Electrical Equipment; General Information; Operation Principle Of Heating Plugs Pilot Indicator-Lamp - Belarus 80.1 Operation Manual

3.18 Electrical equipment

3.18.1 General information

Electric circuit diagram of connections of BELARUS-80.1/82.1/820 tractors is given in
Annex A and B.
Electric circuit diagram of connections of BELARUS -80.1/82.1 tractors with canopy
frame or canopy base on the base of small cabin is given in Annex C.

3.18.2 Operation principle of heating plugs pilot indicator-lamp

As a means of start-up facilitation, tractors BELARUS-80.1/82.1/820 use heating
plugs (HP), which are mounted in cylinder head. To control HP, the electrical equipment cir-
cuit is equipped with a heating plug unit (HPU) and a heating plug relay. The operator se-
lects the operation mode for heating plugs based on the temperature of the engine or the
ambient temperature.
The following modes are available for operation of control and testing system of heat-
ing plugs:
- engine start-up without activating the heating plugs;
- engine start-up with activating the heating plugs;
- emergency modes;
1 Engine start-up without activating the heating plugs
Turn the key of the starter and instruments switch from position I (instruments On) in-
to position II (engine start-up) within less than 2 seconds. In this case, heating plugs are not
activated and the pilot lamp of HP (see figure 2.6.1 or figure 2.25.1) does not light up.
2 engine start-up with activating the heating plugs
Activate the heating plugs. To do this, after turning the key of the starter and instru-
ments switch from position 0 (Off) into position I (instruments On), wait for the heating
plugs to activate (approximately 2 seconds after setting the key into position I). In this
case:
- the pilot lamp of heating plugs operation lights up and glows in continuous mode in
the pilot lamp unit, which indicates the activation of heating plugs;
- when the pilot lamp of HP operation changes from continuous glowing mode to
≈ 1 Hz frequency flashing mode, start the engine by depressing the clutch pedal and turn-
ing the key of the starter and instruments switch from position I (instruments On) into posi-
tion II (engine start-up). After engine start, the pilot lamp of HP operation goes out, but the
heating plugs keep operating for 3 more minutes, and only then they deactivate;
- if no start-up attempt is made within the period of the HP pilot lamp working in ≈ 1
Hz frequency flashing mode, the heating plugs and HP pilot lamp deactivate.
3 Emergency modes
In emergency modes, when there is a fault in the heating plug system, the HP pilot
lamp, instead of working according to the algorithm described in paragraph 2, starts to
work according to one of the following patterns:
- flashing mode with a frequency of ≈ 2 Hz. If the heating plugs did not turn off after
practicing the full cycle of operation described in paragraph 2 (relay contacts may stick or
mechanical breakdown may occur), the pilot lamp turns on intermittently with a frequency
of ≈ 2 Hz until the voltage on the contacts is removed;
- flashing mode with a frequency of "one turn-on every 3 seconds." If during opera-
tion of the heating plugs unit in the "engine start-up with activating the heating plugs"
mode, no voltage is supplied to the HP, then the pilot lamp starts to operate in intermittent
mode "one turn-on every 3 seconds";
- with an increase in the supply voltage to the heating plugs unit (more than 16_V),
the HPU turns off. In this case, after more than 2 seconds after turning the key of the start-
er and instruments switch from position "0" (Off) to position "I" (instruments On), the HP
pilot lamp and heating plugs do not turn on.
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80-0000010B OM