Adjustment of a bulk-material flow splitter chute via two electric actuators with synchronization control

Due to their rugged construction and design, RACO's Heavy Duty electric actuators are used as reliable mechatronic drives to assist in the bulk-material handling technologies. The actuation of flaps, gates and chutes, as well as the exact positioning of bulk-material splitter chutes, are managed by electric linear actuators, which are easy to install and can be remotely controlled. In the case of large-scale bulk-material splitter chutes, two RACO electric actuators are used to synchronize the movements by utilizing the RACOmatic® Controller.

Different configurations of the RACOmatic® also enable force-controlled movement for chain tensioners and belt scrapers. RACOmatic® system solutions including RACO's Micro-PLC allow operating and controlling several electric actuators in a network.

About the project:

As this Gold Mine site grew in scope and size, equipment needed to be controlled from a central location. With distances exceeding 1000 ft (300 M) from the main, central control site location, a huge splitter chute and its actuators had to be controlled. The long distance required a local control to activate the actuators for the splitter chute, but also be networked back to the Main control station. High ambient temperatures of up to 55C required the use of reliable and failure-proof components. The RACOmatic® combined with RACO's Heavy Duty electric actuators, was implemented as a perfect system solution.

Job site and application requirements included: vector-controlled variable frequency drives and a micro-PLC be housed in cabinets equipped with an air conditioning system. RACO's Micro-PLC provides a full-text display (HMI), and offers the capability to control each electric actuator separately. An "Electronic Hand Wheel" mode proved to be very useful during installation and commissioning, particularly when the electric actuators needed to be “jogged” separately into their initial start positions for synchronization.

The programming for synchronous control of the two electric actuators by a vector-controlled frequency inverter and the integrated Electronic Position Sensor (EPS) are proprietary developments of RACO. Parameters, such as speed, acceleration and deceleration ramps for smooth travel to set point positions, as well as limit values for force and speed, are stored and controlled inside the RACOmatic®. All Parameters are secured by password, offering full protection against accidental misuse or improper operation. Only two digital signals are required from the higher-level control for starting and stopping the movement.

RACO electric actuators feature screw designs which together with a special guiding technology ensure a steady support of the thrust tube, even when fully extended. The front cap is equipped with a special double sealing to protect the inside of the actuator against dirt and dust. An additional ice and dirt wiper scrapes off ice and other solid contaminants. A patented spring-loaded nut housing protects the screw nut against axial impact loads. Only RACO electric actuators offer this patented, spring-loaded nut housing technology.

The following was considered for this project:

· Electric actuators provided the best solution to the adverse ambient conditions, in particular, the extreme temperatures and vibrations.

. Exact positioning of the two electric cylinders in synchronization mode was made possible via RACOmatic®, as well as the ability to monitor the operating parameters (acceleration, speed, force, position)

· The customer application solution was from a single source, for turnkey and easier installation into the overall system.