Power Station Control Systems Remote Control Systems Control Room Technology

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  • Relays
    • Annunciator Relays and
      Illuminated Annunciator
      Relays MR
      • Annunciator Relays
        MR 10, MR 20,
        MRE 10 and MRE 20
      • Annunciator Relays
        MR 11, MR 21,
        MRE 11 and MRE 21
      • Illuminated Annunciator Relays MR 12 and MR 22
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Brochures

Products - Annunciator Relays and Illuminated Annunciator Relays MR

Annunciator Relays MR 10, MR 20, MRE 10 and MRE 20

Annunciator relays MR 10

The annunciator relay MR 10 is used for indication of fault and operating conditions in control rooms, switchboards as well as mimic diagrams. Because of its large indicating area and the rigid design, this relay is ideally suited for any environmental condition. Up to 100 annunciator relays can be assembled in banks.

Construction:
The annunciator relay MR 10 is a semi-automatic relay that can be activated optionally by NO or NC input contacts. The required control is adjusted by simply changing the position of two operating screws on the bell crank.

For the optical display no additional auxiliary voltage is necessary beside the coil energizing voltage. This is especially important for applications where the relay is used for the supervision of voltages.

Function:
In the normal condition the indicating area is black. With the action of the relay the indicating flag (a white area with legend) becomes visible. Simultaneously the auxiliary contacts are actuated. By pressing the reset button below the indicating flag the message is acknowledged. The indicating flag remains visible but with an additional area of red/white hatched lines. Simultaneously the contacts are restored to their normal position. After clearance of the fault the indicating flag returns to its normal postion automatically.

In addition to the operation described above the relay is also available with contacts directly driven by the armature, that means they are independent from the acknowledgement.

Annunciator relay MR 20

Application:
Similar to annunciator relay MR 10

Function:
The annunciator relay MR 20 operates fully-automatically. A manual reset and a possibility for the adjustment from normally de-energized to normally energized are not provided. Upon response the contacts are actuated and the legend becomes visible. With the clearance of the fault the legend disappears automatically and the contacts return to their normal position.

Ground fault annunciator relay MRE 10

The annunciator relay MRE 10 is a semi-automatic relay which is used for ground fault indication in three-phase systems.

Function:
The relay is equipped with two coils and must be connected to the open delta winding of a voltage transformer. The relay responds at 30 V AC. With the responding the second coil is connected in series with the first to allow operating voltages up to 100 V AC. The ground fault indication relay can also be supplied for other voltage ranges. The further functions correspond to relay MR 10.

Ground fault annunciator relay MRE 20

The annunciator relay MRE 20 is an automatic relay for indicating ground faults in three-phase systems.

Function:
Similar to annunciator relay MRE 10 but without manual reset and without the possibility of subsequent adjustment from normally deenergized to normally energized.

Annunciator Relays MR10, MRE10, MR20, and MRE20

 

Helmut Mauell Limited
PO Box 183, Calne
Wiltshire, SN11 9BZ

Tel:01249 812 046
Fax:01246 817 096