ATS (Automatic Transfer Switch) enclosures are constructed in accordance with the client’s technical requirements.
They can be both single-phase and three phase inputs. Voltage used can be either 220 or 380 V as well as 6-10 kV.
Enclosures can have a simple design, e.g. with two power cables coming to the building from different sources of electric power. Every power source is provided with phase presence indication. The duty electrician manually switches between the power sources. A more complicated version is automatic and uses contactors. This one is more appropriate for distribution boards where there is no 24-hour duty personnel. Voltage relays are monitoring voltage presence in the input cables (busbars) and should some parameters of the main power source diverge from the norm, they automatically switch to a backup power source.
ATS can also be done with automatic devices with motor drives that are managed by a programmable relay. This option is more reliable, especially where distribution boards are in close proximity to big substations. A significant power consumption reduction takes place at night resulting in voltage increase. With a three-phase input the daytime voltage of 380 V can go up to 420 V at night. This results in voltage increase on the contactors coil which means their temperature goes up and the equipment breaks down faster. ATS with motor drives does not have this vulnerability. First safety category ATS boards can also be used. This means two cables are coming from a power supplying organization and the third cable is coming from a private diesel or battery power station. Other options of ATS design are also possible, including various levels of logics complexity.