DK177646B1

DK177646B1 - A motor-system and a power-system for powering a motor-component

Info

Publication number: DK177646B1
Application number: DK201200381A
Authority: DK
Inventors: Niels Christian Weihrauch
Original assignee: Secop Gmbh
Priority date: 2012-06-04
Filing date: 2012-06-04
Publication date: 2014-01-27
Also published as: DK201200381A

Abstract

A single phase motor-system with a rotor adapted to be driven by a main winding (4) connected between a phase connector (2) and a zero connector (3) for connection of the motor-system to a single phase power supply. An auxiliary winding (5) powered by a start capacitor drives the rotor during startup. A potential relay (6) controls a relay-switch (7) which deactivates the start capacitor when a control voltage reaches a threshold. To avoid unstable, repeated, switching of the relay-switch, the relay according to the invention is located relative to the relay-switch such that switching of the relay-switch changes between a state where the control voltage depends upon the voltage over the auxiliary winding and a state where the control voltage is independent of the voltage over the auxiliary winding.

Description

i DK 177646 B1

A MOTOR-SYSTEM AND A POWER-SYSTEM FOR POWERING A MOTOR-COMPONENT

INTRODUCTION

The invention relates to an AC motor-system. Particularly, the invention relates 5 to an AC single phase motor-system with a rotor which is driven by a main winding connected between a phase connector and a zero connector such that it can be powered by a single phase power supply. The motor-system to which the invention relates further comprises an auxiliary winding which provides additional torque for starting the motor-system. The auxiliary winding is 10 powered via a start capacitor which provides a phase shift of the single phase from the power supply such that the torque increases. A potential relay controls a relay-switch which deactivates the start capacitor when the motor-system runs and the increased start torque is therefore no longer necessary. The potential relay changes position of the relay-switch - i.e. moves the relay-switch between 15 two positions depending on a control voltage over the relay. When the control voltage exceeds a threshold value, the relay moves the controlled relay-switch to a first position where the relay-switch disconnects the start capacitor.

The invention further relates to a motor-system in a compressor for a refrigeration application, to a power system for a motor component, and to a 20 method of controlling a motor.

BACKGROUND OF THE INVENTION

Fig. 1 illustrates diagrammatically a compressor motor known in the art. The potential relay 6 controls the relay-switch 7 and thereby activates or deactivates the start capacitor Cs based on a voltage across the auxiliary winding.

25 When power initially is supplied to the motor, the voltage across the auxiliary winding is low, and the potential relay is therefore in a non-activated and thus 2 DK 177646 B1 conducting, closed, relay-switch configuration shown in Fig. 1. In such a configuration of the relay, the auxiliary winding is connected via the start capacitor and provides a start torque.

As illustrated in Fig. 2, the voltage over the auxiliary winding (ordinate) 5 increases when the speed increases (abscissa). When the voltage reaches a disconnection threshold value, the potential relay moves the relay-switch to the non-conducting, open, switch configuration. This disconnects the start capacitor,

Cs, and operation of the motor continues without the start capacitor, i.e. the auxiliary winding is driven through a run capacitor, Cr, or in motors without a 10 run capacitor, the auxiliary winding is simply disconnected.

In a load point after the start, the run capacitor improves the efficiency of the motor which is the reason for using a run capacitor. The run capacitor is typically 5-10 times smaller than the start capacitor.

By definition herein, we will in the following use the wording activation to 15 describe the activity of the relay which controls a relay-switch to move to a position which leads to disconnection of the start capacitor and deactivation to describe the activity of the relay which controls a relay-switch to move to a position which leads to connection of the start capacitor.

For the sake of stability and to avoid repeated activation and deactivation, the 20 relay is designed with a hysteresis whereby the activation voltage is higher than the deactivation voltage. The hysteresis is illustrated by the four arrows which are connected and form a closed loop in Fig. 3.

