Automatic Transfer Switch (ATS)

An Automatic Transfer Switch (ATS) is an electrical device that automatically switches a load between two power sources, typically the utility (main) power and a backup power source (such as a standby generator, UPS, or solar power system), to ensure continuous and reliable electricity supply.

1. Automatic Power Switching – Detects power loss or abnormal conditions in the main supply and automatically switches the load to a backup source, then restores it when utility power is stable.
2. Power Source Monitoring – Continuously monitors voltage, frequency, and phase to ensure safe and proper switching.
3. Safety Protection – Prevents backfeeding and protects electrical systems from surges, spikes, or faults.
4. Manual Override – Allows operators to manually control switching for testing or maintenance.

An Automatic Transfer Switch (ATS) works by continuously monitoring the utility (main) power and automatically transferring the electrical load to a backup power source, such as a generator or UPS, when a power outage or abnormal condition occurs. Once the utility power is restored and stable, the ATS switches the load back to the main power.

• Open Transition (Break-Before-Make) ATS: An Open Transition ATS disconnects the load from the main utility before connecting to the backup generator.
• Closed Transition (Make-Before-Break) ATS: A Closed Transition ATS briefly parallels the utility and generator before transferring the load, ensuring continuous power supply.
• Delayed Transition ATS: A Delayed Transition ATS introduces a programmable delay before switching to the backup power source.
• Soft Load / Bypass Isolation ATS: A Soft Load or Bypass Isolation ATS allows maintenance or load switching without interrupting the electrical supply.
• Closed-Coupled ATS: A Closed-Coupled ATS integrates directly with the generator control panel, providing a compact installation and reducing wiring complexity.
• Manual-Operated ATS: A Manual-Operated ATS requires human intervention to switch between utility and backup power.