EP Equipment CQD16, Service Manual

Page: 123 / 251

REV. 07/2016
ELECTRICAL SYSYTEM
8
109
8.3 Main Contactor
This truck is using dual contactors with
normally-open contacts. And the ON/OFF of the
contactors is controlled through controller, thus
to achieve the control of ON/OFF of the vehicle.
When the contactor coil is energized, the coil
current will create a magnetic
fi eld, making the
static stator core produce a steady magnetic
force to absorb the core and drive the contactor
actions: normally-opened contact connected, so
the circuit is disconnected.
When the contactor coil is powered off, the
magnetic force disappears, the pressure plate
is released along with the release of spring, and
the contact recovers: normally-opened contact
disconnected, so the circuit is disconnected.
8.3.1 Removal and Installation
Main contactor is installed on the electrical
mounting plate.
-
-
-
Remove the cables and wiring harness on
the main contactor, and remove the main
contactor from the electrical mounting plate;
Unscrew the two fastening screws (4) with a
Phillips screwdriver and remove the top cover
of contactor (3);
Remove the auxiliary contact assembly
(2), replace the assembly or coil (6); (when
replacing the contacts, replace in pairs)
-
-
After the replacement, re-install in reverse
order and tighten the two fastening screws
(2);
Following the reverse order of step 1, fast-
en the main contactor onto the electrical
mounting plate, and re-connect it according
to the original connection methods.
8.3.2 Faults and Causes
1
Fault Contact adhesion or slow release
Cause
a. Contact fusion welding;
b. Contact spring pressure is too
low;
c. Mechanical moving parts
blocked, shaft rusted or crooked;
d. Anti-force spring damaged.
2
Fault
Contact not absorbed or not fully
absorbed
Cause
a. Insuf fi cient voltage of battery;
b. Main contactor coil open circuit;
c. Mechanical moving parts
blocked, shaft rusted or crooked;
d. Control contact poor contact.