ELRv21-31 SFERE Differential Relays are type B earth leakage current limiting relays.
Combined with a measuring toroid and a circuit breaker, they can be used on low-voltage TT, IT and TNS networks to perform the following functions:
Protection against direct contact
Additional protection against indirect contacts
Limitation of leakage current
Protection against fire
Their enhanced immunity and True RMS measurement technique guarantee maximum safety and continuity of electrical operation, avoiding untimely disconnections. What’s more, they have a pre-alarm output so that insulation faults can be anticipated without tripping.
The ELRv30 and ELRv31 have an automatic reclosing function to maintain the continuity of service required in certain sensitive or isolated installations.
Features & Benefits
LCD display
Programmable sensitivity
2 relay outputs: main alarm + reclosing or pre-alarm end-of-cycle contact
Alarm test and reset via keypad or external command
Connection test with toroid
Auto reset function
TECHNICAL SPECIFICATIONS
Timer setting
Trigger setting
Sensitivity setting (I∆n) : 0.030 – 0.1 – 0.2 – 0.3 – 0.5 – 1 – 2 – 3A
Hysteresis setting
Alarm outputs: 1 RT contact per alarm, 8A/250Vac on resistive load
External control
Operating temperature : -5 to +55°C
Protection rating: IP20
Insulation: 2kV-50Hz-1min (between power supply and outputs)
Snap-in cabinet mounting on symmetrical DIN rail
Universal auxiliary power supply: 20 to 250Vac and 20 to 250Vdc