If the motor is over-loaded, i.e. if the motor is loaded above breakdown torque, the voltage across the auxiliary winding will drop below the deactivation voltage 25 for the relay and cause the start capacitor to be connected. This is illustrated in Fig. 3 by the upwardly pointing arrow at low speed. The reinstatement of the start capacitor provides increased torque which thereby overcomes the load. As a result, motor speed and thus the voltage across the auxiliary winding increases until reaching the activation voltage and the start capacitor is 3 DK 177646 B1 therefore disconnected. This sequence will repeat itself, and the relay will activate and deactivate repeatedly e.g. with a frequency in the region of one Hz depending on the mechanical load of the motor.

Due to the repeated activation and deactivation, the auxiliary winding and the 5 start capacitor becomes operative as an over load condition. Typically, the motor is not designed to draw this increased power over longer periods of time, and the electrical system becomes overloaded. Particularly, motor windings and the cabling etc. are in risk of being damaged by excessive heating.

One document, GB 531374, describes an AC single phase motor system 10 including a start capacitor, where the motor system further comprises a potential relay controlling a relay-switch which deactivates the start capacitor when a control voltage reaches a threshold, wherein the relay is located relative to the relay-switch such that movement of the relay-switch between a closed and an open configuration changes between a state where the control voltage 15 depends upon the voltage across the auxiliary winding of the motor system, and a state where the control voltage is independent of the voltage across the auxiliary winding of the motor system.

The present invention introduces a system to ensure a stable switching of the relay-switch in that heavy loading of the motor system does not influence the 20 movement of the relay switch.

SUMMARY OF THE INVENTION

It is an object of embodiments of the invention to provide a motor-system and a power-system for a motor-component which prevent the above mentioned drawback of repeated activation and deactivation of the relay.

25 According to a first aspect, this object is solved by a motor-system where the relay is located relative to the relay-switch such that movement of the relay-switch from a second position to a first position changes the state of the motor-system between a state where the control voltage depends upon the voltage 4 DK 177646 B1 over the auxiliary winding to a state where the control voltage is independent of the voltage over the auxiliary winding.

Since the closing of the relay-switch becomes independent of the voltage across the auxiliary winding, the voltage across the relay becomes independent of the 5 rotor speed (RPM) of the motor-system, and heavy loading of the motor-system therefore doesn't influence the movement of the relay-switch. The relay-switch therefore remains in the first position until the motor-system is completely switched off, and the above mentioned drawbacks of repeated switching between a motor-system configuration where the auxiliary winding is operated 10 via a start capacitor and a motor-system configuration where the auxiliary winding is not operated via a start capacitor is avoided.

In practice, the start capacitor could be located between a first junction and a second junction, the auxiliary winding could be located between the second junction and the zero connector, and the control voltage could be determined 15 between a third junction and the zero connector.

If the relay-switch switches between a first and a second position, in the first position connecting the phase connector and the third junction and in the second position connecting the phase connector and the first junction, and if the second and third junctions are electrically connected by an element which provides 20 impedance, e.g. a run capacitor, the relay-switch, when being in the first position, ensures that the control voltage remains high independently on the load on the motor-system and potential over the auxiliary winding. Accordingly, the voltage over the relay becomes independent on the speed of the rotor (rpm), and heavy loading of the motor-system therefore doesn't influence movement of 25 the relay-switch. The relay-switch therefore remains in the first position until the motor-system is switched off, e.g. for compressor, when the motor-system is switched off by a thermostat in response to reaching a desired temperature.

If the element which provides the impedance is a run capacitor the invention offers a further advantage. Since the relay-switch does not connect both the run 30 capacitor and the start capacitor simultaneously, there will be no charging 5 DK 177646 B1 between the capacitors through the relay-switch, and the contacts in the relay-switch are not charged by the discharge current between the capacitors.

Accordingly, no bleed resistor is necessary.

The element which provides the impedance could also be a resistor or a PTC.

