Bucyrus says it has improved nonproductive longwall move time with the introduction of a Variable Frequency Drive (VFD) to its Vers-A-Trac® 650 model. Approximately 50 of these successful roof support carriers have been shipped since the product’s introduction in 2004. The Vers-A-Trac 650AC, featuring the Bucyrus HiPAC10 control system, represents the latest generation of heavy roof support carriers. The Bucyrus HiPAC10 control system is an innovative variable frequency inverter drive which allows costly DC motors to be replaced by higher power, more efficient AC motors. Traction power is increased by 100% and hydraulic power by nearly 300%. These increases, in turn, nearly double loaded traction speed and gradeability, and improve hydraulic performance.The HiPAC10 drive provides regenerative braking by allowing energy that is required to decelerate the vehicle to supplement the battery capacity. This feature reduces the duty cycle of mechanical brakes, increasing brake life.The 650AC features an upgraded operator’s compartment. All machine operating parameters are visible at a glance on the large display which is also capable of providing fault analysis and data logging. The 650AC also features an ergonomically designed control stick that provides intuitive control of key functions.Rated at 50 t, the 650AC provides the most capacity of any battery-powered roof support carrier as well as enhanced tractive effort capability with the terrain following tri-section rear frame, Bucyrus claims. The combination of heavy lift and carry and the increased traction speed provide for optimum operating performance that improves longwall system move time.