In any of the backup power systems , a critical component is a Transfer Switches ( Automatic or manual ). A transfer switch is used to protect critical and/or selected electrical loads against a loss of power. Its main function is to safely transfer from normal (utility) source of power to emergency (backup) source of power, when utility power is lost. It is also responsible for transferring the load from emergency (backup) power back to normal (utility) power once it’s restored.

In cases where power interruptions must be limited to very short intervals to maintain safety or avoid financial losses, an Automatic Transfer Switch (ATS) should be used.
The ATS will monitor the power source and automatically switch from the utility source over to the generator supplied power source in the event of a power outage. The ATS includes controls (logic) to detect the power failure and initiate the engine start of the emergency power source (generator). When the proper voltage and frequency are reached, the switch transfers the power from normal to emergency power.
Additional ATS features include:

• Alarm and status information
• User programmable set points for various transfer time delays
• System data such as source voltage and frequency

Main Automatic Transfer Switches manufacturers

• Jiangsu Aisikai Elecrtic Co.Ltd , from China