JP3248033U - Three-phase compressor with built-in double protector - Google Patents

Abstract

A three-phase compressor with built-in double protectors is provided, which protects the three-phase compressor with two built-in protectors, thereby improving the immediacy and reliability of three-phase compressor protection and reducing overall installation costs.
SOLUTION
The three-phase compressor with built-in double protector includes a compressor motor, a first protector and a second protector. The compressor motor includes a first phase end, a second phase end, a third phase end, a first winding, a second winding and a third winding, the first winding is connected to the first phase end, the second winding is connected to the second phase end, the third winding is connected to the third phase end, and the first winding, the second winding and the third winding are connected to a neutral point. The first protector and the second protector are disposed on the compressor motor, the first protector is connected to the first winding and the second protector is connected to the second winding, and when the first protector or the second protector overheats, the first protector or the second protector respectively forms an open circuit.
[Selected Figure] Figure 1

Description

This invention relates to a three-phase compressor, and in particular to a three-phase compressor with a built-in double protector.

Referring to FIG. 4, a conventional three-phase compressor 100 is provided with an external protection circuit, which includes a controller 101, an electromagnetic switch 102, a thermal protector 103, and a timer 104. The electromagnetic switch 102 is installed in the controller 101 and electrically connects the thermal protector 103 and the timer 104. The controller 101 controls whether the power supply 200 supplies power to the three-phase compressor 100 by opening and closing the electromagnetic switch 102. In order to prevent damage to the three-phase compressor 100 due to motor stall or power shortage, the thermal protector 103 is usually installed in the housing of the three-phase compressor 100 and senses whether the housing temperature of the three-phase compressor 100 is too high.

If the temperature of the housing of the three-phase compressor 100 becomes too high, the metal sheet inside the thermal protector 103 is deformed by the temperature, creating an open circuit inside the thermal protector 103, turning off the power to the electromagnetic switch 102 in the controller 101, and cutting off the power supply path through which the power supply 200 supplies power to the three-phase compressor 100 via the controller 101, preventing the three-phase compressor 100 from burning out due to abnormal operation.

The internal components of the conventional thermal protector 103 are not protected by an inert gas and are not completely sealed, so the contact points of the internal components of the thermal protector 103 are prone to combustion or explosion due to arc leakage. For safety reasons, the thermal protector 103 cannot be installed inside the three-phase compressor 100 and must be installed in the housing of the three-phase compressor 100.

However, since it takes time for the heat generated by the internal operation of the three-phase compressor 100 to be conducted and convected to the housing and is easily affected by the environment, when the thermal protector 103 is triggered by high temperature, the three-phase compressor 100 is often already damaged, and it is difficult to immediately respond to an abnormal situation of the three-phase compressor 100, so the sensitivity and reliability of the conventional protection mechanism are not good.

Meanwhile, the electromagnetic switch 102 in the controller 101 cannot automatically turn on the power supply, and the timer 104 must be installed separately. The timer 104 controls the electromagnetic switch 102 to turn on again after a waiting time has elapsed after the electromagnetic switch 102 is turned off, and the power supply 200 supplies power to the three-phase compressor 100 again. The conventional electromagnetic switch 102 and the thermal protector 103 usually require 10 to 30 minutes to restart, which is likely to affect the immediacy of subsequent resumption of use of the three-phase compressor 100. In addition, the number of components of the protection circuit connected to the three-phase compressor 100 is relatively large, and the installation cost is relatively high.

Referring to FIG. 5, a conventional three-phase protector 300 includes a first pin 310, a second pin 320, a third pin 330 and a temperature-sensitive elastic sheet 340, the first pin 310 is connected to a first contact 341 of the temperature-sensitive elastic sheet 340 via a pin contact 311, the second pin 320 is connected to a second contact 342 of the temperature-sensitive elastic sheet 340 via a pin contact 321, and the third pin 330 is directly connected to the temperature-sensitive elastic sheet 340, and the first pin 310, the second pin 320 and the third pin 330 are electrically connected via the temperature-sensitive elastic sheet 340. When the temperature-sensitive elastic sheet 340 is deformed by temperature, the temperature-sensitive elastic sheet 340 bends, disconnecting the first contact 341 of the temperature-sensitive elastic sheet 340 from the pin contact 311 of the first pin 310, and disconnecting the second contact 342 of the temperature-sensitive elastic sheet 340 from the pin contact 321 of the second pin 320, causing the first pin 310, the second pin 320, and the third pin 330 to form an open circuit between each other.

