Technical Bulletin TB2000-2 - ◄ back to technical data

Belt Resistivity Categories

The electrical resistance, in ohms, can be found using the test methods in ISO 9563 and the following equation:

where: L = is dry distance between electrodes (inches)
           W = is the width of the belt (inches)
           Test Voltage = 100V

Based on this calculation and experimental results, belts can be categorized according to the following table:

Anti-Static Applications

Specific resistance values for an application are very useful for developing polyurethane formulations and minimizing costs.
For specific anti-static formulations or for empirical test data, please contact the Engineering Department for assistance.

ANTI-STATIC POLYURETHANE TIMING BELTS


Under certain conditions, a polyurethane belt may build-up a significant static electric charge. For applications where belts are intended for operation in a potentially explosive atmosphere or near electrical components, polyurethane belts should be sufficiently conductive to dissipate this electrical charge. Belts can be constructed (using proprietary additives and reinforcement cords) with a relatively low electrical resistance characteristic and are typically referred to as "static conductive" or "anti-static".

Test Methods for Anti-Static Materials

The test methods for determining the resistive properties of a belt are based on one of the following standards:

1) ISO 9563, "Belt Drives - Electrical Conductivity of Anti-static Endless Synchronous Belts - Characteristics
and Test Method"

2) ASTM D991-89, "Standard Test Method for Rubber Property - Volume Resistivity of Electrically Conductive and Antistatic Products"

3) RMA IP-3-3, " Static Conductive Test Method for Power Transmission Belts"

ISO 9563 specifically addresses the surface resistivity of synchronous belts. ASTM D991-89 is more generic in scope and addresses the volume resistivity through the raw materials which will be used in manufacturing the anti-static product. Chemi-Flex uses ISO 9563 as the standard test method for anti-static materials.

 
Chemi-Flex believes the information presented is accurate at the time of publication and is intended for comparison purposes only. It is the end users responsibility to test products to insure they meet requirements for each application. Reference to products not manufactured by Chemi-Flex is neither an endorsement nor unsuitability of similar products.

 
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