JPH08278052A - Operation detecting device for protective device - Google Patents

Abstract

PURPOSE: To judge which protective device has operated, by providing resistor elements having different values of resistance and connected in parallel to respective switching protective devices, a photo coupler for generating a pulse width conformed to a detected voltage, a shaping circuit and a judging means. CONSTITUTION: At the time of normal operation, all bimetals S1 to S4 are in a closed state and a detected voltage having been divided by resistors R1 to R2 through the bimetals S1 to S4 is applied to a photo coupler 3. At this time, a light emitting diode LED of the photo coupler 3 is made ON during a period of time, in which the detected voltage is higher than a forward voltage of the diode. As a result, a period of time, in which a photo diode PD of the photo coupler 3 is made ON, varies depending upon an amplitude of a voltage divided by the resistors R1 and R2 . A value of the amplitude, is such that a divided voltage ratio varies depending upon a resistance value of a series circuit which includes either of the bimetals S1 to S4 . and the resistances R3 to R6 . A output pulse width of a shaping circuit 4 is detected by a CPU 5 to identify a protective device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion detector for a protective device, and more particularly to a fan motor incorporated in an air conditioner,
The present invention relates to an operation detection device that detects an operation state of an overheat protection device provided in a compressor or the like.

[0002]

2. Description of the Related Art Generally, an air conditioner is provided with a protection device which detects a temperature rise of a fan motor, a compressor and the like and stops the supply of power.

FIG. 5 shows a schematic circuit diagram of a conventional operation detecting device of a protection device. In FIG. 5, two fan motors and two compressors are respectively provided with bimetals, and these four bimetals are three-phase alternating current (R, S,
T) between any two phases (in the figure, between R and S) is connected in series.

The operation detecting device 10 includes resistors R1 and R2 for voltage division, and a photocoupler 11 for outputting an original detection signal having a voltage within a predetermined voltage range based on the output voltages of the bimetals S1, S2, S3 and S4. , A diode 12 for preventing a reverse voltage from being applied to the photocoupler 11.
And a rectifying circuit 13 for rectifying the original operation detection signal and outputting the rectified operation operation signal as an operation detection signal to an analog / digital port of a controller (not shown) that controls the entire air conditioner.

Next, the operation will be described. Each bimetal S1,
S2, S3, S4 are in the closed state when the corresponding protective device is inactive. During normal operation, all bimetals S1, S2, S3, S4 are closed (on)
Therefore, the output light level of the light emitting diode LED constituting the photocoupler 11 becomes a constant level proportional to the power supply voltage divided by the resistors R1 and R2. As a result,
The voltage level of the original operation detection signal output from the photodiode PD that constitutes the photocoupler 11 also depends on the resistances R1 and R.
It becomes a constant level proportional to the power supply voltage divided by 2,
The output level of the operation detection signal output by the rectifier circuit 13 is a constant level having a predetermined voltage value.

On the other hand, when an abnormality is detected, any of the bimetals S1, S2, S3, and S4 is opened (OFF state), so that no voltage is applied to the light emitting diode LED that constitutes the photocoupler 11, Rectifier circuit 1
The output level of the operation detection signal output by 3 is lower than that in the normal state. In response to this state, the controller (not shown) determines that one of the protection devices has operated, and notifies (displays, etc.) that an abnormal state has occurred.
I do.

[0007]

By the way, in the above-described operation detecting device 10 for a protection device, when any one of the protection devices operates, only the notification that an abnormality has occurred is issued, and which protection device is activated. There is a problem in that it is not possible to determine whether or not has operated, and the user cannot take an appropriate response.

An object of the present invention is to provide an operation detecting device for a protection device, which can easily determine which protection device has operated when the protection device operates.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 electrically connects in series a plurality of open-close type protective devices for individually protecting a plurality of objects to be protected,
In the operation detecting device of the protection device for detecting the operation of the protection device based on the detection voltage applied via the series circuit, the operation detection device of the protection device has different resistance values and is connected in parallel to each of the switching protection devices. A plurality of resistance elements, a photocoupler for generating a pulse signal having a width corresponding to the detection voltage, a waveform shaping means for shaping the waveform of the output signal of the photocoupler, and the pulse width of the pulse signal And a determination unit that determines the operation of the protection device.

[0010]

According to the first aspect of the invention, all the protective devices are closed in the normal state when the protective device does not work, and a predetermined voltage is applied to the photocoupler through the series circuit formed by the protective device. To be done. The current flowing by this detection voltage is transmitted by the photocoupler in an electrically insulated state by an optical signal. A pulse signal having a pulse width corresponding to the input voltage is output to the output of the photocoupler.

When an abnormality occurs and one of the protection devices opens, a resistance element in parallel with this protection device is inserted in the current path. The detected voltage value changes (decreases). The value of this detection voltage appears as a change (decrease) in the pulse width by the photocoupler, but the resistance value of the resistance element differs for each protection device, so the change in the pulse width of the pulse signal is determined by the determination means. Then, it is possible to determine which protection device has operated.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described with reference to the drawings.

FIG. 1 shows a schematic circuit diagram of an operation detecting device of a protective device for an air conditioner of an embodiment.

The operation detecting device includes fan motors F1 and F2.
And bimetal S provided on the compressors C1 and C2
Protective device 1 consisting of 1, S2, S3 and S4, photo coupler 3 for transmitting a detection signal corresponding to the voltage applied to the protective device in an electrically insulated state, and waveform shaping of the output signal of photo coupler 3 And a waveform shaping circuit 4 for performing.
The output signal of the waveform shaping circuit 4 is sent to the CPU 5 and the operating state of the protective device is determined.

