Interroll: Compact forces in future-proof material handling

Belt conveyors form the heart of modern-day material handling systems. Drum motors from leading material-handling equipment supplier Interroll, which drive automated belt conveyors, are available in asynchronous and synchronous variants. How differ these two technologies?

The quantity of goods being conveyed in industrial environments is getting ever larger, while goods themselves are becoming more complex and more customized. Products requiring transportation range from small to large, light to heavy, soft to hard, with their numbers and properties fluctuating widely depending on the market conditions. During the production processes very slow or very fast transport speeds may also come into the equation.

A hermetically sealed design for hygienic environments

In contrast to classic gear motors, which usually have to be fitted underneath or next to the conveying line and be driven by a power transmission system, drum motors from Interroll are built into the roller, thus eliminating the need for a power transmission mechanism. This makes drum motors perfect for building extremely compact and energy-efficient conveying solutions. They are also easy and cost-effective to fit, and comparatively easy to service and repair. Furthermore, this type of motor has a hermetically sealed design, which is advantageous in environments where hygiene is of utmost importance and areas requiring thorough, regular cleaning.

In industrial applications today, asynchronous motors are by far the most commonly used type of drum motors. They are robust and comparatively cheap to manufacture. They are very efficient and can be operated at constant transport speeds without the need for an additional electronic control system. Asynchronous motors are, therefore, usually the first choice for applications involving a steady flow of medium-heavy goods in standard speed ranges between 0.1 to 1 meter per second.

Synchronous motors satisfy a considerably wider range of applications

Yet, this is where asynchronous motors start to show their limitations. When using synchronous drum motors, the range of possible transport speeds is significantly larger, normally ranging from around 0.01 to just under 3 meters per second. For this reason, these drives are also suited to very slow-flowing processes, during which goods have to be machined manually, for example. Steady flow processes at high speeds— such as those required in distribution centers, for luggage belts or in automated packaging systems—can be implemented, too.

When necessary, asynchronous motors can even be operated at variable speeds (within the limitations of their design) by installing a suitable frequency converter. These converters can be quite expensive, however, so users looking to use an asynchronous motor with a converter should consider opting instead directly for a synchronous motor, which always requires the use of a converter due to its design. This solution offers a lot of additional advantages.

Precise positioning of goods, less energy consumption

Synchronous drum motors enable very quick and frequent stopping and starting that makes them the best choice for handling intermittent flows of material, such as in automated filling or other machining processes. Synchronous motors equipped with the right sensor technology also boast very precise speed and positioning behavior, which is required in automated cutting processes. Furthermore, they generate substantially higher torque in every speed range, making them capable of transporting heavier goods.

Moreover, synchronous motors use less electricity and therefore cost less to run in a material handling system. This offers other benefits: Synchronous motors remain cooler than asynchronous motors, as less of the electrical energy they use is turned into heat. This makes them more suitable for applications such as food processing where temperature is critical. Furthermore, the lower operating cause an extremely long service life.

Even switching to synchronous motors is worthwhile

Switching from asynchronous to synchronous technology has even advantages when modernizing existing material handling systems. Replacing asynchronous motors with comparable synchronous motors offers substantially higher efficiency and flexibility, enabling any future changes in material handling requirements to be accommodated to.

Considerable savings can also be made during day-to-day operation, and not just because of the high level of reliability and low energy costs. Thanks to the wide range of applications, users need significantly fewer—and potentially no other—types of motors which reduces the number of spare parts kept in stock. Anyone looking to build a new material handling solution or upgrade an existing material handling system will therefore benefit from learning more about the basic capabilities offered by asynchronous and synchronous drum motor technologies.