JPS61252464A - Air conditioner - 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] [Industrial Application Field] The present invention relates to an air conditioner equipped with an electric compressor that is driven by three-phase power and requires prevention of reverse rotation, and in particular to prevention of reverse rotation of the electric compressor due to incorrect wiring, etc. Concerning improvements in means.

[Conventional technology]

BACKGROUND ART Electric compressors used in air conditioners include, for example, reciprocating compressors in which a three-phase drive motor rotates in either forward or reverse direction without any problem. A reciprocating compressor allows refrigerant to flow in the forward direction even when the three-phase motor rotates in either the forward or reverse direction. However, this type of electric compressor has the drawbacks of a complicated structure, poor reliability, and high cost. Therefore, rotary type electric compressors and scroll type electric compressors are generally used frequently.

FIG. 5 is a refrigerant circulation system diagram in a conventional air conditioner using a rotary electric compressor. In Figure 5, 1
is a rotary electric compressor, 2 is a discharge pipe, 3 is a condenser,
4 is a pipe, 5 is a pressure reducer, 6 is an evaporator, and 7 is a suction pipe.

When the electric compressor 1 rotates in the forward direction, the refrigerant flows as indicated by the solid arrow. That is, the gas refrigerant at a temperature and high pressure discharged from the compressor 1 passes through the discharge pipe 2 and enters the condenser 3, where it is cooled and condensed to become a high-pressure liquid refrigerant. This high pressure liquid refrigerant is distributed! ! The refrigerant passes through the refrigerant 4 and enters the decompressor 5, where it is decompressed and becomes a low-pressure liquid/gas mixed refrigerant. This liquid/gas mixed refrigerant enters the evaporator 6 and is heated there, whereby the liquid refrigerant evaporates and becomes a low-pressure gas refrigerant. This low pressure gas refrigerant is sucked into the compressor 1 through the suction pipe 7.

By the way, when the electric compressor 1 rotates in the opposite direction, the refrigerant flows as indicated by the dotted arrow. Then, the high-temperature, high-pressure gas refrigerant flows into the evaporator 6, which is used for cooling.
It loses its ability to function as an air conditioner. When the electric compression tI11 continues to rotate in the opposite direction, this electric compression! 1
11 will be subjected to an abnormal load, leading to a failure.

FIG. 6 is an electric circuit diagram for driving a compressor of an air conditioner equipped with means for preventing reversal of the compression I11 by detecting the reverse phase of three-phase electric power in order to prevent the above situation from occurring. In FIG. 6, 11 is a three-phase electric motor for driving the compressor, 12 is a three-phase power supply terminal for supplying power to the three-phase electric motor, 13 is a negative phase detector connected to the three-phase power supply terminal, and 14. Reference numeral 15 denotes an electromagnetic contactor which is selectively energized by the switching contact 13G of the reverse phase detector and includes contacts 140.15G connected by wiring so that the phase order is reversed to each other.

Now, when the power supply wiring is arranged so that the phase order of the three-phase power supplied from the three-phase power supply terminal 12 is positive phase order R→S-+T..., the negative phase detector 13 is It doesn't work. Therefore, the switching contact 13C of the detector 13 is switched to the b side as shown in FIG. Therefore, in this case, the electromagnetic contactor 14 is energized and its contact 14C is in a closed state. Therefore, the three-phase motor 11
is supplied with power with a phase order of U+v→W... and rotates in the normal direction. Therefore, the compression 11!1 also rotates in the normal direction.

On the other hand, when the power supply wiring is arranged so that the phase order of the three-phase power becomes the reverse phase order T-8-R..., the reverse phase detector 13 is activated. Therefore, the switching contact 13C is switched to the a side, and the electromagnetic contactor 15 is energized. As a result, contact 15C closes and contact 14C opens. Therefore, the three-phase motor 11 is supplied with power in the phase order U→V→W as in the previous case. In this way, even if the phase order of the three-phase power supplied from the three-phase power supply terminal 12 is reversed, the combination of the reverse phase detector 13 and the electromagnetic contactor 14, 15 ensures that the three-phase motor 11 is always activated. Can be rotated forward, compression 1
111 can be rotated forward.

