DEMAG DC-Com 1 Operating Instructions Manual page 65

Load distribution
Fig. 37
Functioning of the emergency stop device
When the emergency stop is actuated, the hoist motor is disconnected immediately from the electrical power supply,
the mechanical brake is applied and stops the movement.
Resuming operation by unlatching the emergency stop is only possible, if no lifting or lowering commands are applied
(off-position constraint).
The effectiveness of the emergency stop function depends on the proper condition of the mechanical brake. If an
unusually long braking distance is noted, impermissible wear on the brake may be the cause. In this case, the brake
must be inspected by an experienced technician without delay.
Functioning of the slipping clutch
The chain hoist is fitted with a slipping clutch that is tripped in the event of overload. The brake is then automatically
applied and the motor is switched off. After the slipping clutch has been tripped only lowering is possible.
It is therefore not possible to lift an overload from the ground. A load already suspended can be safely deposited by
actuating the lowering button. When the lowering motion has been completed, lifting is possible again. If the slipping
clutch switches off already at rated load, the slipping force must be measured by an experienced technician and re-
adjusted, as required.
Functioning of the lifting path limiter
After the lifting path limiter has been tripped, only the opposite motion is still possible. The lifting path is limited by
limit stops on the ends of the chain. As a consequence, the slipping clutch becomes effective as an emergency stop
device, the brake is automatically applied and the motor is switched off. Tripping of the emergency stop device
causes a warning message on the display. Operating limit switch contacts prevent travelling against the emergency
stop device, they are actuated by elastic buffers on the limit stop and cut-out the motion before the emergency stop
device is reached. When the DC-Com chain hoist is not eqipped with an operating limit switch, the emergency limit
stop device must not be approached.
CAUTION
Premature wear of the chain guide and chain
Danger of load drop
Avoid unequal loading of the chain falls. This results in chain
breakage and damage of the chain guide.
Blocked chains or excessive play between chain and chain
sprocket destroys the chain guide.
– Eliminate any knots or blockage of the chains before
lifting / lowering.
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