JPH0917578A - Switching device and emergency lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emergency lighting device which can be switched at prescribed or larger voltage regardless of a frequency. SOLUTION: At uninterrupted time of commercial AC power E, when a capacitor C8 is charged up to prescribed voltage through a diode D3, a Zener diode ZD1 is turned on to turn on a TRIAC Q6. A current is allowed to flow in a relay coil RyL, and in each relay contact RyS1, RyS2, RyS3, RyS4, respective filaments FL1, FL2 and stabilizer 1 are connected. Voltage of the commercial AC power E is applied across the filaments FL1, FL2 of a fluorescent lamp FL through the stabilizer 1, to start the fluorescent lamp FL lighted. When the power is interrupted, the capacitor C8 is not charged to place the TRIAC Q6 in an off-condition, with no current flowing in the relay coil RyL, and DC power of a battery B is supplied to an inverter circuit 3, to induce high frequency AC and to high frequency light the fluorescent lamp FL.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching device and an emergency lighting device that perform switching operation according to a power failure and a non-power failure of an AC power source.

[0002]

2. Description of the Related Art As a conventional emergency lighting device, for example, a structure shown in FIG. 5 is known. In the emergency lighting device configured as shown in FIG. 5, the input terminal of the ballast 1 is connected to the commercial AC power source E, and the discharge lamp is connected between the output terminals of the ballast 1 via the relay contact RyS1 and the relay contact RyS2. Is connected to one filament FL1 of the fluorescent lamp FL, and is connected to the other filament FL2 via a relay contact RyS3 and a relay contact RyS4.

The commercial AC power source E has a relay coil Ry.
L is connected, and the primary winding Tr11 of transformer Tr1 is connected in parallel to this relay coil RyL.
The capacitor C1 is connected to the secondary winding Tr12 of 1, and the input terminal of the full-wave rectifier 2 is connected to the capacitor C1.

Further, between the output terminals of the full-wave rectifier 2,
A series circuit of the emitter and collector of the transistor Q1, the resistor R1 and the capacitor C2 is connected, and a series circuit of the resistor R2 and the resistor R3 is connected between the emitter and base of the transistor Q1. A series circuit of a diode D1, a diode D2, and a battery B is connected from a connection point of the resistance R2 and a resistance R3, and a parallel circuit of a resistance R4 and a capacitor C3 is connected to monitor the capacitor C2 in parallel. Light emitting diode LED is connected.

Further, the diode D2 is connected to the push-pull type inverter circuit 3. This inverter circuit 3 is an inverter transformer via the choke coil L1.
This input winding Tr2 is connected to the middle point of the input winding Tr21 of Tr2.
One end of 1 is connected to the negative pole of the full-wave rectifier 2 via the emitter and collector of the transistor Q2, and the other end of the input winding Tr21 is connected to the negative pole of the full-wave rectifier 2 via the emitter and collector of the transistor Q3. There is. Further, a parallel circuit of the constant voltage element Q4 and the capacitor C3 is connected to the input winding Tr21. Further, the inverter transformer Tr2 has a control winding Tr23, one end of which is connected to the base of the transistor Q2 and the other end of which is connected to the base of the transistor Q3, and the base of the transistor Q2 is connected via the resistor R5. hand,
The base of the transistor Q3 is connected to the collector of the transistor Q5 via the resistor R6.
The base of Q5 is connected to the diode D1 and the diode D2 via the resistor R7, and the emitter is connected to the connection point of the diode D2 and the choke coil L1.

The output winding Tr22 of the inverter transformer Tr2 is connected to the filament FL1 of the fluorescent lamp FL via the relay contact RyS2, and the filament of the fluorescent lamp FL via the capacitor C5 and the relay contact RyS3.
Connected to FL2.

The inverter transformer Tr2 has a filament preheating winding Tr24 and a filament preheating winding Tr25. The filament preheating winding Tr24 is an output winding Tr.
Filament FL connected to capacitor 22 via current limiting capacitor C6, relay contact RyS1 and relay contact RyS2
1, the filament preheating winding Tr25 is connected to the filament FL2 via the current limiting capacitor C7, the relay contact RyS3 and the relay contact RyS4.

When the commercial AC power source E is not shut down,
Since current is flowing in the relay coil RyL, each relay contact RyS1, RyS2, RyS3, RyS4 is connected to the ballast 1.

