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Protection Relays

Home > Grid Automation > Protection Relays > Accessories > MMLB / MMLG

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Designed as part of the Midos range, these test blocks offer facilities for monitoring and secondary injection testing of any power system protection scheme when used with the multi-fingered test plug type MMLB 01.

The MMLG test block carries 14 circuits, each of which is brought out to separate pairs of terminals at the rear of the case.

Each circuit comprises a pair of internal contacts which are normally sprung together to complete the circuit link through the block when the associated protective equipment is in normal service.

Insertion of the test plug type MMLB 01 open circuits the contacts which connect terminal pairs, allowing testing to proceed.

Key benefits:

  • Test block can be mounted adjacent to Midos modular relays and systems
  • Test block removes the need to disturb protective system wiring for testing
  • Monitoring, isolation and secondary injection testing are simplified and quickly performed

MMLG Models:

  • MMLG 01 Standard test block
  • MMLG 02 Test block designed for busbar protection schemes
  • MMLG 07 Vertical version w/o dc isolation

Sales of the following MMLG models have been discontinued:

  • MMLG 03 Horizontal version of MMLG 01*
    Sales of MMLG 03 have been discontinued.  As an alternative, please refer to MMLG01.

  • MMLG04  Horizontal version of MMLG 02
    Sales of MMLG 04 have been discontinued.  As an alternative, please refer to MMLG01, MMLG02 or MMLG07.