1. Technical Field
The present disclosure relates to a unit for supplying power to an emergency light in case of a fire or power failure, and more particularly, to an auxiliary power unit (APU) for an emergency light in case of a fire or power failure, which automatically turns on emergency lights installed at emergency paths and emergency exits when a fire occurs in a live wire state of regular power, such that people in danger can safely escape from the building.
2. Related Art
In general, emergency lights are installed at an emergency path and emergency exit in a building such as an apartment house. Typically, the emergency light is turned on in case of power failure, and induces people in danger to move to a safe path.
FIG. 1 illustrates a system which receives emergency power from a conventional ATS (Auto Changeover switch), and FIG. 2 illustrates a system which supplies power to an emergency light and a regular light through a conventional APU (Auxiliary Power Unit).
The ATS automatically switches over between regular power received from a power supply company (for example, Korean Electric Power Corporation (KEPCO)) and emergency power such as generator power, and receives the regular power or emergency power through an input terminal. While the regular power is applied, a relay (Ry1) 10 is energized, and a contact switch (Rs1) 12 of the relay is opened as illustrated in FIG. 1, such that no power is supplied to a magnetic switch (MC) 20. That is, contact switches Ms1 and Ms2 of the magnetic switch 20 are opened to block the supply of emergency power to the APU.
Referring to FIG. 2, a regular driving circuit 30 is installed at a supply terminal of the regular power, and an emergency driving unit 40 is installed at an input terminal of the emergency power. When the regular power is supplied, the emergency driving unit 40 is not operated by the regular driving circuit 30. The changeover switch (S1 to S3) 42 connected to the emergency driving unit 40 connect the circuit to supply the regular power toward a load. As illustrated in the circuit diagram of FIG. 2, the regular power is supplied to the regular light 50, and no power is supplied to the emergency light 60.
When a power failure occurs, the power supply to the relay 10 illustrated in FIG. 1 is blocked, and the contact switch 12 of the relay is closed to supply emergency power to the magnetic switch 20. Then, the contact switches Ms1 and Ms2 of the magnetic switch 20 are closed to apply the emergency power to an APU emergency power input terminal of FIG. 2. Since the regular power is blocked, the regular driving circuit 30 is not operated, but the emergency driving unit 40 is operated by the emergency power. The emergency driving unit 40 switches the changeover switch 42 to supply the emergency power to the emergency light 60. Then, the emergency light 60 is automatically turned on.
In most cases, since a power failure is accompanied when a fire occurs, emergency power is supplied. However, regular power may be still alive in many cases. When a fire occurs in the live wire state of the regular power, the emergency light 60 is not automatically turned on, because the supply of emergency power to the emergency light 60 is blocked. In this case, a lighting switch installed in the emergency light 60 must be manually operated to supply the regular power to the emergency light 60, such that the emergency light 60 can be turned on.
However, since the visual fields of people are hidden by smoke when a fire occurs, the people may not find the lighting switch of the emergency light 60. Furthermore, it is very difficult for the people in the emergency situation to calmly operate the lighting switch of the emergency light 60.
Korean Patent Publication No. 10-2015-0021637 discloses an auxiliary power unit for emergency lighting. The patent document discloses a technology which guides the position of an emergency exit through emergency lighting in order to minimize losses of life when a power failure occurs in a building.
However, the patent document only discloses the technology which automatically turns on the emergency light in case of a power failure. When a fire occurs in the live wire state of regular power, an emergency light is not automatically turned on, but must be manually turned on.