JPS63194523A - Single line switch for protecting lamp from rush current - 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 The cause of disconnection of a light bulb filament is often an inrush current that is 10 times or more of the normal current that flows at the moment the light bulb is turned on. For example, for a 100 watt light bulb, 10
The current is 1 ampere at 0 volts and 100 ohms.
When the filament is at room temperature, the resistance is 10 ohms, so if the AC peak value is 140 volts at the moment of switch-on, 140 volts ÷ 10 ohms = 14 amperes,
The current reaches 14 times the constant current and causes wire breakage.

The present invention relates to a single-wire inrush current prevention switch for light bulbs, which is connected in parallel to a series resistor R1 and a bidirectional conduction element BCR', as shown in the circuit shown in FIG. Series resistance R1 from AC? Is the filament of the light bulb broken by allowing current to flow through the light bulb? This is what we are trying to prevent.

If the value k of the series resistor R1 is 100 ohms, and the room temperature resistance of the light bulb is 10 ohms, the circuit resistance will be 100 ohms + 10 ohms = 110 ohms, and the voltage of 100 volts? Even if it is supplied, the maximum current will be 0.9 ampere.

Even if a wave cylinder value of 140 volts is added, 140 volts ÷ 11
0 ohms = 1.27 amps.

At the moment the switch is turned on, the resistance of the light bulb filament is 10.
Although it is about one ohm, it is heated over time, the temperature rises, and the resistance value increases.

As shown in FIG. 3, the voltage across the parallel resistor R1 decreases with time.

The diode group Dn connected in series to the light bulb circuit has positive and reverse polarities in opposite directions, so each element has approximately 0.7
There is a voltage drop of volts. This value is independent of current.

If there are four urchins in tandem as shown in Figure 1, the voltage drop will be 2.8 volts. That voltage? The diode D2 is used for rectification, and the capacitor C1 is charged. Also, how long does it take to charge capacitor C2 by resistor R2? All R2C2 time constants are 0.
If the time is about 1 second to 0.2 seconds, the thyristor SCR becomes conductive approximately 0.1 seconds to 0.2 seconds after the switch is turned on, and the total charge of the capacitor C2 becomes a bidirectional conducting element from the + of the capacitor C□. A circuit is created in which the flow flows from T1 to G of BCR and from P to K of thyristor SCR, and a negative voltage is applied to the gate electrode of bidirectional conduction element BCR, making it conductive.

As shown in Figure 2, the waveform becomes a switch-off,
The bidirectional conduction element BCR of FIG. 3 becomes conductive, and the voltage across the resistor R1 becomes only the internal voltage drop of the element.

Figure 4 shows that at the moment the switch is turned on, a steady current flow occurs, which means that a little more current is flowing, but after 0.15 seconds, the current drops due to the heating of the bulb filament, and the bidirectional conduction element BC
The series resistor R1 is short-circuited due to the conduction of R, and the current temporarily rises like C, but becomes a steady current after 0.4 seconds.

This switch? By adopting this method, the inrush current at the moment the switch is turned on is completely eliminated, extending the life of the bulb.

[Brief explanation of the drawing]

Figure 1 is the basic electrical circuit of this project Figure 2 is the charging time constant curve of the capacitor Figure 3 is the waveform diagram at both ends of the bidirectional conducting element BCR Figure 4 is the inflow current curve of the light bulb

Claims (1)

[Claims] A circuit with multiple diode groups connected in forward and reverse directions is connected to a bidirectional conduction element and a resistor connected in parallel, and the voltage drop across the diode group is charged to a capacitor by a rectifier, and used as a power source for the thyristor. Due to the time constant of the resistor and capacitor, the thyristor becomes conductive after a certain period of time when the power switch is turned on, and current flows into the gate of the bidirectional conduction element. A single-wire light bulb inrush current prevention switch where a circuit that supplies full voltage to the switch is installed inside the switch or in the current circuit.