V-Belt Sizes

..getting to know v-belts sizes

V-belts are often used as a source of motion, to transmit horsepower efficiently from point to point, or to track relative movement.

V-belts were invented at the turn of the last century to allow horsepower to be transmitted more efficiently that was possible with the standard flat belts of the day. V-belts have become an industry standard on machines that run from automobiles, farm equipment and standard electric motors. V-belts our very cost effective way to transmit horsepower because they don't cost a lot of money with so many manufacturers involved in their production today.

Classical, standard industrial v-belts range in sizes on their top width from A [1/2 inch], B [5/8], C [7/8], D [1-1/4] and E [1-1/2]. The larger the width the higher the horsepower capabilities of the V-belt. V-belts used for light HVAC services in the past also used a 3/8 inch wide belt known as a 3L and they were also made in for 4L and 5L sizes. These factional horsepower v-belt are gradually being phased out of the industry as many standard furnaces and light blower services have gone to the more traditional classical sizes due to increased horsepower and their capabilities in that type of machinery.

There are also 3V [3/8 inch top width], 5V [5/8] and 8V [1/2] industrial style v-belts being manufactured that had a steeper angle on the side walls. These are used where a compact machine design is required. These v-belts are used where higher speed and increased horsepower capacity is required. These types of the v-belts were actually designed after the metric sizes used in Europe for many years. The 3V, 5V and 8V style of the v-belts won't run in standard B or C sheaves design for the classical line of v-belts.

SPZ industrial metric v-Belts [top dimension of 10mm], SPB [17mm] and SOC [22mm] are the standard designations for the most common v-belts used in Europe and quite often in North America when machinery is imported from the European countries.

Classical v-belt lengths can run from 17 inches around to over 400 inches depending on the top width. Note that these measurements are on the in side of the v-belt for the classical style. The old 3L and 4L series were measured on the out side and this has caused quite a bit of confusion when trying to find an equal size in a classical v-belt to replace an FHP style.

A v-belt needs to be sized according to the horsepower that you are trying to transmit from sheave to sheave. Note that if you try to design a v-belt drive that is oversize for the application so that it won't break you may end up with a more serious problem. In many cases the v-belts actually act as a safety device. If something gets stuck in a conveyor system, for example, something has to give. if you can't reach the motor in time to turn it off, something is going to break somewhere in the system. It is better to have a v-belt break or burn off than have a valuable gear reducer strip its bronze gear because that is the next weak point in the system. Always use proper design factors when you design a v-belt drive to protect your most valuable pieces of equipment. V-belts are great pieces of industrial equipment when used correctly.