Therefore, the voltage of the commercial AC power source E is applied between the filaments FL1 and FL2 of the fluorescent lamp FL via the ballast 1 to start and light the fluorescent lamp FL.

On the other hand, the voltage is reduced by the transformer Tr1 and the capacitor
It is smoothed by C1 and full-wave rectified by the full-wave rectifier 2, and the battery B is charged through the resistor R2 and the diode D1. When the charging voltage of the battery B is low, a potential difference is generated in the resistor R2, so that the transistor Q1 turns on and the light emitting diode LED1
Lights up to indicate that charging is in progress. Then, when the charging of the battery B progresses and the current flowing through the resistor R2 becomes small and the voltage of the resistor R2 drops, the transistor Q1 turns off,
The light emitting diode LED1 is turned off to indicate that the battery B has been charged.

Since the base of the transistor Q5 is reverse-biased, the inverter circuit 3 is not supplied with power and does not operate, and the filament preheating winding is not operated.
No current flows through Tr24 and Tr25.

When the commercial AC power source E fails, no current flows through the relay coil RyL, and the relay contacts RyS1,
RyS2, RyS3, RyS4 are connected to the inverter circuit 3 side.

Then, the DC power of the battery B is supplied to the inverter circuit 3, and the inverter circuit 3 oscillates at a high frequency to induce a high-frequency AC at the output winding Tr22, and the fluorescent lamp FL.
Is turned on at high frequency. Also, filament preheating winding Tr2
A voltage is also induced in Tr4 and Tr25, and the current values are made almost constant by capacitors C5 and C6 to preheat filaments FL1 and FL2. The output from the inverter circuit 3 is the ballast 1
Lower than the output from.

[0014]

However, in the case of the conventional example shown in FIG. 5, the relay coil RyL detects a power failure and a non-power failure of the commercial AC power source E.
As shown in, the operating sensitivity of the relay coil RyL differs depending on whether the power supply frequency of the commercial AC power supply E is 50 Hz or 60 Hz.

That is, when the power supply frequency is 60 Hz, the sensitivity is lower than that when the power supply frequency is 50 Hz, and there is a possibility that the sensitivity may be lower than the operating voltage specified by the Lighting Equipment Industry Association (IEC). There is.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a switching device and an emergency lighting device that can perform a switching operation at a predetermined voltage regardless of the frequency.

[0017]

A switching device according to claim 1 is a series circuit of a bidirectional switching element having a relay coil for driving a relay contact connected in parallel to an AC power source and a control terminal. A series circuit of a rectifying element and a capacitive element connected in parallel to the AC power source, and a constant voltage element that controls a control terminal of the bidirectional switching element when the voltage of the capacitive element rises by a predetermined value or more. A bidirectional switching element is connected in series to a relay coil that drives a relay contact, and the capacitive element is charged via a rectifying element. Since the element is turned on and the control terminal of the bidirectional switching element is controlled, the sensitivity of the relay coil can be easily set by the constant voltage element regardless of the frequency.

According to another aspect of the present invention, the emergency lighting device detects a power failure and a non-power failure of the commercial AC power source and switches them by a switching circuit, and supplies electric power from the commercial AC power source when the commercial AC power source is unpowered. In an emergency lighting device that charges a battery with the commercial AC power supply, converts DC from the battery by an inverter circuit and supplies the DC power when the commercial AC power supply fails, and lights a discharge lamp.
The switching circuit is connected in parallel to the commercial AC power supply, and a series circuit of a bidirectional switching element having a relay coil for driving a relay contact connected in parallel to the commercial AC power supply and a control terminal. And a constant voltage element connected between a connection point of the rectifying element and the capacitive element and a control terminal of the bidirectional switching element, and driving a relay contact. A bidirectional switching element is connected in series to the relay coil, and the capacitive element is charged via the rectifying element.When the voltage of the capacitive element reaches a specified value or more, the constant voltage element turns on and the bidirectional Since the control terminal of the switching element is controlled, the sensitivity of the relay coil can be easily set by the switching circuit using the constant voltage element regardless of the frequency of the commercial AC power supply. Power reliably detect the power failure and non-power failure.

