MX2013009819A

MX2013009819A - Winding switching circuit and thermal protection for dual voltage hermetic induction motor of hermetic cooling compressor.

Info

Publication number: MX2013009819A
Application number: MX2013009819A
Authority: MX
Inventors: Flavio J H Kalluf; Alejandro Amauri De Espindola
Original assignee: Whirlpool Sa
Priority date: 2011-02-25
Filing date: 2012-02-24
Publication date: 2013-10-17
Also published as: CO6870007A2; WO2012113048A3; KR20140052975A; CN103503302A; JP2014508493A; WO2012113048A2; BRPI1101882A2; WO2012113048A8; SA112330301B1

Abstract

The present invention refers to a winding switching circuit and thermal protection for dual voltage hermetic induction motors used in hermetic cooling compressors, the circuit comprising two coils of the main winding (M1 and M2), an auxiliary winding (A), three switches (R1, R2 and R3) that are connected and disconnected based on the desired connections for each of the power arrangements (115V or 220V), a start-up relay (R) and thermal protection means that protect the two main windings (M1, M2) from overheating, and the circuit is operative in a first and in a second arrangements, where in the first arrangement, the first switch (R1) and the third switch (R3) are connected, the second switch (R2) is disconnected, and the first main winding (M1), and second main winding (M2) and the auxiliary winding (A) are connected in parallel; and in the second arrangement, the first switch (R1) and the third switch (R3) are disconnected, the second switch (R2) is connected, and the first main winding (M1) and the second main winding (M2) are connected in series and the auxiliary winding (A) is connected in parallel only to the second main winding (M2).

Description

WIRING CIRCUIT CIRCUIT AND THERMAL PROTECTION FOR MOTOR INDUCTION HERMETIC DOUBLE COMPRESSOR VOLTAGE HERMETIC COOLING FIELD OF THE INVENTION The present invention relates to a winding switch circuit and thermal protection for single phase double voltage induction motors, normally used in hermetic compressors for cooling, which allows the motors to operate within the entire voltage range between approximately 90 and 260 V.

BACKGROUND OF THE INVENTION The single-phase induction motors used in hermetic compressors for cooling, are normally designed to make it possible for them to be used in a limited voltage range. Typically, the design allows 10% of undervoltage to 10% overvoltage to be applied to the motor. This means that a motor designed for 115V should work without problems when an interval of 103V to 127V is applied to it. For voltage variations greater than 10%, it is not possible to use the same project, and a new winding arrangement must be used for this voltage.

Another factor that prevents the use of the same Ref.243485 project of winding circuit for a wide range of voltages, is the specification of the other electrical components such as capacitors, relays, thermal protectors, etc., which are normally adjusted to size to operate within a limited variation voltage, and may lose functionality when subjected to voltages outside this range.

The majority of energy concessionaires around the world supply low voltages of 115-127V (United States, Brazil and others) or 220-240V (Europe, China and others). This difference requires that electric motors be customized for each voltage.

Some arrangements for single-phase induction motors of the double voltage type that are capable of operating with voltages of 115-127V or 220-240V are already known in the state of the art.

The single-phase induction motors have a primary winding and a secondary winding through which circulate currents with a phase separation that drives and energizes the stator of the motor. In induction motors of the double voltage type, two primary windings Mi and 2 and a secondary winding A are used.

When a voltage of approximately 115V is applied to the motor, the two primary windings MI and M2 are connected in parallel, as shown in Fig. 1A, whereas for a power voltage of 220V, the two primary windings MI and M2 must be connected in series, as shown in figure IB. These circuit arrangements are based on the T-connection principle, shown in Figures 2? and 2B in 115V and for 220V arrangements. Accordingly, it is necessary to provide the circuit of the series connection for the parallel connection of the primary windings MI and M2, depending on the power voltage.

The T-connection is a simple way to ensure the viability of the voltage change of the electric motor without the need for different designs for voltages close to 115V and for voltages of approximately 220V. The main windings and the auxiliary windings are exactly the same for 115V and 220V, which makes it possible for the motor design to be standardized, eliminating the need to create codes and facilitating manufacturing logistics.

However, in motors for hermetic compressors, access to the compressor terminals is limited, being normally in the form of a hermetic 3-pin terminal. This prevents the application of T-connection circuits, since there is no possibility of independent access to the terminals of the MI and M2 windings, unless a new terminal with a greater number of pins is used.