5 Herein the terms "start capacitor" and "run capacitor" refer to capacitors which operate during starting or running of the motor-system and which have a corresponding capacity, i.e. the start capacitor being large compared with the run capacitor.

Herein, the term "junction" covers any point of attachment between two entities 10 or electrical components as specified further in the claims. I.e. a junction between two entities or electrical components is simply that electrical conductor, wire, or cable which connects those two entities.

By way of example, the start capacitor is located between the first and the second junction and the auxiliary winding is located between the second junction 15 and the zero connector, the second junction thereby simply constitutes that electrical passage or connector existing between the start capacitor and the auxiliary winding.

The relay-switch which is controlled by the relay could particularly be of the kind having two positions, herein referred to as "two-position-switches" and which 20 conducts a current in both positions, i.e. a relay-switch which changes between conduction from a delivering branch to one out of two receiving branches. When used in electrical motors, such two-position-switches provides a benefit over a relay-switch which only conducts in one out of two possible positions since the relay-switch can separate e.g. a run and a start capacitor and only activate one 25 at the time without having to open or close e.g. a start capacitor while the run capacitor is active. This may effectively prevent discharging of one capacitor into another capacitor and the high currents caused by such discharging.

6 DK 177646 B1

Particularly, the motor-system may be for driving a compressor. Herein, the term "compressor motor" covers a motor for any kind of compressor. Particularly for a refrigeration compressor, particularly a single phase AC motor, e.g. of the kind which is encapsulated in a hermetic sealing shell with the compressor 5 structure which is driven by the motor.

A run capacitor may be connected between the phase connector and the second junction. In that way, the auxiliary phase will be driven via the run capacitor once the motor-system is started and the relay-switch is in the first position.

In the first position, the relay-switch may connect the third junction to the phase 10 connector via a fourth junction. Between the fourth junction and the third junction, the motor-system may comprise a run capacitor, e.g. a capacitor with a capacitance in the range of 1/1000 - 1/10 of the capacitance of the start capacitor.

As a consequence of the invention, the motor-system only has one single chance 15 of starting, i.e. if the motor-system has not completely entered a stable runmode when the relay is activated, it will not have a second chance to restart. To reduce this risk, a PTC could be connected between the third junction and zero connector.

Particularly, the PTC may be inserted such that it forms a voltage deviator for 20 the voltage over the auxiliary winding. As a consequence, the PTC, in cold condition, causes a voltage over the relay which is significantly lower than the voltage over the auxiliary winding. When the PTC becomes warm and changes to high resistance, the voltage deviation effect is reduced whereby the relay experiences essentially the same voltage as experienced by the auxiliary winding 25 via a run capacitor. As a result of the PTC, the relay stays deactivated for a longer period of time, namely for that period where the PTC is cold. The PTC therefore delays the shifting of the relay-switch.

7 DK 177646 B1

Due to the delay in the activation of the relay, the motor-system has a better chance of getting started, and the PTC therefore provides an improved support for starting the motor-system.

The PTC could be 5, 25, 47 or 56 ohm in cold condition, and the value should be 5 selected such that the relay activates shortly after the startup phase of the motor-system in a worst case condition (slow startup) is completely ended.

Due to the increasing voltage over the auxiliary winding with increasing rpm, the PTC will be self-perpetuating. When the motor-system is started, the voltage has increased and the PTC heats up very quickly due to the increased voltage, 10 whereby the resistance increases and the relay shifts. The PTC will remain hot when the motor-system runs, and therefore the PTC does not support resetting of the motor-system.

In an alternative implementation of the PTC, the PTC is inserted between the first junction and the phase connector. By this position of the PTC, the PTC 15 provides the desired delay in the activation of the relay in a different way.

When the power is turned on, the relay-switch is in the second position and the PTC is bypassed whereby no heating of the PTC occurs. Accordingly, the PTC is immediately ready for activation because it is in a cold condition and therefore provides a low resistivity.

