JPS61143998A - Emergency lamp switching circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is configured to start emergency lighting by operating an emergency power source and oscillating an inverter during a power outage of an AC power source. This invention relates to an emergency light switching circuit configured to delay the oscillation of an inverter relative to the operation of the contacts in order to prevent welding of the contacts during operation.

[Background technology]

FIG. 3 shows a conventional emergency light switching circuit, and FIG. 4 shows its time chart.

This conventional example was recently invented by the inventor of the present invention.

In Figure 3, E is an AC power supply (commercial power supply), RY is a relay coil, Ryl, R) +2 is a relay contact, T1 is a power transformer, T2 is an oscillation transformer, Re is a full-wave rectifier,
B is a secondary battery such as a Ni-Cd storage battery, CHl is a choke coil, CH2 is a ballast, La is a discharge lamp, G is a glow lamp, In is a ballast type self-excited inverter, D
1 to D3 are diodes, C1 to C4 are transistors, R
1-R6 is a resistor, and C1 to C6 are capacitors.

A smoothing capacitor C5 is connected between the output terminals of the full-wave rectifier Re, and a series circuit in which a transistor Q3 is connected in series to a parallel circuit of a relay coil RY and a diode D2 is connected between both ends of this capacitor C5. Further, a secondary battery B is connected between both ends of the capacitor C6 via a resistor R1 and a diode D1.

The emitter of transistor Q4 is connected to the positive terminal of secondary battery B, and the collector of transistor Q4 is connected to resistor R2.
, R3 of the inverter In. Q
Connected to the base of 2.

Switch transistor Q3 for driving relay coil RY
and a switch transistor Q for driving the inverter In.
The control circuit Con for 4 and 4 is a C-MOS game) (
It consists of NOT, OR).

That is, the emitter of the transistor Q3 connected to the relay coil RY is connected to the input terminal of the series circuit of the NOT circuit b, and this input terminal is connected to the negative terminal of the full-wave rectifier Re via the Zener diode ZD2. has been done.

The base of the transistor Q3 is connected to the output terminal of the OR circuit via a resistor R2 and a Zener diode ZD.

On the other hand, the base of the transistor Q4 is connected to the output terminal of the OR circuit g via a resistor R5.

The emitter of this transistor Q4 is connected to the cathode of a Zener diode ZD2 via a diode D3. This cathode serves as an output terminal for constant voltage VDD.

The output terminal of the series circuit of the NOT circuit circuit b is connected to one input terminal of the OR circuit as a NOT circuit circuit valve, and is also directly connected to one input terminal of the OR circuit g.

Furthermore, the output terminal of the series circuit of NOT circuit circuit b is connected to the full-wave rectifier R through the series circuit of resistor R6 and capacitor C6.
The positive terminal of this capacitor C6 is connected to one input terminal of the OR circuit g via the series circuit of the NOT circuit d, and the connection point of the NOT circuit d is connected to the negative terminal of the capacitor C6.
Connected to one input terminal of the R circuit.

Next, the operation will be explained based on the time chart of FIG.

■~■ represent the voltage of the circuit portion.

(1) When the AC power supply E is energized, the voltage output to the secondary side of the power transformer T1 is rectified and smoothed by the full-wave rectifier Re and the smoothing capacitor C5, and the waveform is converted by the Zener diode ZD2 and the NOT circuit b. After shaping, an H'' level output voltage is obtained as shown in ■.

At this time, the voltage of ■ is at the "H" level. The voltage of ■ is on the NOT circuit and is on the "L" level. The voltage of ■ is on the NOT circuit and is on the H level. It is set to "L" level.

Therefore, the two-man power of OR times Iaf is "L".

Since it is "L", its output voltage (■) becomes "L" level. Therefore, transistor Q3 is turned on, relay coil RY is energized, and relay contact Ry1
．． R) 12 is connected to the normally open contact NO, and the discharge lamp La is in a commercial lighting state.

