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Overcurrent Relay

AL-5 - overcurrent relay

The overcurrent relays AL-5 are two-phase and two-level devices of protection on the maximum current without operational supply voltage with two output relays. These relays are used for replacement of electromechanical RT-80, RT-90 relays, microelectronic relays of the RS-80M2 and RST-82 series.

# Download the detailed description of the relays АL-5

The devices are intended in schemes of relay protection and antiemergency automatic equipment, and also they are modern microprocessor analogs of electromechanical and microelectronic current relays.

Supply voltage of the devices scheme (in the case of performing the main protection functions) is carried out only from controlled chains of current.

Devices provide:

  • the maximum current protection (MCP) with one independent and two dependent characteristics of actuating which can be chosen by microswitches on the front panel;
  • the current cut-off (CCO) with two settings of the actuating time of (50-70) ms and (100-120) ms which are set from the front panel;
  • possibility of shutdown of a current cut-off from the front panel or remotely by means of locking of external contact for the organization of the logical protection of bus (LPB);
  • an opportunity to set (common for two phases ) the settings of actuating current of MCP, actuating current of a cut-off (multiple to actuating current of MCP from 2 to 20 with a step 0,25), MCP actuating time;
  • LED indication with actuating memory of output relays which for two light-emitting diodes is provided within not less than 8 hours after release of current, one light-emitting diode – not less than 12 hours;
  • possibility of viewing and shutdown of indication of an actuating by means of the button on the front panel.

Technical characteristics

Version Functions of output contacts RB CCО* Delay of CCО The replaced analogs
Output 1 Output 2
AL-5-1 CCО+МCP CCО+МCP no 50 or 100 ms 2 relays RТ-81, RТ-82, RТ-91;
1 relay RS80М2-1,5
1 relay RS80М2-1,5і (АL-5-2)
AL-5-2 CCO+MCP CCO+MCP yes 200 or 400 ms
AL-5-3 CCO+MCP CCO no 50 or 100 ms 2 relays RТ-81, RТ-82, RТ-91;
1 relay RS80М2-2,6
1 relay RS80М2-2,6і (АL-5-4)
AL-5-4 CCО+МCP CCО yes 200 or 400 ms
AL-5-5 CCО+МCP MCP no 50 or 100 мс 2 relays RТ-83, RТ-84;
1 relay RS80М2-3,7
1 relay RS80М2-3,7і (АL-5-6)
АЛ-5-6 CCО+МCP MCP yes 200 or 400 ms
AL-5-7 CCO MCP no 50 or 100 ms 2 relays RТ-83, RТ-84;
1 relay RS80М2-4,8
1 relay RS80М2-4,8і (АL-5-8)
АL-5-8 CCO MCP yes 200 or 400 ms
AL-5-9 CCO+MCP MCP start-up no 50 or 100 ms 1 relay RS80М2-9,16,17
AL-5-10 CCO+MCP MCP start-up yes 200 or 400 ms 1 relay RS80М2-10,15,15i
* - remote blocking of a current cut-off

Universality: the wide range of actuating currents from 1 to 99 А in the same version with time delay 0,1…99 s. There is the possibility of connection for using in one-phase and two-phase modes.

Схемы защиты на реле серии РТ-80 и АЛ-5

Use of inexpensive and reliable devices of protection AL-5 series will allow to solve a problem of replacement of the outdated equipment with small financial and labor expenses.

АЛ-5 - connection circuits
Connection circuits of the device АL-5

AL-5 - front side

Multipleness of a cut-off setting in relation to MCP setting 2-20
step 0,25
Time setting МCP 0,1-99 s
step 0,1 s
Long-time current of thermal ability 2 Іrated
Short-time current of thermal ability 20Irated
The number of the output relays 2
Type and the number of the relay contacts in each circuit 1 make contact
Actuating time of the output relay (the setting is equal to zero) at increase in current from zero to:
- 1,2 of actuating current
- 3 of actuating current

not more than 60 ms
not more than 50 ms
Relay release time not more 60 ms
Term of life of the relay not less 12 years
Relay weight not more 0,5 kg

The relay is installed by means of projection mounting with front/back connection of external wires by screw.

There are 10 modifications of the relay of series AL-5.

The relays of series AL-5-1 … AL-5-10 are intended for the objects with operational AC. These relays are provided by make contacts which are able to switch on (at locking) AC up to 5 A and DC up to 1 A at voltage of 250 V. Breaking capacity of the relay contacts for active and inductive loads of the relay makes up: for AC - power up to 700 VA at cosφ = 0,5; for DC - power up to 60 W at t ≤ 0,015 s. Such switching ability is sufficient for direct locking of a chain of shutdown of the switch. However disconnection of a chain has to be made by auxiliary contact of the switch or additional intermediate relays.

The relays of series AL-5-1, AL-5-2, AL-5-3, AL-5-4 are intended for the protection of the feeding and distributive lines in networks of 6-35 kV, for protection of electric motors from interphase and turn lockings with action without endurance of time for shutdown (cut-off) and for protection against the overload operating with endurance of time also for shutdown and also for protection of transformers.

The relays AL-5-2 and AL-5-4 can be used in diagrams of the switch of input for the logical protection of buses (LPB) by reception of a signal in the form of locking of dry contact of the relay from connections which take place in the case of actuating of the starting organs of operating connections. It causes blocking of a current cut-off of the AL-5-2 (AL-5-4) relay for the period of the closed condition of contact or for the maximum time 2 seconds. The second contact in these relays can be used for a signaling of operation of protection on switch-off.

The relays АL-5-5, АL-5-6, АL-5-7, АL-5-8 are intended for the protection the lines and transformers. Protection against interphase K3 (cut-off) affects on shutdown by means of contact K1, and protection against an overload - with endurance of time for a signal by means of contact K2. The relays can be used also for protection of electric motors from interphase and turn lockings (cut-off) with action on shutdown (K1), and from an overload - with action on a signal or technological unloading (K2).

The relays AL-5-6, AL-5-8 can be used in schemes of the input switch for the LPB organization.

The relays AL-5-9, AL-5-10 are used for protection of the outgoing lines against interphase lockings and for protection against an overload.

The devices AL-5 can be delivered as a part of a set of relay protection of KRZA-5.

Устройства устанавливаются выступающим монтажом с передним, либо задним присоединением внешних проводов под винт.

# Download the detailed description of the relays АL-5