JPH06302241A - Power source switch device - Google Patents

Abstract

PURPOSE:To prolong the life of a contact by restraining the bounce of a contact- attached switch and the abrasion of the contact due to inrush current. CONSTITUTION:A rectifying diode bridge 6 and a smoothing capacitor 5, a capacity load, are connected in parallel to an A.C. power source 4 to convert A.C. into D.C. A contact-attached switch 2 opening/closing a power source feed line is connected to one end of the A.C. power source 4. An inductor 3, a delaying means, is inserted by one respectively in power source feed wires on both the ends of the A.C. power source 4. A power source switch device 1 is composed of the contact-attached switch 2 and the inductor 3. The value of the inductance of an inductor 3 is set so that inrush current flowing in a circuit can reach a peak value after the bounce of the contact-attached switch 2 is focused when the contact-attached switch 2 is closed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power switch device for a circuit having a capacitive load.

[0002]

2. Description of the Related Art As a circuit device having such a capacitive load, there is an inverter lighting device 8 for a discharge lamp 9 shown in FIG. As shown in FIG. 4, the voltage of the AC power supply 4 is rectified and smoothed by the diode bridge 6 and the smoothing capacitor 5 into a direct current, and this direct current is converted into a high frequency alternating current by the inverter circuit 7 to drive the discharge lamp 4. High frequency lighting. In this case, the smoothing capacitor 5 corresponds to the capacitive load.

By the way, in such an inverter lighting device 8, a contact switch 2 such as a pull switch or a seesaw switch for turning on / off the power supply from the AC power supply 4 is inserted in the power supply line.

[0004]

In such an inverter lighting device 8, when the contact switch 2 is turned on,
The AC current supplied from the AC power source 4 flows to the smoothing capacitor 5 after being rectified by the diode bridge 6, but immediately after the contact switch 2 is turned on, there is no accumulated charge in the smoothing capacitor 5 and the power supply line is connected. Causes a large current to instantaneously flow as shown in FIG. This current is a so-called inrush current, and it may flow at 100 A or more depending on the electrostatic capacity of the smoothing capacitor 5, and the contact of the contact switch 2 generates heat due to the inrush current, causing melting and contact wear. On the other hand, since the contacts of the contact switch 2 such as a pull switch and a seesaw switch are mechanically opened and closed, as shown in FIG. 5B, a contact bounce occurs immediately after the contact switch 2 is turned on. easy. Therefore, when the contacts are opened due to the bounce, an arc is generated between the contacts, the heat of the contacts is caused by the energy of the arc voltage and the energy of the inrush voltage, and the contacts are further worn.

As described above, contact wear occurs due to the inrush current every time the contact switch 2 is opened and closed, which shortens the life of the contacts and causes problems such as poor contact and welding of the contacts. Also, in order to prevent these, it is necessary to form the contact with an expensive material,
There is also the problem of cost. By the way, in order to reduce the inrush current, it has been proposed to insert a resistor of several Ω into the power supply line, but in this case there is power loss in the resistor and the heat generated by the resistor itself is radiated. In order to do so, the size of the resistor must be increased, and there is the problem that space is required.

Further, as shown in FIG. 6, a resistor 12 is inserted in the power supply line, a relay contact 13 is provided in parallel with the resistor 12, and the relay contact 13 is connected immediately after the contact switch 2 is turned on. It is opened by the relay 10 and the inrush current is suppressed by the resistor 12,
By driving the relay 10 and closing the relay contact 13 after a fixed time by the timer circuit 11 connected to
It has also been proposed to prevent power loss in the resistor 12 in the steady state. However, also in this case, there is a problem that a space for arranging the timer circuit 11 and the relay 10 is required.

An object of the present invention is to solve the above problems, and to provide a power switch device capable of suppressing contact wear due to bounce and inrush current of a contact switch and prolonging the life of the contact. To do.

[0008]

In order to achieve the above object, the present invention provides a contact switch means for opening and closing a power supply line to a capacitive load, and a power supply line when the contact switch means is closed. The power supply switch device is configured with a delay unit that makes the time until the transient current flowing becomes maximum longer than the time until the bounce that occurs when the contact switch unit is closed is converged.

