Belt conveyors use a gearbox as the main component that reduces the motor's high-speed motion to the belt conveying speed and generates the torque required to rotate the drive drum. For this reason, the capacity of a conveyor line is often determined not by motor power but by the torque capacity and output speed of the selected gearbox.

Three values stand out when selecting a conveyor gearbox: the output torque required at the drive drum, the output speed needed to achieve the target belt speed, and the service factor determined according to the operating duty of the line. When these three values are calculated correctly, the same line can operate with both a smaller motor and a longer-lasting drive system.

The consequences of an incorrect selection quickly become apparent: the belt struggles during start-up, the housing overheats, gear and bearing life is shortened, and in the worst case production comes to a halt. Below, we examine gearbox selection for conveyor applications step by step, explain which type suits which line, and outline sector-specific applications.

Where Is the Conveyor Gearbox Located and What Does It Do?

In a belt conveyor, the drive unit is generally located at the discharge end of the line. The motor, gearbox and drive drum come together at this point, where the belt also receives its pulling force. The gearbox reduces the roughly 1400 rpm motion from the motor to the low speed required by the drum while increasing torque by the same ratio.

The belt speed must remain constant. When material flow increases at the loading point or resistance rises as the line moves through an inclined section, the gearbox must have sufficient torque reserve to absorb this change. Neglecting this reserve on lines operating continuously at full load causes premature wear on gear surfaces.

Another function is to protect the line against rollback. On inclined conveyors, when the motor stops, the loaded belt tends to move backward under its own weight. For this reason, on inclined lines the gearbox unit is planned together with a backstop or brake system.

Key Criteria in Conveyor Gearbox Selection

The selection decision is based not on a single value but on several interrelated parameters. Clarifying the following points at the quotation stage eliminates most capacity problems that could arise later:

• Material to be conveyed and flow rate: The tonnage to be conveyed per hour, the material's bulk density and particle structure determine the belt pulling force.
• Belt speed and drum diameter: The target speed together with the drum diameter determines the output speed, which directly affects the gearbox ratio.
• Line length and inclination angle: Long and inclined lines require significantly higher torque than horizontal lines.
• Operating time and start-up frequency: A line operating 24 hours a day is not evaluated with the same service factor as a line operating in shifts.
• Environmental conditions: Dusty, humid or high-temperature environments change seal selection, oil type and housing cooling requirements.
• Installation space and connection type: The available volume for the drive unit determines whether the gearbox should be hollow-shaft, flange-mounted or torque-arm mounted.

Even if you do not have all of this data, a safe preliminary selection can be made when the conveyed material and line geometry are known. For a more detailed approach, the steps on our gearbox selection page will provide guidance.

How Are Torque and Speed Calculated?

The calculation starts with the target belt speed. When the drum diameter and desired belt speed are known, the drum's revolutions per minute can be calculated. Dividing the motor speed by this value gives the required gearbox ratio. If intermediate ratios do not exactly match standard stages, it should be checked whether the small deviation in belt speed affects production flow.

For torque, the product of the belt pulling force and the drum radius is used. The pulling force is the sum of the material weight, the belt's own weight, idler friction and the component caused by the incline. If the calculated value exceeds the gearbox's nominal output torque, the next larger housing size should be selected.

Start-up is a separate consideration. When a loaded belt starts moving, it requires torque significantly above the steady-state value. Therefore, a service factor is applied during selection; this factor is increased for lines with heavy starts and frequent stops. For those who want to see the calculation steps with examples, our gearbox calculation page and torque calculation guide provide a practical starting point.

Which Gearbox Type Is Suitable for Which Conveyor?

For most horizontal and slightly inclined lines, helical gearboxes are preferred. Their high efficiency keeps energy consumption low, they operate quietly and provide a long service life under continuous duty. This type is a practical solution where the motor is positioned in line with the belt.

In drive units where the motor must be positioned perpendicular to the belt and installation space is limited, bevel-helical series come to the forefront. Having the input at 90 degrees to the output enables a more compact drive arrangement alongside the line. This configuration is frequently used in heavy mining and cement conveyor lines.

On short lines requiring low speed and high torque, especially low-capacity belt and chain conveyors, worm gearboxes are an economical alternative. Their self-locking characteristic provides an additional advantage in some inclined applications, although their efficiency is lower than that of helical types.

For heavy-duty lines that demand very high torque within a limited installation volume, planetary gearboxes are used. Because they distribute the load across multiple gears, they transmit significantly higher torque within the same housing size.

Why Are Mounting Position and Connection Type Important?

The way the gearbox is connected to the drum affects both the cost of the drive unit and ease of maintenance. In hollow-shaft solutions, the gearbox is mounted directly onto the drum shaft and the housing is fixed with a torque arm, eliminating the need for a coupling and base. This arrangement is especially preferred where space beside the line is limited.

In flange-mounted and foot-mounted connections, the gearbox is installed on a base and connected to the drum shaft with a coupling. This arrangement, which makes removal easier during service, is more common at high torque levels. Base flatness and alignment accuracy are decisive here.

The mounting position also changes the oil level and the location of the breather plug. Using a housing designed for horizontal operation in a vertical position can result in insufficient lubrication and premature bearing damage. For details, we recommend reviewing our installation and alignment page and our article on gearbox mounting positions.

Applications of Conveyor Gearboxes

Belt conveyors are found in almost every facility where material must be transported continuously. Gearbox requirements are shaped by the material handled by the facility:

• **Mining:** On long lines carrying ore and waste rock, high torque, dust protection and backstop systems are priorities.
• **Cement:** Lines conveying clinker, limestone and additives operate under abrasive dust and continuous-duty conditions.
• **Iron and steel:** Scrap and slag lines must withstand both impact loading and high ambient temperatures.
• **Beverage and food:** Lines conveying bottles, crates and packages require low-speed accuracy and washdown-resistant sealing.
• **Paper and packaging:** Quiet operation and speed stability are key on reel and carton conveying lines.
• Recycling and waste facilities: A high service factor is required to withstand sudden torque increases caused by mixed and variable loads.

The same torque requirement in each of these fields can be met with different housing and equipment combinations. For sector-specific examples, you can review our application areas page.

Maintenance, Lubrication and Early Warning Signs

Oil is at the center of conveyor gearbox maintenance. The first oil change after initial commissioning is especially important because it removes metal particles generated during running-in. Subsequent intervals are determined according to operating temperature and daily operating time.

In high-dust facilities, seals and the breather plug should be checked regularly. Oil leaking from a seal both lowers the oil level and allows dust to enter from outside. A clogged breather, meanwhile, creates pressure inside the housing and puts stress on sealing elements.

For teams monitoring the line, three signs allow early intervention: unusual noise, a sudden rise in housing temperature and increased vibration at the connection point. When any of these is observed, checking alignment and oil level is the first step. For detailed maintenance topics, our gearbox maintenance and common problems pages can be used as reference sources.

The Right Solution for Conveyor Applications with Remak Redüktör

Manufacturing gearboxes and gear units since 1987, Remak Redüktör provides solutions for conveyor drive units across a wide range of industries, from mining to food. Our helical, bevel-helical, planetary and worm gearbox series can be configured in different housing sizes according to your line's torque and speed requirements.

When you provide belt width, conveyed material, line length and inclination information, our technical team determines the appropriate ratio and housing size together with you. Auxiliary equipment such as the motor, brake and backstop can also be planned within the same drive group.

In short, the right conveyor gearbox is an investment that not only drives the line but also keeps energy consumption under control, reduces downtime and provides years of trouble-free service. If you would like technical support and a quotation for your project, you can reach us through our contact page and review our technical documentation for product details.