Belarus 3522.5, Руководство оператора

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3522.5-0000010 OM
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7.4.2 Voltage presence testing
Voltage presence testing is carried out in case of the loop malfunction. Connect one
of the tester’s wires to the battery negative pole or safe tractor “ground”. Another tester’s
wire shall be connected to the loop circuit coupling terminal which shall preferably be the
closest to the AB or the fuse. Flashing of the test lamp indicates the voltage presence in
this circuit interval, which confirms the loop operability between the given terminal and the
AB. Continuing the operation in the similar manner inspect the remaining loop interval. De-
tection of null voltage indicates the occurrence of the failure along the interval between the
given loop point and the last of the recently checked points (under the voltage). In most
cases the electrical connections slacking and defects in contacts quality are the causes of
failures. Note that power for some of the loops of the board electrical equipment is sup-
plied only when the starter switch and the instruments are in position “I” (the instruments
are switched on) or “II” (the starter is switched on (unfixed position)).
7.4.3 Short circuit detection
One method of short circuit detection is withdrawal of the fuse and connection of a test
lamp or a voltmeter instead of it. There shall not be voltage in the loop. Jerk the wiring looking
at the test lamp. Blinking lamp indicates the occurrence of the ground failure somewhere in
this cable caused by worn out wire insulation. Similar check can be carried out for each loop
component including the loop switch.
7.4.3 “Ground” presence in the electrical element testing
The check is intended for detection of the stable “ground” of the electrical element.
Disable it by the accumulator battery disconnect switch and connect one of the wires,
equipped with an independent power supply of the test lamp, to the knowingly stable
“ground”. Another test lamp wire shall be connected to the cable or the terminal being un-
der test. Flashing lamp indicates the working earthing (and vice versa). If the high-current
load negative power supply circuit is tested the application of the test lamp with power of
not less the 21 W is recommended, as in case of poor contact of the “ground” the high-
current load will not work and the low-power lamp will light up.
7.4.4 Electrical circuit breaks testing
Testing is carried out with a purpose to detect the electrical circuit breaks. After the
loop power supply shutoff check it by the test lamp, equipped with the local battery. Con-
nect the tester’s wires to the both loop ends (or to the “power” end (+) and to the stable
tractor “ground”); if the test lamp lights up there is no break in the loop. No light indicates
bad circuit conductivity. Operability of the switch can be checked in the same way by con-
necting the tester to its terminals. When setting the switch into the “On” position the test
lamp shall light up. If the switch commutating the power supply to the high-current load is
tested the application of the test lamp with power of not less the 21 W is recommended
also, as in case of poor contacts inside the switch, the high-current load will not work and
the low-power lamp will light up.
7.4.5 Break localization
When testing for the possible loop breaks it is hard to detect a failure by means of
visual inspection, as it is hard to reach the terminals in order to see if there is any corro-
sion or defect in their quality, due to limited access (usually the terminals are covered by a
backshell). Jerking of a sensor backshell or its cable with wires will result in many cases in
conductivity reconditioning conductivity. Remember this when you try to localize the cause
of failure which is suspected to be the loop break. The emerging failures that are not
common may be caused by terminals corrosion or defect in terminals quality.
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