JPH0442847B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filter protection circuit connected in parallel to a power supply line.

In recent years, with the remarkable progress in electronics, the frequency of equipment has increased, and the amount of feedback noise from the load side to the power supply input has increased, causing noise interference to other equipment connected to the same power feed line. , has become obvious. In order to improve the filtering effect of the feed line against such noise, a method has been implemented in which a filter is inserted in series with the feed line to remove noise (see Figure 1). Or, in the event of a failure, the circuit breaker on the power supply line must be disconnected, and for this reason, the operation of the equipment must be stopped or a bypass circuit must be prepared in advance, and especially in the case of a filter failure, equipment and equipment may suddenly stop. However, there were drawbacks such as the long time required for filter repair and device operation, which resulted in enormous losses.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and therefore, the purpose of the present invention is to perform maintenance and inspection of filters, maintenance and inspection of filters without stopping the equipment in operation at the time of failure, and maintenance while continuing operation. The object of the present invention is to provide a new protection circuit that can be inspected and repaired in the event of a failure.

In order to achieve the above object, a filter protection circuit according to the present invention includes at least one diode,
A resistor and a capacitor are connected in parallel, one overcurrent circuit breaker with one end open is connected to both ends of the parallel connection circuit, and the parallel connection circuit of the diode and resistance capacitor is connected in series to the power supply line. connected and configured.

In the present invention, when a fault occurs in the filter due to a drop in the internal impedance of the filter, the overcurrent circuit breaker disconnects the faulty circuit, and power is continuously supplied to the load through the parallel bypass circuit made up of diodes, resistors, and capacitors.

Next, a preferred embodiment of the present invention will be specifically explained with reference to the drawings.

Referring to FIG. 2, one embodiment of the present invention includes a filter protection circuit 25, 27 of the present invention connected to the feed lines 20, 21, and components of the filter protection circuit including capacitors 28, 55, resistors 29, 54, Diodes 30, 31, 52, 53, overcurrent breaker 3
2, 33, 50, 51, a filter circuit 26 connected to these protection circuits, inductances 39, 40, 44, 45 as examples of its components, capacitors 41, 43, and a grounding lead terminal 23 from their midpoint 42. and power supply lines 57 and 58 to the load. Next, the operation of the filter protection circuit with the above configuration will be explained.

In normal operation, overcurrent circuit breakers 32 and 5 are protected against noise voltage intrusion from the feed lines 20 and 21 through the connections 22 and 24 of the protection circuits 25 and 27.
0, is guided to the filter circuit 26, is blocked by inductances 40 and 45, and becomes inductance 3.
9, 44, capacitors 41, 43, and is led to the ground point 23 via the connection point 42, where the noise is absorbed. A high-quality power source from which noise has been removed passes through filter outputs 38 and 47, passes through circuit breakers 33 and 51, and passes through protection circuit outlets 34 and 56 to the load feed line 5.
7, 58 and connected to the load.

Here, the impedance of the capacitor 41 of the filter circuit 26 becomes extremely low, and the power supply current becomes 23
When the current flows to the ground wire through the terminal, the circuit breaker 32 of the filter filter protection circuit 25 detects the overcurrent and operates to disconnect the filter circuit together with the interlocking circuit breaker 33.
Electric power is supplied to the load from the power supply line 57 without interruption via either one of 0 and 31, the resistor 29, and the capacitor 28 for absorbing transient vibrations during switching.

Generally, in a symmetrical filter circuit as shown in filter circuit 26, capacitors 41 and 43 rarely deteriorate at the same time, and since one side is operating normally, they can be completely separated even if the filter effect decreases. It is possible to continue operating the equipment without any problems. Further, even if an accident occurs in both circuits, stable power supply can be continuously provided by the bypass circuit as explained in connection with the protection circuit 25.

As explained above, the present invention has the advantage that by having the structure as in the first and second embodiments, the filter can be effectively protected without impairing the filter effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional filter protection circuit, and FIG. 2 is a circuit block diagram showing an embodiment of the present invention. 3, 4, 32, 33, 50, 51... Overcurrent breaker, 5, 26, 59... Filter circuit, 25, 27
...Filter protection circuit, 30, 31, 52, 53...
Diode, 29, 54...resistance.

Claims (1)

[Claims] 1. One overcurrent breaker each connected to each coil of a filter circuit consisting of two coils and at least one capacitor provided at an intermediate connection point between the two coils and capable of opening one end. , a protection circuit formed by connecting at least one diode, a resistor, and a capacitor in parallel and connected in series to a power supply line, and the protection circuit A filter protection circuit characterized in that it is connected in parallel to a filter circuit.