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Hook
Up & Down safety switch
This
switch prevents the accidental hitting of hook on the boon or hitting
the ground. The hook will stop automatically even if the switch
has not been turned off 1 MTR below the boom or 1 MTR above ground
level.
Trolley
In & Out limit switch
The
switch stops the trolley 20 CMS before trolley reaches either end
of the boom.
Over
Load Limit switch
If
the load lifted beyond the rated capacity of the crane at various
boom lengths would result in sounding of the alarm & stopping
of the hoist circuit.
Moment
cut out switch
If
the maximum load was lifted at the permissible length and the load
is trolled outward would result in severe accident in the absence
of this switch.
Slewing
limit switch
This
limit restricts the slewing system to prevent accidental hitting
of the boom to any other crane or the building within its radius.
As
we are concerned with the trouble free and safe working fo your
machines at all times, we would recommend the insertion of the Phase
Failure Relay into the existence circuitry of the machine.
The salient features of the Phase Failure Relay are as under:
To
cut off the power supply in the event of one phase not reaching
through the D.B to the equipment thus saving the motors from single
phasing that causes burning out of the motors.
Whatever
the safety features are operational in the equipment would not function
if the phase reversed to the equipment.
The
control transformer of the equipment is fed through two phases our
of three phase supply and if the third phase which is not connected
to the transformers is blown out, it would not reacfh the motors
but the existing two phases connected ot the transformers will activate
the circuits connected through the transformer and will energize
the BRAKES of hoisting motors to open and since the power reaching
to the motors is not sufficient it would not raise the load lifted
but instead the load would fall free with acceleration and force
causing serious accidents if the operator is not attentive at all
times.
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