JPS61220221A - Fault detector for switch - 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 present invention relates to a device for detecting the state of

[Conventional technology]

Conventionally, semiconductor devices such as thyristors, transistors, or diodes have been used in switches, and there is a trend toward electronic devices in the future.

[Problem that the invention seeks to solve]

However, switches using semiconductors often become conductive when an element fails, and in this case, the problem is that power continues to be supplied to the load even when a stop signal is received, making it impossible to stop the load. was there.

This invention was made to solve the above-mentioned problems, and its purpose is to provide a device that can detect failures in semiconductor elements used in switches and prevent load runaway. [First Means to Solve the Problem] The switch failure detection device according to the present invention takes two signals, the load side voltage and the control voltage of the switch, as input signals, and uses these two signals as input signals.
The device is equipped with a mismatch detection circuit that outputs an output signal when two signals are mismatched.

[Effect]

The mismatch detection circuit of Jin's invention compares the load side voltage of the switch with the control voltage, and issues an output signal if the above do not match. [Embodiment of the Invention] An embodiment of the invention will be described below. Explain the diagram (1b)
(2) is a control circuit that provides a gate signal to the triator element (16) by the operation of the control signal contact (3) for driving the switch (1);
is a load device, (4) is a diode with a three-phase block 9° configuration that rectifies the three-phase voltage, (5) and (6) are voltage dividing resistors for signal voltage level conversion, and (7) is a mismatch detection circuit. Exclusive O
7 (8) consisting of an R circuit is a failure detection output, (9
) The three-phase power supply voltage of the Hao circuit, αO is the control voltage for the switch drive and the input signal of the mismatch detection circuit (7), and (2) is the control voltage for converting the control voltage to the input level of the mismatch detection circuit (7). Next, the operation of the level conversion circuit will be explained.

In Fig. 1, when the control signal contact (3) is turned on, voltage is applied to the control circuit (1b) of the gate opener (1), and the trial element (1a) becomes conductive and power is applied to the load (2). Supplied. At this time, a three-phase voltage is applied to the terminals of the load (2), which is full-wave rectified by the diode (4), passes through the voltage dividing resistors (5) and (6), and is input to the mismatch detection circuit (7). . At the same time, the driving voltages of the switch (1) both go to ``HH level'', and the mismatch detection circuit (7) does not operate and the output becomes 1L level.When the load is stopped, the mismatch detection circuit (7) also goes to the ``HH level''. Both input signals are at the 5L level' and their outputs are also at the 1L level.If the switch (1) is in a normal state as in 2 or more, the output (8) is at the 1L' state. Element (]a) is 2
If the unit fails and only two phases become conductive, single-phase power will be applied to the load (2) through the conductive element even if the control signal contact (3) is in the OFF state7. The signal level input from the main circuit side is H level, and the signal from the control circuit (lb) or A is 1L level', and this signal is input to the mismatch detection circuit (7) to generate an output signal. As a result, a failure of the switch (1) is detected.Furthermore, even if the control signal (3) is in the ON state due to a failure of the control circuit (1b) or the try-awake element (lB) of the switch (1), the switch When (1) is not conductive and the load is not starting, #ζ similarly, the signal from the main circuit is at 1L level', and the control circuit (1b) is applied at 1H level'.

In this case as well, the output of the mismatch detection circuit (7) is at the -flI level', so an output signal is generated to perform failure detection.

In the above manner, non-operation of the switch (1) or contact continuity failure can be detected.

Note that FIG. 2 shows a circuit that outputs an output from the mismatch detection circuit (7) of the circuit shown in FIG. 1 through a timer circuit (b).

For example, with a load such as motor 0, a residual voltage is generated when a new circuit is used, but in such a load, if a discrepancy is detected immediately after the load is opened or closed, voltage is generated at the load terminal of the switch (1), resulting in an erroneous detection. Therefore, once the residual voltage is attenuated and the fault output is performed, the fault detection is output via the timer circuit (6) with a time limit longer than the residual voltage duration.

In addition, it is possible to detect a fault in the switch (1) without false detection even in the case of a load that generates residual voltage, such as a motor (2) in a shallow area.By the way, in the above embodiment, the switch has a semiconductor element Although we have shown an example using an electromagnetic switch, it goes without saying that the same effect can be obtained by combining it with an electromagnetic switch.

〔Effect of the invention〕

As described above, according to the present invention, a mismatch detection circuit is provided which uses the load side voltage of the switch and the control voltage as input signals and generates an output signal when these two input signals do not match. This has the effect of providing a switch failure detection device that can detect failures in semiconductor elements and prevent load runaway.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the invention, and FIG. 2 is a circuit diagram showing another embodiment of the invention.
(1) is the switch, (2) is the load, (July, discrepancy detection circuit, (8) is the output, αG is the control voltage, and αυ is the time limit circuit. In addition, in the figure, the - wind sign is the same 6 lines showing the parts I Figure 7: Child-1L history: & circuit B: Nu force 1 o: storage] 1 j;

Claims (2)

[Claims] (1) A switching device characterized by comprising a discrepancy detection circuit that receives the load-side voltage of the switch and the control voltage of the switch as input signals, and emits an output signal when the two signals are in a discrepancy state. equipment failure detection device. (2) The failure detection device for a switch according to claim 1, wherein the mismatch detection circuit emits an output signal after a certain period of time has elapsed after the signal is input.