1995-08-11_REVISION - M1977493 (12)

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5-SHAFT PUMP STATION DESCRIPTION OF OPERATION March 20, 1995 GENERAL The 5-shaft pump station is comprised of 3-200 HP pumps operated on 480vac 3 phase power. One pump will be powered by a variable speed motor drive with a automatic bypass in the event of drive failure. The other two pump motors will be powered by individual NEMA size 5 motor starters. The electrical controls are located in the 5-shaft personnel tunnel at elevation 11,145.5 feet. Two of the pumps, #1 and #2 are suspended in the shaft at elevation 10,975.0 feet and the third pump is located a elevation 11,134.5 feet. START/STOP CONTROL Each pump is equipped with local start/stop control allowing a local operator to start and stop the pumps from the pump platform. Each pump will also be tied to a programmable logic controller (PLC) allowing for remote control from the mill control room. The start/stop control is hardwired to allow for control of the pumps in the event of PLC failure. AUTO/MANUAL When the local Auto/Manual selector switch is placed in the Auto position, the sump level control signals as defined below will be directed to the individual pump controllers. When the local Auto/Manual selector switch is placed in the Manual position, the local start and stop push buttons as well as the PLC start and stop control outputs are directed to the individual pump controllers. LEVEL CONTROL The primary control for the pumping system is through a system of level controllers. Pump #1 - Primary level control for this pump is provided by a Milltronics Airanger analog level control. The analog level signal will be used as a process variable in a PID loop controller for the VSD. The operator will be able to set an operating level to be maintain in the shaft through the use of the VSD PID loop controller. The ultrasonic level sensor is located just below the pump platform at elevation 11,144.5 feet and has a maximum range setpoint value of 169 feet or elevation 10,944.5 feet.