WKE60 Datasheet, PDF (1/4 Pages) Littelfuse – Ground Fault Relays

Ground Fault Relays
GFR4000 Continuous On and Off-Line Monitor
The GFR 4000 ground fault relay is specifically
designed to provide complete motor protection
without the problems associated with high sensitivity
nuisance tripping. The GFR 4000 is unique because
it has predictive as well as protective capabilities.
The unit operates continuously in one of two modes,
either on-line or off-line. The GFR4000 has metering
output signals for use with a remote meter or PLC so
that ground faults may be detected at an early stage.
The GFR 4000 operates on grounded, high
resistance grounded and ungrounded systems. The
unit can be directly connected to supplies up to
1300V, 1PH or 3 PH, 50-60 HZ. For supplies from
1300 V to 5000 V, the GFR 4000 must be connected
to the HTC 5000 high tension coupling unit.
Operation
On-Line Mode Under normal running conditions the
GFR 4000 operates as a sensitive ground fault relay
working in conjunction with a separately connected
core palance current transformer. The alarm range
is adjustable with a 10 position range of fixed
operating points between 10 mA and 3A. Time delay
is adjustable between 0 and 1 seconds. When the
preset response value is exceeded, the GFR4000
operates the output relay after the preset time delay.
There is instant LED indication. The unit can be set
for Active or Failsafe mode and has memory and
auto reset facilities. The GFR 4000 also monitors
the loop connection to the current transformer and
provides LED indication should it detect a C.T. fault.
The metering output signal is proportional to the
actual leakage current and is expressed as a
percentage of the GFR 4000 leakage current setting.
The output is 0 – 1mA FSD with the meter reading
scaled 0 to 100% relating directly to the selected
current trip value.
Littelfuse, Inc. POWR-GARD Products
800 E. Northwest Highway, Des Plaines, IL 60016
Off-Line Mode The GFR4000 automatically changes
state by means of a small auxiliary contact on the main
contactor when the motor (or load) is switched off. The
unit becomes a high performance insulation resistance
monitor. It imposes a small DC current onto the
network which travels through the motor windings and
interconnecting cable from the motor starter. A green
LED indicates that the off-line monitoring function is
active. The insulation resistance function of the GFR
has an adjustable alarm range from 250 kΩ – 2 MΩ.
The red LED indicates “low resistance” and operates
instantly when the trip relay is activated. The off-line
feature also has an Active/Failsafe Mode and
Memory/Auto Reset facilities. The metering output is 0-
1mA FSD and relates to an insulation range of 0 to
infinity.
WKE Series Current Transformer
The WKE series C.T.s are specifically designed to
operate with POWR-GARD relays. These C.T.s are
protected from open circuit burnout and will saturate at
low voltages to prevent damage to the C.T. There are
varying diameters of C.T. s ranging from 1” to 8 ¼ “.
The C.T. is connected across terminals 16 and 17. It is
essential when installing C.T.s that only the load cable
conductors L and N (1 PH) or L1, L2, and L3 with N (3
ph or 3 or 4 wire), are passed through the center of the
C.T. The ground wire must remain outside the C.T.
core.
Features/Benefits
ƒ Adjustable sensitivity from 10 mA t to 3.0 A to
reduce nuisance trips.
ƒ Precise insulation resistance readings indicate
problems in advance
ƒ Adjustable time delay adapts to unique
applications.
ƒ Fail-safe operation
ƒ On Line monitoring of ground to detect any change
in leakage current
ƒ Off line monitoring of insulation resistance to notify
or halt unacceptable levels
ƒ C.T. Loop Monitoring
ƒ Test/Reset buttons to assure operation
ƒ NO/NC form “C” output alarm relay contacts
1-800-TEC-FUSE | www.littelfuse.com