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Hvac_vibe

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Reply with quote  #1 
Does anyone have gear tooth counts for Amarillo Drives?  I have a single reduction Model 135 with a 6:1 ratio.  
John from PA

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Reply with quote  #2 
Note: edited

Single or double reduction?  Unfortunately the nameplate value of ratio may not be accurate, in fact at one time I think AGMA asked for +/- 2% on nameplate values on "catalog" or stock type drives.

Do you have input and output RPM?  The more accurate they are the better for the calculation.

Some spectrums to help pick out possible frequencies would be helpful, especially if a double reduction.

Some background information...in 1959, AGMA published information sheet #271.02, "Ratios for Helical and Herringbone Gear Speed Reducers" which listed "standard" ratios based on a (1.5)^0.5 progression. It included a table of "Gear Ratio Tolerances": ± 3, 4, 4 and 4% for single reduction, double, triple and quadruple reduction, respectively.  AGMA 420.04 (enclosed drive standard) in 1975 repeated the ratios, but modified the tolerances to 3, 4, 4, and 5%.  Current enclosed drive standards (e.g., 6010 or 6009) have a clause on preferred ratios, but any mention of tolerances has been deleted. The standards only say that ratio is to be indicated on the nameplate, but does not stipulate nominal or exact.  Checking Falk, Flender and Hansen websites it is interesting to see what they do in their catalogs. Falk's standard products state the 3-4-4-5% tolerances apply. The other manufacturers indicate they give exact ratios, but only to three or four significant figures.
Danny Harvey

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Reply with quote  #3 
Amarillo states in their catalogue that the exact ratio for this drive is 6:1. They don't give the tooth counts but they should not be too hard to divine from the spectra.
John from PA

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Reply with quote  #4 
Good catch Danny, my 77 year old eyes missed that the OP had already stated single reduction Model 135.  I'm surprised it is exactly 6:1 but that is what the catalog shows.

Anyway, the graphic below is a catalog drawing of a single reduction.  These drives have an inspection opening.  So do you have a spare drive (or gearset) in a warehouse where you can count the teeth?  And if you are concerned about a particular drive, perhaps it a good time to look inside anyway.

Capture.jpg

Hvac_vibe

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Reply with quote  #5 
Thanks for the info guys.  I completely forgot they had the inspection covers.  I knew they were there too. [redface]  I was just wondering if anyone had some inside info.  I have 3 we are beginning to monitor and are changing out 2 next week.  Ill pull the inspection cover and check for myself before we send the others back for rebuild.  Thanks again.
John from PA

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Reply with quote  #6 
Once determined, I’d still be interested in the tooth combination.
Hvac_vibe

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Reply with quote  #7 
9 tooth pinion and 54 tooth ring gear. No gear damage.  Just worn and a lot of "slop" between ring and pinion.  Also looks like we had some moisture in the oil.  New one is up and running.  Need to go by and epoxy my targets/studs and get a baseline.  Also verify alignment with the drive shaft.



Tower Gear pic.jpg 

fburgos

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Reply with quote  #8 
Whats the gear assembly frequency?

3*3=9
3*3*3*2=54 or 9*3*2=5

3 or 9?


John from PA

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Reply with quote  #9 
9...frequencies below based on 1800 RPM at the pinion.  Proportion as needed if different speed.

Interesting tooth combination by the way.  Without looking it up 9 is about at the bottom of what you can cut in a spiral bevel without some undercutting of the tooth.  It would be interesting to know what drove the engineering decision or compromise.

Capture.jpg

John from PA

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Reply with quote  #10 
Quote:
Originally Posted by fburgos
Whats the gear assembly frequency?

3*3=9
3*3*3*2=54 or 9*3*2=5

3 or 9?



The definition of the number of assembly phases is
Quote:
The number of assembly phases (Na) in a given tooth combination is equal to the greatest common divisor (GCD) or the product of the prime factors common to the number of teeth in the gear and pinion.


I've emphasized the common.  So what is common?

Capture.jpg 



Hvac_vibe

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Reply with quote  #11 
I’m just a level 2. 😂. Y’all are throwing my mind for a loop. But I’m gonna research and learn.
John from PA

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Reply with quote  #12 
Quote:
Originally Posted by Hvac_vibe
I’m just a level 2. 😂. Y’all are throwing my mind for a loop. But I’m gonna research and learn.


Go to the thread at https://www.machineryanalysis.org/post/not-your-typical-beat-8128991?highlight=gear+generated+spectra&trail=30, specifically reply #16 where I’ve posted a paper about the frequencies you can get from two toothed wheels in mesh.
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