Service Training
Section 6
Page 12
6.1.5.4 Starting the controller LAC - 1A1
- Emergency stop is made => The positive +24V arrives at the input of the line contactor 1K2 and the key switch.
- The key is turned => the positive +24V pass through the key and the auxiliary microswitch of the emergency stop
7S5. 7S5 ensures the complete halt of the truck if the operator activates the push button (it is an auto feed of the
electronics when the traction motor is generator).
- The LAC is then fed => +24V terminals 1X1:23/11, and terminal direct negative 1X1:48.
- An internal voltage regulator provides the +8.2V => accelerator potentiometer supply in terminals 1X1:22/68,
and supply of the speed sensor and the inclinometer terminals 1X1:46/69.
- The 2 microprocessors for traction and hydraulic are supplied in +5V by a second regulator.The two controllers
start and launch the LAC internal test program.
- If there is no serious internal fault at the LAC => the start-up conditions are consolidated.
The internal safety relay is then controlled. Its contact is connected between the terminals 1X1:1/24.
This relay provides the supply positive +24Vfor => the line contactor 1K2, the electrobrake Y1, the lowering valve 2Y2
and the two valves of the left and right stabilisers 2Y8 and 2Y9.
- The line contactor 1K2 is supplied to negative terminal 1X1: 2 => after closing 1K2, the power stage is supplied +24V
in terminal:+.
Characteristics of the contactor coil:
Resistance (20° C) 44 Ohms
Coil interference Only free wheel diode.
No series resistance.
TRACTION / HYDRAULIC LINE CONTACTOR 1K2
EMERGENCY CIRCUIT BREAKER -7S1 / 7S5
ATTENTION: Always make sure that the emergency circuit-
breaker is pressed before disconnecting or reconnecting
the battery.
7S5
7S1
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