[0009]

In the structure of the present invention, there is provided the contact switch means for opening and closing the power supply line to the capacitive load, and the time until the transient current flowing through the power supply line becomes maximum when the contact switch means is closed. Since the power switch device is configured with the delay means that makes the bounce that occurs when the contact switch means is closed longer than the time it takes to converge, an arc is generated between the contacts due to the bounce of the contact immediately after the contact switch is turned on. It is possible to shift the timing and the timing at which the transient current becomes the maximum, suppress the contact heat generated by the transient current and the arc synergistic effect and the contact wear caused by melting, and it is possible to extend the life of the contact. .

[0010]

EXAMPLES The present invention will be described in detail below based on examples.
FIG. 1 is a circuit configuration diagram showing the present embodiment, in which a rectifying diode bridge 6 and a smoothing capacitor 5 which is a capacitive load are connected in parallel to an AC power supply 4 to convert AC to DC. A contact switch 2 for opening and closing a power supply line is connected to one end of the AC power supply 4. This contact switch 2 is
Any kind of mechanical switch may be used as long as it mechanically opens and closes the contacts, such as a pull switch or a seesaw switch. Further, one inductor 3 is inserted in each of the power supply lines at both ends of the AC power supply 4. The number of inductors 3 to be inserted is not limited to this. The power switch device 1 is configured by the contact switch 2 and the inductor 3 described above.

By the way, the transient current i flowing in the circuit when the switch inserted in the series circuit of the power source of the power source voltage E, the inductance L and the resistor R is closed is expressed by the equation 1.

[0012]

[Formula 1]

The relationship between the time t and the transient current i is shown in FIG.
As shown in, even if the switch is turned on at t = 0,
Since the inductance L is connected to the circuit, the transient current i exponentially rises from i = 0, and becomes a steady value i = E / R after a certain period of time. Here, as is clear from Equation 1, as the value of the inductance L increases, the time until the transient current i reaches the steady value becomes longer. That is, the inductor 3 serves as a delay means.

Therefore, by inserting the inductor 3, it is possible to lengthen the time from when the contact switch 2 is turned on to when the transient current, that is, the inrush current reaches the peak value. However, when the timing when the inrush current reaches the peak value coincides with the timing T when the contact point of the contact switch 2 bounces, as indicated by the current waveform shown by the dotted line in FIG. 3, the arc and inrush current generated between the contact points On the contrary, the contact wear is promoted by the synergistic effect of. Therefore, in the present embodiment, the inductance value of the inductor 3 is appropriately selected so that the inrush current reaches the peak value after the bounce of the contact switch 2 converges, as shown by the current waveform in FIG. I have to. When a pull switch is used as the contact switch 2, generally the time until the bounce converges is about 0.6 ms, but there is a difference depending on the structure, and the value of the inductance of the inductor 3 is appropriate depending on the switch used. It is set in.

[0015]

The present invention has the contact switch means for opening and closing the power supply line to the capacitive load, and the time until the transient current flowing through the power supply line becomes maximum when the contact switch means is closed. Since the power switch device is configured with the delay means that makes the bounce that occurs when the contact switch means is closed longer than the time it takes to converge, an arc is generated between the contacts due to the bounce of the contact immediately after the contact switch is turned on. It is possible to shift the timing and the timing when the transient current becomes maximum. As a result, contact heat generation due to the synergistic effect of transient current and arc, contact wear caused by melting can be suppressed, and the life of the contact can be extended,
There is an effect that an inexpensive contact material can be used and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the above, and is a waveform diagram showing a transient current of the RL series circuit.

FIG. 3 is a diagram for explaining the operation of the above, and is a diagram showing a temporal relationship between a waveform of a transient current flowing in the circuit and bounce of a contact.

FIG. 4 is a schematic circuit configuration diagram showing a conventional example.

FIG. 5 is a diagram for explaining the operation of the above, FIG.
FIG. 4B is a waveform diagram of a transient current flowing in the circuit, and FIG. 7B is a diagram showing a relationship between the bounce of the contact and time.

FIG. 6 is a circuit configuration diagram of a main part showing another conventional example.

[Explanation of symbols]

 1 power switch device 2 contact switch 3 inductor 4 AC power supply 5 smoothing capacitor 6 diode bridge

Claims (1)

[Claims] 1. A contact switch means for opening and closing a power supply line to a capacitive load, and a contact switch means for setting a time until a transient current flowing through the power supply line becomes maximum when the contact switch means is closed. A power supply switch device, comprising: delay means for making the bounce occurring when closed to be longer than the time until the bounce converges.