An emergency lighting device according to a third aspect of the present invention detects a power failure and a non-power failure of the commercial AC power source and switches them by a switching circuit, and supplies electric power from the commercial AC power source when the commercial AC power source is unpowered. In an emergency lighting device that charges a battery with the commercial AC power supply, converts DC from the battery by an inverter circuit and supplies the DC power when the commercial AC power supply fails, and lights a discharge lamp.
The switching circuit is connected in parallel to the commercial AC power supply, and a series circuit of a bidirectional switching element having a relay coil for driving a relay contact connected in parallel to the commercial AC power supply and a control terminal. A series circuit of a rectifying element and a capacitive element, a voltage dividing circuit connected in parallel to the capacitive element, and a constant voltage connected between the voltage dividing circuit and the control terminals of the bidirectional switching element. When a bidirectional switching element is connected in series to a relay coil for driving a relay contact, and the capacitive element is charged via a rectifying element, the voltage of the capacitive element becomes a predetermined value or more. The voltage of the voltage dividing circuit also rises and the constant voltage element is turned on to control the control terminal of the bidirectional switching element, so the constant voltage element is controlled by the switching circuit regardless of the frequency of the commercial AC power supply. Easily set the sensitivity of the relay coil, reliably detect the power failure and non-power failure of the commercial AC power source through.

According to another aspect of the present invention, the emergency lighting device detects a power failure and a non-power failure of the commercial AC power source and switches them by a switching circuit, and supplies power from the commercial AC power source when the commercial AC power source is unpowered. In an emergency lighting device that charges a battery with the commercial AC power supply, converts DC from the battery by an inverter circuit and supplies the DC power when the commercial AC power supply fails, and lights a discharge lamp.
The switching circuit is connected in parallel to the commercial AC power supply, and a series circuit of a bidirectional switching element having a relay coil for driving a relay contact connected in parallel to the commercial AC power supply and a control terminal. A breakover type two-terminal thyristor that triggers the control terminal at breakover is provided, and the switching circuit connects a bidirectional switching element in series to the relay coil that drives the relay contact, and the voltage of the commercial AC power supply is predetermined. When the value exceeds the value, the breakover type 2-terminal thyristor turns on and controls the control terminal of the bidirectional switching element. Therefore, the breakover type 2 terminal is controlled by the switching circuit regardless of the frequency of the commercial AC power supply.
The sensitivity of the relay coil can be easily set by the terminal thyristor, and power failure and non-power failure of the commercial AC power supply can be reliably detected.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an emergency lighting device of the present invention will be described below with reference to the drawings. The parts corresponding to those of the conventional example shown in FIG.

The emergency lighting device having the structure shown in FIG.
The input terminal of the ballast 1 is connected to the commercial AC power supply E, and the output terminal of the ballast 1 is connected to one filament FL1 of the fluorescent lamp FL as a discharge lamp via the relay contact RyS1 and the relay contact RyS2. And is connected to the other filament FL2 via relay contact RyS3 and relay contact RyS4.

A switching circuit 4 is connected to the commercial AC power source E, and the switching circuit 4 is connected in parallel to the commercial AC power source E in series with a relay coil RyL and a triac Q6 as a bidirectional switching element. And a series circuit of a diode D3 as a rectifying element and a capacitor C8 as a capacitive element is connected. Further, the voltage dividing circuit 5 is connected in parallel with the capacitor C8, and the voltage dividing circuit 5 is composed of a series circuit of resistors R8 and R9. Then, these resistors R8 and R9
The connection point of is the Zener diode ZD1 as a constant voltage element.
It is connected to the gate which is the control element of TRIAC Q6 via. A parallel circuit of a capacitor C9 and a resistor R10 is connected between the gate and one end of the triac Q6.

Further, the primary winding Tr11 of the transformer Tr1 is connected in parallel to the capacitor C8, and the transformer Tr1
A capacitor C1 is connected to the secondary winding Tr12, and the input terminal of the full-wave rectifier 2 is connected to the capacitor C1.

A series circuit of the emitter and collector of the transistor Q1, the resistor R1 and the capacitor C2 is connected between the output terminals of the full-wave rectifier 2, and the resistor R2 and the resistor R3 are connected between the emitter and the base of the transistor Q1. A series circuit is connected. A series circuit of a diode D1, a diode D2 and a battery B is connected from the connection point of the resistors R2 and R3, and a resistor R4 and a capacitor are connected.
A parallel circuit of C3 is connected, and a light emitting diode LED for monitoring is connected in parallel to the capacitor C2.

