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Are you confident your relay is detecting proper phase rotation?

The microprocessor-based ES-47 compares both positive and negative sequence components.

The simple, yet advanced, fundamental sensing ES-47 Phase Sequence relay can be used on A-B-C (L1-L2-L3) or A-C-B (L1-L3-L2) systems. The relay can be connected directly to systems up to 480 V or connected through voltage transformers to systems with higher voltages.

Correct phase sequence operation is ensured when the positive sequence component is greater than the negative sequence component, and greater than 75% of the nominal input voltage. The ES-47 energizes the output relay and lights the green “123” LED. A flashing “Power” LED indicates a relay fault.

These advanced calculations provide three key benefits:

  • Ensure proper phase sequence
  • Prevent operation on harmonics quantities
  • Enable detection of a loss of phase or undervoltage condition

For more information about the advanced, microprocessor-based features visit the ES Series Protection Relays page.