However, in order to bend the temperature-sensitive elastic sheet 340 at both the first contact 341 and the second contact 342, the overall size of the temperature-sensitive elastic sheet 340 becomes large, and the size and cost of the three-phase protector 300 cannot be further reduced. Because the size of the temperature-sensitive elastic sheet 340 is large, a higher temperature is required to cause deformation of the temperature-sensitive elastic sheet 340. Therefore, the three-phase protector 300 can only be used in large electromechanical devices with an operating current of 18 amperes (A) or more, and is generally not applicable to a three-phase compressor 100 that uses a commercial power source.

This shows that there is still room and need for improvement in the protection mechanisms of conventional three-phase compressors 100.

In view of this, the present invention provides a three-phase compressor with built-in double protectors that protects the three-phase compressor with two built-in protectors, improving the immediacy and reliability of three-phase compressor protection and reducing overall installation costs.

In order to achieve the above object, the three-phase compressor with a built-in double protector of the present invention includes a compressor motor, a first protector, and a second protector, and includes a first phase end, a second phase end, a third phase end, a first winding, a second winding, and a third winding, the first winding is connected to the first phase end, the second winding is connected to the second phase end, and the third winding is connected to the first phase end, the first winding, the second winding, and the third winding are connected in a Y-shape, and the first winding, the second winding, and the third winding are connected to the neutral point of the compressor motor, the first protector is attached to the compressor motor and connected to the first winding, and when the first protector overheats, the first protector forms an open circuit, and the second protector is attached to the compressor motor and connected to the second winding, and when the second protector overheats, the second protector forms an open circuit.

In the three-phase compressor with built-in double protector of the present invention, the two protectors installed inside the compressor motor provide a three-phase protection function to the compressor motor, and when the internal temperature of the compressor motor rises due to an abnormality, an open circuit is formed, preventing the compressor motor from continuing to operate improperly and protecting the compressor motor. Compared to conventional thermal protectors, the two protectors are installed on the compressor motor and can provide a protection function in response to temperature changes in the compressor motor with more immediacy and reliability, and the present invention does not require the installation of separate components such as timers and electromagnetic switches, which helps reduce installation costs.

1 is a circuit diagram of a three-phase compressor incorporating a double protector according to a first embodiment of the present invention; FIG. FIG. 4 is a circuit diagram of a three-phase compressor incorporating a double protector according to a second embodiment of the present invention; FIG. 2 is a partial cross-sectional view of the protector of the present invention. FIG. 1 is a circuit block diagram of a conventional three-phase compressor and its protection circuit. FIG. 1 is a partial cross-sectional view of a conventional three-phase protector.

Referring to Figures 1 and 2, the three-phase compressor 1 with a built-in double protector 11 of the present invention includes one compressor motor 10 and two protectors 11, and the three-phase compressor 1 is powered by a three-phase power supply provided by a power supply 2. The compressor motor 10 includes a first phase end R, a second phase end S, a third phase end T, a first winding U, a second winding V, and a third winding W, and the power end of the first winding U is connected to the first phase end R, the power end of the second winding V is connected to the second phase end S, and the power end of the third winding W is connected to the third phase end T. The first winding U, the second winding V, and the third winding W are connected in a Y-shape, and the load end of the first winding U, the load end of the second winding V, and the load end of the third winding W are connected to the neutral point N of the compressor motor 10, and the neutral point N can be further connected to a load by a neutral line. The first winding U is connected to the power supply 2 via the first phase end R, the second winding V is connected to the second phase end S, and the third winding W is connected to the third phase end T.

When the power supply 2 provides a three-phase power supply to the compressor motor 10, the current of the three-phase power supply flows from the first phase end R, the second phase end S, and the third phase end T to the first winding U, the second winding V, and the third winding W, respectively, and when the current flows through the first winding U, the second winding V, and the third winding W, a current magnetic effect occurs, forming a rotating magnetic field to operate the compressor motor 10.

For example, the phase angle difference between the first winding U, the second winding V, and the third winding W is all 120 degrees, so that the current of the three-phase power supply first flows from the first phase end R to the first winding U, and then, during phase commutation, the current of the three-phase power supply can be changed to flow from the second phase end S to the second winding V. When the phase is commutated again, the current of the three-phase power supply is changed to flow from the third phase end T to the third winding W, and a rotating magnetic field is generated in each of the first winding U, the second winding V, and the third winding W due to the different current flow directions, thereby rotating the rotor of the compressor motor 10. The above is a brief description of the operation process of the compressor motor 10, but the phase commutation and operation method of the compressor motor 10 are not limited to this embodiment.

