Description
Operation
Principal of Operation
Under normal conditions, the current in one wire of a two
wire load is equal in strength but opposite in direction. The
two wires together create cancel magnetic fi elds, a condi-
tion known as “Zero Sum Current”. If any current leaks to
ground (Ground Fault), the two currents become unbalanced
and there is a net resulting magnetic fi eld. The AGV sensor
detects this minute fi eld and changes the output state. This
concept extends to three phase systems such as 3 wire Delta
(grounded) and also 3 or 4 wire Wye.
AGV 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 opening in the
sensor. (See “Principal of Operation”) Be Sure all wires
in a three phase system are oriented so current fl ows in the
same direction.
Installation & Wiring
AGV Series sensors monitor all current carrying wires in
single or three phase systems to detect ground faults. They
provide a contact output that can operate relays, contactors
or signal automation systems. The design goal is to provide
a reliable detection with less spurious tripping.
Wiring to unit
Use 22-14 AWG copper wire and tighten terminals to 5-7
inch-pounds torque. See Diagram.
Power
Connect power wiring to Terminals 1 & 2. Be sure that
the power supply matches the power supply limits on the
sensor label.
Output
Connect output wiring to Terminals 3&4 (NC) or 4&5 (NO).
Reset Switch (Latching Models) Terminals 6&7
Momentary Reset
The sensor will not work properly if the reset terminals are
closed (shorted) continuously. Only close the reset terminals
momentarily.
Parallel Reset Connection
Multiple sensors may be connected to the same reset switch
in parallel. Only the sensors that have detected a fault and
have latched will be reset. A sensor will not reset unless the
fault has dropped below setpoint.
AGV Series Latching Ground fault sensors operate in one of
two states: Reset or Latched. If control power is removed,
the sensor remains in it’s last state (latched or reset).
Reset
The sensor has not detected a fault and the output is in the
“normal” position.
Latched
Upon detecting a fault or when the TEST switch is pressed,
the output will switch (NO 4&5 closes and NC 3&4 opens),
and “latches”. The output will remain latched until the ground
fault is removed and the output is reset by a momentary dry
contact on Terminals 6 &7.
With DEN type models, the NO contact (4&5) closes on a
fault and the NC (3&4) contact opens.
With ENE type models, the NO contact (4&5) closes when
power is applied to the sensor, opens on a fault and the NC
(3&4) contact opens when power is applied, and closes on
a fault. The sensor contacts also revert to “shelf state” when
power is removed from the ENE type models.
Testing
To test operation, gently press the TEST button. This
simulates a fault and tests the internal switching circuits.
After the test is complete, reset the sensor with a momentary
dry contact on Terminals 6 & 7. CAUTION: Any circuit
connected to the sensor will be operated. Do not apply
voltage to the reset terminals.
Monitored Circuit
Feed the wires carrying the monitored circuit current through
the sensing aperture. The same sensor can monitor a single
phase (hot and neutral), two phases (two hot) or three phase
load up to 600 VAC. If the monitored load uses the neutral,
it must pass through the aperture. The bond or ground wire
should never be included.
Output table
Normally Energized Models( -ENE Option)
Protection from faults and control power loss.
Control Power Applied
No Power No Fault Fault
N.C. Normally Closed closed closed open
N.O. Normally Open open open closed
Control Power Applied
No Power No Fault Fault
N.C. Normally Closed closed open closed
N.O. Normally Open open closed open
Latching Models (-LA Option) from factory power up initially in the
reset (normal) mode. If there is a fault condition or the test button is
pushed, the output contacts will change state and latch. The output will
remain latched regardless of whether the fault is cleared or control power
is removed. To reset the output apply a momentary contact across “reset”
terminals.
Connect a momentary dry contact to the reset terminals
(6&7). Limit wire run to 200’ of 18 AWG or larger wire.
Normally De-energized Models( -DEN Option)
Protection from faults.
490061007 REV 1