In the T-connection known in the state of the art, it is even possible to use the same design of the main and auxiliary windings for the 115V or 220V power, other electrical components connected to the circuit, such as the relays, the capacitors and the thermal protector, which are different for each applied voltage.

There is thus no type of arrangement used to date in hermetic cooling compressors that can use the same array of electrical devices for 115V and 220V voltages, which requires specific arrangements for each voltage range, increasing the number of codes of engineering, adversely affecting the manufacturing, distribution and logistics of control.

Some prior art documents show alternatives to the winding circuit arrangement that carry out the interruption between the 115V and 220V arrangements.

Patent document JP61102189 describes a pump controlled by a motor with automatic interruption between voltages of 220V and 115V. The motor has an auxiliary circuit to adapt to the two voltages. The circuit has an auxiliary winding and two main winding combinations. When the power voltage is 115V, the relays are switched, such that the two combinations of the main windings are connected in parallel. When the power voltage is 220V, the relay is switched and places the two main windings connected in series. The switching between the 115V mode and the 220V mode is performed by a complete circuit of different relays. In all the arrangements shown in this patent document, the positive poles of the two main windings are directly connected to each other.

Patent document US5867005 describes a motor circuit that is also adapted to allow the motor to operate with 115V or 220V. The circuit has first and second main windings and an auxiliary connection with an auxiliary winding permanently connected in series with a capacitor. In a first arrangement with a lower input voltage, the first main winding and the second main winding are connected in parallel and a power voltage of approximately 115V is applied on the first main winding. In a second arrangement for the 220V input voltage, the first and second main windings are connected in series. A power voltage is applied to the first and second main windings. The circuit has an integrated circuit that functions as a switch connected to the main windings to perform this switching. In all the arrangements shown in this patent document, the positive poles of the two main windings are directly connected to each other. Therefore, this circuit arrangement has the disadvantage that the number of poles is not the same in the 115V and 220V arrangements.

Patent document GB632468 shows an improvement in single phase double voltage motors, where a main winding is divided into two windings, preferably all wound on the poles of the motor. An auxiliary winding is connected to the phase space in parallel with the main winding, and is also connected in series with a capacitor. In the connection for the 220V power voltage, the main windings are connected in series in relation to the power terminals, and the auxiliary winding is connected in parallel to the main winding. In the connection with the 115V power voltage, the main windings are connected together in parallel and in relation to the power terminals, and the auxiliary winding is connected in parallel to the main terminals. The change between the two connection arrangements is made by a current relay.

All the circuits described in these prior art documents are based on the T connection and use different connection arrangements between the windings, the relays and the capacitors to adapt the 115V and 220V power voltages.

However, none of the motors of the state of the art is a hermetic motor and therefore does not need to use the hermetic terminals, not offering the limitations of access to the pegs that exist in the case of hermetic motors of the type of the present invention. . further, the use of hermetic terminals with independent plugs for each branch of the main coil requires protection against overheating to be carried out separately for the two branches of the main windings. None of these circuits of the state of the art proposes the connection arrangements of winding circuit for inductive motors that also use their own thermal protectors for each winding that operate in the two arrangements (115V and 220V), and therefore these are susceptible to the damage caused by overheating. In the prior art documents engines that are not hermetic, the protection could be in series with the energy, therefore, these would not need two protectors connected between the other components of the motor windings circuit. The coupling of thermal protectors to the winding circuit ultimately increases their complexity and prevents winding between the 115V and 220V arrays.

OBJECTIVES OF THE INVENTION An object of the invention is to provide a winding switch circuit and thermal protection for double voltage induction motors that are suitable for use in hermetic compressors and susceptible to changing the 115V arrangement to the 220V arrangement by using them. electrical components and with independent thermal protection for the two main windings.

It is also an object of the invention to provide a winding switch circuit and thermal protection for double voltage induction motors which allows the induction motor to operate within the entire range of 90V to 260V.

