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Gallagher 3E1164 Power Fence Systems User Manual
Glossary
9. Glossary
9.1 Electrical Terms
Electrical
Terms
Symbol
Definition
a.c.
Alternating current as from mains.
Ampere
A
Value of current flow (amps). The equivalent in water flow is litre/hr.
Circuit
A conducting path around which electrons (current) flow.
Current
I
Flow of electrons, measured in amperes. It is the duration and rate
of flow of the current which causes a shock. Increasing the voltage
increases the current. Increasing Resistance decreases Current.
d.c.
Direct current as from batteries.
Electrolysis
Corrosion between different metals in a wet environment such as
between copper and galvanised wires on a fence line. Avoid this by
only using galvanised wire.
Induction
Power transfer without contact. For example, the charging of dead
or neutral fence wires which run parallel to live ones. The closer
the live and neutral wires and the further they travel together, the
greater the amount of inductance.
Joule
J
Unit of energy. One joule is one watt for one second. It is the
measure of “kick” of a pulse. Joules are the most important
measure of the power of an energizer.
Leakage
Energy caused by poor insulation, shorts and/or vegetation on the
wires resulting in a drop in voltage.
Ohm
Unit of resistance = volts/amps. The resistance to earth scale is
a reverse one, in that a lower value indicates increased shorts to
ground. Zero Ohms is a direct short to ground, while very large
reistance to ground indicates that the fence is well insulated. 500
Ohms is also the usual energizer test load.
Pulse
A brief electrical current or shock emitted by an energizer. Each
pulse is on for about 0.0003 of a second. Pulses are spaced about
one second apart.
Resistance
R
Measured in ohms. It is the equivalent of friction in water.
Volt
V
Unit of electrical pressure which causes current to flow.
1000 V equals 1kV Voltage = current x resistance.
Watt
W
Unit of power, both electrical and mechanical.
Volts x Amps = Watts
746 Watts = 1 h.p.
