Electrified fence power supply - has air gapped transformer monitoring leakage current and overvoltage protection

摘要

The power supply for electrified fences minimises the possibility of false alarms and subsequent loss of creditability by constant monitoring of the fence leakage current. The supply unit is based on the use of a two transistor oscillator fed from a regulated D.C. supply, loaded by two almost identical multi-winding transformers. Both transformers are connected into the fence lines via rectifier bridges, one including a spark gap circuit shunted by a resistor chain to ground providing overvoltage protection, this transformer also monitoring the leakage current. The second transformer provides the fence electrification supply proper.