BRIEF DESCRIPTION OF THE INVENTION The objects of the invention are achieved by means of a winding switch circuit and the thermal protection for two-phase, single-phase, hermetic induction motors of a hermetic cooling compressor, comprising: a first main winding with the negative pole connected to a first node and the positive pole connected to a second node, a second main winding with the positive pole connected to a third node, and the negative pole connected to a fourth node, a first switch connected between the second node and the third node, and a starter relay connected to the third node, an auxiliary winding with the positive pole connected to the starter relay and the negative pole connected to the fourth node, and the auxiliary winding is connected in parallel with the second main winding, a second switch connected between the third node and the first node, a third switch connected between the first node and the fifth node, and a voltage source connected between the second node and the fifth node; where the circuit is operative in a first and in a second arrangement, where the first arrangement is, the first switch and the third switch are connected, the second switch is disconnected, and the first main winding, the second main winding and the winding auxiliary are connected in parallel; in the second arrangement, the first switch and the third switch are disconnected, the second switch is connected, the first main winding and the second main winding are connected in series and the auxiliary winding is connected in parallel only to the second main winding, and the circuit comprises the thermal protection means that carry out the thermal protection of the first and the second main windings (MI, M2) in the first and in the second arrangements.

The circuit is operative in a voltage range between 90V and 260V, and preferably the first array operates in a voltage range closer to 115V and the second array operates in a voltage range closer to 220V.

The thermal protection means may comprise a simple three-phase thermal protector having three terminals, a terminal being connected to the positive pole of the first main winding, a terminal connected to the first switch and a terminal connected to the positive pole of the power supply.

Alternatively, the thermal protection means may comprise a first thermal protector connected between the positive pole of power supply and the second node, and a second thermal protector connected between a first switch and the second switch. Also alternatively, the thermal protection means comprises a first thermal protector connected between the positive pole of the first main winding and the second node, and a second thermal protector connected between the fourth node and the fifth node. Also alternatively, the thermal protection means comprises a first thermal protector connected between the negative pole of the power supply and the fifth node, and a second thermal protector connected between the fifth node and the terminal 5.

The thermal protection means can be placed internally of the shield of the circuit, in contact with the main windings, and be open when the temperature of the windings exceeds a threshold value, or even these can be placed externally of the shield of the circuit, and be opened when the compressor current exceeds a threshold value . The switches can be mechanically operated, and they can be electronic switches or they can be electromechanical relays controlled by means of an electronic circuit.

Preferably, the first and second main windings are divided into two equal parts, one on each side of the stator, being connected in series, containing the same number of windings per notch. Consequently, the magnetic flux generated by each half of each winding is balanced.

The winding circuit can be placed inside a hermetic shell of the compressor, which comprises a hermetic five-pin terminal, and the first pin is located at the positive pole of the first main winding; the second pin is coupled between the negative pole of the first main winding and the first node; the third pin is coupled between the positive pole of the second main winding and the third node; the fourth plug is coupled between the positive pole of the auxiliary winding and the starting relay; and the fifth pin is located between the fifth node and the fourth node.

BRIEF DESCRIPTION OF THE FIGURES The present invention will now be described in greater detail based on an exemplary embodiment shown in the figures. The figures show: Figures 1A and IB are diagrams of connections of a winding circuit in the arrangements for the 115V and 220V power voltages of the type used in the state of the art; Figures 2A and 2B are diagrams of the T connection arrangements according to the state of the art of power voltages of 115V and 220V; Figures 3A and 3B are diagrams of a first embodiment of the connections of the winding switch circuit and the thermal protection of the present invention in the arrangements for the 115V and 220V power voltage; Figure 4 is a schec view of the arrangement of the main windings of the circuit of the present invention in the induction motor; Figure 5 is a diagram of a second embodiment of the connections of the winding switch circuit and the thermal protection of the present invention for power voltages of 115V and 220V, with the use of a three-phase thermal protector for circuit protection; Figures 6 and 7 are diagrams of the third and fourth alternative embodiments of the connections of the winding switch circuit and the thermal protection of the present invention for power voltages of 115V and 220V, with the use of two thermal protectors dedicated to protect The circuit.

