08 Contactor panel

Workshop Manual 7032 - 34 / 38 - 40 / 48 - 50

Contactor panel or support Mechanical configuration

The contactor panel is located under the engine bonnet on the LH side. Protected against water splashes by a removable plastic hood with gasket, all components are mounted to a carrier plate. The following components are mounted on the contactor panel: 1K3 - engine start-contactor

1K4 - driving contactor

1U1 - current sensor with p.c.b. 1 A6 and fuses F2, F3, F4. F5. F6

9K3 - glow plug relay (DFG) 9F4 - main power fuse 250A Main power fuse

Since August 1992 the positive (+) supply lead to the battery is protected by a 250 amp main power fuse.

Retrofit

The fuse can be retrofitted to older truck models in this range. Mounting holes have been provided to that effect.

As a temporary solution proceed in compliance with Fig. 3 since the contact bridge from contactor to fuse is not yet available.

IMPORTANT

In the event of a blown fuse the alternator must on no account be disconnected from the battery. The wire connection between battery positive (+) and alternator 13+/9G2 must absolutely be placed in front of the fuse

DFG - Glow plug system The glow plug system consists of

4 glow plugs 9E13 - 9E16 inside the engine, the series resistor 9R8

fitted to the RH frame section (from he inside between the two vibration mounts of the diesel generator unit), and the

glow plug relay 9K3 - 24 volts/50 amps

Glow plug relay 9K3 and thereby the pre-glow period are controlled by p.c.board 9A4 ‘engine starting via generator’.

Once the engine is started the glow system will remain in circuit for a period which depends on engine temperature. This period too is controlled by p.c.b. 9A4.

Note:

Due to the different glow periods which vary with the type of engine (VW or MB), the p.c.board ‘engine starting via generator’ is avaiable under

1G1

M

1M1

1K4

1U1(1A6)

G

G1

G2

1K3

1K3

1 F4

12 Volt

1K3 / 1K4

60°

( - )

( + )

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Contactor panel

Workshop Manual 7032 - 34 / 38 - 40 / 48 - 50

The task of contactor 1K3 consists in establishing during the starting operation the battery current up to an intensity of abt. 160 amps.

Once the engine has started, contactor 1K3 is opened and following a short delay contactor 1K4 will close the armature circuit between generator 1G1 and drive motor 1M1.

Control voltage

Once the safety relay incorporated in power board 1A2 has been closed, both contactor coils will be supplied with voltage by the positive battery terminal. Contactor coil 1K3 is then supplied via keyswitch S1 with voltage by the positive battery terminal, while the coil of contactor 1K4 is supplied with voltage directly

The contactor coils have been designed for the 12 volts operating voltage, at the same time being controlled by p.c.b. 9A4 (engine starting via generator) against the neg. terminal of the battery, thus not being supplied with full battery voltage! Mechanical configuration

The contactor frame is made of impact resistant plastics. At its upper half the frame comprises 4 M8 studs imbedded in the plastic material.

The lower two studs serve as terminals for connecting the contact bridge of the armature by means of flexi- ble links. The contact screws/tips are screwed from the inside into the upper studs.

The coil assembly comprises:

Coil - magnetic core - frame - protective circuitry. The protective circuitry consists of: Diode 1 N 4005 and 10 Q resistor. Coil resistance is approx. 5.11 ohms in the case of 12 volts battery voltage.

The movable part of the contactor - the armature assembly - is mounted between contactor frame and coil frame.

The contact screws/tips of contactor housing and armature are identical.

Torque loading of contact screws = 10 + 1 Nm in which case contact screws must be screwed fully home (i.e. up to the thread root) and further tightened with 60* angle of rotation

60°

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Workshop Manual 7032 - 34 / 38 - 40 / 48 - 50

STILL contactor

Contact pressure of contactor in the fully operated state: Required value 9.0 ... 10.5 N for each contact, centre of contact taken as a reference.

Adjustment

-Fully actuate contactor (electrically or mechanically) - Attach contacts centrally to a spring balance or scale and apply a load of 950 to1050 grammes at the maximum (equals 9.5-10.5 N).

Contact pressure can now be accurately adjusted by operating on the hex. head screw passing through the contact spring. Rotating the hex. head screw in a clockwise direction will increase the pressure.

Note:

The contact spring is subjected to a certain degree of friction. The contact pressure is therefore correctly adjusted if when applying a pressure load of 10 ... 10.5 N the contact during slow approach does not yet close, but in the case of a rapid approach makes contact and remains closed.

2. Pull-in stroke

Provided the contactor is correctly assembled, a spacing of 1.3 to 2.7 mm between contact bridge and support finger must be achieved with contactor being pulled in.

3. Torque loadings

The contact screws must be tightened to a torque of 10 + 1 Nm. To achieve this torque loading without using a torque wrench, the contact screws must be screwd fully home and then rotated through a further 60°.

4. Mounting the arc blow-out magnets

To install the arc blow-out magnets or arc suppression chambers on the contactors, a screwdriver must be passed through a hole in the leaf spring. By exerting a light pressure on the leaf spring the latter is pressed inwards until the arc blow-out magnet has reached its final position. After withdrawal of the screwdriver the leaf spring will retain the arc blow-out magnet in position.

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