WINDSHIELD WIPER UTILITY SYSTEM

WINDSHIELD WIPER UTILITY SYSTEM Learning Objective: Recognize motor and converter assembly components for wind- shield wiper utility systems. The windshield wiper system on the S-3 air- craft is typical of this system and provides visual clearance for the pilot and copilot in adverse flight conditions up to speeds of 300 knots. The wind- shield wiper system consists of a motor assembly, converter assembly, an arm assembly, a blade assembly, and an anti-icing and windshield control panel assembly. The motor assembly is a three-phase, two- speed electrically driven motor, which provides the source of power to the converter assembly. The converter assembly is a motion converter, which converts the circular motion of the motor to the oscillating motion required by the wind- shield wiper arm. The arm assembly uses the oscillating motion of the converter assembly to impart a sweeping motion to the windshield wiper blade assembly. The blade assembly consists of a spring-loaded holder subassembly and a rubber wiper blade. The blade assembly uses the motion of the arm assembly to sweep rain from the windshield. The anti-icing and windshield control panel provides mounting for bleed-air, wiper, rain repel, washer, and heat control switches. The windshield panel consists of a mounting plate, an edge-lighted panel, six switches, and a wiring harness. WINDSHIELD WASHER UTILITY SYSTEM Learning Objective: Recognize reservoir pump and nozzle assembly components and capabilities for windshield washer util- ity systems. The windshield washer utility system (fig. 1-21) on the S-3 aircraft is typical of this system and is located in the unpressurized nose compartment at the base of the windshield. The washer switch on the windshield panel, mounted on the overhead panel, is a two-position switch. When the washer switch is set to ON, the pump motor is energized to cause fluid to be sprayed on both windshields. The spray continues as long as the switch is held in the ON position. The washer pump supplies fluid for approximately 6 minutes when the fluid reservoir is full. A reservoir fillercap dipstick indicates fluid quantity. Washer fluid consists of 80% isopropyl alcohol and 20% distilled water. The windshield washer system consists of a reservoir pump assembly and nozzle assemblies. RESERVOIR PUMP ASSEMBLY The reservoir pump assembly provides storage for a supply of windshield washer fluid and for mounting of the motor/pump subassembly (with filter element), the pump housing subassembly, and the fillercap/dipstick subassembly. The motor/pump subassembly, which is mounted submerged in the windshield washer reservoir, provides a flow of windshield washer fluid in sufficient quantity and pressure to wash the windshield. When the washer switch on the windshield panel is set to ON, dc power from the left primary dc bus is applied to actuate the K57 relay switch in the left load center. The relay switch, in turn, applies an ac voltage to the motor/pump subassembly, which pumps washer fluid out through the nozzle assembly and on to the windshield. NOZZLE ASSEMBLY A nozzle assembly is mounted at the base of each windshield. When the windshield washer system is in operation, the nozzle assemblies spray washer fluid onto the windshields. RAIN REPELLENT UTILITY SYSTEM Learning Objective: Identify functions and components for rain repellent utility systems. The rain repellent system discharges fluid onto the pilot’s and copilot’s windshields from a 1-28