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CONTACTOR TRAY
The Contactor Tray contains all electrical wiring for
the contacts. See Figure 7-3.
Figure 7-3
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.
VPL400-X: SECTION 7
TROUBLESHOOTING
BRAKE RESISTOR
The 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. Ensure the BRAKE RELEASE toggle switch is in the
down position.
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.
WARNING
!
Load resistors could be very hot. Do not touch.
GEARMOTOR
The VPL uses a 2/3 Hp gearmotor mounted to the top
of the tower frame. The brake on the back of the
gear motor is a "fail safe," electromagnetic holding
brake. The Motor Gearbox on the front of the motor
is a vented 26:1 worm drive gear reduction with
synthetic gear and bearing oil.
VPL400-X:
21JULY2023 | 630-00159 B
Install Manual
33
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