The Problem

The Braking Challenge: the original OEM that manufactured the conveyor brakes was no longer supporting the product. Because conveyor length varies over time due to panel development and movement of the longwall machine as it retreats, a braking control is needed to maintain the stopping time regardless of the conveyor length.

The Solution

Adam Coward, Syntron Application Engineer, worked to supply the end user with a new brake system that utilized the latest smart breaking technology. The new solution is used on two downhill longwall panel conveyors. Each conveyor is approximately 14,500 ft. long with 725 ft. of drop from tail to head. The 54 in. wide conveyor belt is driven by two 300 HP regenerative ABB VFD’s while operating at a speed of 630 ft / min. to move 1200–1800 tph of coal. The conveyor required up to 70,000 ft. lbs. of braking torque when extended to full length. The target stopping time was 35 seconds. The conveyor layout was non-traditional since it is a panel conveyor and the tail is being moved regularly. “Typically, the brake would be installed on the tail pulley, but in this case, the mine’s preferred brake position was toward the head end of the conveyor,” according to Coward. “This configuration required a very smooth, gentle stopping ramp to minimize belt tensions during shutdown. Also, since it was an underground installation, the brake disc diameter was required to be relatively small because there was limited space to work."