HIGHLANDER II VERTICAL PLATFORM LIFTS:
Install Manual
17FEB2021 | 630-00113 REV C
35
TROUBLESHOOTING
HIGHLANDER II: SECTION 6
CONTACTOR TRAY
The Contactor Tray contains other control
electronics wired to motor and control tray.
See Figure 6-6.
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.
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.
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.
Do not manually switch the position indicator as
all safeties would be bypassed.
WARNING
!
Load resistors could be very hot. Do not touch.
WARNING
!
Motor
Brake
Fan
Load
Resistors
UP
Contactor
DOWN
Contactor
E-Brake
Resistor
Motor
Motor
Gearbox
