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 Mr 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.
Mr 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.
Mr 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.