How Does an Automatic Transfer Switch Work?

An automatic transfer switch (ATS) is a device that automatically transfers a power supply from the primary source of power like your mains utility power from the grid to your standby generator when it detects a failure or outage.

A typical transfer sequence when the primary power source fails includes:

  1. The transfer switch detects a mains failure and sends a signal to your generator to start.
  2. Once the transfer switch detects the generator voltage and frequency is up to the correct levels, it will then transfer the load from mains utility power to generator power.
  3. The transfer switch will detect the mains utility power has restored and will monitor the power for a pre-set period of time to ensure that it is stable.
  4. After this time period has lapsed and the mains has proven steady, the transfer switch will transfer the load back from the generator to the mains utility power again.
  5. The transfer switch will keep the generator running for a pre-set period of time to allow the generator to run off the load and cool down before turning off.
  6. Once the generator switches off, the transfer switch and generator will return to automatic mode and is ready for the next mains failure event on site.

What are the benefits of an Automatic Transfer Switch?

  1. Reliability – you don’t need to worry about manually connecting your generator and it is more efficient.
  2. Safety – an ATS handles the power, reducing the risk of harm to your team members.
  3. Ease – an ATS simplifies restoring power and relieves pressure on your business to continue running when there are disruptions to your power supply.

Shanahan Power offers multiple transfer switch options for our full range of generators and UPS systems. Contact a member of our team to find out more