Synchronous Belt Drives
Belt Drive: Synchronous vs. V-Belt
Belt drives that have teeth that match teeth in the drive sprocket to prevent slippage and maintain high efficiency throughout their service life.
Item ID: 436
Commercial, Industrial, Agricultural
Motors & Drives--Drives
One-third of electric motors in the commercial and industrial sectors use belt drives, with most using standard V-belts. V-belts use a trapezoidal cross-section to create a wedging action on the sheave groove to increase friction and improve power transfer capability. V-belt drives can have a peak efficiency of 95% to 98% at the time of installation, but efficiency deteriorates by as much as 5% over time if the belt is not periodically re-tensioned and slippage occurs. Increased slippage results in additional heat generation and energy losses.
In contrast, synchronous belts are toothed and require the installation of mating toothed-drive sprockets. They operate with an efficiency of 98% and maintain that efficiency over a wide torque range and throughout their service life. The recommended tension for a synchronous belt is less than that for a standard V-belt so motor and driven equipment bearings operate under lower loads, providing a longer service life. Synchronous belts require minimal maintenance and re-tensioning.
Synchronous belt sprockets must be sized to take into account the absence of belt slippage. Operating costs increase if a centrifugal load is driven at a higher operating speed. A properly designed synchronous belt drive should ensure that the final rotating equipment speed is equal to the original or required rotating equipment speed. However, synchronous belts are noisier than V-belts, transfer more vibrations due to their high stiffness, and are less suitable than V-belts for shock-loaded applications. Cost-effectiveness is improved if the synchronous belt is installed at the end of a V-belt life or during a scheduled replacement.
Baseline Description: 40 hp Motor with V-Belt
Baseline Energy Use: 137345 kWh per year per motor
Belt drives are power transmission systems that are often used to increase torque and decrease speed. They allow an 1800 RPM synchronous to drive a pump or fan at a speed of 1300 RPM (or whatever the pump or fan is designed for). They are used extensively with smaller pump, fan, and air compressor drive motors. Consider a Premium Efficiency 40 hp belted fan drive motor that is 75% loaded and runs for two shifts, 7-days per week. The motor efficiency is 94.9% at this load point. The average energy use for this motor is: 0.75 x 40/0.949 x 0.746 kW/hp x 5,824 hours/year = 137,345 kWh/year.
Manufacturer's Energy Savings Claims:
Currently no data available.
Best Estimate of Energy Savings:
"Typical" Savings: 3%
Energy Savings Reliability: 5 - Comprehensive Analysis
Consider a Premium Efficiency 40 hp belted fan drive motor that is 75% loaded and runs for two shifts, 7-days per week. The motor efficiency is 94.9% at this load point. The average energy use for this motor is: 0.75 x 40/0.949 x 0.746 kW/hp x 5,824 hours/year = 137,345 kWh/year. If a 98% synchronous belt is used to replace a 95% efficient V-Belt, the annual energy savings are: 137,345 kWh/year x ( 1 - 95/98) = 4,204 kWh/year. This is about 3% of the initial energy consumption.
Energy Use of Emerging Technology:
133,224.7 kWh per motor per year
Energy Use of an Emerging Technology is based upon the following algorithm.
Baseline Energy Use - (Baseline Energy Use * Best Estimate of Energy Savings (either Typical savings OR the high range of savings.))
Potential number of units replaced by this technology:
The "United States Industrial Electric Motor Systems Market Opportunities Assessment" report was completed for the U.S. DOE by Xenergy in 1998. It is still the best estimator for motors in service within the industrial/manufacturing sector. Assume that motors of 100 hp and smaller are the best candidates for belt drives. The population of motors from >5 hp to 100 hp is about 4,781,502 units nationwide. Prorating by the Northwest population of 4% of the nationwide total indicates that they are about 191,260 candidate motors in the Northwest. This does not include the thousands of motors in use in the commercial sector for air handlers, chiller compressors, and boiler combustion air fans.
Regional Technical Potential:
0.79 TWh per year
Regional Technical Potential of an Emerging Technology is calculated as follows:
Baseline Energy Use * Estimate of Energy Savings (either Typical savings OR the high range of savings) * Technical Potential (potential number of units replaced by the Emerging Technology)
Currently no data available.
Simple payback, new construction (years): N/A
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.