Automatic source-changeover ASC
Automatic source-changeover (ASC) is a basic way to ensure uninterrupted power supply. ASC system automatically switches the electromagnetic contactor to the main electric power supply line on the backup. This method is carried out in panels (cabinets) ASC.
Switchboard ASC
- Automatic source-changeover (ASC) is used to automatically start the backup power sources in emergency situations or faults that impede the normal operation of the main power supply lines. Also, the equipment automatically performs a switch back to the main power line when resuming normal operation of the line.
Usually ASC panels are mounted in metal wall hanging or floor standing enclosures. Inside the housing is placed a special frame for the installation of electrical equipment on it. On the door of ASC panel are installed indication and control devices.
Automatic source-changeover (ASC) cabinet types
ASC panels differ each from other depending on the electrical equipment installed inside. The main types of panels are:
- with contactors;
- with automatic switches;
- with remote operated switch disconnectors
Drawings of ASC cabinets
There are three main types of ASC switch boards:
- with two independent inputs, which are connected to one output. During normal and emergency operation power line connects one of the incoming feeds;
- With two independent inputs and two independent outputs connected to the output contactor, which is automatically activated when power fails at one of the inputs. During normal operation power is supplied with both inputs, in an emergency supply is provided by the input, where voltage is present;
- with three independent inputs which are connected to the output of a single load circuit. In normal and emergency operations one of the inputs is connected to the load. When implementing the input circuit, which occurs on power varies depending on the presence or absence of voltage at the respective two other inputs. In this case power supply is provided by the input depending on the voltage difference or power loss compared with two other inputs.