Contactor Tray; Up And Down Contactors; E-Brake Resistor; Load Resistors - Harmar Mobility HIGHLANDER II Installation & Service Manual

CONTACTOR TRAY

The Contactor Tray contains other control
electronics wired to motor and control tray.
See Figure 6-6.
Motor
Brake
Fan
Load
Resistors
UP DOWN
Contactor Contactor
Figure 6-6 (wires not shown)
UP AND DOWN
CONTACTORS
Both contactors have 3-poles with an auxiliary
circuit that are switched by 24V AC coils. On top of
the contactors is a switch position indicator that
can be observed to verify switching is occurring
properly. Contactors operate independently and are
controlled by the control board.
! WARNING
Do not manually switch the position indicator as
all safeties would be bypassed.
Motor
Motor
Gearbox
E-Brake
Resistor
HIGHLANDER II VERTICAL PLATFORM LIFTS:
HIGHLANDER II: SECTION 6
TROUBLESHOOTING

E-BRAKE RESISTOR

The E-Brake resistor electronically slows the
motor quickly via eddy current braking. When
both contactors are OFF the resistor essentially
shorts the motor leads which resists motor shaft
rotation. Braking is proportional to motor speed,
so this brake slows the motor very quickly, but
does not hold the motor from drifting after it stops.
The electromagnetic holding brake on the motor
is engaged after the motor comes to a stop. If the
platform is taking too long to come to a stop there
could be an issue with this resistor or the wiring on it.

LOAD RESISTORS

The load resistors function is to slow the platforms
speed in the DOWN direction. The resistors are
in-circuit only when the DOWN contactor is ON and
will generate significant heat as they dissipate some
of the downward energy. The fan located next to
the load resistors is there to cool the resistors.
WARNING
!
Load resistors could be very hot. Do not touch.

COOLING FAN

The cooling fan is primarily to cool the load
resistors, but also cools the top compartment as it
pulls air from the tower below. The fan is controlled
by a thermostatic switch located on a load resistor.
If the fan is not cutting off when the temperature
drops there could be an issue with the switch.

BATTERY BACKUP

If the VPL is equipped with a Battery Backup System,
it will be located inside the tower below the top
plate. See Figure 6-7.
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Install Manual
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