NK TECHNOLOGIES AGT Series User manual

INSTRUCTIONS
1. Run all current carrying conductors through sensor
window.
A. Use an auxiliary CT if conductors do not fi t. Consult
Factory for CT selection.
2. Mount the indicator to a surface if needed.
3. Connect output & power wiring.
A. Use 30-12 AWG copper conductors only and tighten
to 5-7 in-lbs torque.
B. Make sure fault current levels match the output
range shown on the sensors’ label.
• Loop Powered 4-20 mA sensor output.
• Connect power supply in series with the load as
shown on next page.
C. Make sure power supply voltage is no lower than
12 and not greater than 35 VDC at the sensor ter-
minals.
AGT 1 - 420 - 24L - FL
Model Number Key
Specifi cations
Quick “How To” Guide
Power Supply Notes AGT SERIES
Ground Fault Indicator
Analog Output
292080302 Rev 3
Output Type:
420 - 4-20 mA proportional to fault current
Power Supply:
24L - 24 VDC Loop Powered
Input Range:
1 - 0-50 mA
2 - 0-100 mA
AGT Series Ground Fault Indicator
Power Supply 24 VDC Nominal (see chart below)
Use Class 2 or power limited supply only
Power Consumption 2 VA
Input Range AGT1: 0-50 mA
AGT2: 0-100 mA
Isolation Voltage Up to 600 VAC (Monitored Circuit)
Frequency Range 40-400 Hz (Monitored Circuit)
Output Signal 4-20 mA loop powered
Output Loading 600 Ω maximum @ 24 VDC
Response Time 600 mS 90% step change
Dimensions 2.5”H x 3.86”W x 1.45”D
(64 x 98 x 37 mm)
Sensing Aperture 0.75” (19 mm) diameter
Case UL94 V-0 Flammability Rated
Environmental -4 to104°F (-20 to 40°C), 0-95% RH,
Non-condensing
Listings UL/cUL
System Grounding
3511 Charter Park Drive, San Jose, CA 95136
Phone: [phone] or 408-871-7510
Fax: [phone]
[e-mail], www.nktechnologies.com
Know Your Power
Other NK Technologies Products Include:
AC & DC Current Transducers
AC & DC Current Operated Switches
1 & 3Power Transducers
Current & Potential Transformers (CTs & PTs)
All low-current Ground-Fault Sensors are sensitive devices
that require reasonable care in system design to avoid false
indication caused by high electrical noise levels. Keep in
mind that the best way to reduce noise in a system is to sup-
press it at its source.
1. Keep the sensor power isolated from noisy circuits.
2. Do not power the sensor with the same circuit that switches
contactors or other high current, inductive loads.
Good design practice and code require that all AC power
systems be grounded. AG Series sensors are designed to
work on grounded AC power systems. They may not operate
properly on ungrounded systems.
Housing:
FL - Solid-Core

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