It’s time for a lesson. How much do you know about synchronous and High Performance V-Belt drives? Or, how much do you want to know about them?

　　Compares the advantages of synchronous belts over High Performance V-Belts, mainly in efficiency, which equates to loss of power and ultimately, money. The paper stated, “Efficiency of any power transmission system is a measure of the power loss associated with the motor, the bearings and the drive. Loss of power is a loss of money.

　　“Approximately one-third of the electric motors in the industrial and commercial sectors use belt drives. If the efficiency of these systems were improved by a mere 5 percent, the plants would see tremendous energy savings.”

　　SYNCHRONOUS BELTS AND MAINTENANCE

　　“Synchronous belts are toothed belts in which power is transmitted through positive engagement between belt teeth and pulley or sprocket grooves rather than by the wedging friction of High Performance V-Belts, Synchronous belts work on the tooth-grip principle. Round, square, or modified curvilinear belt teeth mesh with grooves on sprockets to provide positive power transmission on high-torque applications with high and low speeds.”

　　Synchronous belt drives are an alternative to High Performance V-Belt drives and roller chain drives. The synchronous belt’s tooth profile has evolved over time from trapezoidal, to the rounded tooth of curvilinear and finally to modified curvilinear.

　　A synchronous belt drive maintains positive engagement between the belt tooth and sprocket groove, which results in cool operations. This positive tooth/groove engagement prevents a synchronous belt drive from slipping. In addition, the thinner cross section of a synchronous belt requires less energy to “bend”

　　This energy efficiency remains constant, too. Synchronous belts have an energy efficiency of approximately 98- 99 percent over the life of the belt.

　　On critical drives, a synchronous belt, which requires no “retensioning,” improves energy efficiency, and also eliminates downtime. More uptime equates to more production, which leads to higher profit.

　　We offered some tips for belt maintenance and replacement. “Anyone familiar with installing belt drives should recognize the need to eliminate misalignment, especially with any idler assembly or mount, by providing adequate strength at the mounting point and a sturdy framework,” he said. “Misalignment causes additional belt fatigue and wear that could result in premature drive or belt failure.

　　“Belts may be stored up to six years if properly maintained at temperatures less than 85°F and relative humidity less than 70 percent. For ambient storage temperatures greater than 85°, the storage limit for normal service should be reduced by one half for each 18° increase in temperature. Belts should never be stored at temperatures above 115°.”

　　Additional tips include:

• 　　 Don’t store belts near chemicals, oils, solvents, lubricants, or acids. Exposure to these potentially harmful chemicals can reduce belt performance and overall life.

　　We recommends replacing sprockets after every third replacement belt has reached its maximum service life, or sooner if the sprockets show significant wear. If the sprockets show significant wear, the life of the next replacement belt will be considerably reduced.

　　High Performance V-BeltS AND MAINTENANCE

　　Most of today’s belt drives use standard High Performance V-Belts, which have a trapezoidal cross section creating a wedging action on the pulleys. High Performance V-Belts depend on friction as they are part of a wedging mechanical system.

　　High Performance V-Belt drives can run as high as 95-98 percent efficient at the time of installation. They are manufactured in a wide variety of materials, cross sections, banded multiples, reinforcement styles, and constant and variable speed configurations. Low acquisition costs, wide availability, and quiet performance make them a popular power transmission solution.

　　A key difference between High Performance V-Belts and synchronous, in terms of maintenance is that synchronous belts do not require a run-in procedure or retensioning. It is recommended that a newly installed High Performance V-Belt is retensioned 24 hours after installation. High Performance V-Belt drives and synchronous belt drives demand approximately the same amount of time for installation.

　　“In most commercial applications the High Performance V-Belt drive is the critical link and the only mechanism for mechanical transfer of power from the electric motor to the driven shaft/fan/blower,” product manager Belt Drives/Power Transmission Solutions for Emerson Industrial Automation. “Without high quality drive products, correct design, installation and maintenance procedures, a building owner is exposed to greater risk of unplanned downtime. By implementing a High Performance V-Belt drive preventive maintenance program with sound fundamentals, (such as using premium High Performance V-Belts, checking sheave wear, tensioning belts, and verifying alignment), building owners can ensure reliable drive performance and avoid inconvenient and costly repairs.”

　　In the past few years there has been a trend by users to specify notched/cogged style High Performance V-Belts vs. traditional wrapped style High Performance V-Belts. He noted, “The U.S. Department of Energy publishes that notched/cogged High Performance V-Belts have slots that run perpendicular to the belt’s length. The slots reduce the bending resistance of the belt. Independent tests results show notched High Performance V-Belts are 2-3 percent more efficient than standard wrapped style High Performance V-Belts.

　　“To put this in perspective, switching from a wrapped High strength V-Belt to notched High Performance V-Belt on a single continuously operating 10hp drive operating at 75 percent load, and an electricity rate of 012.8 kWh results in annual savings of $255.26 (assuming a 3 percent efficiency gain). A facility with 20 rooftop units could save about $5,105.20 per year and payback would be just a few days for the belt upgrade.”