The two protectors 11 are installed inside the compressor motor 10, and the two protectors 11 are each connected to one of the first winding U, the second winding V, and the third winding W, i.e., the first winding U, the second winding V, and the third winding W are each connected to the protector 11, and when the two protectors 11 overheat, the two protectors 11 form an open circuit. Here, the two protectors 11 may each be a single-phase protector. In the embodiment of FIG. 1 and FIG. 2, the two protectors 11 are a first protector 11A and a second protector 11B, and the first protector 11A is electrically connected to the first winding U and the second protector 11B is electrically connected to the second winding V, but the first protector 11A may be electrically connected to the first winding U and the second protector 11B may be electrically connected to the third winding W. Alternatively, the first protector 11A is electrically connected to the second winding V and the second protector 11B is electrically connected to the third winding W, but is not limited to this embodiment. The embodiment of FIG. 1 and FIG. 2 only shows that two of the first winding U, the second winding V, and the third winding W are each connected to a protector 11, and does not limit the connection phase of the two protectors 11.

In the embodiment of FIG. 1, the first protector 11A is electrically connected between the first winding U and the first phase end R, and the second protector 11B is electrically connected between the second winding V and the second phase end S. In the embodiment of FIG. 2, the first protector 11A is electrically connected between the first winding U and the neutral point N, and the second protector 11B is electrically connected between the second winding V and the neutral point N. The first protector 11A and the second protector 11B provide three-phase protection to the compressor motor 10.

In addition, in a preferred embodiment, the first protector 11A is electrically connected between the first winding U and the first phase end R, and the second protector 11B is electrically connected between the second winding V and the neutral point N. Alternatively, the first protector 11A is electrically connected between the first winding U and the neutral point N, and the second protector 11B is electrically connected between the second winding V and the second phase end S.

Referring to FIG. 3, each of the protectors 11 of the present invention may include an insulating housing 12, a sealed shell 13, a first pin 14, a second pin 15, and a temperature-sensitive elastic sheet 16. The insulating housing 12 covers the sealed shell 13, and the first pin contact 141 of the first pin 14, the second pin contact 142 of the first pin 14, the pin contact 151 of the second pin 15, and the temperature-sensitive elastic sheet 16 are arranged in the sealed shell 13, isolating the first pin contact 141 of the first pin 14, the second pin contact 142 of the first pin 14, the pin contact 151 of the second pin 15, and the temperature-sensitive elastic sheet 16 from the external environment, preventing the internal members from being affected by the external environment, and the sealed shell 13 is filled with an inert gas to prevent the sealed shell 13 from arcing or burning.

The first pin contact 141 of the first pin 14 is electrically connected to the second pin contact 142 via the seal inner shell 13. One end of the temperature-sensitive elastic sheet 16 is fixedly connected to the second pin contact 142 of the first pin 14, and the other end of the temperature-sensitive elastic sheet 16 is in contact with and connected to the pin contact 151 of the second pin 15, so that the first pin 14 and the second pin 15 are electrically connected via the temperature-sensitive elastic sheet 16.

The temperature-sensitive elastic sheet 16 deforms and bends when heated, and one end of the temperature-sensitive elastic sheet 16 is fixed to the second pin contact 142 of the first pin 14. Therefore, when the two protectors 11 overheat, the temperature-sensitive elastic sheet 16 of the two protectors 11 is heated and bent, and the other end of the temperature-sensitive elastic sheet 16 is tripped from the pin contact 151 of the second pin 15, forming an open circuit between the temperature-sensitive elastic sheet 16 and the second pin 15, and as a result, forming an open circuit between the first pin 14 and the second pin 15. Here, the temperature-sensitive elastic sheet 16 takes only 10 to 30 seconds to return to its normal state after deformation, which is useful for quickly restarting the compressor motor 10.

When the first protector 11A is connected between the first phase end R and the first winding U as shown in FIG. 1, the first pin 14 of the first protector 11A can be connected to the first phase end R, and the second pin 15 of the first protector 11A can be connected to the first winding U. If the current flowing through the first winding U is too large, the temperature-sensitive elastic sheet 16 in the first protector 11A is deformed by heat, forming an open circuit between the first pin 14 and the second pin 15 in the first protector 11A, generating an open circuit between the first phase end R and the first winding U, preventing abnormal overcurrent from continuing to flow from the first winding U to the compressor motor 10 and avoiding damage to the compressor motor 10. In addition, the first pin 14 of the first protector 11A may be connected to the first winding U, and the second pin 15 of the first protector 11A may be connected to the first phase end R, without affecting the operation of the first protector 11A.

