"Combination" Sheaves

[CRS1]

I have recently been seeing a number of Browning "B5V" sheaves used in air handler applications. The claim is made by the manufacturer that these are usable with both standard and narrow belt profiles. It would seem that it must be a compromise, fitting neither well, and in addition, it is impossible to gauge to judge sheave wear using standard gauges. Anyone with opinions, experience...?

Thanks.

Tim

 

[willdo]

I have been very pleased with the B5V sheaves. You can run A, B, or 5V section belts on them so it cuts down on the amount of spare parts you have to stock. You can't use banded belts with them. Combination sheaves have been used successfully for years. The belts ride in different parts of the grooves so you have to look up the actual pitch diameters for the belt cross section when designing drives.

 

[unclesyd]

Just check today and have to concur with willdo. We have over 30 large air handling units and about half are now running on combination sheaves. A combination sheave is the standard replacement. These units are 150 to 300 Hp and run 24/7/365. Pulling up the 10 year maintenance records show no problems with the sheaves. Other than changing belts the only major problems, on two units, was some idiot pulling the belts too tight and breaking the motor shaft, it happened twice.

 

[Tmoose]

"pulling the belts too tight"

Did that one use an unusually long belt span and smallish motor sheave ?

 

[unclesyd]

Yes, on these particular units the ratio was high. These were 1950's vintage Buffalo’s and the fan was quite heavy and slow compared to the newer units. The belts were installed close to being right and after operating a short time the heating and air conditioning technicians requested that the belts be tightened to mediate the belt noise and the mechanic evidently tighten them until there was no noise. The first two times the problem was masked due to having a spare motor and spare shafts. I was appraised of the problem when asked about replacing the outboard pedestal bearings and getting a new material for the shaft when the third and fourth shafts broke.

 

[diskullman]

These pullies are "suitable" but not optimum, as some efficiency will be lost. It makes it easier for the distributor that can cover more applications with less product on hand

Russell Giuliano
Unique Technologies Associates - Cobra Solid Lubricant

http://www.uniquetechnologies.com