The diode D2 is connected to the push-pull type inverter circuit 3. This inverter circuit 3 is an inverter transformer via the choke coil L1.
This input winding Tr2 is connected to the middle point of the input winding Tr21 of Tr2.
One end of 1 is connected to the negative pole of the full-wave rectifier 2 via the emitter and collector of the transistor Q2, and the other end of the input winding Tr21 is connected to the negative pole of the full-wave rectifier 2 via the emitter and collector of the transistor Q3. There is. Further, a parallel circuit of the constant voltage element Q4 and the capacitor C3 is connected to the input winding Tr21. Further, the inverter transformer Tr2 has a control winding Tr23, one end of which is connected to the base of the transistor Q2 and the other end of which is connected to the base of the transistor Q3, and the base of the transistor Q2 is connected via the resistor R5. hand,
The base of the transistor Q3 is connected to the collector of the transistor Q5 via the resistor R6.
The base of Q5 is connected to the diode D1 and the diode D2 via the resistor R7, and the emitter is connected to the connection point of the diode D2 and the choke coil L1.

The output winding Tr22 of the inverter transformer Tr2 is connected to the filament FL1 of the fluorescent lamp FL via the relay contact RyS2 and the filament of the fluorescent lamp FL via the capacitor C5 and the relay contact RyS3.
Connected to FL2.

The inverter transformer Tr2 has a filament preheating winding Tr24 and a filament preheating winding Tr25, and the filament preheating winding Tr24 is an output winding Tr.
Filament FL connected to capacitor 22 via current limiting capacitor C6, relay contact RyS1 and relay contact RyS2
1, the filament preheating winding Tr25 is connected to the filament FL2 via the current limiting capacitor C7, the relay contact RyS3 and the relay contact RyS4.

Next, the operation of the above embodiment will be described.

First, when the commercial AC power source E is not interrupted, the capacitor C8 is charged through the diode D3, and when the capacitor C8 is charged and reaches a predetermined voltage, the voltage at the connection point of the resistors R8 and R9 rises. Zener diode ZD
When 1 turns on and TRIAC Q6 turns on, a current flows through the relay coil RyL and each relay contact RyS1, RyS
2, filaments FL1 and FL2 and ballast 1 are connected to RyS3 and RyS4, respectively.

Therefore, the voltage of the commercial AC power source E is applied between the filaments FL1 and FL2 of the fluorescent lamp FL via the ballast 1 to start and light the fluorescent lamp FL.

In addition, the voltage of the commercial AC power source E is set to the transformer Tr.
The voltage is stepped down by 1, smoothed by the capacitor C1, full-wave rectified by the full-wave rectifier 2, and the battery B is charged through the resistor R2 and the diodes D1 and D2. When the charging voltage of the battery B is low, a potential difference occurs in the resistor R2, so
Q1 turns on and LED LED1 emits light to indicate that charging is in progress. Then, the charging of the battery B progresses and the resistance
When the current flowing through R2 decreases and the voltage of the resistor R2 decreases, the transistor Q1 turns off, the light emitting diode LED1 turns off, and the battery B indicates that charging is completed.

Since a reverse bias is applied to the base of the transistor Q5, the transistor Q5 is turned off, so that the inverter circuit 3 is not supplied with power and does not operate, and the relay contact RyS1. ， Ry
Since S2, RyS3, and RyS4 are connected to the ballast 1, no current flows through the filament preheating windings Tr24 and Tr25.

When the commercial AC power supply E fails, the capacitor C8 is not charged, the voltage at the connection point of the resistors R8 and R9 does not rise, and the Zener diode ZD1 is kept in the off state to turn off the triac Q6. , Relay coil
No current flows through RyL, relay contact RyS1 connects filament FL1 and capacitor C6, relay contact RyS3 connects filament FL2 and the output winding of inverter transformer Tr2.
Tr22 and filament preheating winding Tr24 are connected, and relay contact RyS2 is used for filament FL1 and inverter transformer Tr.
The second output winding Tr22 and the filament preheating winding Tr25 are connected, and the relay contact RyS1 connects the filament FL2 and the capacitor C7.

