dear all

i face to high vibration at low frequency of planetary ring gear .this gear monitor by two proximity sensor by on line monitoring . frequency rang of on line monitoring system set (10-10k) HZ.at this frequency rang overall vibration is low and accept.but when i measure bu portable vibration analyzer with range of frequency set (0-10k)HZ, I find 6 hz with high amplitude vibration that increase overall vibration to trip .input speed of gearbox is 3000 rpm and out put set to 8000 rpm, so the ring gear rotate at 360 rpm(6 HZ).  i suspect to ski slope FFT that i attach it but the instrument staff check the sensor by oscilloscope and find that 6 HZ frequency with high vibration and stable .we check  other  same sensor mounted on  another gear box  were ok .

does it related to rotational frequency of ring gear?

those this frequency and amplitude is real ? pls share your idea 

best regards  

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John from PA posted:

Tooth combinations?  

Can you provide a cross sectional drawing?  In a planetary arrangement, as opposed to a star or solar arrangement, the ring gear does not rotate.  These are all arrangements of what are termed epicyclic gears.  See my attachment.

 

dear jhon

i think because of input member type of gear is solar 

we have torque converter before gear that set  the ring gear speed  between 0 to 360 rpm.out put shaft speed is max 7200  .i attach sensor list.i get  measurement from sx39.14 and sy 39.15 that i show it by arrow at picture attached . 

best regards

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With input speed of 3000 RPM and output of 8000 RPM the ratio falls well outside the capability of a solar arrangement.  

Also, if you can please use the print screen feature of windows or some “clipping” device and insert your graphics into a Word document,  converted to PDF, if possible.  The detail on the graphics from a phone camera isn’t very good.

 

John from PA posted:

With input speed of 3000 RPM and output of 8000 RPM the ratio falls well outside the capability of a solar arrangement.  

Also, if you can please use the print screen feature of windows or some “clipping” device and insert your graphics into a Word document,  converted to PDF, if possible.  The detail on the graphics from a phone camera isn’t very good.

 

thats right jhon.as you say the ratio fall out side. may i mistake so the gear should be star type.but according to sensor list that say out put voltage is 24 DC ,for proximity sensors this voltage use to just  dc gap but i get  AC signal from sensor bu analyzer .am i right ?

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John from PA posted:

Tooth combinations?  

Can you provide a cross sectional drawing?  In a planetary arrangement, as opposed to a star or solar arrangement, the ring gear does not rotate.  These are all arrangements of what are termed epicyclic gears.  See my attachment.

 

 Type of gear is vorecon voith gear box.

As you find attachment ,the in put is ring gear and the out put is sun gear. So that is non of type arrangement of epicyclic .  

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John from PA posted:

Probably best if you state the exact make/model of “proximity sensor.”

For BN/GE the proximitor is supplied with -24 vDC and the output is negative DC, proportional to the gap between the target and probe tip, and an AC signal that represents the dynamic motion.

 

On line monitoring set the lower frequency at 10hz.does it correct setting when we have rotatating ring at below 10hz.

 On the other hand by setting this lower frequency maybe affected by high or low  mechanical noise frequency and create some high amplitude low frequency below 10 hz. So what should be done  for this case?

Several of us here have helped someone in the past with a Voith compound drive.  You should review the thread at https://www.maintenance.org/to...3#399590942964471203.  Note that understanding these drives can be complex so be prepared to print out some of the attachments from the thread.  In doing so note that Vorecon2.pdf is the correct file to use.  Vorecon.pdf had some incorrect information.

John from PA posted:

Several of us here have helped someone in the past with a Voith compound drive.  You should review the thread at https://www.maintenance.org/to...3#399590942964471203.  Note that understanding these drives can be complex so be prepared to print out some of the attachments from the thread.  In doing so note that Vorecon2.pdf is the correct file to use.  Vorecon.pdf had some incorrect information.

Thanks in advance 

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