EZ Align Service

Do you have a Gates EZ Align laser alignment tool in need of repair?  If so, we have someone for you to talk to.  Contact Bill Seiffert at Seiffert Industrial for assistance:

Bill Seiffert
Seiffert Industrial
972-671-9465 x 102

HVAC Equipment Inspection

Many air handling drives have structures that are not particularly rigid, which can create belt tension and drive alignment problems resulting in unusual and premature belt wear. Synchronous belts are sensitive to fluctuations in center distance that can be caused by inadequate bracketry. Under start up conditions, an AC motor can be required to provide 150% to 200% of its rated capacity. Synchronous belts cannot slip, and must transmit the higher start-up torque. Under these conditions, the drive center distance may collapse if the

structure is not sufficiently rigid.  With the drive shut off and safely locked out, a simple method to use when

inspecting potential drive conversions is to grab the two belt spans and push them together while observing the motor. If any significant relative change in center distance or motor position is noticed, the drive’s structural strength is most likely insufficient for a simple conversion. The structure would need to be

reinforced to obtain optimum performance from a synchronous belt drive. The best conversion candidates have motors that are mounted solidly on support bracketry that is part of the fan’s structural system. When possible, select synchronous drives with diameters similar to existing V-belt sheave diameters. This will maintain similar belt pulls and loads on the shafts and structure.

Frequency and Tension

Occasionally we get asked about how to calculate tension based on the Sonic Tension Meter frequency measurement.  The STM will calculate tension in pounds or Newtons for you with the proper input, but the math behind it is really pretty simple.  Here's how to do it by hand:

Formula:

T = 4 x M x W x S^2 x f^2 x 10^-9

Where:

T = Belt span tension
M = Belt mass constant
W = Belt width or number of strands
S = Length of the span to be measured
f = Natural frequency of the belt

Make sure to use proper units!

Gates North America Engineering Support

We are often contacted by Gates customers all over the world, yet there is very little support we can provide to customers outside of North America. Gates product lines vary throughout the world. Technical information from Engineers in North America will not apply to the products available in other regions. For assistance in your area please go to www.Gates.com and select your region using the map in the top left of the screen. You may also use these contacts:

Europe:                 pteusupport@gates.com
Australia:               gatestech@gates.com
Asia Pacific:          guatc@gates.com
India:                      customercare@gatesind.com
South America:     br.ind@gates.com
Inter America:       gatesinteramerica@gates.com

Taper-Lock Type Sprocket Installation and Removal

Taper-Lock Bushings attach a sprocket to a shaft.  They are for the most part industry standard, but when people see them for the first time, many times they are confused about how to install them.  Luckily, our Drive Design Manuals (such as our Poly Chain GT Carbon Drive Design Manual) have a step by step process listed for easy installation and removal of these bushings.  You can find the specific page below, or download the entire manual here: http://www.gates.com/catalogs/index.cfm?requesting=ptcatalog&location_id=2999 

Speed Limit Evaluations For Belt Drive Hardware

Rotational speed limitations for belt drive hardware is based on material composition and balancing standards.  The traditional industry accepted speed limitations for gray cast iron material and static balancing is 6500 ft/min.  For speeds higher than this, materials such as ductile iron, steel and aluminum may be considered, but are typically available on a made-to-order basis at higher cost.  Dynamic balancing is also recommended for operating speeds above the 6500 ft/min limit to prevent excessive vibrations.

In more recent years, the Mechanical Power Transmission Association (MPTA) published the MPTA-B2C - Standard Practice For Sheave/Pulley Balancing Standard based on International Standards Organization (ISO) and American Gear Manufacturing Association (AGMA) balancing standards.  This MPTA standard provides a more accurate and objective evaluation of whether static or dynamic balancing is required. 

The MPTA-B2C balancing standard includes a simple maximum static balancing speed calculation based on diameter and face width.  When operating speeds are not known, static and dynamic balancing recommendations are also provided based on material and hardware weight.

Gates Design Flex Pro drive selection software utilizes the MPTA-B2C balancing calculation.  This may prevent the selection of some drive combinations that would otherwise operate below the traditional 6500 ft/min limit for gray cast iron and static balancing.  Warning notes indicating a need for dynamic balancing at operating speeds below 6500 ft/min may also appear due to this.

In summary, while the traditional industry accepted 6500 ft/min limit for gray cast iron materials and static balancing is a reasonable guide, the MPTA-B2C balancing standard provides a more accurate and objective evaluation of the need for dynamic balancing based on diameter and width.  This calculation is utilized in Gates Design Flex Pro software and may limit drive selections that would otherwise appear to be acceptable.

For questions or additional information, feel free to contact Product Application Engineering at (303) 744-5800 or ptpasupport@gates.com.

Minimum Pulley Diameters: How small is too small

As technology advances and systems get smaller and smaller so too does the desire for smaller drive pulleys.  Though size can be decreased, it is important to ensure that none of the drive pulleys fall below the minimum recommended diameters given this can result in shortened belt life, premature belt wear, and overall poor drive performance. Below are the minimum pulley sizes for both V-belt sheaves and Synchronous sprockets.

It is still important however to check with the motor or gearbox manufacturers to ensure that these small pulley sizes do not result in excessive shaft load or fall below any NEMA (National Electric Motor Association) standards which could prove to be detrimental to the drive components. For any additional questions feel free to contact us at ptpasupport@gates.com or 303-744-5800.