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Current Relay of Ground Protection
AL-4-1, AL-4-2


AL-4-1 - current relay of ground protection

The relay AL-4-1 is a full analog of the relay AL-4 with controlled delay of an actuating.

In its turn the relay AL-4-2 is a full analog of the relay RTZ-51. This is not slowed down and at the same time it is highly sensitive with one current chain and operational supply voltage. The device is used with the current transformer of the zero sequence in schemes of protection against short circuit to the earth and also in other protection schemes, antiemergency and industrial automatic equipment.

# Download the detailed description of the relays АL-4-1, АL-4-2

The relays must be mounted in the closed premises with the range of working temperatures from -40 to +55 ºС and with relative humidity of air - to 80% at a temperature of 25 ºС.

The environment has to be inexplosive and it must not contain dust and gases destroying isolation of the relays.

Vibration of the relay mounting places has to be no more 3g in the range of frequencies up to 15 Hz and no more 1g in the range of frequencies up to 100 Hz.

Technical characteristics


Rated supply voltage AC 110V; 220V
DC 100V; 220 V
Rated input current 0,16 А, 50 Hz
The range of the settings of an actuating from 0,02 to 0,2 А
with the step 0,002 А
Relay actuating time at the current 3·Isetting not more 0,04 s;
for the relay AL-4-1 it is controlled in the rage 0,1-10s or 0,3-30s
Reset factor, not less 0,9
Accuracy class 5
The relays have to stand supply voltage, which is equal 1,2*Urated, for a long time
The relays have one change-over contact and are able to switch currents from 0,02 to 2 А at voltages from 24 to 250 V and power:
  - in DC circuits

  - in AC circuits

not more than 60 W at τ=0,005s and
not more than 30 W at τ=0,02s;

not more than 300 VА at cosφ=0,5
Allowable current of the contacts (for a long time) not more than 4А
Mechanical durability, cycles, not less 100 000
Electrical endurance, cycles, not less 20 000
Mean life 12 years
Weight, kg, not more than 0,8
Protection level of the relay:
  - enclosure
  - contact outputs
IP 40
IP 20
The relay can be mounted on the plane in any positions by means of projection mounting with front/back wires connection. For the back wires connection it is necessary to remove the covers from the terminals and reinstall the screws and the washers on the same terminals from the back side.


АЛ-4 - габаритные размеры
Outside dimensions


# Download the detailed description of the relays АL-4-1, АL-4-2