ZELK-3 Arc Protection Device

Name: ZELK-3
Brand: IEL

Arc protection device monitoring up to 18 optical probes with two static trip elements.

ZELK-3 provides fast arc detection in switchgear installations with a larger number of optical probes. It can be used independently or with the SM current module for non-selective protection, while combinations with ZELK-2, SM and IM enable selective protection by section or feeder bay.

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Up to 18 optical probes

Probes are connected through an auxiliary terminal block and grouped for local fault-location indication.
Two trip elements

Two fast semiconductor triacs operate breakers supplied by DC or AC voltage.
Sub-1 ms operation

Optical detection and static trip elements help detect the arc at its earliest stage.
Non-selective or selective protection

ZELK-3 with SM supports non-selective protection, while combinations with ZELK-2, SM and IM cover selective configurations.
Operation after supply loss

The galvanically isolated supply keeps the device functional for approximately 250 ms after external supply loss.
Local and remote signalling

LED indication, numeric display and signalling relays show availability, operation and fault location.

Number of probes: max. 18
Probe cable length: 4, 7 or 10 m; other lengths on request, maximum 20 m
SM input: galvanically isolated, 12 V / 20 mA
Outputs for IM, ZPM and ZELK-2: open collector, 12 V / 20 mA
Number of trip elements: 2 static trip elements
Trip current: 10 A for 300 ms
Maximum voltage: 600 V DC
Rated voltage: 220 V AC or DC
Operating delay: < 1 ms
Remote signalling: 1 or 2 signalling relays; 220 V AC, 300 V DC, 5 A; K1 NC, K2 NO contact
Local signalling: green availability LED and numeric fault-location display
Supply voltage: 24, 48, 110 or 220 V DC +40% / -20%; or 220 V AC +10% / -20%
Consumption: standby 3.6 VA, max. 5 VA
Operation after supply loss: approx. 250 ms
Temperature range: -10...+55 °C
Insulation: 2.5 kV, 50 Hz, 1 min between all galvanically isolated circuits
Mounting: DIN EN 50022-35 rail or wall
Dimensions: 100 x 74 x 120 mm