Electrical System - TM-5-5420-279-230051

TM 5-5420-279-23

1-10-35 Electrical System

The electrical supply is provided from the launcher vehicle and regulated to 24 V dc by a

voltage regulator installed in the electrical control cabinet. The regulator also provides RFI

filtration for the system. The electrical system incorporates a voltage overload protection device to

cater for an EMP spike in the launcher vehicle electrical system.

The system is fail safe with controls spring-loaded to the `Off' position. Interruption to the

electrical power supply returns the control logic program to its start point with only the `Power On'

light illuminated and no function available to be operated. This safety feature applies to switching

off of the chest pack or disconnection of either end of the umbilical cable. Non-operation of the

controls for approximately five minutes returns the control logic to the start position.

1-10-36 Hydraulic System

The hydraulic system is separated into three circuits, which are used to operate the services of

the chassis, the A-Frame and the launching equipment. Hydraulic fluid is drawn from a reservoir

to the transmission-driven pump and directed through a pressure filter to the control valves, which

operate the various hydraulic functions of the circuits. Four types of flexible hose are used to

carry the fluid around the circuits and include pressure hoses, capable of a working pressure of

4423 Psi (30495.51kPa), and return hoses rated at 235 Psi (1620.26 kPa). Smaller diameter

drain and load-sensing hoses are provided for each circuit.

1-10-37 Hydraulic Reservoir

The hydraulic reservoir provides bulk storage of hydraulic fluid for operation of the

hydraulic circuits. Internal baffles ensure heat dissipation, contamination settling and the escape

of trapped air from the hydraulic fluid. A suction isolation valve prevents fluid loss during pump

maintenance. Air is allowed into and out of the reservoir during hydraulic cylinder operation via a

breather, which filters incoming air to a finer level than the hydraulic fluid.

A low-level warning switch is fitted to coincide with the minimum fluid level (operational)

and a further low-level warning switch, coinciding with the minimum fluid level (pump damage),

stops the equipment functions if this level is reached.

Temperature of the hydraulic fluid in the center of the reservoir is sensed by a gauge

thermometer probe device.

1-10-38 Built-In Test Equipment (BITE)

The launcher vehicle is equipped with various items of built-in test equipment to monitor, test and

fault find on the electrical and hydraulic systems.

1-10-39 Hydraulic Test Points

Test points are fitted at strategic locations to assist monitoring and fault finding of the hydraulic

system. All test points can be used for hydraulic fluid sampling.

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