Similarly, when the second protector 11B is connected between the second phase end S and the second winding V as shown in FIG. 1, the first pin 14 of the second protector 11B can be connected to the second phase end S, and the second pin 15 of the second protector 11B can be connected to the second winding V. If the current flowing through the second winding V is too large, the temperature-sensitive elastic sheet 16 of the second protector 11B is deformed by heat, forming an open circuit between the first pin 14 and the second pin 15 of the second protector 11B, and generating an open circuit in the second phase end S and the second winding V.

2, when the first protector 11A is connected between the first winding U and the neutral point N, the first pin 14 of the first protector 11A can be connected to the first winding U, and the second pin 15 of the first protector 11A can be connected to the neutral point N. If the current flowing through the first winding U is too large, the temperature-sensitive elastic sheet 16 of the first protector 11A is deformed by heat, forming an open circuit between the first pin 14 and the second pin 15 of the first protector 11A, and generating an open circuit between the first winding U and the neutral point N.

Similarly, when the second protector 11B is connected between the second winding V and the neutral point N as shown in FIG. 1, the first pin 14 of the second protector 11B can be connected to the second winding V, and the second pin 15 of the second protector 11B can be connected to the neutral point N. If the current flowing through the second winding V is too large, the temperature-sensitive elastic sheet 16 of the second protector 11B is deformed by heat, forming an open circuit between the first pin 14 and the second pin 15 of the second protector 11B, and generating an open circuit between the second winding V and the neutral point N.

When the three-phase power supply supplies power to the compressor motor 10, current flows from one of the first winding U, the second winding V, and the third winding W, and then flows to the other winding. Therefore, by simply installing two protectors 11 on the first winding U, the second winding V, and the third winding W, various phase changes and abnormal conditions of the first winding U, the second winding V, and the third winding W can be covered.

For example, if a phase loss occurs at the first phase end R, the current in the first winding U connected to the first phase end R becomes zero, and the operation of the compressor motor 10 must be completed by the remaining second winding V and third winding W. If the current flowing through the second winding V and the third winding W is too large and the internal temperature of the compressor motor 10 becomes excessively high, making it prone to burnout, the temperature-sensitive elastic sheet 16 of the second protector 11B connected to the second winding V will deform due to heat, causing the second protector 11B to break.

When a phase loss occurs at the second phase terminal S, the current in the second winding V connected to the second phase terminal S becomes zero, and the operation of the compressor motor 10 must be completed by the remaining first winding U and third winding W. If the current flowing through the first winding U and third winding W is too large, the temperature-sensitive elastic sheet 16 of the first protector 11A connected to the first winding U will deform due to heat, causing the first protector 11A to break.

When a phase loss occurs at the third phase terminal T, the current in the third winding W connected to the third phase terminal T becomes zero, and the operation of the compressor motor 10 must be completed by the remaining first winding U and second winding V. If the current flowing through the first winding U and the second winding V is too large, the temperature-sensitive elastic sheet 16 of the first protector 11A connected to the first winding U and the temperature-sensitive elastic sheet 16 of the second protector 11B connected to the second winding V will deform due to heat, causing the first protector 11A and the second protector 11B to break, respectively.

In addition, a phase loss is only one of the operational abnormalities caused by the compressor motor 10. When the three-phase power supply is not balanced, the voltage of the three-phase power supply is too high or too low, an abnormality in a load device connected to the compressor motor 10 occurs, a winding is broken or damaged, a winding is short-circuited, a circuit pin is dropped, a mechanical failure occurs, or any of these may cause the internal current of the compressor motor 10 to become high or cause overheating due to abnormal operation, and the two protectors 11 instantly form an open circuit in response to a change in the internal temperature of the compressor motor 10, thereby providing a protective function for the compressor motor 10.

In a preferred embodiment, the three-phase compressor 1 of the present invention is applied to a refrigeration device and further includes a pressure switch, which is electrically connected to the neutral point N via a neutral wire and is used to detect the environmental pressure, and when the environmental pressure is greater than a preset value, the pressure switch forms an open circuit. For example, when the environmental pressure of the refrigeration device increases due to refrigerant leakage, in order to avoid damage to humans and equipment due to refrigerant leakage and to prevent each of the protectors 11 from being unable to accurately detect temperature changes and provide immediate protection to the compressor motor 10 due to refrigerant leakage, when the pressure switch detects that the environmental pressure is greater than the preset value, the pressure switch forms an open circuit, causes the refrigeration device to stop operating, and does not continue to leak refrigerant.

