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Power cable warning device
Page 82
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ALEAFLET describing a device capable of warning the operator of a crane or tower wagon when he is close to overhead power cables is available from John Davis and Son (Derby) Ltd.
The device comprises three units—a sensing device, a master control unit and a warning horn. Once the master control is switched on the operation of the unit is completely automatic and the horn will continue to sound as long as the projection (jib or tower) is close to the power line. The unit is sensitive to both AC and DC and will give warning over a range of from 240 to 275,000V.
In the event of the unit failing, a warning light will flash in the operating cab and continue until the unit is either repaired or switched off. It is claimed that the unit has a long life and that it can be adequately maintained by a radio service engineer.
Issued by: John Davis and Son (Derby) Ltd., All Saints Works, Derby.