JPS61153330A - Air conditioner - Google Patents

Abstract

PURPOSE:To protect a motor and the like from abnormal voltage when the titled air conditioner is connected to a power source different from the rated power source by a structure wherein an abnormal voltage detecting circuit is provided on the secondary side of a power transformer and, in addition, a protection circuit, which rejects the receipt of the signal from the operating part of an air conditioner, when said abnormal voltage detecting circuit detects any abnormal voltage. CONSTITUTION:If the plug 17 of a power cable 16 is connected to an AC power source different from the rated power source, an abnormal electric voltage is applied across the secondary side of a power transformer 2 and inputted through a rectifier 3 to a constant-voltage circuit 4. At this time, the constant- voltage circuit 4 outputs the rated voltage even when the input voltage is abnormal and puts a control circuit 5 into operating state. In addition, the abnormal voltage is inputted to an abnormal voltage detecting circuit 18, resulting in flowing the detecting signal in the base of the transistor of a protection circuit so as to turn ON the transistor Tr in order to bring a receiving circuit 10 out of actuation. Thus, the transformer 2, the rectifier 3 and the constant-voltage circuit 4 are also protected against the abnormal voltage.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an air conditioner, and particularly to an air conditioner that can protect equipment from abnormal voltage when the power cord is accidentally connected to a power source other than the rated power source. It is something.

[Technical Background of the Invention and Problems Therewith] A conventional circuit for driving and controlling devices such as a compressor and a fan motor of an air conditioner will be explained with reference to FIG.

A power transformer 2 is connected to an AC power source 1, and a rectifier 3 is connected to the secondary side of the power transformer 2 to rectify the secondary side AC voltage to DC, which is then passed through a constant voltage circuit 4, for example, 5
A DC voltage of v is applied to the control circuit 5.

As shown in FIG. 4, this control circuit 5 includes a microcomputer 6 operated by a constant voltage circuit 4, a display circuit 7. Temperature reading circuit 8. Consisting of a motor control circuit 9 and a receiving circuit 10, the receiving circuit 10 receives a transmission signal from the transmitting circuit 11 of the wireless remote controller, and transmits the signal to the microcomputer 6.
The display circuit 7 displays the received operating mode, etc., and the temperature, such as the room temperature, is input from the temperature reading circuit 8 to the microcomputer 6, and the display circuit 7 displays the temperature, and the status of the room temperature, etc. Depending on the indoor or outdoor 7? The motor control circuit 9 operates the motor, compressor, etc.

In the circuit shown in Figure 3, a surge absorber 12 and a noise filter 13 are connected between the primary side of the power transformer 2 and the AC voltage 1 to prevent surge voltage from being transmitted to the secondary side, and also to prevent overcurrent. A fuse 14 and a positive characteristic thermistor 15 whose resistance value becomes high when the 1Ti pressure current is constant are connected.

However, the plug 17 of the power cord 16 that connects to the AC power supply 1 has a T-shape (7) that can be used for both 100V and 200V, which may cause problems if an air conditioner operated at 100V is accidentally connected to 200V. arise.

In other words, even if the constant voltage circuit 4 connected to the secondary side of the power transformer 2 is mistakenly connected to 200V, the rated voltage is still 5V.
outputs a DC voltage of , and therefore the control circuit 5 is operated,
When you press the operation button on the wireless remote control, the receiving circuit 10
This causes the microcomputer 6 to operate, the motor control circuit 9 to operate, and a voltage of 200V to be applied to the fan motor and compressor, resulting in damage to the fan motor and the like.

In this case, fuse 14 may be blown, or positive temperature coefficient thermistor 1 may be blown.
However, if the fuse 14 blows or the positive temperature coefficient thermistor 15 operates for a long time, the wireless connection will be disabled immediately after connecting to the 200V AC power supply. When operating the remote control, it is impossible to prevent the voltage of 200V from being applied to the fan motor etc. as described above.

[Object of the Invention] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an air conditioner that can protect equipment such as a fan motor from abnormal voltage when connected to a power source other than the rated power source. purpose.

[Summary of the Invention] In order to achieve the above object, the present invention provides an air conditioner that receives an operation signal from an operation section having a start/stop switch and operates according to the signal.
The device is characterized by comprising an abnormal voltage detection circuit that is connected to the secondary side of the power transformer and detects abnormal voltage, and a protection circuit that prevents reception of operation signals from the operation unit using an abnormal signal from the abnormal voltage circuit. If the power cord of the air conditioner is mistakenly connected to a power source other than the rated power source, the abnormal voltage detection circuit detects the abnormal voltage, transmits it to the protection circuit, and the protection circuit prevents operation from the control unit. By not accepting signals, the fan motor and compressor are prevented from operating, thereby protecting the equipment from abnormal voltages.

[Embodiment 1 of the Invention] A preferred embodiment of the air conditioner according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is an AC power supply, 2 is a power transformer connected to the AC power supply 1, 3 is a rectifier connected to the secondary side of the power transformer 2, 4 is a constant voltage circuit connected to the rectifier 3, and 5 7 is a control circuit for an air conditioner connected to a constant voltage circuit 4, and as explained in the conventional example shown in FIGS. 3 and 4, a microcomputer 6° display circuit 7. Temperature reading circuit 8. It consists of a motor control circuit 9 and a receiving circuit 10.

In addition, a surge absorber 12 is installed on the primary side of the power transformer 2.
and the noise filter 13 are connected and the fuse 1
4 and a positive temperature coefficient thermistor 15 are connected in series. Also, the power cord 16 has a plug 17 for connection to the AC power source 1.
is provided.

