Apparatus for detecting power lines.

摘要

Apparatus for mounting on a crane (10) or other con­struction equipment for detecting the presence of an electrical power line (12). A reference pickup coil (30) mounted on an upper machinery works (18) or other portion of the equipment generates a reference signal proportional to the strength of a magnetic field in a work area. Other pickup coils (35-38) mounted on a crane boom (17) or other portions of the equipment which may extend into closer proximity to power lines (12) develop signals which are compared with the reference signal. When any of these signals exceed the reference signal by a predetermined amount a warning signal is developed. Coils having the proper ratio of core length to diameter and having coil winding which extend along approximately half the core length provide output signals which have a predictable amplitude.