BELT DRIVE MONTHLY | July, 2009
WHAT IS BELT MATCHING AND
IS IT IMPORTANT?
BELT MATCHING
Before explaining in more
detail “what it is” it is
important to understand
the “why it’s important”.
When using a sheave with more than one
groove it is critical that the v- belts be the same
length so they share the transmitted load. “Belt
Matching” is a term used to define v-belts are
of equal length. If belts are not the same length
and specification, the shortest belt carries
the load as it tensions in the sheave first and
the remaining belts are simply going along
for the ride. Length can vary widely among
manufacturers.
For example, a “non-matched” B38 wrapped
v-belt has a published tolerance from The
Rubber Manufacturers Association (RMA)
of +0.7 – 0.7. or 45/64 of an inch (RMA
engineering standard IP-20).This means each
belt can vary as much as 1.4 inches and still
be called a B38. Manufacturers make v-belts
within RMA tolerances, but each makes
slightly different based on their manufacturing
process. For this reason, a drive should
never be installed with v-belts from different
manufacturers. The “matched” tolerance
published by the RMA is significantly closer
at 0.15 or only 1/64 of an inch variation.
All Browning v-belts meet or exceed RMA
“Matched” tolerances OFF THE SHELF!
THE DOWNSIDE TO NOT HAVING A SET OF
V-BELTS WITHIN MATCHED RMA TOLERANCE
LIMITS IS:
1.Belts cannot work together as a team
and belts can fail prematurely
2.Transmitting maximum HP is
compromised
3.V-belts and sheave grooves will wear
unevenly
4.Belt whip & vibration is increased
WHAT IS BELT MATCHING AND IS IT IMPORTANT?
MATCHING METHOD 1 – MANUFACTURING DATE
MATCHING (NOT RECOMMENDED)
There are basically three “v-belt matching” methods
that are often used incorrectly or interchangeably. The
first is the assumption you can match v-belts by using a
manufacturing date code of the same production week
or day. There is absolutely no assurance that a v-belt
made in the same production time frame will have a
length within matched tolerance limits. This method is a
myth.
MATCHING METHOD
2 – CODE MATCHING
Browning CODE 1
marking ensures belt
length meets or exceeds
RMA matching limits
As discussed, the
Rubber Manufacturers
Association publishes
length variation match
tolerances based on
overall belt length.
Some manufacturers
offer CODE matching
to designate matched
length compliance. (Like codes mean v-belts fall
within matching limits). Browning belts are designated
by a CODE 1 printed boldly on the belt and ensure
customers that all Browning belts meet or exceed
RMA matched tolerance limitations right off the shelf.
Not all competitors use code matching and instead fall
within “standard” tolerances.
Regal® Power Transmission Solutions
7120 New Buffington Road
Florence, KY 41042
Customer Service: 800-626-2120
Fax: 800-262-3292
Technical Service: 800-626-2093
MATCHING METHOD 3 – MACHINE MATCHING
While CODE matching is satisfactory for most
applications, some critical applications require length
variation below RMA matched standards. As a result,
some manufacturers offer machine matching from the
factory. This is a secondary physical measurement
of each belt before shipment to ensure lengths are
identical and meet or exceed RMA tolerances. Some
competitors charge for this service. This service is
currently offered at no charge from Browning and can
be performed in our National Distribution Center in
Florence, KY the same day.
IN SUMMARY
Specifying Browning v-belts assure a customer that they
will get a premium quality belt off the shelf that meets
or exceeds RMA matched tolerances. If a demanding
application requires even tighter tolerances we can
assist same day with our machine matching service.
Future article ideas or questions can be
Submitted to [email protected]
www.RegalPTS.com
APPLICATION CONSIDERATIONS
The proper selection and application of power transmission products and components, including the related area of product safety,
is the responsibility of the customer. Operating and performance requirements and potential associated issues will vary appreciably
depending upon the use and application of such products and components. The scope of the technical and application information
included in this publication is necessarily limited. Unusual operating environments and conditions, lubrication requirements, loading
supports, and other factors can materially affect the application and operating results of the products and components and the customer should carefully review its requirements. Any technical advice or review furnished by Regal Beloit America, Inc. and/or its affiliates (“Regal”) with respect to the use of products and components is given in good faith and without charge, and Regal assumes no
obligation or liability for the advice given, or results obtained, all such advice and review being given and accepted at customer’s risk.
For a copy of our Standard Terms and Conditions of Sale, please visit http://www.regalbeloit.com (please see link at bottom of page
to “Standard Terms and Conditions of Sale”). These terms and conditions of sale, disclaimers and limitations of liability apply to any
person who may buy, acquire or use a Regal product referred to herein, including any person who buys from a licensed distributor of
these branded products.
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