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Electrical
Improper microswitch
adjustment may re-
sult in serious bodily
injury and/or property
damage.
WARNING
Microswitches:
Three micro-
switches (limit switches) are
incorporated in the RA300 Ramp
electrical system. Ramp micro-
switches are: Drift-In, Drift-Out
and Counter.
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 deacti-
vated. Current is allowed to pass
from the vehicle Deploy Relay,
which directs current to the Bidi-
rectional Pump motor in direction
A (hydraulically drives cylinders to
deploy ramp).
When the ramp’s platform reach-
es the Drift-In limit (approx. 45°
above ground level), the micro-
switch 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 se-
quence.
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
in direction B (hydraulically drives
cylinder to stow ramp).
When the ramp’s platform reach-
es the Drift-Out limit (approx. 45°
above ground level) and deacti-
vates the microswitch, the current
to the Stow Relay will be inter-
rupted.
SYSTEMS DESCRIPTIONS
Details and photos of the micro-
switches are provided below.
Adjust microswitch(es) as detailed
(if necessary only).
Summary of Contents for BF3255Y-12V
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