DETAILED DESCRIPTION OF THE INVENTION As can be seen in figures 1A and IB, the prior art circuits for single-phase double-voltage induction motors use three connection pins 1, 2 and 3, a main winding with two main windings MI and M2 which are connected between pins 1 and 3, and windings MI and M2 are connected in parallel for a power voltage of 115V and in series for a power voltage of 220V. The auxiliary winding represented by the two coil parts Al, A2 are connected between pins 2 and 3, in parallel with the main coil, either in the arrangement where the two main windings are in series or in parallel. In addition, in some cases, a simple thermal protector P is connected between the negative terminal of the power supply and the plug 3. This simple thermal protector allows only the thermal protection of the two main windings MI and M2. A starting relay R is connected in series with the auxiliary winding A before pin 2.

As mentioned in the description of the prior art, this arrangement of circuits requires that the auxiliary winding has different characteristics for energies of 115V or 220V, having to be changed from one arrangement to the other. This is because the full voltage of the power supply, which varies from 115V to 220V, is always applied to it.

Figures 3A and 3B show a first embodiment of the arrangements of the winding switch circuit and the thermal protection of the present invention respectively for power voltages of 115V and 220V. It should be noted that the same electrical components are used in both arrangements, and it is only the electrical connections between the components that are changed from one arrangement to another by means of the switches that open and close.

The circuit according to the present invention uses five connection pins 1, 2, 3, 4, 5 in a hermetic terminal, instead of only three pins used in the circuits of the state of the art. The circuit comprises a main winding with two windings MI and M2, and an auxiliary winding A. In FIGS. 3A and 3B, each winding of the main windings MI and M2 is represented by two independent winding parts Mla Mlb, M2a M2b, which represent the two poles of the engine. The winding of the auxiliary winding is also represented by the two independent windings Aa and Ab. The circuit also comprises a starting relay R and three switches Rl, R2 and R3 that are connected and disconnected based on the desired connections for each of the arrangements (power of 115V or 220V). In addition, the circuit comprises the thermal protection means that are connected to the other components of the circuit, such that they perform the same thermal protection against overheating of the first and second main windings MI, M2 in the 115V and 220V arrangements. The thermal protection means may be in the form of a simple three-phase thermal protector P or in the form of two independent thermal protectors Pl, P2.

In the circuit arrangements shown in figures 3A, 3B, 5, 6 and 7, the circuit points to which more than one device is connected, were identified as the nodes NI, N2, N3, N4 and N5, in order to facilitate the understanding of the connections of circuit.

The circuit operates essentially in two arrays that vary based on whether the switches Rl, R2, R3 are open or closed and that they can be observed in Figures 3A and 3B. However, the circuit connections described below are common to two preferred operation arrays.

The first winding of the main winding MI, represented by the independent windings Mla and Mlb, is placed with the negative pole connected to a first node NI and the positive pole connected to a second node N2. This first main winding is connected between pins 1 and 2, and the negative pole connected to pin 1, and the positive pole connected to pin 2.

The second winding of the main winding M2, represented by the independent windings M2a and 2b, is placed with the positive pole connected to a third node N3, and the negative pole connected to a fourth node N. The positive pole of the winding 2a is also connected to the plug 3 of the hermetic terminal.

The auxiliary winding A, represented by the independent windings Aa and Ab, is placed with the positive pole connected to the starting relay R and the negative pole connected to the fourth node N4. The starting relay R "is also connected to the third node N3, consequently, the auxiliary winding A is connected in parallel to the second main winding M2, pin 4 of the hermetic terminal is coupled between the starting relay and the positive pole of the winding Aa.

The first switch Rl is connected between the second node N2 and the third node N3. The second switch R2 is connected between the third node N3 and the first node NI. The third switch R3 is connected between the first node NI and the fifth node N5. The pin 5 is located between the fourth node N4 and the fifth node N5. The voltage source is connected between the second node N2 and the fifth node N5.

The connections identified above are used in the four embodiments of the invention described herein, and shown in Figures 3A, 3B, 5, 6 and 7, in the 115V and 220V power arrangements. It is only the connections with the thermal protection means that vary between each of the modalities.

In this first embodiment of the invention of Figures 3a, 3b, two independent thermal protectors, Pl and P2, are used. The first thermal protector Pl is connected between the second node N2 and the pin 1 of the hermetic terminal, being connected in this way to the positive pole of the first main winding. The second thermal protector P2 is connected between the fourth node N4 and the fifth node N5, being connected in this way to the negative pole of the second main winding M2 and of the auxiliary winding A.

