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DC MOTOR-DRIVEN PUMP The left and right hydraulic systems each have one DC Motor-driven Pump (DCMP). The primary purpose of the DCMPs is to pressurize the hydraulic systems during an engine or EDP failure. The DCMP serves also the ground maintenance operation purposes. The DCMP contains a DC electric motor which is attached to a variable-delivery hydraulic pump. The DC motor operates the pump, which can change the volume of fluid flow to maintain the necessary system pressure. The left and right hydraulic system DCMPs are installed on their respective side of the aft equipment compartment. Electrical power is supplied by the DC bus through an electrical connector on the DCMP. The generator of the right engine supplies power to the left DCMP. The generator of the left engine supplies power to the right DCMP. The left and right DCMPs are each controlled by a three-position switch. The switch positions are OFF, AUTO, and ON. The OFF and ON allow manual operation. The AUTO position is the normal position for flight. In this position, the DCMPs will be off with flaps up, and on with flaps set at 10° or greater. In addition, if low hydraulic system pressure is detected, the DCMP will automatically turn on. HYDRAULIC SHUTOFF VALVE Each of the left and right hydraulic systems contain a firewall shutoff valve (SOV) placed in the EDP suction line outside of the pylon area. In the case of engine fire, this valve can be closed to stop hydraulic fluid from reaching the engine area. Both SOVs are located inside the aft equipment compartment forward of the hatch opening. The valves are normally in the open position, however, pressing the L (R) SOV push button on the HYDRAULIC control panel or the L (R) ENG FIRE push button on the ENGINE control panel closes the corresponding hydraulic shutoff valve. Control logic also closes the valve automatically when the system fluid temperature exceeds 275 °F. When a firewall SOV is operated, the DCMPs are the only hydraulic pressure source available for the left or right hydraulic systems. HYDRAULIC RESERVOIR Each of the hydraulic systems contains a reservoir for the storage of hydraulic fluid. The reservoir provides the necessary fluid volume demanded by the hydraulic system, including pressurization of the pump inlet. Changes in the fluid volume due to thermal expansion/contraction, system leakage and differential area of the user actuators have been taken into ac-count in sizing and volume of each reservoir. The left and right hydraulic system reservoirs are installed on their respective sides in the aft equipment compartment. The fluid volume of the left hydraulic reservoir is 13 quarts (12.3 liters). The fluid volume of the right hydraulic reservoir is 9.1 quarts (8.6 liters). Each reservoir has a bleed/relief valve, visual quantity in-dicator, suction shutoff valve, and ports for installation of the temperature switch and temperature transducer. There is also a check valve installed in the fluid return port. The bleed valve is accessible to maintenance personnel and is manually opened by depressing a lever. When released, the lever automatically returns to the closed position. The location of the valve at the high point of the reservoir, as well as the routing of the internal porting to the valve, assures that air in the fluid will migrate to the outlet and be released when the valve is opened. Flow from the valve is routed to the ecology bottle. 中国公务机网 www.gongwuji.com 公务机翻译 www.aviation.cn 本文链接地址：庞巴迪挑战者300公务机机组操作手册 Bombardier Challenger-液压(4) |
