MCC / SWR Loop Checks Procedure

We discuss about MCC / SWR Loop Checks Procedure. Loop checks involves DCS loop checks, VSD loop checks, PLC loop checks and Transmitter loop checks.

MCC / SWR Loop Checks Procedure

  1. Check the Power Transmitter linearity on each cubicle wherever applicable VSD commands i.e. AO/AI Shall be included, and the Testing requirements if no test position available.

  2. Check and verify the DCS configuration for applicable points.

  3. If ESD logic / interlocking are involved in applicable loop, by forcing the applicable ESD points on ladder logic, same procedure to be carried out for DCS logic.

  4. Remove the control power transformer primary and secondary fuses for applicable MCC/SWR units (check / confirm if MCC/SWR unit is on test position by electrical).

  5. Apply 120Vac power (external power from building outlet) on the secondary fuses load side to energize the control circuit.

  6. Apply the command from DCS / ESD Field for start, stop or trip as applicable.

  7. Verify the running / stop or trip status in DCS / Field / Sub Station as applicable.

  8. Check and verify the local / remote switch function if applicable.

  9. After completion of the applicable loop check, the fuses should be returned on the
    control transformer.

  10. All the above mentioned steps can be carried out with removing the pad lock on the MCC/SWR unit breakers.

  11. Removal of the pad lock on the breakers required permission from Electrical Mechanical section.

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