In the 115 V power arrangement shown in Figure 3A, the first switch Rl and the third switch R3 are connected, and a second switch R2 is off. Since the third switch R3 is closed (connected), the nodes NI and N5 are connected to each other and the second thermal protector P2 is connected between the pins 2 and 5. Furthermore, the connected switch Rl forms a short circuit between the nodes N2 and N3 By means of this arrangement, the windings MI and M2 are in parallel. The auxiliary winding A is also in parallel with the main windings MI and M2. Since all the windings MI, M2 and A are connected in parallel between the nodes N2 and N5 (or the node NI that is shorted the node N5), to which the voltage source is also connected, so in this arrangement , all the windings are subjected to the same source voltage, normally of approximately 115V. In this arrangement, each thermal protector Pl and P2 will be protecting a branch of the main winding (PI protects MI and P2 protects M2). It can be noted that the poles of the main windings MI and M2 are not directly connected to each other, since the thermal protector Pl is connected between the two poles. Therefore, the number of poles is maintained equal in the 115V array as in the 220V power array.

In the connection for a 220V power, the changes in the connections between the circuit components are caused by the change in the state of the switches. Switches Rl and R3 are disconnected / open, and only switch R2 is connected / closed. In this way, nodes NI and N3 are short-circuited. Pin 2 of the hermetic terminal is then connected to the starting relay R and pin 3. Since the switch Rl is open, the nodes N2 and N3 are not connected to each other. In addition, with the third switch R3 open, the nodes Ni and N5 are disconnected from each other, such that the negative pole of the first main winding MI is no longer connected to the negative pole of the voltage source. Therefore, windings MI and M2 are connected in series. The auxiliary winding A remains connected to the pin 4 and the starting relay R, but since the switch Rl is open and the switch R2 is closed, the positive pole of the auxiliary winding A is thereafter connected, by means of the pin 4 and the starting relay R, at the point between the negative pole of the first main winding MI and the positive pole of the second main winding M2, more specifically at the third node N3, at the voltage dividing point between the windings MI and M2 . Therefore, the auxiliary winding is subjected to a voltage of approximately 115V, or an approximate value corresponding to the voltage divider of the two main windings MI and M2, which depends on the design of each winding. In this arrangement, since the switches Rl and R3 are disconnected, only the second node N2 is connected to the positive pole of the power supply, and consequently, the first thermal protector Pl is connected between the power supply and the positive terminal of the first MI main winding. The negative pole of the power supply is connected to the fifth node N5, to the thermal protector P2, to the plug 5 and at the end to the fourth node N4, all in series. The negative poles of the main winding M2 and the auxiliary winding A are also connected to the fourth node N4, and, therefore, are protected by the second thermal protector P2 connected in series with the fourth node N4. Therefore, the 220V power voltage is only applied to the series connection of the main windings MI and M2. The protectors Pl and P2 are connected in series with the windings MI and M2, both protecting the two at the same time.

The present invention also allows some alternative form of connection of the thermal protectors to the circuit, reaching the same objective independent protection for the two branches of the main windings of the motor in both 115V and 220V arrangements.

In the alternative arrangement shown in Figure 5, thermal protection is realized by the use of a simple three-phase thermal protector P having three terminals, such that a first terminal is connected to pin 1 of the hermetic terminal and to the positive terminal of the terminal. first main winding Mi, a second terminal is connected to the first switch Rl and a third terminal is connected to the positive pole of the power supply. This thermal protector can be located at the position of the second node N2. When the first switch Rl is closed in the power array with approximately 115V, the three-phase thermal protector is connected to the positive poles of the two main windings MI and M2. When the first switch Rl is open and the second switch R2 is closed, the thermal protector P is connected between the positive pole of the power supply and the positive pole of the first winding MI, and performs the protection of the two main windings MI and M2 which are connected in series by means of switch R2.