In summary, the present invention provides a three-phase compressor 1 with a built-in double protector 11, and the two protectors 11 installed inside the compressor motor 10 provide a three-phase protection function for the compressor motor 10. If an abnormality occurs in the compressor motor 10 and the internal temperature rises, the two protectors 11 immediately form an open circuit, preventing the compressor motor 10 from continuing to operate abnormally and protecting the compressor motor 10. Compared to conventional thermal protectors, the internal components of the two protectors 11 are arranged in the seal inner shell 13, which is safer and eliminates the risk of component burnout due to arc leakage. The two protectors 11 are arranged inside the compressor motor 10, which helps to take immediate protective action in response to temperature changes in the compressor motor 10, avoiding the situation where the compressor is often already damaged when the conventional thermal protector is triggered by high temperatures. In addition, the two protectors 11 are directly connected to the internal windings of the compressor motor 10, which eliminates the need to install additional components such as timers and electromagnetic switches, helping to reduce installation costs.

On the other hand, the two protectors 11 of the present invention are different from conventional three-phase protectors in that one end of the temperature-sensitive elastic sheet 16 of the two protectors 11 is fixed, and the temperature-sensitive elastic sheet 16 of the two protectors 11 can form an open circuit in the two protectors 11 with only minor deformation. Therefore, the size of the temperature-sensitive elastic sheet 16 in the two protectors 11 is smaller than that of the temperature-sensitive elastic sheet of a conventional three-phase protector, which requires both ends to be deformed simultaneously, and the relatively small size of the temperature-sensitive elastic sheet 16 of the two protectors 11 allows the two protectors 11 to be triggered to generate an open circuit without requiring an excessively high temperature change. The two protectors 11 can be applied to small electric machines that use commercial power and have an operating current of 0.5 to 15 A, that is, the two protectors 11 can be applied to three-phase compressors 1 that use commercial power sources that are common on the market.

REFERENCE SIGNS LIST 1 Three-phase compressor 100 Three-phase compressor 2 Power supply 200 Power supply 10 Compressor motor 11 Protector 11A Protector 11B Protector 12 Insulating housing 13 Sealed inner shell 14 First pin 15 Second pin 310 First pin 320 Second pin 330 Third pin 141 First pin contact 142 Second pin contact 151 Pin contact 311 Pin contact 321 Pin contact 16 Temperature-sensitive elastic sheet 340 Temperature-sensitive elastic sheet 101 Controller 102 Electromagnetic switch 103 Thermal protector 104 Timer 300 Three-phase protector 341 First contact 342 Second contact R First phase end S Second phase end T Third phase end U First winding V Second winding W Third winding N Neutral point

Claims (8)

a compressor motor, a first protector, and a second protector;
the first winding is connected to the first phase end, the second winding is connected to the second phase end, the third winding is connected to the first phase end, the first winding, the second winding and the third winding are connected in a Y-shape, and the first winding, the second winding and the third winding are connected to a neutral point of the compressor motor;
the first protector is attached to the compressor motor and connected to the first winding, and when the first protector overheats, the first protector forms an open circuit;
A three-phase compressor with a built-in double protector, wherein the second protector is attached to the compressor motor and connected to the second winding, and when the second protector overheats, the second protector forms an open circuit. A three-phase compressor with a built-in double protector according to claim 1, wherein the first protector is connected between the first phase end and the first winding, and the second protector is connected between the second phase end winding and the second winding. A three-phase compressor with a built-in double protector according to claim 1, wherein the first protector is connected between the first winding and the neutral point, and the second protector is connected between the second winding and the neutral point. A three-phase compressor with a built-in double protector according to claim 1, wherein the first protector is connected between the first phase end and the first winding, and the second protector is connected between the second winding and the neutral point. A three-phase compressor with a built-in double protector according to claim 1, wherein the first protector is connected between the first winding and the neutral point, and the second protector is connected between the second phase end and the second winding. the first protector and the second protector each include a first pin, a second pin, and a temperature-sensitive elastic sheet, the temperature-sensitive elastic sheet being connected between the first pin and the second pin;
2. A three-phase compressor with a built-in double protector as described in claim 1, wherein when the first protector and the second protector overheat, the temperature-sensitive elastic sheets in the first protector and the second protector thermally deform, forming an open circuit between the first pin and the second pin. A three-phase compressor with a built-in double protector as described in claim 1, wherein the first protector and the second protector are each single-phase protectors. The three-phase compressor with built-in double protector of claim 1 further includes a pressure switch connected to the neutral point of the compressor motor, and when the pressure switch detects an environmental pressure exceeding a preset value, the pressure switch forms an open circuit.