Functioning Algorithm Of Pilot Lamp To Indicate Operation Of Heating Plugs - Belarus 1523.5 Operator's Manual

2.7.2 Functioning algorithm of pilot lamp to indicate operation of heating plugs

As a means of start facilitation, heating plugs (HP) are used in tractors "BELARUS –
1523.5" which are mounted in the cylinder unit head. For individual control of heating plug
operation modes and indication of their operation, a heating plug control unit is used.
The heating plugs are not activated, if the engine temperature exceeds +5°C. In this case
heating plug pilot lamp 4 (figure 2.7.1) lights up for 2 sec. or does not light up at all.
If the engine temperature is below +5°C, the heating plugs are activated automatically as
the key of starter and instrument switch is turned from position "0" (off) into position "I" (In-
struments on). In this case heating plug pilot lamp 4 lights up in the pilot lamp unit of the
dashboard. The heating plug operation time depends on the engine temperature according
to table 2.2. It is necessary to start the engine as lamp 4 goes out after the time specified
in table 2.2. After the engine start-up, the heating plugs remain activated for some time,
then they go out. The heating plug operation time after the engine start-up depends on the
engine temperature at the moment of the heating plug activation. (see table 2.2).
The heating plug operation algorithm has the following emergency modes:
- as the key of starter and instrument switch is turned from position "0" (Off) into position "I"
(Instruments on) the heating plug pilot lamp starts to flash continuously with
quency. This means that there is a failure in the heating plug operation – all heating plugs
are closed-circuit or their connection is disturbed (disconnected from the heating plug con-
trol unit), the heating plug control unit is not powered or the power supply wire is damaged.
In case of short circuit, the heating plug control unit cuts power supply (12V) to the heating
plugs.
- after the engine start-up the heating plug pilot lamp 4 starts flashing for one minute with 3
sec. of cycle duration and 0,25 sec. of flash duration. The number of flashes can be differ-
ent. The start-up procedure runs in an ordinary way. This means that one or more (but not
all) heating plugs are faulty. The number of flashes within one cycle equals to the number
of faulty heating plugs;
If the specified failure is not eliminated, it may be difficult to start the engine at low temper-
ature.
- during the pre-start heating before the engine start-up, pilot lamp 4 flashes with 1 Hz fre-
quency. This points at short-circuit of the heating plug temperature sensor, or breakage in
the heating plug temperature sensor circuit, or sensor failure. The time of engine pre-start
heating as well as plug heating after engine start-up is specified in table 2.2
TRACTOR OPERATION IS FORBIDDEN UNTIL FAILURES OF THE HEATING PLUG
SYSTEM ARE DETECTED AND ELIMINATED. OTHERWISE IT MAY LEAD TO DIS-
CHARGE OF ACCUMULATOR BATTERIES!
Table 2.2 – Heating plug operation time depending on engine temperature
Engine temperature, °С Time of engine pre-start
-40
-20
0
+20
+40
+50
+60
sensor breakout
heating, sec., at least
50
33
20
13
9
8,5
0
33
30
1523.5-0000010 OM
Time of heating after engine
start-up, sec., at least
183
183
74
45
33
31
0
183
2 Hz fre-