Versalift VST-9000I-E100 Service And Installation Manual Download

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102-6

VERSALIFT VST-9000-I-E

THEOR

OF OPERA

TION

There are two circuits that can energize the solenoid.
One circuit is through the lower boom-limit switch
and the other circuit is through the outrigger limit-
switches and toggle switch.

With the boom stored and the outriggers retracted,
the boom limit switch is open and both outrigger limit
switches are open. Therefore, both circuits to the
solenoid are open and the solenoid is de-energized,
hydraulic fl ow is directed to the outrigger controls.
Note that under these conditions, the toggle switch
has no effect on the solenoid which prevents
operating the lift without extending the outriggers.
When the outriggers are extended to ground, the
outrigger limit switches close, completing the circuit
to the toggle switch.

If the toggle switch is open, the solenoid remains
de-energized. Closing the toggle switch energizes
the solenoid, thereby directing hydraulic fl ow to the
lift controls.

Raising the lower boom off the boom rest closes the
boom limit switch. This completes a second circuit
to the solenoid.

If the toggle switch is now opened or if one outrigger
raises off the ground, the solenoid valve remains
energized through the boom limit switch and
hydraulic fl ow remains directed to the lift controls.

If the optional override switch is installed, the
solenoid can be de-energized by opening the
switch. This directs hydraulic fl ow to the outrigger
controls regardless of the other system conditions.

two-position, maintained, toggle switch is mounted
on the turret control valve cover. The emergency
power solenoid is energized or de-energized
depending on the position of the toggle switch.

OPERATION

Control Circuit -

Power for the control circuit

comes from the “on” terminal of the ignition switch.
This means that the key must be in the ignition and
turned on before the system will operate. Current
fl ow is from the “on” terminal of the ignition switch,
through the solenoid coil, and through pressure
switch to ground.

OUTRIGGER/BOOM INTERLOCK

The outrigger/boom interlock option is a safety
feature designed to prevent the lift from being
operated until the outriggers are properly extended.
The interlock also prevents the outriggers from
being retracted before the lift is properly stored.
Refer to the “Outrigger/Boom Interlock Installation”
in “Parts & Assemblies” Section. for installation
drawing. The outrigger/boom interlock components
and their functions are described below.

Outrigger Limit Switch -

One switch is mounted

at each outrigger upper cylinder pin. When the
outrigger contacts the ground, the upper pin moves
upward actuating the switch.

Toggle Switch -

This switch is located near the

outrigger control valves. It is used to select between
lift controls and outrigger controls, provided the
interlock requirements are met.

Boom Limit Switch -

This switch is mounted at

the boom rest to indicate the position of the lower
boom. The switch is open when the boom is stored.

Solenoid Valve -

This valve directs the hydraulic

fl ow from the pump to either the lift controls or the
outrigger controls. When the solenoid is energized,
hydraulic fl ow is directed to the lift controls.

Override Switch (Not Included) -

If required, this

switch may be installed as shown in the schematic.
It allows the interlock to be temporarily defeated.
Continuous actuation is required to accomplish this.

OPERATION THEORY OF OUTRIGGER/BOOM
INTERLOCK

The outrigger/boom interlock system operates by
energizing or de-energizing the solenoid valve.