20 When the relay-switch moves to the first position, the PTC starts conducting the current to the start capacitor, and heating of the PTC is initiated. This provides an added duration with the active start capacitor and therefore continued high start torque for the motor-system even though the relay is activated. The continued high starting torque last until the PTC becomes hot and shifts to the 25 high resistive mode.

This embodiment is particularly relevant when the motor-system has an internal safety-switch which means that it is located directly after a junction after the main and auxiliary windings. In this case, the PTC will become cold when the 8 DK 177646 B1 safety-switch deactivates the motor-system and the relay will not react.

However, the auxiliary winding will then be reactivated via the PTC.

Normally, motors of this kind comprise a safety-switch for disconnection in case of excessive currents. If the motor-system is over loaded, such a safety-switch, 5 herein referred to as the first safety-switch will become hot whereby the motor-system is stopped. According to the invention, the motor-system may comprise an additional resetting safety-switch, herein referred to as the second safety-switch. The second safety-switch may be located between the fourth and the third junction.

10 The first and second safety-switches may advantageously be provided such that they activate by essentially equal currents, e.g. within a deviation of less than 20 percent such that the second safety-switch opens at a current in the range of 80-120 percent of that current which opens the first safety-switch. Preferably, the second safety-switch must be more sensitive than the first safety-switch 15 since otherwise there is a risk that the second safety-switch never reaches a current level which can activate the second safety-switch. Accordingly, the second safety-switch may preferably be activated at a current below 100 percent of the current which activates the first safety-switch.

If the motor-system is blocked and never starts correctly, one situation may 20 occur where the first safety-switch activates prior to the activation of the second safety-switch namely, when the relay is not yet activated. Once the relay has activated, the first safety-switch should not open until after the second safety-switch has opened.

When the second safety-switch opens, the relay can no longer senses a potential 25 difference, and the relay-switch therefore moves to the second position whereby the auxiliary phase is operated via the start capacitor. Accordingly, the second safety-switch resets the position of the relay-switch to the second position in case of excessive currents. This will enable restarting of the motor-system with the auxiliary winding and start capacitor being activated.

9 DK 177646 B1

The relay may particularly be a potential relay of the kind comprising an anchor which is mechanically moved by a magnet field provided by a coil, and the motor-system may particularly form part of a compressor for a refrigeration system. However, the motor-system may be generally used for any purpose, 5 and the relay may not necessarily have to be an electromechanical relay but could also be an electronic relay.

In a second aspect, the invention provides a power system for powering a motor-component with a rotor adapted to be driven by a main winding connected between a phase connector and a zero connector for connection of 10 the motor-component to a single phase power supply, and adapted to be started by the help of an auxiliary winding being powered via a start capacitor which provides a phase shift of the single phase from the power supply, the power system comprising a potential relay controlling a relay-switch which is connectable to the motor-component such that it deactivates the start capacitor 15 when a control voltage over the relay exceeds a threshold, wherein the relay is located relative to the relay-switch such that movement of the relay-switch between a second position and a first position changes between a state where the control voltage depends upon the voltage over the auxiliary winding of a connected motor-component and a state where the control voltage is 20 independent of the voltage over the auxiliary winding of the connected motor-component.

In a third aspect, the invention provides a method of controlling a single phase compressor motor with a rotor adapted to be driven by a main winding connected between a phase connector and a zero connector for connection of 25 the motor to a single phase power supply, and adapted to be started by the help of an auxiliary winding being powered via a start capacitor which provides a phase shift of the single phase from the power supply, the method comprising the step of moving a relay-switch between a second and a first position thereby deactivating the start capacitor based on a control voltage between control 30 junctions, where the relay-switch is arranged relative to the control junctions such that movement of the relay-switch between the second and first position changes between a state where the control voltage depends upon a voltage over 10 DK 177646 B1 the auxiliary winding and a state where the control voltage is independent of the voltage over the auxiliary winding.

