JPS626671Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a capacitor in which a safety device is built into the container to automatically cut off the electrical circuit in the event of an internal failure.

Recently, in medium and low voltage phase advance capacitors, if a failure occurs inside the capacitor, the capacitor automatically cuts off the current and prevents the accident from spreading. Many capacitors are equipped with a fuse safety device inside the capacitor, which consists of a conductive foil and a fusible piece that uses the rise in temperature inside the container to interrupt the electrical circuit. In such capacitors, even if the safety device is activated, it often goes unnoticed, resulting in disadvantages such as a drop in power factor.

In order to eliminate the above-mentioned drawbacks, the present invention aims to promptly detect the activation of the safety device, issue a signal, and take measures such as issuing an alarm.

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

Figure 1 is an internal wiring diagram of a capacitor, where 11 is a capacitor element, and 12 is a safety device that automatically cuts off the electrical circuit in the event of a failure inside the capacitor.For example, if the internal pressure of the container exceeds a predetermined value, the container The fuse consists of a metal conductor foil that rapidly expands and is pulled to cut the electrical circuit, or a fusible piece that melts and interrupts the electrical circuit when the internal temperature of the container rises and reaches a predetermined temperature. Device 1
It is a resistance heating element such as a high resistance metal wire connected in parallel with 2.

Figure 2 is a cross-sectional view of the main parts of this capacitor.
is a capacitor element, 32 is a container that stores the capacitor element 11, 33 is a terminal bushing attached to the container 32, 21 is a resistance heating element disposed inside the container 32, and 41 is close to the resistance heating element 21. This is a temperature-sensitive electrical contact made of bimetal that is attached to the outside surface of the vessel wall.

Since the present invention is constructed as described above, it is possible to prevent the protection device 12 from occurring due to internal failure of the capacitor.
When the resistance heating element 21 is cut, a current flows through the resistance heating element 21 and generates heat, heating the part of the container 32 close to the resistance heating element 21 and increasing the temperature, and the temperature-sensitive electrical contact 41 attached to this part is activated. emit a signal. By using this signal to issue an alarm or shut off the power, it is possible to quickly notify the occurrence of a failure.

In the above embodiment, a three-phase capacitor is used as an example, but a single-phase capacitor can also be constructed in the same manner. In addition, although the above embodiment shows a temperature-sensitive electrical contact that can take out a bimetal direct contact signal, it is also possible to convert this into a contact signal electrically using a temperature-sensitive element that causes a change in resistance, such as a thermistor. Of course, the same applies to the case.

As described above, according to the present invention, it is possible to easily and reliably detect the operation of the safety device and issue a signal, which can lead to inconveniences such as being left with a low power factor without noticing the operation of the safety device. It has great practical value, as it has the effect of avoiding such problems.

[Brief explanation of the drawing]

FIG. 1 is an internal wiring diagram of an embodiment of the capacitor of the present invention, and FIG. 2 is a sectional view of essential parts of an embodiment of the capacitor of the present invention. 11: Capacitor element, 12: Safety device, 2
1: Resistance heating element, 32: Container, 33: Terminal bushing, 41: Temperature-sensitive electrical contact.

Claims (1)

[Scope of utility model registration request] In the event of an internal failure, the container has a built-in fuse safety device consisting of a metal conductor foil that automatically cuts off the electrical circuit when the container swells due to an increase in internal pressure, or a fusible piece that automatically cuts off the electrical circuit when the internal temperature rises. In the capacitor, a resistance heating element is connected in parallel with this safety device, and this resistance heating element is placed inside the capacitor wall,
A capacitor in which a temperature-sensitive electrical contact made of a bimetal or a thermistor is provided on the outside of the wall of the capacitor, which opens and closes depending on the temperature rise of the wall of the capacitor.