[Problem that the invention seeks to solve]

The conventional air conditioner having the above configuration has the following problems. That is, the terminals d, e, f at the contact point 14C of the electromagnetic contactor 14 and the terminal j at the contact point 15G of the electromagnetic contactor 15, the terminals U, V, of the three-phase motor 11 for I,
If W is incorrectly connected, the three-phase motor 11 will rotate in the opposite direction, potentially causing a failure. For example, if the connections between terminals U and ■ of the three-phase motor 11 have been swapped, and three-phase power is supplied from the three-phase power supply terminal 12 in the positive phase order of R-8 → T... Since the phase detector 13 does not operate depending on the above phase order, the electromagnetic contactor 14 is energized. As a result, three-phase power in positive phase order is about to be supplied to the three-phase motor 11 via the contact 14C. However, this three-phase power is not connected to the three-phase motor 1 due to the connection error.
To the terminal No. 1, the signals are supplied in the phase order W-+V-4U, . . . . As a result, the compressor 1 rotates in the opposite direction, leading to a risk of failure.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an air conditioner equipped with a reversal prevention means that can prevent malfunctions due to reverse rotation of an electric compressor even if there is incorrect wiring to a three-phase electric motor.

[Means for solving problems]

In order to solve the above problems and achieve the objects, the present invention is characterized by taking the following measures.

That is, the air conditioner of the present invention detects the rotation direction of the electric compressor by detecting the temperature or pressure of the refrigerant flowing through at least one of the suction piping and the discharge piping of the electric compressor using the rotation direction detection means, and The electric compressor is characterized in that the electric compressor is driven to rotate in the forward direction by the forward rotation driving means in accordance with the direction of rotation.

[Effect]

By taking the above measures, when the electric compressor starts to rotate in reverse, it is detected that the concentration, pressure, etc. information due to the reverse rotation is different from that during normal rotation, and the compressor is Forward rotation drive control will be performed.

[Embodiment] FIG. 1 is a refrigerant circulation system diagram according to a first embodiment of the present invention, and FIG. 2 is an electric circuit diagram for driving a compressor of the same embodiment.

Note that the same parts as in FIGS. 5 and 6 are given the same reference numerals, and detailed explanations of those parts will be omitted.

In FIG. 1, reference numeral 21 denotes a temperature sensor attached to the discharge pipe 2 of the compressor 1, which detects the temperature of the refrigerant flowing within the discharge pipe 2 and supplies a detection signal to the controller 22.

As shown in FIG. 2, the controller 22 operates in response to the detection signal and controls switching of a changeover switch 23 for selectively energizing the electromagnetic contactors 14, 15.

In this embodiment configured as described above, when an operation command is given to the controller 22, the first switching control signal is output from the controller 22, and the changeover switch 23 is switched to the b side.

Therefore, the electromagnetic contactor 14 is energized and its contact 14G is closed. Therefore, if there is no incorrect wiring etc., the three-phase motor 11
rotates in the normal direction, and the compressor 1 also rotates in the normal direction. As a result, the refrigerant flows as indicated by the solid line arrow in FIG. At this time, the discharge pipe 2
The temperature will be higher than before operation. This temperature is detected by a temperature sensor 21, and a detection signal thereof is supplied to a controller 22. Then, the controller 22 determines that the compression 11 is rotating in the forward direction, and no signal is output from the controller 22. Therefore, the changeover switch 23 is maintained at the b side.

On the other hand, if the electric compressor 1 rotates in the opposite direction due to incorrect wiring or the like, the refrigerant flows in the direction of the dotted line arrow in FIG. Then, the temperature of the discharge pipe 2 becomes lower than that before operation. This temperature is detected by a temperature sensor 21, and a detection signal thereof is supplied to a controller 22. Then controller 2
2, it is determined that the compressor 1 is rotating in reverse, and the controller 22 outputs a second switching control signal.

Therefore, the changeover switch 23 is switched from the b side to the a side. Therefore, the energization of the electromagnetic contactor 14 is cut off, and the energization of the electromagnetic contactor 15 is energized. Therefore, contact 14C opens,
Contact 15G closes. Since the contact 15C is wire-connected so that the phase order is opposite to that of the contact 14G, the three-phase motor 11 is supplied with three-phase power in the normal phase order. Therefore, the three-phase electric motor 1111 rotates in the forward direction, and the compressor 1 also rotates in the forward direction.

In this way, according to this embodiment, even if there is incorrect wiring to the terminals U, V, and W of the three-phase motor 11, reverse rotation of the compressor 1 can be prevented at an initial stage, and moreover, it is possible to immediately restore normal rotation. I can do it. In this embodiment, reverse rotation of the compressor 1 is detected by detecting the temperature of the refrigerant flowing through the discharge pipe 2, so it is not only possible to prevent reverse rotation due to incorrect connection to the terminals of the three-phase motor 11. Of course, it is also possible to prevent reverse rotation of the compressor 1 due to reverse phase of the power supply wiring.

