Belt Drive Monthly
Volume 20 March 2010
How Does Heat Impact V-belt Life?
This is a very common question and the answer comes from understanding the
environment and drive product options available. The Rubber Manufacturers
Association publishes (Technical Bulletin RMA IP-3-1) that “Normally, belt drives
operating in an ambient temperature above 85 (30 C) but below 140 (60 C) can be
handled adequately with a stock belt drive selection, though some reduction in belt
life may occur”. Most manufacturers as well as RMA publish that for every 35 F
(20 C) increase in prolonged ambient temperature above 85 F (30 C), a v-belts
service life is cut in half.
To help further explain heat impacts it is important to understand what factors
contribute to overall v-belt drive operating temperature.
1. Ambient temperature
2. Center distance (the longer the belt the more time it has to dissipate heat as it rotates)
3. Sheave (pulley) diameter
4. Sheave groove wear (Sheaves with wear greater than 1/32” contribute to slippage and added heat)
5. Belt flex rate
6. Tension level
7. Sheave alignment
8. V-belt type (Notched or sometimes cogged v-belts run cooler than wrapped belts)
9. Belt guard design / drive enclosures
Heat is generated in a v-belt because of the physical “flexing” as it enters and exits a
sheave and because of “friction” as the belt is wedged into the groove. There are
many things to consider when trying to design a drive where warm temperatures are
present.
Best Practice Tips
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Use the largest sheave possible for the allowable space. It will help reduce
belt bending flex/resistance and improve cooling
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Properly align sheaves and tension belts to manufacturers recommendation
•
Use Browning Gripnotch belts and lower operating temperature as well as
improve efficiency approximately 3%
•
Check sheaves for wear and replace if wear exceeds 1/32” in the groove.
•
Consider adequate ventilation and air flow in belt guard designs
Belt Guard With Adequate Ventilation
Note: Notched V-belts Should Not be Used In Clutching Applications Where Slip Is Desired
E M E R S O N. C O N S I D E R I T S O L V E D.
Belt Drive Monthly
Volume 20 March 2010
Tell Tale Signs Of Belt Slippage (#1 Cause Of Excess Heat Generation)
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Excessive belt dust in and around belt drive and guard
Belts are loose and/or squeal
Underside of belt is cracking
Glazing of belt (shiny appearance and sometimes brittle)
Rapid sidewall wear
Sheaves with groove wear exceeding 1/32”
Premature failure
Options For Higher Temperature Environments
Premium Griptwist offers advantages for temperature
sensitive applications and can be very effective on heat
recovery equipment and high-temp exhaust fans such as
those ventilating commercial kitchens. Operating
temperature range is -40 F to 240 F (-40 C to 116 C).
Browning Griptwist is adjustable to length and available in
5ft. Sections or 100’ boxes.
Browning’s Premium Griptwist belts can be used in most
every application traditional v-belts can be used in, and
more. Premium Griptwist belts are interchangeable with
traditional 3L, 4L, 5L, A, and B section v-belts. Premium
Griptwist AP and BP provide the full ratings of Browning A
and B Gripbelts.
In summary, operating temperature can often be reduced with proper drive
component selection, installation and routine maintenance. Visit us at
www.emerson-ept.com for our full suite of literature and product e-tools to help
you select your next drive. For personal assistance in specifying the right parts
for your v-belt drive or troubleshooting heat related belt driven applications,
please contact our Application Engineering Department at 1-800-626-2093 MonFri 7:30a.m. – 5:30p.m. EST.
EMERSON and EMERSON. CONSIDER IT SOLVED are trademarks, service marks and/or trade names of Emerson Electric Co.
Future article ideas or questions can be submitted to don.sullivan@emerson.com
E M E R S O N. C O N S I D E R I T S O L V E D.