In another alternative arrangement of the invention shown in Figure 6, a thermal protection is made by using the two thermal protectors Pl and P2 dedicated to each voltage, with Pl set to size for the current of 115V and P2 adjusted to an appropriate size for the 220V current. The first thermal protector Pl is connected between the positive pole of the power supply and the second node N2, being also connected to the positive pole of the first main winding MI. A second thermal protector P2 is connected between a first switch R1 and the second switch R2, and may be located between the third node N3 and the second switch R2. Accordingly, when the switches are accommodated for the 115V connection, with the first and third switches Rl and R3 closed and the second switch R2 open, the protector P2 will be out of circuit, disconnected by the second switch R2, and the protector Simple circuit will be Pl, which will be in series with the power supply. In contrast, when the switches are arranged for the 220V connection (first and third switches Rl and R3 open and the second switch R2 closed), the protector P2 will be active and in series between the two main windings Mi and M2, and the protector Pl, although still in the circuit, will not have an active function because it is subject to a very low current for which it was adjusted to size.

In another alternative arrangement of the invention shown in Figure 7, the same principle as the arrangement of Figure 6 is used, but with the use of a protector Pl connected between the negative pole of the power supply and the node N5, and the second protector P2 which is connected between the fourth node N4 and the fifth node N5. In the 115V power arrangement, with the switches Rl and R3 closed, and the switch R2 open, the second thermal protector P2 protects the second main winding 2 and the second thermal protector Pl protects the first main winding MI. In the 220V power arrangement, with the switches Rl and R3 open, and the switch R2 closed, the first and the second thermal protectors Pl and P2 are connected in series and then with the first and second main windings MI and M2 and perform the thermal protection of both windings.

Although the above arrangements are appropriate for values close to 115V and 220V, the circuit is operational in the full voltage range between 90V and 260V.

The thermal protectors Pl and P2 can be placed internally of the shield of the circuit, in direct contact with the main windings MI and M2. The devices used as thermal protectors in this embodiment of the invention are sensitive to temperature, and due to their arrangement, they directly detect the temperature level of the windings, and open the circuit when this temperature reaches a certain threshold value, with which prevents overheating of the windings.

Alternatively, the thermal protectors Pl and P2 are located externally of the shell of the circuit, preferably being fixed on the external side of the compressor, with the shell. These thermal protectors work normally by monitoring the temperature of the shell and the compressor current, such that when the shell temperature and / or the compressor current exceeds a threshold value, the shields open and interrupt the circuit. In a preferred form, the compressor current passes through the internal circuit of the thermal protector, and heats a resistor that is placed below a bimetallic disk. When the current is lower, the heating of the resistance is also lower, and therefore, it is not sufficient to heat the bimetallic disk. However, when the compressor current increases and exceeds a threshold value which may correspond to the circuit overheating, the bimetallic disk is also heated further, and flexes, opening the circuit and interrupting the current.

According to the present invention, the switches Rl, R2 and R3 used in the circuit can be mechanically operated manual switches. Electronic switches can also be used, such as devices in solid state, which open or close depending on the value of the power voltage, or switches Rl, R2, R3 can be electromechanical relays controlled by means of an electronic circuit.

Figure 4 shows how the windings of the two main windings MI and M2 are placed in the motor, in the form of two independent winding parts, Mla Mlb, M2a M2b. Normally, these independent winding parts are wound in sequence, without interruption of the wire. However, according to the present invention, each winding MI, M2 of the main winding must be divided between two equal independent parts Mla Mlb; M2a M2b. The independent parts of the same winding contain the same number of windings per notch, are connected in series and are each connected on one side of the stator. Consequently, the magnetic flux generated by each half of each winding is balanced.

In this way, the first branch MI is subdivided into two parts, the first part Mla of the first winding which is placed on one side of the stator and the second part Mlb of the first winding placed on the opposite side of the stator. The two windings of the second branch are placed in the same manner, the first part M2a which is placed on the same side of the stator as the first part Mla of the first winding, and the second part M2b of the second winding placed on the same side of the stator as the second Mb part of the first winding. The auxiliary winding is not altered, and remains with the windings of each pole connected in series. This arrangement allows that there is no imbalance of flow between the poles of the stator, which can cause loss of operation and the creation of harmonic torsion moments.

One of the main advantages of the winding switch circuit and the thermal protection of the present invention is the possibility of using the same electrical devices, such as windings, starting relays, capacitors (not shown) and thermal protectors for voltages in the range from 115 to 127V as in the 220-240V range, facilitating maintenance, reducing component storage and reducing engineering code numbers, facilitating production and distribution logistics. In addition, this circuit allows the thermal protection of the main windings MI and M2 to be carried out separately for each of the windings and operating both for 115V as well as for 220V, only opening or closing the switches Rl, R2, R3, with the protectors which are placed internally or externally of the shell.

