The History of the Development of Automatic Transfer Switches and Classsification

1.The history of the development of automatic transfer switch equipment (ATSE)

2.Automattic transfer switch equipment (ATSE) development trend world wide

Most countries in the world use PC class automatic transfer switch equipment, integrated PC class automatic transfer switch equipment is the world technology trend.

3.The Classification of automatic transfer switch equipment (ATSE)

Automatic transfer switches fall into two categories: derived ATSE and specialized ATSE.

Derived ATSE:

CC class: use the contactor as the main switch, general complete set of electrical manufacturers will use CC class lap.
Derived PC class: use load isolation switch as the main switch, such as SOCOMEC products.
CB class: use circuit breaker as the main switch, such as ABB, Schneider,  products.

Specialized ATSE is specialized PC class ATS, such as Asco, GE products.

4.What are the specific differences between the All kinds of automatic transfer switch equipment (ATSE)?

PC Class: Able to connect and load current, but is not used for breaking short circuit current.

CB class: ATSE with current release, its main contact can be switched on and used to break short circuit current.

Derived CB calss: It is equipped with two isolating switches, which can be switched on and loaded. It is not used to break short circuit current.

CC class: Able to connect and load current, but is not used for breaking short circuit current.The main body is composed of electromechanical contactor to meet the requirements. Main contact is allowed for fusion welding after being impacted by short-circuit current. However, in ATS, fusion welding is not allowed.

So, all ATSE made up of circuit breakers are class CB ATSE. The ATSE composed by load isolating switch belongs to the derived PC class ATSE. The integrated design combination ATSE is special ATSE.