Further, since the two outputs of the OR circuit g are "H" and "H", the voltage of the output (■) is at the "H" level. Therefore, transistor Q4 is turned off and inverter I
n is stopped. Then, the voltage of the AC type #E is stepped down by the power transformer T1, full-wave rectified by the rectifier Re, and the secondary battery B is charged.

(2) Next, when the AC power supply E is cut off due to a power outage, the voltage of ■ goes to the “L” level, and therefore the voltage of ■ goes to the “L” level, the voltage of ■ goes to the “H” level, and
The voltage also becomes "H" level.

On the other hand, when the voltage of ■ becomes "L level", capacitor C6
Due to the discharge of , the voltage of ① gradually drops, and accordingly, the voltage of ②, which is the output of the delay circuit De, reaches the ``H level'' with a delay of time t1 from the fall of the voltage of ②.

Therefore, the voltage of ■ becomes “L” level, and the voltage of ■ also becomes “L” level.
- As a result of the above, transistor Q3 is turned off, relay coil RY is demagnetized, relay contacts Ry1 and Ry2 are connected to normally closed contact NG, transistor Q4 is turned on, and inverter In starts oscillating.

In this case, relay contacts Ry1. Since the switching of Ry2 precedes the start of oscillation of the inverter In, even if chattering occurs at the relay contact Ry1, no high frequency high voltage is applied during this chattering period, and the relay - The contact life of the contact Ry1 is not adversely affected by chattering.

(3) Next, a case in which power is restored from a power outage will be explained.

In this case, the voltage of ■ changes from "L" to "H", so the voltage of ■ changes from "H" to "Lo".
The voltage of “ is delayed by time t2 due to the delay circuit De.
The voltage of ■ changes from “H” to “L”, and along with this, the voltage of
It changes from “L” to “H”.

During time t2, ■ is -L' and ■ force is H'', so
(2) still maintains the H'' level.

Moreover, since ■ becomes H" and ■ becomes "L", ■ becomes "H" level at the same time as ■ rises.

On the other hand, after the elapse of time t2, ■ becomes "L" and ■ becomes "H", so that ■ changes to "L" level.

■ maintains the H” level.

That is, the voltage of ■ becomes the "H" level before the voltage of (2) becomes "L", turning off the transistor Q4 and stopping the oscillation of the inverter In. After that, the voltage at ■ becomes the "L" level, turning on the transistor Q3 and switching the relay contacts Ry1 and Ry2 to the normally open contact No side, but at the time of this switching, the high frequency high voltage has already been applied. Therefore, even if the relay contact Ry1 moves away to the commercial lighting side, no arc occurs. Therefore, wear and tear on the relay contact Ry1 is also avoided.

Note that the delay times 11 and 12 are set to a time that can cover the response time and chattering time of the relay.

According to this conventional example, (i) The life of relay contact Ry1 can be extended.

(ii) Since a mechanical contact (relay contact Ry1) is used for switching the lighting circuit of the discharge lamp La, there is no on-resistance that occurs in the case of a semiconductor switch, and the startability is good.

(iii) Since there is no current flow that occurs in the case of semiconductor switches and the insulation is good, there is no adverse effect on the emergency lighting characteristics.

(iv) A semiconductor switch (
Since it uses a transistor Q4), there are no problems such as voltage drop or contact failure caused by contact resistance that occur with mechanical contacts, and it has the advantage of high reliability.

However, the following problems may occur in this conventional example.

■As shown in the time chart, switching time 11.1
The period 2 is the extinguishing period of the discharge lamp La, and if this switching time 11.12 becomes longer, there is no problem at normal temperature, but there is a risk that the discharge lamp La may go out at high temperatures such as in the event of a fire.

This point will be explained in detail with reference to FIG.

(A) in FIG. 2 shows the relationship between the starting voltage of the discharge lamp and the secondary voltage of the inverter with respect to the ambient temperature, and (B) shows the relationship between the starting voltage of the discharge lamp and the secondary voltage of the inverter with respect to the ambient temperature.
The graph shows the relationship between the restartable time and the ambient temperature on the same scale as (A), and the upper right side of the characteristic curve X represents the non-lighting area, and the lower left side represents the lighting area.

