V-Belts; Proper Tension & Alignment Part 1

Hello Technicians;

  One of the many pieces of equipment that moves our product throughout the building and drives our gearboxes powered roller conveyors are V-Belts. Without the proper care for these durable but yet susceptible to damage, down time can be very costly and easily avoidable. When the belts are installed incorrectly and with too much tension, friction and heat increases, this begins to “cook” the belt and weakens it. Similar to taking a small piece of coat hanger and bending it back and forth, it heats up and eventually it breaks; so does v-belts over time.

  Properly aligned v-belt will have just enough pressure under the carrier rollers to turn them. Too much pressure and the v-belt will look like rolling hills, going up and down and thus the belt is now “bending up and down” and the friction is heating up the belt. The life of the belt is greatly shortened due to the unnecessary tension against the rollers. 

  Proper v-belt tension and sheave alignment will improve the life of the belt. Skipping out on the preventative maintenance and daily inspections can cause a surprised down time. I have had many emergency repairs in my career. I remember getting a radio call on a section of a conveyor not running, and when I got there and seen the v-belt; it was shocking! There was a crack half way through the belt every 5/6 inches! This conveyor was ignored excessively long!

 

  Improper V-belt tension is the most common operating problem for belt-driven electric motors, followed by alignment, and that worn sheaves greatly reduce system efficiency while adding to maintenance costs. V-belt drives can have a peak efficiency of 95 percent or higher when installed properly.

  To combat tensioning problems, maintenance professionals should have a strong arsenal of tools that they are well trained to use. These include:

• A tension meter to measure V-belt deflection and tension;
• Infrared tools that identify over-tension;
• Vibration analyzers that identify loose or damaged belts; and
• Strobe lights or tachometers

This web site has a lot of info on v-belts and tension practices.

 

  I am following Grainger on Twitter at this time; they have a lot of good info and I do suggest looking into their news and blog feeds.

  The second major issues are the sheaves alignment. Here is a short video on why the sheaves needs to aligned and how to make the proper adjustments.

  As you have watched, it is not hard to accomplish this task and there is many ways to do so. All three ways should be used to make the corrections. In many cases, a laser may not fit on small sheaves, such as those used to put pressure on carrier rollers.

 

  MI How 2 has many support videos that would greatly enhance your knowledge of the industrial best practices. Motion Industries is one of the leading companies that specializes in belts that transport products or drives motor and carrier rollers. I have worked with a couple of gentlemen from that company and sat in one of their Belt Lacing classes.