Hi,

GB details: Double stage single helical for cooling water pump application.

Power:  1450kW; Input/Output speed: 5900/590 (10:1 ratio)

Recently I was shared a site vibration data of a high speed gearbox , The housing vibrations measurement details are attached;

  • From the spectrum data , the dominant frequency  is at 53,000 cpm which is close to 9X of Input pinion shaft rpm.
  • The vibrations are found dominant at pinion shaft non drive end (28 mm/sec)

Kindly share your views.

 

Santosh S

Attachments

Original Post

Q1.  What is the tooth combination?

Q2.  Fluid film or rolling element bearings?

Q3.  Is the casing a weldment or a casting?

Q4.  What is the exact transducer being used?

Q5.  I see 16 mm/secas your highest level acceleration.  I could have done the conversion incorrectly (I'm working from a tablet) but in making the conversion to g's I get the following.  In comparison to API 613, the levels you have measured seem low.

 

 

 

 

Attachments

Photos (1)

The spectrum document shows both acceleration (g) and velocity (mm/sec) plots. Point #4 12.7 g acceleration and 16.7 mm/sec velocity at cursors. The gear tooth mesh (51 to 53 kHz) appears to have modulation sidebands. Suggest more resolution to identify which shaft/gear may have a fault.

Walt

John from PA posted:

Q1.  What is the tooth combination?

Q2.  Fluid film or rolling element bearings?

Q3.  Is the casing a weldment or a casting?

Q4.  What is the exact transducer being used?

Q5.  I see 16 mm/secas your highest level acceleration.  I could have done the conversion incorrectly (I'm working from a tablet) but in making the conversion to g's I get the following.  In comparison to API 613, the levels you have measured seem low.

 

 

 

 

I stand corrected, I quickly scanned the spectra for frequency and relied on the spreadsheet for amplitudes, which are only micron, mm/sec and mm/sec2  

My questions Q1 through Q4 remain to be answered.

Are you certain this is a single helical?  Is the ratio supposedly 10:1 exactly.

Q1. What is the tooth combination?

AI: It is single helical double stage gearbox,

Teeth count: I/P P/S: 26; Int P/S:32 & Int G/W:85; O/P G/W:99

Speed: Input shaft: 5900; Intermediate shaft: 1805 & Output shaft: 590

Q2.  Fluid film or rolling element bearings?

A2: It is hydrodynamic bearings

Q3.  Is the casing a weldment or a casting?

A3: Fabricated casing with weldments

Q4.  What is the exact transducer being used

A4: Accelerometer

Q4.  What is the exact transducer being used

By "exact" I had hoped to learn the make and model of the accelerometer.  In addition it would be good to know how it is mounted, and where.  Is it mounted on a relatively thin portion of the casing or the thick portion of the casing near the bearing.  Any pictures of transducer when mounted?

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