The power system and method according to the second and third aspects of the invention may further include any of the features or steps being compliant to 5 those features mentioned relative to the first aspect of the invention.

DETAILED DESCRIPTION

In the following, embodiments of the invention will be described by way of example with reference to the figures in which:

Fig. 1 illustrates a diagram of a prior art single phase motor; 10 Fig. 2 illustrates in a graph, voltage as a function of rotor speed (RPM);

Fig. 3 illustrates in a graph, torque as a function of rotor speed (RPM);

Fig. 4 illustrates a diagram of a motor-system according to the invention;

Figs. 5-9 illustrate diagrams of alternative embodiments of the invention.

Further scope of applicability of the present invention will become apparent from 15 the following detailed description and specific examples. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.

20 Fig. 1 illustrates a diagram of a single phase AC asynchronous motor 1 with an electrical potential relay. Such a motor exists already. The motor is connected to an AC power supply 2, 3. The motor comprises a main winding 4, an auxiliary winding 5, a run capacitor, Cr, a start capacitor, Cs, and an electrical potential relay 6 (PR) which controls the state of a relay-switch 7 which connects or 11 DK 177646 B1 disconnects the start capacitor. The relay 6 is inserted between opposite sides of the auxiliary winding 5 and therefore controls the relay-switch based on an electrical potential over that winding. The bleed resistor, BR, reduces the electrical potential between the run capacitor and start capacitor and thereby 5 protects the relay-switch 7 against excessive current and voltage. The protector 8 opens based on the current in both the auxiliary winding and main winding and disconnects the motor in case of excessive heating.

Fig. 4 illustrates a motor-system according to the invention. The motor-system comprises a rotor (not shown) which is driven by a main winding 4 connected 10 between the phase connector 2 and zero connector 3 for connecting the motor-system to a power supply.

The auxiliary winding 5 is powered by a start capacitor, Cs, and drives the rotor during startup. The potential relay 6 controls the relay-switch 7 based on a control voltage, herein being the voltage between the third junction 10 and the 15 zero connector 3, i.e. determined across the relay 6.

During start-up, the relay-switch 7 is in a second position (as shown in Fig. 4) in which it connects the first junction 8 with the phase connector 2. This is the situation illustrated in Fig. 4.

In the second position of the relay-switch, the voltage over the relay 6 depends 20 on the voltage over the auxiliary winding, and the relay can therefore deactivate the start capacitor when a control voltage over the relay and thus the voltage over the auxiliary winding exceed a threshold value. In Fig. 4, the voltage between the junction 10 and zero connector 3 corresponds essentially to the voltage over the auxiliary winding 5 since the run capacitor Cr provides a 25 connection between the junctions 9 and 10. Due to the low power consumption of the relay 6, the voltage drop over the run capacitor is insignificant.

Once the threshold value is reached, the relay 6 moves the relay-switch to a first position where it connects the phase connector 2 and the third junction 10. This deactivates the start capacitor. By this step, the relay-switch also separates the 12 DK 177646 B1 auxiliary winding 5 from the relay 6 - i.e. the relay operates based on the voltage between the junction 10 and the zero connector 3 and that voltage is independent of the voltage over the auxiliary winding between the junction 9 and the zero connector 3. Accordingly, the control voltage is independent of the 5 voltage over the auxiliary winding when the start capacitor and/or the auxiliary winding is/are deactivated.

In the embodiment shown in Fig. 4, the start capacitor is located between the first junction 8 and the second junction 9, the auxiliary winding 5 is located between the second junction 9 and the zero connector 3. The control voltage is 10 determined between the mentioned third junction 10 and the zero connector 3, and the second and third junctions are electrically connected by an element 11 which provides impedance. The element could, as illustrated be a capacitor, e.g. a run capacitor (Cr) as illustrated in Fig. 4, it could be a resistor, e.g. a PTC or any other element or group of elements which provides an electrical impedance.