An abnormal voltage detection circuit 18 is connected to the secondary side of the power transformer 2 to detect abnormal voltage. This abnormal voltage detection circuit 1
8 consists of a comparator 19 that detects the input voltage and output voltage of the constant voltage circuit 4, for example.
A protection circuit 20 having a transistor Tr that is turned on and off by the output of the transistor Tr is provided. One input terminal of the comparator 19 receives the output voltage of the constant voltage circuit 4 through resistors R1 and R2.
A reference voltage v1 divided by the resistors R3 and R4 is input to the other end, and a comparison voltage v2, which is the input voltage of the constant voltage circuit 4 divided by the resistors R3 and R4, is input to the other end. Transistor of protection circuit 2o
A power supply line 21 for output voltage is connected to the collector side of the transistor Tr, and a receiving circuit 1o is connected to operate on this power supply line 21, and the emitter side of the transistor Tr is grounded.

The wireless remote controller 22 also has a transmitting circuit 11 for transmitting data to the receiving circuit 10, and the transmitting circuit 11 has a
It has an operation section 11a consisting of a switch that sends operation signals such as stop and temperature settings.

Next, the present invention will be explained in detail.

When the plug 17 of the power cord 16 is connected to a 200V AC power source other than the rated voltage (100V), the secondary side of the power transformer 2 becomes an abnormal voltage, which is input to the constant voltage circuit 4 via the rectifier 3. At this time, the constant voltage circuit 4 outputs a rated voltage (for example, 5V) even if the input voltage is abnormal, and the control circuit 5 becomes operational.

Further, the abnormal voltage on the secondary side of the power transformer 2 is input to an abnormal voltage detection circuit 18, and it is detected whether the voltage is abnormal. That is, the reference voltage 1 corresponding to the output voltage of the constant voltage circuit 4 is input to one side of the comparator 19,
A voltage v2 corresponding to the abnormal voltage is applied to the other side, and V2
>V+, the output signal of the comparator 19 flows to the base of the transistor T of the protection circuit 20, turning on the transistor Tr, and therefore, the power supply line 21 of the receiving circuit 10 is brought to approximately ground potential by the transistor Tr, so the receiving circuit 10 does not work, so wireless remote control 2
Even if an operating signal is transmitted from the transmission circuit 11 of No. 2, it is inactive and does not output the signal to the microcomputer 6. Therefore, the motor control circuit 9 explained in FIG. 4 is not activated, and the fan motor and compressor Abnormal voltage of 200μ is not supplied.

In addition, when connected to an abnormal power supply as described above, the voltages on the input side A and output side B of the constant voltage circuit 4 become as shown in Fig. 2, and after T1 time (approximately 10 seconds) has passed, the positive characteristic thermistor As a result of the increase in the resistance value of the power transformer 2, which lowers the current flowing into the power transformer 2, the voltage can be lowered after the elapse of time T1. Rectifier 3. The constant voltage circuit 4 can be protected from abnormal voltage.

As described above, since the control circuit that turns on and off devices such as fan motors is made inactive, the number of circuit parts can be reduced and the cost can be reduced.

Also, connect the plug 17 of the power cord 16 to the rated 100V AC.
When connected to the power supply, the input voltage V of comparator 19
Since l > V2 and no output is generated from the comparator 19, the transistor Tr is turned off, and therefore the receiving circuit 10 is supplied with the rated power from the constant voltage circuit 4 through the power supply line 21, and operates normally.

The fuse 14 and surge absorber 12 are designed to be able to withstand abnormal voltages sufficiently.

In the above-mentioned embodiment, an example was explained in which the operation is mainly controlled by a wireless remote control, but an air conditioner using a wired remote control may also be used. In this case, the receiving circuit 10 does not accept the transmission signal from the wireless remote controller, but the protection circuit 20 disables the microcomputer 6 due to the abnormal output of the comparator 19, even if the operating signal is not received from the operating section of the wired remote controller. It is preferable to configure the microcomputer 6 so that it does not receive the signal even if it is sent.

[Effects of the Invention] As is clear from what has been described in detail above, the present invention exhibits the following excellent effects.

By installing an abnormality detection circuit that detects abnormal voltage on the secondary side of the power transformer, and using the abnormality detection signal to disable the receiving circuit that receives the transmission signal from the wireless remote control,
This prevents damage to equipment such as fan motors even if you accidentally connect to a power source other than the rated one.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an embodiment of the air conditioner according to the present invention, Fig. 2 is a diagram showing the operating state of the positive temperature coefficient thermistor in Fig. 1, and Fig. 3 is a circuit diagram of a conventional air conditioner. , 4th
The figure is a circuit diagram showing details of the control circuit of FIG. 3. In the figure, 1 is an AC power supply, 2 is a power transformer, 10 is a receiving circuit, 18 is an abnormal voltage detection circuit, and 20 is a protection circuit. Agent Patent Attorney Noriyuki Chika (1 other person) Figure 1 Figure 2 U 7t Jikai Figure 3 Figure 4

Claims (1)

[Claims] Abnormal voltage that is connected to the secondary side of the power transformer and used to detect abnormal voltage in air conditioners that have a control circuit that receives operation signals from the operation part that has a start/stop switch, etc., and controls the operation according to these signals. An air conditioner comprising: a detection circuit; and a protection circuit that is connected to the abnormal voltage detection circuit and prevents operation signals from an operation unit from being accepted in response to an abnormal signal from the abnormal voltage circuit.