초록 ▼

In an electric fence energizer there is an exterior earth connection such as an earth connection post (16). The electric fence energizer comprises in the conventional way a transformer (T) having a primary winding (L.sub.1) and a secondary winding (L.sub.2), one exterior terminal (9) of which is con

In an electric fence energizer there is an exterior earth connection such as an earth connection post (16). The electric fence energizer comprises in the conventional way a transformer (T) having a primary winding (L.sub.1) and a secondary winding (L.sub.2), one exterior terminal (9) of which is connected to the conductor (17) in the electric fence and the other exterior terminal (11) is connected to the earth connection, high voltage pulses being induced over the secondary winding (L.sub.2) when voltage pulses are applied over the primary winding (L.sub.1). For a determination of the quality of the earth connection, the voltage over a small part of the secondary winding (L.sub.2) is obtained capacitively by means of an extra winding (L.sub.3) in the transformer (T). For an evaluation of this voltage, it is connected, only for a determined polarity, to a charging circuit for a capacitor (C.sub.2), which is discharged over a known resistor (R.sub.2, R.sub.3). The voltage (V.sub.21) over this capacitor (C.sub.2) is processed for a determination of the quality of the connection to earth. Then the time difference can be determined between the time (t.sub.0) when the induction high voltage pulse over the secondary winding (L.sub.2) starts, and the times (t.sub.1, t.sub.2) when a voltage change of the capacitively obtained signal after that starts and when the voltage returns to its stationary value. These time differences are compared to threshold values for determination of the quality of the connection to earth. The capacitively obtained voltage can also be used for other determinations in the electric fence energizer.

대표청구항 ▼

[ We claim:] [1.] A method for determining the quality of a connection to earth by way of an earth connection post of an electric fence energizer delivering high voltage pulses to an electric fence, the energizer including a transformer having a primary winding and a secondary winding, a first exter

[ We claim:] [1.] A method for determining the quality of a connection to earth by way of an earth connection post of an electric fence energizer delivering high voltage pulses to an electric fence, the energizer including a transformer having a primary winding and a secondary winding, a first exterior terminal of the secondary winding being connected to a conductor of the electric fence and a second exterior terminal thereof being connected to the earth connection, high voltage pulses being induced over the secondary winding when voltage pulses are applied to the primary winding, the method comprising the steps of:evaluating a voltage between the second exterior terminal of the secondary winding, which is connected to the earth connection, and a ground potential, whereinsaid voltage used for the evaluation is obtained capacitively from a small portion of the secondary winding.