Then, the DC power of the battery B is supplied to the inverter circuit 3, and the inverter circuit 3 oscillates at a high frequency to induce a high-frequency AC at the output winding Tr22, and the fluorescent lamp FL.
Is turned on at high frequency. Also, filament preheating winding Tr2
A voltage is also induced in Tr4 and Tr25, and the current values are made almost constant by capacitors C5 and C6 to preheat filaments FL1 and FL2. The output from the inverter circuit 3 is the ballast 1
It is set lower than the output from.

Next, another embodiment will be described with reference to FIG.

The emergency lighting device shown in FIG. 2 is different from the emergency lighting device shown in FIG. 1 in the configuration of the switching circuit 4.

That is, in parallel with the commercial AC power source E, a series circuit of a film current limiting film capacitor C11, a diode D4 and a capacitor C12, and a series circuit of a resistor R12 and a diode D5 are connected and a capacitor is connected.
The connection point of C11 and the diode D4 is connected to the connection point of the resistor R12 and the diode D5, and the voltage dividing circuit 5 is connected in parallel to the capacitor C12. Since the divided voltage is applied to the capacitor C12, the capacitor C12 may have a relatively small capacitance.

Although the basic operation is similar to that shown in FIG. 1, the voltage of the commercial AC power source E is rectified by the diode D4 to charge the capacitor C12 at the time of non-power failure, and the voltage of the capacitor C12 rises. Then Zener diode ZD
When 1 turns on and the triac turns on, the relay coil RyL is energized. That is, capacitor C11
When the capacitor C11 side of the commercial AC power supply E is positive in the state where the electric charge is not charged in the capacitor C12, it is rectified by the diode D4 and divided into the capacitors C11 and C12 to charge, and the capacitor C12 of the commercial AC power supply E is charged. If the side is positive, the capacitor C11 is reset via the diode D5. Also, the relay coil RyL is not energized at the time of power failure because the capacitor C12 is not charged.

Further, another embodiment will be described with reference to FIG.

The emergency lighting device shown in FIG. 3 is different from the emergency lighting device shown in FIG. 1 in the configuration of the switching circuit 4.

That is, a series circuit of a relay coil RyL and a triac Q6 as a bidirectional switching element is connected, and a diode D6, an SSSQ7 as a breakover type two-terminal thyristor and a capacitor are connected.
The series circuit of C15 is connected. A resistor R11 is connected between the connection point of the SSS Q7 and the capacitor C15 and the gate of the triac Q6, and a capacitor C9 and a resistor R10 are connected to the gate.

The basic operation is the same as that shown in FIG. 1, but the voltage of the commercial AC power source E is S when there is no power failure.
Since it is higher than the breakover voltage of SSQ7, SSSQ7 is turned on to charge the capacitor C15, and a gate voltage is applied to the triac Q6 to turn on the triac Q6, thereby energizing the relay coil RyL. Further, since SSSQ7 does not reach the breakover voltage and does not turn on during a power failure, the gate voltage is not applied to the triac Q7 and the relay coil RyL is not energized.

In any of the above-described embodiments, the triac Q6 is controlled by the Zener voltage of the Zener diode ZD1 or the breakover voltage of SSSQ7 to control the energization of the relay coil RyL.
Even if the operation of the relay coil RyL is designed according to, the relay coil RyL operates according to the operation of the TRIAC Q6 at a high sensitivity of 50 Hz, that is, with the sensitivity slightly lowered, so the commercial AC power supply E When the voltage of becomes a predetermined voltage, the relay coil RyL can be operated.

In any case, the same effect can be obtained by using an inverter circuit for high frequency oscillation having a rectifying circuit or the like instead of the ballast 1.

[0046]

According to the switching device of the first aspect, the capacitive element is charged through the rectifying element, and when the voltage of the capacitive element becomes a predetermined value or more, the constant voltage element is turned on, and the bidirectional Since the control terminal of the switching element is controlled, the sensitivity of the relay coil can be easily set by the constant voltage element regardless of the frequency.

According to the emergency lighting device of the second aspect,
When the capacitive element is charged through the rectifying element and the voltage of the capacitive element exceeds a specified value, the constant voltage element turns on and controls the control terminal of the bidirectional switching element. The sensitivity of the relay coil can be easily set by the constant voltage element regardless of the frequency, and the power failure and non-power failure of the commercial AC power supply can be reliably detected.

