Diagnostics & testing

Phase-Guard testing procedures

Use these procedures to verify relay operation, confirm phase identification, and recognize signs that a unit may need factory evaluation.

Procedure 01

Test relay operation

Repeat the phase-loss test for all three input phases.

  1. Remove one input phase

    Carefully remove any one of the three input phases or fuses connected to the Phase-Guard relay terminal strip.

  2. Allow the time delay to complete

    When a phase is removed, the time-delay cycle begins immediately. After the configured delay has elapsed, the output relay should change state—pickup or dropout—depending on the model being tested.

  3. Restore the phase

    Reconnect the missing phase. The unit should reset to its normal state immediately.

  4. Repeat for the other phases

    Perform the same procedure on each of the remaining two phases.

Procedure 02

Correct phase identification

Use this procedure when the Lost Phase Identifier reports a different phase than the one removed.

  1. Simulate an L2 phase loss

    With normal voltage on the Phase-Guard, remove the input wire on L2.

  2. Check the display

    If “Phase Loss – L2” appears, no correction is needed. If L1 appears, continue to the next step.

  3. Connect the Admin Tool

    Connect to the Phase-Guard via USB and launch the free Admin Tool software.

    Download Admin Tool →
  4. Apply the correction

    Locate “Phase Identifier Correction,” make the swap, and select Apply Changes.

  5. Verify the result

    Repeat the first step and confirm that the display identifies L2.

Troubleshooting

Signs a unit may need evaluation

Phase-Guard relays are designed for long service, but certain conditions can indicate damage or a defective unit.

01

Frequent nuisance trips

The unit trips repeatedly without evidence of a serious phase loss or phase-unbalance condition.

02

Incorrect reverse-phase alert

The red reverse-phase LED is illuminated when no reverse-phase condition exists.

03

Reluctant to reset

The unit does not readily return to its normal state after balanced three-phase power is restored.

04

Immediate trip during testing

The unit trips immediately when one phase is removed instead of completing its normal time delay.

Factory service

Think your Phase-Guard needs repair?

We evaluate returned units at no charge and provide an estimate before beginning repair work. Repaired units are updated to current specifications.

Review return instructions