Page 26
Improper microswitch
adjustment may re-
sult in serious bodily
injury and/or property
damage.
Microswitches:
Three micro-
switches (limit switches) are
incorporated in the RA300 electri-
cal system. Ramp microswitches
are: Drift-In, Drift-Out and Coun-
WHU$GMXVWPLFURVZLWFKHVDV
detailed (if necessary only).
Microswitch Sequence
Stowed Position:
When the
ramp is in the stowed posi-
tion, the Drift-Out and Counter
microswitches are deactivated
(common and normally closed
terminals have continuity). In
contrast, the Drift-In microswitch
is activated.
Deploy Sequence:
When the
ramp is in the stowed position,
the Drift-Out microswitch is
deactivated. Current is allowed
to pass from the vehicle Deploy
Relay, which directs current to the
bidirectional pump motor (hydrau-
lically drives cylinders to deploy
ramp).
When the ramp platform reaches
the Drift-In limit (approximately
45° above ground level), the
microswitch is activated (common
and normally open terminals have
continuity), and the current to the
Deploy Relay is interrupted thus
stopping the current to the pump
motor. The platform then “drifts”
downward to ground level, during
which, at some position, the Drift-
Out microswitch is activated. The
Drift-In microswitch is deactivated
during the deploy movement of
the platform. Note: Neither of the
other 2 microswitches have any
bearing on the deploy sequence.
Deployed Position:
When the
ramp is in the deployed posi-
tion, the Drift-Out and Counter
microswitches are activated. In
contrast, the Drift-In microswitch
is deactivated.
Stow Sequence:
When the
ramp is in the deployed posi-
tion, the Drift-In microswitch is
deactivated, allowing current to
pass from the vehicle Stow switch
circuit and energize the ramp
Stow Relay,
which directs current
to the bidirectional pump motor
(hydraulically drives cylinder to
stow ramp).
When the ramp platform reaches
the Drift-Out limit (approximately
45° above ground level) and
deactivates the microswitch, the
current to the Stow Relay will be
interrupted.
MICROSWITCH ADJUSTMENT
Summary of Contents for BF3248Y-2
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