According to the emergency lighting device of the third aspect,
The capacitive element is charged via the rectifying element, and when the voltage of the capacitive element exceeds a predetermined value, the voltage of the voltage dividing circuit also rises and the constant voltage element turns on, controlling the control terminal of the bidirectional switching element. Therefore, the sensitivity of the relay coil can be easily set by the constant voltage element in the switching circuit regardless of the frequency of the commercial AC power supply, and the power failure and the non-power failure of the commercial AC power supply can be reliably detected.

According to the emergency lighting device of the fourth aspect,
The switching circuit connects a bidirectional switching element in series to the relay coil that drives the relay contacts, and when the voltage of the commercial AC power supply exceeds a specified value, the breakover type two-terminal thyristor turns on and bidirectional switching is performed. Since the control terminals of the elements are controlled, the switching circuit can easily set the sensitivity of the relay coil by the breakover type two-terminal thyristor regardless of the frequency of the commercial AC power supply, and can reliably detect power failure and non-power failure of the commercial AC power supply. .

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of an emergency lighting device of the present invention.

FIG. 2 is a circuit diagram showing an emergency lighting device of another embodiment of the same as above.

FIG. 3 is a circuit diagram showing an emergency lighting device according to another embodiment of the above.

FIG. 4 is a graph showing the relationship between the frequency of the relay coil and the operating voltage.

FIG. 5 is a circuit diagram showing a conventional emergency lighting device.

[Explanation of symbols]

3 Inverter circuit 4 Switching circuit 5 Voltage dividing circuit B Battery C8 Capacitor as capacitive element D3 Diode as rectifying element E Commercial AC power supply FL Fluorescent lamp as discharge lamp Q6 Triac as bidirectional switching element Q7 Breakover type 2 SS as terminal thyristor
S RyL Relay coil RyS1, RyS2, RyS3, RyS4 Relay contact ZD1 Zener diode as constant voltage element

Claims (4)

[Claims] 1. A series circuit of a bidirectional switching element having a relay coil for driving a relay contact connected in parallel to an AC power source and a control terminal, and a rectifying element connected in parallel to the AC power source. And a series circuit of capacitive elements, and a constant voltage element that controls a control terminal of the bidirectional switching element when the voltage of the capacitive element rises by a predetermined value or more. 2. A commercial AC power source detects a power failure and a non-power failure and switches by a switching circuit. When the commercial AC power source does not fail, the commercial AC power source supplies power and the commercial AC power source charges a battery. However, in the emergency lighting device that converts the direct current from the battery by the inverter circuit and supplies it when the commercial AC power source fails, the switching circuit is connected in parallel to the commercial AC power source. A series circuit of a bidirectional switching element having a relay coil and a control terminal for driving the relay contact, a series circuit of a rectifying element and a capacitive element connected in parallel to the commercial AC power supply, and the rectifying element And a constant voltage element connected between the connection point of the capacitive element and the control terminal of the bidirectional switching element. Emergency lighting apparatus characterized by. 3. A commercial AC power source detects a power failure and a non-power failure and switches by a switching circuit. When the commercial AC power source is not in a power failure state, power from the commercial AC power source is supplied and a battery is charged by the commercial AC power source. However, in the emergency lighting device that converts the direct current from the battery by the inverter circuit and supplies it when the commercial AC power source fails, the switching circuit is connected in parallel to the commercial AC power source. A series circuit of a bidirectional switching element having a relay coil for driving a relay contact and a control terminal, a series circuit of a rectifying element and a capacitive element connected in parallel to the commercial AC power supply, and the capacitive circuit. A voltage dividing circuit connected in parallel to the element, and connected between the voltage dividing circuit and the control terminal of the bidirectional switching element. Emergency lighting apparatus, characterized by comprising a constant voltage element. 4. A commercial AC power supply detects a power failure and a non-power failure and switches by a switching circuit. When the commercial AC power supply does not fail, power from the commercial AC power supply is supplied and a battery is charged by the commercial AC power supply. However, in the emergency lighting device that converts the direct current from the battery by the inverter circuit and supplies it when the commercial AC power source fails, the switching circuit is connected in parallel to the commercial AC power source. A series circuit of a bidirectional switching element having a relay coil for driving a relay contact and a control terminal, and a breakover type two-terminal thyristor connected in parallel to the commercial AC power source and triggering the control terminal at the time of breakover. An emergency lighting device comprising: