Managing Phase Rotation and CT Connections for Three-Phase zappi Installations

NOTE: When using zappi in a three-phase setup, it is essential to optimise phase rotation and CT connections to ensure balanced loading and correct operation.

Overview

When charging a single-phase EV on a three-phase zappi, the power is always drawn from the L1 phase of the zappi.

In setups where multiple zappis are installed, and all are charging single-phase EVs, this can lead to uneven load distribution, where phase L1 is heavily loaded, while phases L2 and L3 remain underutilised.

To balance the load across all three phases, you can adjust the physical connections so that each zappi's L1 terminal corresponds to a different supply phase.

How to Change Phase Rotation

To redistribute the load, you can adjust the phase rotation setting on each zappi. Follow these steps for each device:

  1. Go to the zappi you want to modify.
  2. Access the menu: Installer Menu → Supply Grid → Device.
  3. Locate the Phase Rotation Setting option.
  4. Select the desired phase rotation from the following options:
    • 1/2/3: L1 → Phase 1, L2 → Phase 2, L3 → Phase 3.
    • 2/3/1: L1 → Phase 2, L2 → Phase 3, L3 → Phase 1.
    • 3/1/2: L1 → Phase 3, L2 → Phase 1, L3 → Phase 2.
  5. Save the changes.
  6. Repeat this process for each zappi device to distribute the phases as required.

Adjusting CT Connections

When altering phase rotation, you must also adjust the CT (Current Transformer) connections to ensure they align with the corresponding phases at the supply point (e.g., the electricity meter).

  • CT on Phase L1 must connect to zappi CT1.
  • CT on Phase L2 must connect to zappi CT2.
  • CT on Phase L3 must connect to zappi CT3.

These adjustments ensure accurate measurement of energy flows and proper operation of the zappi system.

Example Phase Rotations and Connections

zappi Device L1 Terminal L2 Terminal L3 Terminal Phase Rotation Setting
zappi #1 Phase 1 Phase 2 Phase 3 1/2/3
zappi #2 Phase 2 Phase 3 Phase 1 2/3/1
zappi #3 Phase 3 Phase 1 Phase 2 3/1/2

Additional Notes

  • Proper adjustments to phase rotation and CT connections ensure balanced load distribution and efficient operation in multi-zappi installations
  • Always verify the settings and connections after making changes to confirm they align with your installation requirements.
  • For further assistance, please contact our support team via the provided phone number or email address.

By following these steps, you can optimise your three-phase zappi installation for balanced and efficient EV charging.

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