V-belts are available not only in the standard version, but also as "heavy duty belts" — these may also be referred to as "power bands".
This applies to well-known profiles including Z, A, B, C and D, SPZ, SPA, SPB and SPC, as well as XPZ, XPA, XPB and XPC. Heavy-duty versions of the Polyflex and Predator belts are also available. The aforementioned belts are the most common types — the complete range of heavy-duty models is much more extensive.
As with the basic V-belts, heavy-duty belts are equipped with tension cords — a factor for determining belt thickness. The production material depends on the type of heavy-duty belt. Most belts are made from polychloroprene (PCP) or polyurethane (PU) and most tension cords are made from polyester (PES) or, in one instance, aramid. Aramid has an extremely low elongation propensity, meaning that very a high level of performance transmission can be achieved.
Several factors determine which type of V-belt or heavy-duty belt is best suited to a particular drive, for example the application (what is being driven?), the power to be transferred, the desired speed (acceleration or deceleration) as well as the centre distance of the pulleys and any possible impact loads.
It is also important to know what ambient conditions are present and whether there are any space limitations (what is the maximum width and diameter of the pulleys?).
It is very important that the belt is pre-tensioned correctly for optimal drive function. Tension can be measured with a testing device such as the Sonic Tension Meter. This device uses sound waves transmitted by the belt to determine its vibration frequency and then calculates a tension value from this. As well as correct tensioning, it is important that the pulleys are aligned correctly: this is achieved with a laser-guided alignment system.
As with as an ordinary V-belt, a heavy-duty belt must be re-tensioned after a certain operating time or run-in time. There is also a model that requires no maintenance whatsoever; namely the maintenance-free heavy-duty belt "Quad-Power 4". Once the initial tension has been set, this V-belt does not require subsequent re-tensioning.
Common standards for V-belt drives include DIN2211, DIN2217, DIN7867, ISO4183, ISO5290 and ISO9981. Furthermore, it is important whether the V-belts need to be static-conductive to meet ISO1813 (ATEX environments).
