Protection And Switching Unit - Belarus 3522.5 Operator's Manual

2.19 Protection and switching unit

The protection and switching unit (PASU) is intended to distribute power supply be-
tween tractor electronic control systems and to protect electrical lines from short circuit and
current load excess. The tractor "BELARUS-3522.5" is equipped with a PASU of configu-
ration БКЗ-3522.5.
Place of installation is a cab rear part, to the right behind the side consol.
To access the relay and fuses of the PASU 5 (figure 2.19.10) it is required to unfas-
ten three screws 4 and remove a plastic cover 6. Then it is needed to unfasten four screws
on the PASU and lift an iron cover up.
1 – side console; 2 – OPU of the HLL; 3 – IEP; 4 – screw; 5 – PASU; 6 – cover.
Figure 2.19.1 – Installation of the protection and switching unit
The unit consists of twelve electric fuses 1 (figure 2.19.2) (F1 ÷ F20), eleven elec-
tromagnetic relays 4 (K1 ÷ K11) commutating power supply to elements of tractor elec-
tronic control systems. Signal led lamps of red color 5, located on the front panel beside
each fuse, are intended to indicate blow-out of a corresponding cutout fuse. Besides, there
are signal led lamps of yellow color 2 and 3. The led lamp 2 indicates availability of con-
stant current supply of PASU, irrespective of the AB disconnect switch position. The led
lamp 3 indicates availability of current supply to the PASU only with the AB disconnect
switch turned on.
Allocation diagram of fuses, relays and other elements in the PASU is presented in
figure 2.19.2.
1 – cutout fuse; 2, 3 – signal led lamp of yellow color; 4 – electromagnetic relay; 5 –
signal led lamp of red color.
Figure 2.19.2 – Protection and switching unit
77
https://tractormanualz.com/
3522.5-0000010 РЭ