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HOISTS
MLC150-1 SERVICE/MAINTENANCE MANUAL
5-18
Published 03-21-2021, Control # 264-01
Free Fall System (Optional)
.
Drum 1, Drum 2, or both drums can be equipped with the
free fall option. When free fall is enabled, the large spring-
applied, hydraulically-released disc brake on the end of
drum is used to control the lowering of a load. Raising a load
when free fall is enabled works the same as in normal
operation.
NOTE
When the crane is not in free fall mode, depressing
the free fall brake pedal has no effect on hoist
operation.
The motor and the disc brake on the motor end of the drum
used on the free fall drum are the same as those used on the
non-free fall drum.
When equipped with free fall, the CCS determines whether
drum speed is taken from the motor speed sensor
) or from the free fall speed sensor
The speed sensor sends a signal to the rotation indicator
(thumper solenoid) in the control handle. The rotation
indicator pulsates with a varying frequency to indicate drum
rotational speed. The direction of rotation is also displayed
on the main display via an arrow on the corresponding drum
icon.
Cooling oil flow through the brake is continuous whether or
not the free fall mode is enabled. Cooling oil flow at 5 bar (73
psi) is provided by the free fall cooling pump, which is
dedicated for this purpose.
Brake release pressure is provided by a the free fall pump
which is relief-valve limited to 75 bar (1090 psi). The CCS
receives a position signal from the free fall brake pedal and
uses this information to proportionally adjust the brake
release pressure in order to allow the drum to free fall.
Drum Control Handle—Raise
Hoist Operates Normally
Drum Control Handle—Neutral
The load is controlled by the operator
using the clutch/brake pedal
Free fall brake is spring-engaged—
Brake shaft does not rotate; it is
disconnected from drive gears.
Free fall brake can be
hydraulically released—
Brake shaft can rotate as the
clutch/brake is released. Brake
shaft is connected to drive gears.
Motor shaft disconnected from
drive gears
M100826
FIGURE 5-12
REFERENCE
ONLY
Содержание MLC150-1
Страница 1: ...Service Maintenance Manual Manitowoc MLC150 1 R E F E R E N C E O N L Y ...
Страница 2: ...R E F E R E N C E O N L Y ...
Страница 4: ...THE ORIGINAL LANGUAGE OF THIS PUBLICATION IS ENGLISH R E F E R E N C E O N L Y ...
Страница 98: ...MLC150 1 SERVICE MAINTENANCE MANUAL 5 iv Published 03 21 2021 Control 264 01 R E F E R E N C E O N L Y ...
Страница 205: ...R E F E R E N C E O N L Y ...
Страница 206: ...R E F E R E N C E O N L Y ...