SE-601 DC Ground-Fault Monitor
Rev. 2-C-073123
1
1. GENERAL
The SE-601 is a microprocessor-based ground-fault
monitor for ungrounded dc systems. Its output relay can
operate in the fail-safe or non-fail-safe mode for
undervoltage or shunt-trip applications. The SE-601 has
one output relay with isolated normally open and normally
closed contacts for use in independent control circuits.
Additional features include LED power and faulted-bus
indication, autoreset or latching trips with front-panel and
remote reset, trip memory, test button, self diagnostics,
0- to 5-V analog output, and digital selector switches. The
SE-601 can be DIN-rail, surface, or panel mounted.
Ground-fault current is sensed using an SE-GRM-series
Ground-Reference Module—a resistor network that limits
ground-fault current to 25 mA. The trip level of the ground-
fault circuit is selectable from 1 to 20 mA. Trip time is
selectable from 0.05 to 2.5 s.
2. OPERATION
2.1 CONFIGURATION-SWITCH SETTINGS
See Fig. 1.
2.1.1 RELAY OPERATING MODE
Switch 1 is used to set the operating mode of the output
relay. In the fail-safe mode, the output relay energizes when
the SE-601 is energized and the ground-fault circuit is not
tripped. If tripped, and the supply voltage is cycled, the
SE-601 will remain tripped, with the trip relay de-energized
and a TRIP LED on, until reset.
In the non-fail-safe mode, the output energizes when a
ground-fault trip occurs. In the non-fail-safe mode, trip
status is not retained in non-volatile memory.
2.1.2 RESET MODE
Switch 2 is used to select autoreset or latching trips. See
Section 2.2.3.
2.2 FRONT-PANEL CONTROLS
2.2.1 GROUND-FAULT TRIP LEVEL
The LEVEL (mA) selector switch is used to set the
ground-fault trip level.
Ground-fault current is a function of fault resistance,
system voltage, and the SE-GRM-series Ground-Reference
Module. Table 1 lists the SE-601 trip levels and fault-
resistance values for 24-, 48-, 125-, 250-, 500-, 780-, 1000-,
and 1500-Vdc systems.
2.2.2 GROUND-FAULT TRIP TIME
The SE-601 has a definite-time trip characteristic. The
TIME (s) selector switch is used to set the ground-fault trip
time.
2.2.3 RESET
If the Reset Mode switch is in the LATCHING position,
a trip remains latched until the RESET button is pressed or
the remote-reset terminals (6 and 7) are momentarily
connected. In the non-fail-safe mode, cycling the supply
voltage will also reset the SE-601.
If the Reset Mode switch is in the AUTORESET
position, a trip will reset when the fault is removed.
The reset circuit responds only to a momentary closure so
that a jammed or shorted button will not prevent a trip. The
front-panel RESET button is inoperative when remote-reset
terminals are connected.
2.2.4 TEST
The TEST button is used to test the ground-fault circuit,
trip indication, and the output relay. When the TEST button
is pressed for one second, a test signal is applied to the
ground-fault-detection circuit, the circuit will trip, both
“-BUS”and “+BUS” TRIP LED’s will light, and the output
relay will operate.
TABLE 1. SE-601 TRIP LEVELS AND FAULT-RESISTANCE VALUES
