Bonfiglioli Transmission (Aust) has combined its HD helical or bevel helical drives with its proven Trasmital planetary gear box to present an ideal solution for apron feeders. Bonfiglioli apron feeder drives provide high torque in a compact, efficient design with various mounting options.
An important part of materials handling operations in mining applications, apron feeders or feeder conveyors allow the controlled input of materials. Apron feeders are generally a low speed application offering very high breakout torque with the starting torque up to five times higher than the normal running torque; the gear box therefore needs to be able to handle a larger torque range.
Bonfiglioli’s apron feeder drive solution delivers optimum performance with a high torque ratio of up to 1000:1 as well as a good thermal rating. The Trasmital planetary gear box has a very high torque rating and compact design.
According to Kris Jaryn, Business Development Manager, Bonfiglioli, the power of such combinations was further extended recently with two new gear unit sizes that increased the torque capacity of the range up to an impressive 1,100,000 Nm.
The input stage box not only reduces the input speed to the planetary head (which operates best with lower input speeds) but it can also be fitted with a shaft cooling fan to increase the allowable installed power. The drives can either have a hollow output shaft with a shrink disc, or a solid output shaft with a rigid coupling.
Jaryn explains that Bonfiglioli can design the drives to suit individual needs. For instance, the motors are flange mounted in the horizontal position in most instances. However, if sufficient room is not available around the drive, the motor can be mounted vertically. In these cases the drive is supplied with a motorised oil pump, which lubricates the top bearing of the box.
When really big motors over 200 kW are required but are too heavy to be flange mounted, the drives can be supplied with locally designed baseplates attached to the gear units, still offering a relatively compact drive. All drives are shaft mounted and fitted with a torque arm, which in most cases is attached to the outside of the planetary box.
The motors are typically controlled using a variable frequency drive (VFD), which allows smooth speed changes and control while also limiting the motor starting torque, usually to about 150% of the full load torque. Ranging from 0.25-400 kW, Bonfiglioli’s VFDs can practically supply the complete drive solution for any apron feeder application, designed, engineered and built locally at their Glendenning facility in NSW.
Mr Jaryn says customers can have the assurance that they are getting the best drive for the job at the best price since Bonfiglioli ensures correct drive selection at the optimal price by using their calculations software, which checks and calculates bearing life and gear strength.
Jaryn explains that gear boxes are basically torque multipliers, so the bigger the ratio, the bigger the output torque of the machine, and lower the speed. When a relatively small motor is used with a high ratio box, a high torque can be created to move a large or heavy load. Bonfiglioli uses a combination of a planetary gear head with a bevel helical input gear unit to build big ratios in a relatively small package.