FIG. 3 is a diagram showing the main parts of a refrigerant circulation system in a second embodiment of the present invention. This second embodiment differs from the first embodiment in that a temperature sensor 24 is attached to the suction pipe 7.

In this second embodiment, the temperature sensor 24
When it is detected that the temperature of the refrigerant flowing through the suction pipe 7 is lower than the temperature before operation, the compressor 1
is determined to be rotating in the forward direction, and when it is determined that the temperature is higher than before operation, it is determined to be rotating in the reverse direction. Thus, the switching control of the changeover switch 23 is performed in the same manner as described above, and the compression l1i1 can be rotated in the forward direction.

FIG. 4 is a refrigerant circulation system diagram showing a third embodiment of the present invention. This third embodiment is similar to the first embodiment. The difference from the second embodiment is that detectors 21 and 24 are attached to both the discharge pipe 2 and the suction pipe 7.

In this third embodiment, when the compressor 1 is rotating in the forward direction, the temperature of the refrigerant flowing through the discharge pipe 2 detected by the temperature sensor 21 is the same as that of the suction pipe detected by the temperature sensor 24. higher than the temperature of the refrigerant flowing through 7. Therefore, when a signal indicating the humidity difference is supplied to the controller, it is determined that the compressor 1 is rotating in the forward direction, and the changeover switch 2
3 is controlled to be held on the b side. Further, when the compressor 1 is rotating in the opposite direction, the temperature of the refrigerant flowing through the suction pipe 7 becomes higher than the temperature of the refrigerant flowing through the discharge pipe 2.

Therefore, when a detection signal indicating such a temperature difference is supplied to the controller 22, it is determined that the compressor 1 is rotating in reverse, and the changeover switch 23 is switched to the a side. By doing so, the same effects as in each of the embodiments described above can be achieved. Furthermore, even if there is little difference between the pipe temperatures before and after operation due to the influence of ambient temperature, etc., there will always be a temperature difference between the discharge pipe 2 and the suction pipe 7. This has the advantage that the direction can be detected more accurately.

Note that the present invention is not limited to the above embodiments.

For example, in the embodiment described above, a means for detecting the temperature of the refrigerant flowing in the piping was shown as a means for detecting the rotational direction of the compressor 1, but a pressure sensor is installed in place of the temperature sensor 21 or 24, The rotation direction of the compressor 1 may be detected by detecting the pressure of the refrigerant flowing through the compressor 1.

Furthermore, although the above embodiments show examples in which the present invention is applied to air conditioners, it is also applicable to heat pump machines and the like. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

The air conditioner of the present invention detects the rotation direction of the electric compressor by detecting the temperature or pressure of the refrigerant flowing through at least one of the suction piping and the discharge piping of the electric compressor using the rotation direction detection means, and The electric compressor is characterized in that the electric compressor is driven to rotate in a forward direction by a forward rotation drive means corresponding to the rotation direction.

Therefore, according to the present invention, when the electric compressor starts to rotate in reverse, it is detected that information such as temperature and pressure due to the reverse rotation is different from that during normal rotation, and the forward rotation drive control of the compressor is performed. will be carried out. As a result, it is possible to provide an air conditioner equipped with a reverse rotation prevention means that can prevent failures due to reverse rotation of the electric compressor even if there is incorrect wiring to the three-phase motor.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a refrigerant circulation system according to a first embodiment of the present invention, FIG. 2 is an electric circuit diagram for driving a compressor of the same embodiment, and FIG.
This figure shows the main parts of a refrigerant circulation system according to a second embodiment of the present invention, and FIG. 4 is a diagram showing a refrigerant circulation system according to a third embodiment of the present invention. FIG. 5 is a diagram showing a refrigerant circulation system of a conventional device, and FIG. 6 is an electric circuit diagram for driving a compressor of the conventional device. DESCRIPTION OF SYMBOLS 1... Electric compressor, 2... Discharge piping, 7... Suction piping, 11... Three-phase electric motor for driving the compressor, 13...
・Reverse phase detector, 14.15...Magnetic contactor, 21.2
4...Temperature detector, 22...Controller, 23.
...Selector switch. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 1 Figure 112 jI! Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In an air conditioner equipped with an electric compressor that is driven by three-phase power and requires reverse rotation prevention, the temperature or pressure of the refrigerant flowing through at least one of the suction piping or the discharge piping of the electric compressor is detected. An air conditioner comprising: a rotational direction detection means for detecting a rotational direction; and a forward rotation drive means for driving the electric compressor in a forward rotation in accordance with the rotational direction detected by the rotational direction detection means. Device.