Abstract: In one aspect of the present invention, a motor control system includes a rectifier module enclosed in a first flame-proof enclosure, and having a first input and one or more rectifier circuits configured to convert a first AC voltage at the first input to a DC voltage to be output to a DC bus, and one or more variable-frequency drive (VFD) modules, each VFD module being enclosed in a respective second flame-proof enclosure and having a second input coupled to the DC bus, where each VFD module includes one or more inverter circuits configured to convert the DC voltage on the DC bus to a second AC voltage to be output to one or more motors.

Abstract: The present invention relates to an automated continuous haulage apparatus and method designed for use in underground environments. Each mobile bridge carrier (10) contains distance measurement (70) and angular position (74) means for determining the mobile bridge carrier's (10) position and the angular position of attached piggyback conveyors (30). Means for determining the ceiling height (76) are utilized to adjust the height of the piggyback conveyors (30). On each mobile bridge carrier (10), input from the various sensors is received by an electronic controller (80) that calculates the position and orientation of the bridge carrier (10) and attached piggyback conveyors (30). The controller then plans an optimal path of movement for the bridge carrier (10) and computes the rate of movement for each independently operated track assembly on the bridge carrier such that the bridge carrier (10) and piggyback conveyors (30) arrive as close as possible to the planned path.

Abstract: Embodiments of the present invention are directed to a method and apparatus for safety protection control of temporary roof support. In one embodiment, a temporary roof support has a load sensing member. In another embodiment, a beam structure of temporary roof support is supported by a load sensing pin. Strain gages are installed within the pin to measure the load placed upon the pin. An unusually high load being sensed by the pin indicates that the roof has fractured and the temporary roof support is supporting loose rock. In one embodiment, when an unusually high load is measured at the pin, the temporary roof support controls at the front of the machine are disabled. A second set of remotely located temporary roof support controls remain operative. In one embodiment, the second set of controls is located at the rear of the machine.

Abstract: Embodiments of the present invention are directed to a method and apparatus for safety protection control of temporary roof support. In one embodiment, a temporary roof support has a load sensing member. In another embodiment, a beam structure of temporary roof support is supported by a load sensing pin. Strain gages are installed within the pin to measure the load placed upon the pin. An unusually high load being sensed by the pin indicates that the roof has fractured and the temporary roof support is supporting loose rock. In one embodiment, when an unusually high load is measured at the pin, the temporary roof support controls at the front of the machine are disabled. A second set of remotely located temporary roof support controls remain operative. In one embodiment, the second set of controls is located at the rear of the machine.

Abstract: The present invention relates to an automated continuous haulage apparatus and method designed for use in underground environment. Each mobile bridge carrier (10) contains distance measurement (70) and angular position (74) means for determining the mobile bridge carrier's (10) position and the angular position of attached piggyback conveyors (30). Means for determining the ceiling height (76) are utilized to adjust the height of the piggyback conveyors (30). On each mobile bridge carrier (10), input from the various sensors is received by an electronic controller (80) that calculates the position and orientation of the bridge carrier (10) and attached piggyback conveyors (30). The controller then plans an optimal path of movement for the bridge carrier (10) and computes the rate of movement for each independently operated track assembly on the bridge carrier such that the bridge carrier (10) and piggyback conveyors (30) arrive as close as possible to the planned path.