Al Ahsan Technology Co. (L. L. C.)
P. O. Box 27186
Sharjah, U. A. E.
 
Tel:   009716 - 533 1288
Fax:  009716 - 533 1289
Mob: 050 - 4425934
0097150 - 6117425
 


Function of Safety Switches

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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.