This practical guide shows you how to complete a signed, QR-verified Data Center ATS / STS Fast Transfer Test Report certificate in OhmCert Module #17 and how to troubleshoot non-compliant readings on site.

1. Step-by-Step OhmCert UI Workflow

  1. Open Module #17: Navigate to Data Center ATS / STS Fast Transfer Test Report from the Dashboard.
  2. Load a 1-Click Standard Annex Preset: Open the blue Standard Annex banner at the top and click a preset (such as "Data Center Static Transfer Switch (STS, 50 Hz, <= 5 ms)") to populate target limits automatically.
  3. Enter Your Field Measurements: Fill in the measured inputs (Switch Type, Measured Transfer Time, System Frequency, Phase Angle Difference at Transfer, Voltage Dip During Transfer, Duration of Voltage Dip, Retransfer Time, Load During Test). Blank inputs stay neutral PENDING.
  4. Complete the 16-Point Checklist: Grade each item, attach photos if needed, and export the SHA-256 signed PDF certificate.

2. Worked Numerical Field Case Study

Scenario: Data Center Static Transfer Switch (STS, 50 Hz, <= 5 ms) (IEEE 3008 STS) — Quarter-cycle static transfer between UPS Bus A and UPS Bus B..

  • Switch Type: STS (static)
  • System Frequency: 50 Hz
  • Load During Test: 50 %

3. Engineering Troubleshooting: Corrective Actions When a Reading Fails

  1. Tighten STS gate-drive zero-crossing detection or replace aging SCR thyristors if static transfer exceeds 1/4 cycle (4.17-5.0 ms).
  2. Adjust closed-transition ATS overlap timer to stay below 100 ms and verify ANSI 25 sync window <= 10 deg.
  3. Configure overlapping 4-pole neutral switching where required by IEEE 3008 ground-fault protection coordination.

→ Try This Worked Example Live in Module #17 (ATS / STS Transfer Test)