well within the limits  including overspeeding.

regards,

Ravishankar

 

 

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