The starting voltage is at its lowest when the ambient temperature is around 25° C., and the starting voltage increases both above and below that temperature. This is thought to be due to pressure changes in gases such as argon and mercury vapor sealed inside the discharge lamp.

By the way, discharge lamps used as emergency lights must be turned on reliably in the event of a power outage to the AC power supply in the event of a fire. This is stipulated by the Building Standards Act. In addition, the Japan Lighting Industry Association Technical Standards (JI L
5501. J I Li2O2), Ta
Emergency lighting at =140°C is specified. The restartable time at this temperature Ta is only 30@s.

Therefore, if the ambient temperature rises due to a fire outbreak or other causes and the restartable time becomes shorter than the switching time t1 to t2, there is a problem in that the discharge lamp cannot be restarted. Particularly, it is extremely dangerous for the signal to disappear during the switching time t1, and this must be avoided at all costs.

In order to prevent the discharge lamp La from going out under high temperatures, it is conceivable to make the secondary voltage vI of the inverter In higher than the starting voltage vL of the discharge lamp La.

However, in this case, under normal usage conditions, the secondary voltage of the inverter In is higher than necessary, which lowers its efficiency and makes the insulation more complicated, resulting in higher costs. be.

[Purpose of the invention]

The purpose of this invention is to solve the problems of the conventional example,
To provide an emergency light switching circuit that prevents a discharge lamp from going out and restarts it satisfactorily when switching the state of the discharge lamp under high temperature.

[Disclosure of the invention]

The emergency light switching circuit of the present invention has the following configuration based on the above considerations. That is, an inverter connected to an emergency power source via a first switch, a second switch connecting this inverter and a discharge lamp, a third switch connecting the discharge lamp to an AC power source, and an AC power source. based on the power outage detection circuit of the power outage/power restoration detection circuit, and the second
a first control means that turns on a switch, turns off the third switch, and turns on the first switch; the second switch is turned off, and the second switch is turned off and the third switch is turned off.
a control circuit having a second control means for turning on a switch, and the switching time of the first switch during a power outage of the AC power supply is longer than the operating time of the second switch; It is set to be shorter than the extinguishing time of the discharge lamp.

According to the configuration of this invention, the following effects are achieved.

(al) When the power outage/power restoration detection circuit detects a power outage in the AC power supply, it turns on the second switch (switch on the output side of the inverter) that connects the inverter and the discharge lamp, and connects the inverter to the discharge lamp. After this delay, the first switch (switch on the input side of the inverter) for connecting the emergency power source and the inverter is turned on, oscillation of the inverter is started, and emergency lighting is performed.

Further, the third switch connecting the AC power source and the discharge lamp is turned off to electrically isolate the AC power source and the discharge lamp.

(b) During this power outage, since the switching time of the first switch is set longer than the operating time of the second switch, in other words, the switching time of the first switch is set to be longer than the operating time of the second switch. Since the second switch is turned on later than the connection between the inverter and the discharge lamp, even if chattering occurs in the second switch, no high-frequency voltage is applied during this chattering period. The life of the switch is not adversely affected by chattering.

In addition, since the switching time of the first switch in the event of an AC power outage is set shorter than the turn-off time of the discharge lamp, the inverter is oscillated to start and turn on the discharge lamp before the discharge lamp goes out. This makes it possible to reliably prevent the discharge lamp from going out.

Example A first embodiment of this invention will be described.

The circuit configuration is the same as the conventional example (FIG. 3).

The difference is that the switching time 11.12 due to the time constant of the delay circuit De is longer than the operating time tR of the relay contacts Ry1 and Ry2, and the turn-off time t of the discharge lamp La is
The point is that it should be set shorter than L.

That is, tR×t11t2<tL. Switching time in this case 1. ．． 12 is the time under high temperature.

Specifically, it is as follows.

Usually, relay contacts Ry1. The operating time of Ry2 is approximately IQm
a, startable switching time 11 at 140°C
．． 12 depends on the type of discharge lamp La, but according to experimental data, it was about 30 tones.

