ATS & Changeover Panel Diagnosis

Automatic transfer switch and changeover panel faults — why a switch refuses to transfer, how to separate a control decision from a mechanical failure, and the interlock rules that exist to stop utility and generator being connected together.

Scope

• ▪Failure to transfer on mains loss
• ▪Failure to return to utility
• ▪Sensing, thresholds and timer settings
• ▪Contactor, motor operator and interlock faults
• ▪Position indication and auxiliary contacts

Diagnosis guides

• ATS Not Changing Over — Automatic Transfer Switch Diagnosis

  Contactor-based and motorised automatic transfer switches, single- and three-phase, controlling utility and generator supplies

  8 diagnostic steps · advanced · qualified electrician

• Generator Will Not Transfer Back to Mains

  Contactor-based and motorised automatic transfer switches on utility and generator supplies, single- and three-phase

  7 diagnostic steps · intermediate · qualified electrician