Airstream INTERNATIONAL TRAILER, Owner'S Manual

Page: 47 / 138

AIRSTREAM INTERNATIONAL TRAILER OWNERS MANUAL
D-13
HOW ELECTRIC
BRAKES WORK
FIGURE A
The electric brakes on your
trailer are similar to the drum
brakes on your automobile.
The basic difference is that
your automotive brakes are
actuated by hydraulic pressure
while your electric trailer
brakes are actuated by an
electromagnet. With all of the
brake components connected
into the system, the brakes will
operate as follows:
(See
Figure A).
When electrical current is fed
into the system by the
controller, it flows through the
electro- magnets in the brakes.
The high capacity
electromagnets are energized
and are attracted to the rotating
armature surface of the drums,
which moves the actuating
levers in the direction that the
drums are turning.
The resulting force causes the
actuating cam block at the
shoe end of the lever to push
the primary shoe out against
the inside surface of the brake
drum.
The force generated by the
primary shoe acting through
the adjuster link then moves
the secondary shoe out into
contact with the brake drum.
Increasing the current flow to the electromagnet causes the magnet to grip the armature surface of the brake
drum more firmly. This
results in increasing the pressure against the shoes and brake drums until the
desired stop is accomplished.