Hi, I'm Vance and welcome to Spec. Sense.
Over the last 100 years, V-belts have been widely used in household appliances,
commercial HVAC systems, compressors and industrial machines.
They are easy to install, and don't require any lubrication.
The most common types are the Classical V-belts, Fractional Horsepower belts, and narrow or
deep wedge belts.
Each type uses a different belt code to describe
the length and size, and each size is rated for different loads,
so overall its important to find an exact match.
In this episode we'll first learn how to measure a V-belt,
and then we'll use the belt codes to find a replacement.
To find a match, first measure the top width.
Next measure the depth.
These 2 measurements can be used to match the belt type and size.
Now make a mark on the belt to help measure the length.
If you have a soft tape measure, it can be wrapped around the belt
to get the outside circumference.
Alternatively you can use a piece of string to wrap around the belt,
and then measure the string.
If you have no other options, align the mark with the start of the tape measure,
then roll the belt until the mark touches again.
Now that you've measured the width, depth
and outside circumference you have everything you need to find a replacement.
But keep in mind that belts do stretch over time, so its best to error on the side of a smaller belt.
Classical V-belts are your standard industrial belt.
These belts use a letter prefix to identify a specific top width and depth
For example A refers to a 1/2 inch top width,
where B refers to a 21/32nds inch top width.
Classical belts are also available as cogged belts, which adds an X to the prefix.
Unlike other belts, Classical belts are designated by the inside circumference.
This means an A34 belt is 1/2" wide and will have an outside
circumference of 36 inches.
Therefore you can determine the belt number from the outside measurement.
For example an A belt subtracts 2 inches from the outside circumference,
B subtracts 3, C subtracts 4 and so on.
Fractional Horsepower or FHP belts are used in light duty motors under 1 horsepower.
These are found in appliances, furnaces and other small machines.
FHP belts are identified by the prefixes 3L, 4L, and 5L
Unlike classical belts, FHP belts are measured by the outside circumference.
For example, a 4L360 belt is a 1/2 inch wide Light duty belt
with an outside circumference of 36 inches.
Keep in mind some FHP and classical belts
are interchangeable as they overlap in size.
Deep V or Narrow belts offer higher power ratings for each width when compared to classical belts
This makes them good for compact drives.
These belts are identified by the prefixes 3V, 5V, and 8V.
Deep V belts are also available as cogged belts, which adds an X to the prefix.
These belts are also measured by the outside circumference.
This means a 3V250 belt is a 1/2" wide deep V belt with a 25 inch outside circumference.
Hopefully you have gained a better understanding of how to use V-belt codes.
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And if you need help,
you can call or visit an AMRE location to talk with our knowledgeable staff.
Thanks for watching.