Basic principle of automatic transfer switch appliances ATS

1. An overview of how ATS works

Automatic transfer switch appliance is abbreviated as ATS, is the abbreviation of Automatic Transfer switching equipment. The ATS is mainly used in emergency power supply systems to automatically switch load circuits from one power supply to another (standby) power supply to ensure continuous and reliable operation of critical loads. Therefore, ATS is often used in important electric places, and its product reliability is particularly important. Once the conversion fails, it will cause one of the following two hazards: short circuit between power supplies or power failure of important loads (even temporary power failure), the consequences are serious, which will not only bring economic losses (make production stop, financial paralysis), but also may cause social problems (make life and safety in danger). Accordingly, industrial developed country all the production of automatic switch electric appliance, use lists key product to try to restrict and norm.

An ATS consists of two parts: switch body and controller. And the switch body has PC level ATS (integral) and CB level ATS (circuit breaker).

1. PC level: integrated structure (three-point type). It is a special switch for double power supply switching, with simple structure, small size, self-interlocking, fast conversion speed (within 0.2S), safety, reliability and other advantages, but need to be equipped with short circuit protection appliances.

2. Class CB: ATS equipped with overcurrent trip, its main contact can be connected and used to break short circuit current. It is composed of two circuit breakers and mechanical interlocking, with short circuit protection function;

Controller is mainly used to detect by monitoring the power (two way) working conditions, when the monitoring of the power failure (such as any phase under voltage, phase, or frequency deviation) pressure loss, the controller action, switch ontology is carrying load from one power automatic conversion to another power, standby power supply its capacity is generally only commonly used power supply capacity of 20% ~ 30%.

Figure 1 shows a typical ATS application circuit. The controller is connected with the incoming line end of the switch body.