Drive belt behavior

[cdsl810 181]

I had an opportunity to watch the drive belt in action with the engine running and the belt cover off of my 520-H. I expected to see nice smooth belt travel--like watching a serpentine belt on a car turning. Instead, what I observe is the belt jiggling quite a bit during operation. The idler seems to be oscillating a bit as well instead of maintaining a taught position. Is this normal? Or is the belt tension loose? If the belt is loose, what is the best procedure for properly setting the belt tension? Thanks...

[W9JAB 156]

Well let’s say that your pulley, bearings, and belts are in reasonable shape.

 

Know that “V†belts, do their gripping on the sides of the “V†and not the bottom.

 

 

A properly tension “V†belt has approximately an inch of up and down play, center of the belt, between pulleys. Over tightening a belt will put unnecessary were on bearings and shafts.

 

 

Pulleys, even though they look all heavy duty, and cast irony, were out! The walls of the “V†dish out after time, depending on tension and application three to five belt changes would be considered normal were. Many belts are blamed for bad pulleys.

 

 

Now add in the clutching feature, and we open a fresh can of worms.

 

In order for the clutching to work the belt needs to slip on the pulley, and ideally come to a stop, while slipping in the pulley.

 

Cogged or notched belts, (AX-BX) have the most aggressive grip, run cooler, and can make tighter turning radices then the solid “V†but will not work well in clutching applications.

The use of Kevlar wrapped belts keep them from “burning rubber†when clutching.

 

The longer the belt, or center distant between shafts, the more shaking, jumping, hopping, etc. will occur. The use of well placed idlers, and belt stop “fingers†will reduce the unwanted action dramatically.

[W9JAB 156]

After thinking about your model, if your running a hydro, or any application were the belt needs to transfer as much H.P. as possible like large alternators, pumps etc. Or high speed is a requirement.

 

You can use a synchronous gear belt, Those are the flat belts with teeth, that ride in a like cogged pulley.

 

The up side is the smother and better power transfer.

 

 

They come in a full range of “flavors†inch / metric, square. Round, and trapezoidal tooth design and unique spacing between the teeth. With and length of belt, and style of system very with power transfer and speed requirements.

 

 

The down side is, the belts and pulleys are very specific to each other. The wrong belt will grind off teeth in moments. So be sure that you have replacement belts on hand. The chance of finding your belt at the local hardware store are slim.

 

Also synchronous gear belts need a “clean†environment to run in. I have lost belts from grass getting tangled up in them.

 

Hopes this helps out.