Description
Operation
Principal of Operation
AGT Series sensors work in the same environment as mo-
tors, contactors, heaters, pull-boxes, and other electrical
enclosures. They can be mounted in any position or hung
directly on wires with a wire tie. Just leave at least one inch
distance between sensor and other magnetic devices.
Run all current carrying conductors through the sensor ape-
ture in the same direction. (See “Principal of Operation”)
Connect loop power wiring to the sensor. Be sure that the
power supply matches the power rating on the sensor label.
Use up to 30-12 AWG copper wire and tighten terminals to
5-7 inch-pounds torque. Wiring polarity is critical.
Installation & Wiring
Load
Panel Meter, PLC or Process Controller
24 VDC
Power
Transducer Adjustment
AGT Series ground fault indicators are factory calibrated and should never require fi eld calibration adjustments.
Under normal conditions, the current in one wire of a two
wire load is equal in strength but opposite in sign to the
current in the other wire. The two wires create magnetic
fi elds that cancel, a condition known as “Zero Sum Cur-
rent”. If any current leaks to ground (Ground Fault), the
two currents become unbalanced and there is a net resulting
magnetic fi eld. The AGT sensor detects this minute fi eld and
produces a signal representing the fault current magnitude.
This concept extends to three phase systems such as 3 wire
Delta and to 4 wire Wye.
AGT Series ground fault indicators monitor all current car-
rying wires in single or three phase systems to detect ground
faults. They provide an analog output signal proportional
to the sensed residual (earth fault) current. Used to oper-
ate a panel meter, PLC input or other system automation
controller.
Single Phase (Phase
& Neutral or Phase to
Phase)
3 Phase Delta (Include
neutral if the load uses
neutral)
3 Phase Wye (Include
neutral if load uses
neutral)
3 Phase Load, using an auxiliary Current Transformer. Contact
factory for details.
The AGT sensor can be used to monitor residual (earth leakage) current by passing all of the current carrying conduc-
tors (not the ground wire) through the sensing aperture. It can also be used to monitor circuits of varying frequencies or
distorted wave shapes, but very low current usage. Circuit voltage has no bearing on the sensor if the primary conductors
are insulated to contain the primary circuit potential. The sensor output is capped at 23 mA, but the accuracy specifi ca-
tion is stated only within the range limitations.
Troubleshooting
1. Sensor has no output.
A. Power supply is not properly sized. Check voltage and current rating.
B. Polarity is not properly matched. Check and correct wiring polarity.
2. Output signal is always at 4 mA.
A. Monitored circuit is not AC, or there is zero leakage current. Check to be sure that the monitored circuit is
alternating current.
3. Output signal is always at 20 mA.
A. There is leakage current in the system over the sensor range. Check wiring for insulation integrity, Remove
any faults to earth.
B. Not all current carrying conductors are passed through the sensor aperture. All wires connected to the moni-
tored load must pass through the sensing window, including the neutral if it is used, but not the ground con-
ductor.
292080302 Rev 3