FIG. 2 shows an example of a detailed circuit of the operation detecting device. Fan motors F1 and F2 and compressors C1 and C
2 is provided with bimetals S1, S2, S3, and S4, which are connected in series between the two phases R and S of the three-phase alternating current (R, S, T) and function as protective devices.
Voltage dividing resistors R3, R4, R5, and R6 having different resistance values are connected in parallel to the bimetals S1, S2, S3, and S4.

A current limiting resistor R2 and an output resistor R1 for current / voltage conversion are connected between one end of the bimetal S2 and the S phase. A light emitting diode LED of the photocoupler 3 and a free wheeling diode D opposite to the LED are connected to both ends of the output resistor R1. The base of the transistor Q that forms the waveform shaping circuit 4 is connected to the collector of the light receiving transistor PD of the photocoupler 3. The output signal of the transistor Q is input to the CPU 5.

Next, the operation will be described with reference to FIGS. The bimetals S1, S2, S3 and S4 are assumed to be in the closed state when the corresponding protective device is not operating.

During normal operation, all bimetals S1 ...
S4 is in a closed state (on state), and the detection voltage divided by the resistors R1 and R2 is applied to the photocoupler through the series circuit of the bimetals S1 to S4. In this state, the resistors R3, R4, R5 and R6 are almost equivalent to the case where they are not connected. At this time, the light emitting diode LED of the photocoupler 3 is in the ON state while the detection voltage is higher than the forward voltage of the diode (about 1.4V).

As a result, the period in which the photodiode PD of the photocoupler 3 is in the ON state depends on the amplitude of the voltage divided by the resistors R1 and R2. This amplitude value changes the voltage division ratio according to the resistance value of the series circuit including any of the bimetals S1 to S4 and the resistors R3 to R6, and the amplitude of the detection voltage also changes, so the ON period of the photodiode PD also changes, and the photodiode PD By detecting the ON period (= pulse width) of the bimetal S1 turned OFF,
A protection device corresponding to any of S4 can be specified. For example, if the detected signal waveform is the waveform WW0 shown in FIG. 3 (a), the waveform P0 of the pulse signal output from the pulse signal generator 4 will be as shown in FIG. 3 (b). The width is W0.

On the other hand, when the protective device is in operation, one of the bimetals is in an open state (off state), so that the voltage applied to the light emitting diode LED constituting the photocoupler 3 is lowered and the generated pulse is generated. The pulse width of the signal becomes narrower than that during normal operation.

Specifically, for example, if the fan motor F1 is in an abnormal heating state and the bimetal S1 is in an open state (off state), it means that the resistor R3 is inserted in the circuit, and the detection signal waveform is as shown in FIG. Waveform WW shown in (a)
1, the waveform P1 of the pulse signal output from the waveform shaping circuit 4 is as shown in FIG. 3B, and the pulse width is W1 (W1 <W0).

Similarly, the pulse width W2 when the fan motor F2 is in the abnormal heating state, the pulse width W3 when the compressor C1 is in the abnormal heating state, and the pulse width W3 when the compressor C is in the abnormal heating state The width W4 is shown in Figure 4.
As shown in, the relationship of W0>W1>W2>W3> W4 is satisfied.

Therefore, by detecting the output pulse width of the waveform shaping circuit 4 by the CPU 5, it is possible to specify which protection device has operated and the bimetal has been turned off. Based on this specification result, the remote control is performed. It is possible to notify the user by displaying it on the display unit of the device.

Therefore, the user can accurately understand the cause of the operation of the protection device and take appropriate measures.

In the above description, the bimetals S1 to S4 are described as being in the closed state when the protective device is not operating, but conversely, when the protective device is not operating, the bimetal S1. It is also possible to configure .about.S4 to be in the open state.

In this case, since the pulse width of the pulse signal output from the waveform shaping circuit 4 is expanded by the operation of the protective device, which protective device is operated by detecting this expansion. Can be specified.

Further, in the above description, the case where any one of the protective devices operates has been described. However, even when a plurality of protective devices operate, the resistance (the above-mentioned resistance) corresponding to the operated protective devices is described. If the sum of the resistance values of the resistors R3 to R6) is set not to be equal to the resistance value of any of the resistors, there is one combination of resistance values corresponding to the sum of the resistance values. It is possible to specify the plurality of protection devices.

[0028]

According to the first aspect of the present invention, it is possible to specify the active protection device based on the change in the pulse width of the pulse signal and notify the user, and the user can perform the protection based on the notification result. It is possible to accurately grasp the cause of the operation of the device and take action.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an operation detection device of a protection device according to an embodiment.

FIG. 2 is a detailed circuit diagram of the operation detection device of the protection device of the embodiment.

FIG. 3 is an operation explanatory diagram (1) of the embodiment.

FIG. 4 is a diagram (2) illustrating the operation of the embodiment.

FIG. 5 is a schematic configuration diagram of an operation detection device of a conventional protection device.

[Explanation of symbols]

 1 Protective device 2 Detection unit 3 Photocoupler 4 Wave shaping circuit 5 CPU S1, S2, S3, S4 Bimetal R3, R4, R5, R6 Resistance

Claims (1)

[Claims] 1. A plurality of switching protection devices for individually protecting a plurality of protection targets are electrically connected in series, and the operation of the protection device is detected based on a detection voltage applied via the series circuit. In the operation detecting device of the protection device, a plurality of resistance elements having different resistance values and connected in parallel to each of the switching protection devices, and a photo signal generating a pulse signal having a width corresponding to the detection voltage are provided. A protection device comprising: a coupler, a waveform shaping means for shaping a waveform of an output signal of the photocoupler, and a discrimination means for discriminating an operation of the protection device based on a pulse width of the pulse signal. Motion detection device.