Having described an example of a preferred embodiment, it should be understood that the scope of the present invention encompasses other possible variations, being limited only by the content of the appended claims, the potential equivalents being included therein.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A winding switch circuit and the thermal protection for a hermetically sealed double-voltage induction motor of a hermetic cooling compressor, characterized in that it comprises: a first main winding with the negative pole connected to a first node and the positive pole connected to a second node, a second main winding with the positive pole connected to a third node, and the negative pole connected to a fourth node, a first switch connected between the second node and the third node, and a start relay connected to the third node, an auxiliary winding with the positive pole connected to the starting relay and the negative pole connected to the fourth node, and the auxiliary winding is connected in parallel with the second main winding, a second switch connected between the third node and the first node, a third switch connected between the first node and the fifth node, and a voltage source connected between the second node and the fifth node; where the circuit is operative in a first and in a second arrangement, where in the first arrangement, the first switch and the third switch are connected, the second switch is disconnected, and the first main winding, the second main winding and the winding auxiliary are connected in parallel; in the second arrangement, the first switch and the third switch are disconnected, the second switch is connected, the first main winding and the second main winding are connected in series and the auxiliary winding is connected in parallel only to the second main winding, and the circuit comprises the thermal protection means that perform the thermal protection of the first and second main windings in the first and in the second arrangements, each of the thermal protection means comprise a resistance.

2. The winding switch circuit and thermal protection according to claim 1, characterized in that the circuit is operative in a voltage range between 90V and 260V, and the first arrangement operates in a voltage range closer to 115V and the second arrangement operates in a voltage range closer to 220V.

3. The winding switch circuit and the thermal protection according to any of claims 1 and 2, characterized in that the thermal protection means comprise a simple three-phase thermal protector having three terminals, one terminal being connected to the positive pole of the first main winding, a terminal connected to the first switch and a terminal connected to the positive pole of the power supply.

4. The winding switch circuit and the thermal protection according to any of claims 1 and 2, characterized in that the thermal protection means comprise a first thermal protector connected between the positive pole of the power supply and the second node, and a second protector thermal connection between the first switch and the second switch.

5. The winding switch circuit and the thermal protection according to any of claims 1 and 2, characterized in that the thermal protection means comprise a first thermal protector connected between the positive pole of the first main winding and the second node, and a second protector thermal connection between the fourth node and the fifth node.

6. The winding switch circuit and thermal protection according to any of claims 1 and 2, characterized in that the thermal protection means comprises a first thermal protector connected between the negative pole of the power supply and the fifth node, and a second protector thermal connection between the fourth node and the fifth node.

7. The winding switch circuit and the thermal protection according to any of claims 1 to 6, characterized in that the thermal protection means are placed internally of the shield of the circuit, in contact with the main windings, and are opened when the temperature of the windings exceeds a threshold value.

8. The winding switch circuit and the thermal protection according to any of claims 1 to 6, characterized in that the thermal protection means are externally placed on the shield of the circuit, and are opened when the current or the temperature of the shell of the compressor exceeds a threshold value.

9. The winding switch circuit and the thermal protection according to any of claims 1 to 8, characterized in that the switches are mechanically driven.

10. The winding switch circuit and the thermal protection according to any of claims 1 to 8, characterized in that the switches are electronic switches.

11. The winding switch circuit and the thermal protection according to any of claims 1 to 8, characterized in that the switches are electromechanical relays controlled by means of an electronic circuit.

12. The winding switch circuit and the thermal protection according to any of claims 1 to 11, characterized in that the first and the second main windings are each divided into two independent winding parts, and connected in series, each winding part of the winding The same winding is placed on one side of the stator.

13. The winding switch circuit and the thermal protection according to any of claims 1 to 12, characterized in that it is placed inside a hermetic shell of the compressor, comprising a hermetic five-pin terminal, wherein: the first pin is located at the positive pole of the first main winding; the second pin is coupled between the negative pole of the first main winding and the first node; the third plug is coupled between the positive pole of the second main winding and the third node; the fourth plug is coupled between the positive pole of the auxiliary winding and the starting relay; Y the fifth pin is located between the fourth node and the fifth node.