Therefore, the switching time 11.12 is 10m5~30m
It is set within the range of 5.

It should be noted that the secondary battery B is an example of the "emergency power source" as referred to in the constitution of the invention, and the transistor Q4 is an example of the "emergency power source" as referred to in the constitution of the invention.
This is an example of the first switch, and the relay coil RY is
This is an example of the "power outage/power restoration detection circuit" referred to in the configuration of the invention. Further, the relay contact Ry1 serves as a part of the "second switch" and a part of the "third switch" in the configuration of the invention, and the relay contact Ry2 also serves as a part of the "second switch" in the configuration of the invention. This switch also serves as a part of the "switch" and a part of the "third switch."

Next, the operation will be explained.

As mentioned above, normal/emergency switching time 1 under high temperature
1.12 is the relay contact Ry1. Since the operating time tR of Ry2 is longer than the relay contact Ry,.

Since the inverter In oscillates after Ry2 is connected to the oscillation transformer T2, no arc occurs, and therefore,
Welding of relay contacts R) Fl and Ry2 is prevented.

Moreover, since the switching time 11.12 is shorter than the extinguishing time tL, there is no problem in restarting the discharge lamp La.

As described above, according to this embodiment, (i) Relay contact Ry1 under high temperature. Switching Ry2 can also prevent the discharge lamp La from going out.

(ii) There is no need to set the secondary voltage of the inverter In high, and the efficiency of the inverter In can be made high.

A second embodiment of the invention will be described based on FIGS. 1 and 2.

In FIG. 1, the same reference numerals used in FIG. 3 relating to the conventional example refer to the same parts as the parts 9 indicated by the reference numerals.

This embodiment differs from the conventional example in the following points.

In the delay circuit De of the control circuit ConH, a thermistor Rt, which is a temperature-dependent resistance with negative characteristics, is inserted between the resistor R6 and the capacitor C6 in FIG.

By inserting this thermistor Rt, the switching time 11.12 is changed from room temperature to 14
It is in the lighting region over a temperature range above 0°C and varies inversely with temperature.

At room temperature, the thermistor Rt has a high resistance, and the resistance R
6. The time constant determined by the thermistor Rt and capacitor C6 is large, and when transitioning from energization to power outage or from power outage to energization, the change in voltage shown in Figure 4 (■) becomes more gradual, resulting in a shorter switching time. 11.12 becomes longer. For the switching time 11.12 at this time,
Relay contact Ry1. The operating time of Ry2 is set to be shorter.

Since the other configurations are the same as those of the conventional example, the same parts are given the same reference numerals and the explanation will be omitted.

Next, the operation will be explained.

As mentioned above, the switching time L1°t2 under high temperature is the relay contact Ry1. Since it is longer than the operating time tR of Ry2, the switching time 11.12 is naturally longer than the operating time tR at low temperatures, and relay contacts Ry1. Ry2
Since the inverter In oscillates after the inverter In is connected to the oscillation transformer T2, no arc is generated and therefore welding of the relay contacts Ry1 and Ry2 is prevented.

In addition, even if the switching time 11.12 is long, as is clear from Fig. 2, the restartable time is sufficiently long (because the switching time 11.12 is shorter than the extinguishing time tL, the restarting time of the discharge lamp La is There is no problem.

When the temperature increases, the resistance value of the thermistor Rt decreases and the time constant of the delay circuit De becomes smaller, so that the switching time 11.
12 becomes shorter. For switching time 11.12 at this time, relay contact Ryl.

The operating time of Ry2 is set to be shorter.

Therefore, even if the restartable time is shortened due to high temperatures, the switching time is 1
1.12 remains shorter,
The discharge lamp La restarts without any problem and does not go out.

Regarding prevention of welding, the following can be said.

That is, in the first embodiment, since the delay time of the delay circuit De is fixed, there is no response to temperature changes, and the normal/emergency switching time 11.12 is uniformly determined. And this fixed normal/emergency switching time 11.12
is very short, 101M5~30IIIs,
During this very short normal/emergency switching time 11.12, relay contact Ry1. There is a problem in that the possibility of Ry2 welding remains.

