Generator, ATS & Emergency Power Sequence Simulator

Generator and ATS systems are one of the most critical and least-understood parts of facility power infrastructure. Engineers design them, technicians commission them, and facility managers operate them — but the detailed sequence of events from utility loss to stable generator supply and back is often tribal knowledge. This simulator makes the full sequence visible and configurable: set start delay, generator warm-up time, ATS transfer delay, re-transfer delay, and cooldown time, then initiate a utility outage and watch the system step through each state in real time. The One-Line tab shows a live single-line diagram with the utility source, ATS, generator, and loads, with active paths highlighted at each sequence step. The State tab shows the sequence state machine, making it clear which state is active and what conditions trigger each transition. The Timeline tab displays a chronological breakdown of the sequence showing exactly how long each load was without power. The Scenario tab provides quick-access preset sequences. Controls include load shedding percentage. Designed for engineers involved in emergency power system design, commissioning, and testing.

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A live look at the app you'll launch — every control on the left drives the visualizations on the right in real time.

• 01List the sequence of states from utility loss to stable generator supply and identify timing requirements for each
• 02Explain the purpose of start delay, warm-up, ATS transfer delay, re-transfer delay, and cooldown periods
• 03Interpret a state machine diagram for a generator/ATS system and identify trigger conditions for each transition
• 04Determine total load outage duration for critical versus non-critical loads based on transfer timing
• 05Explain why re-transfer to utility uses a longer delay than initial transfer to generator
• 06Identify NEC 700 and NFPA 110 timing requirements relevant to emergency and standby systems