In addition, the normal/emergency switching time 11.12 is reduced from 1Oas to 3
In order to set it within the range of 0, fairly high-precision circuits and elements are required, which may result in an increase in cost.

In contrast, according to the second embodiment, by using the thermistor Rt with negative temperature characteristics, the normal/emergency switching time 11.12 at normal low temperatures can be set much longer than in the first embodiment. Therefore, when switching the power on and off frequently, relay contacts Ry1. R) There is no risk of F2 welding.

In addition, relay contact Ry1 under high temperature. Switching of Ry2 occurs very rarely, so relay contacts Ry, , Ry
The problem of deterioration in No. 2 can be almost ignored.

As described above, according to this embodiment, (i) Relay contact Ry1 under high temperature. Switching Ry2 can also prevent the discharge lamp La from going out.

(ii) Relay contact Ry1. Ry2's credibility is high.

(iii) There is no need to set the secondary voltage of the inverter In high, and the efficiency of the impark In can be made high.

(iv) The configuration of the control circuit Con1 is relatively simple;
This is effective in reducing costs.

In addition to the above embodiments, the present invention includes the following embodiments.

(A) A relay contact dedicated to the second switch and a relay contact dedicated to the third switch are provided separately.

(B) A mechanical switch is used in place of the transistor Q4 and other semiconductor switches as the first switch.

(C) Items that use something other than secondary batteries as an emergency power source.

〔Effect of the invention〕

According to this invention, there are the following effects.

In the event of an AC power outage, the switching time of the first switch is set longer than the operating time of the second switch. Since the second switch is turned on later than the connection between the inverter and the discharge lamp, even if chattering occurs in the second switch, no high-frequency voltage is applied during this chattering period, so the second switch The life of the switch is not adversely affected by chattering.

In addition, since the switching time of the first switch in the event of an AC power outage is set shorter than the turn-off time of the discharge lamp, the inverter is oscillated to start and turn on the discharge lamp before the discharge lamp goes out. This makes it possible to reliably prevent the discharge lamp from going out.

[Brief Description of the Drawings] Fig. 1 is a circuit diagram of a second embodiment of the present invention, Fig. 2 is a characteristic diagram showing the relationship between ambient temperature, discharge lamp starting voltage, and restartable time, Fig. 3 are circuit diagrams of the first embodiment and the conventional example, and FIG. 4 is a time chart thereof. E...AC power supply, B...secondary battery (emergency power supply),
In...Inverter, La...Discharge lamp, RY...
Relay coil (power outage/recovery detection circuit), Q4...transistor (semiconductor switch, first switch), Ryl
. RY2... Relay contact (mechanical switch, part of the second switch and part of the third switch), De...
Delay circuit, Con, Con1...control circuit, Rt...
・Thermistor Figure 4 Hand 3 Da ε Ne Fusho (1) October 30, 1985

Claims (3)

[Claims] (1) An inverter connected to the emergency power supply via a first switch, and a second switch connected to the inverter and the discharge lamp.
a third switch that connects the discharge lamp to an AC power source; a power failure/power restoration detection circuit for the AC power source; and a power failure/power restoration detection circuit that turns on the second switch based on the power failure detection of the power failure/power restoration detection circuit. a first control means that switches the third switch to OFF and switches the first switch to ON; and switches the first switch to OFF based on the power restoration detection of the power failure/power restoration detection circuit; and a control circuit having a second control means for switching off the second switch and switching on the third switch, and controlling the switching time of the first switch during a power outage of the AC power supply to the third switch. The emergency light switching circuit is set to be longer than the operating time of the second switch and shorter than the extinguishing time of the discharge lamp. (2) The delay means of the first control means in the control circuit is provided with a thermistor having a negative characteristic temperature dependence for shortening the delay time as the ambient temperature rises. Emergency light switching circuit described in (1). (3) The emergency light switching circuit according to claim (1), wherein the first switch is a semiconductor switch, and the second switch and the third switch are mechanical switches.