15 When the relay-switch 7 is in the illustrated second position, the relay 6 is maintained by the voltage provided through the run capacitor. When the relay-switch moves from the second position to the first position, the relay is continuously supplied by the run capacitor until the relay-switch reaches the first position whereby the relay 6 is supplied directly from the phase connector 2.

20 Fig. 4 further illustrates a first safety-switch 12 which is located between the zero connector 3 and the fifth junction 13.

In Fig 5, the motor-system from Fig. 4 includes a second safety-switch 15. In this embodiment the relay-switch 7, in the first position, connects the phase connector 2 and the third junction 10 via a fourth junction 14, and the second 25 safety-switch 15 is located between the fourth junction 14 and the third junction 10.

Fig. 6 illustrates an embodiment where the first safety-switch 12 is moved into the internal structure of the motor-system, i.e. in Fig. 5, the safety-switch is located between the zero connector 3 and the fifth junction 13, whereas the 13 DK 177646 B1 safety-switch 12, in Fig. 6, is located between the sixth junction 16 and the fifth junction 13.

Fig. 7 illustrates an embodiment where a PTC 17 is inserted between the first junction 8 and the phase connector 2. When the power is turned on, the relay-5 switch is in the second position and the PTC is bypassed. When the relay-switch moves to the first position, the PTC starts conducting the current to the start capacitor, and heating of the PTC is initiated. This provides a continued high start torque for the motor-system until the PTC becomes hot and shifts to the high resistive mode.

10 Fig. 8 illustrates an embodiment with a run capacitor Cr inserted between the second junction 9 and the phase connector 2. In this embodiment, an additional capacitor 18 is inserted between the fourth junction 14 and the third junction 10. The additional capacitor 18 brings the voltage from the phase to the relay, and the additional capacitor thereby conducts the relay current.

15 Fig. 9 illustrates an embodiment where a PTC 19 is inserted between the third junction 10 and the zero connector. The advantage of this PTC is that the PTC, in cold condition, forms a voltage deviator. As a consequence, the voltage over the relay becomes very low when the PTC is cold. In this embodiment a run capacitor Cr is inserted between a seventh junction 20 and the second junction 9, 20 where the PTC 19 extends between the seventh junction 20 and the zero connector 3.

The PTC provides a delay in the activation of the relay 6 such that premature activation of the relay is prevented.

In any illustrated embodiments, Figs. 4-9, a bleed resistor may inserted to bleed 25 the charge of the start capacitor and thus reduce wear on the contacts of the relay-switch 7.

Claims

A single-phase alternating motor system with a rotor to be driven by a main winding (4) connected between a phase line (2) and a zero line (3) for connecting the motor system to a single-phase power supply, the motor system further comprising an auxiliary winding (5) for supplying increased torque when supplied with power from a starting capacitor (Cs), which delivers a phase change on the single phase from the power supply, and wherein the motor system further comprises a voltage relay (6) for controlling a relay contact (7) which deactivates the starting capacitor when a control voltage reaches a limit where the relay (6) is such that the relay contact (7) switches the relay contact between a second position and a first position between a state where the control voltage depends on the voltage over the auxiliary winding (5). ) and a state in which the control voltage is independent of the voltage across the auxiliary winding (5), characterized in that the starting capacitor (Cs) is disposed between a first joint (8) and a second joint (9), the auxiliary winding (5) is disposed between the second joint (9) and the neutral wire (3), the control voltage is determined between a third joint (10) and the neutral wire where it the second and third joints are electrically connected by an element (11) which supplies an impedance and the relay contact (7) is switched between a first and a second position, where in the first position it connects the phase line (2) to the third joint ( 10) and in the second position connect the phase line and the first assembly (8).

An engine system according to claim 1, characterized by a further operating capacitor connected to the second assembly. DK 177646 B1 2

An engine system according to claim 1, characterized in that the element (11) is an operating capacitor (Cr).

An engine system according to any one of claims 1-2, characterized in that the element (11) provides an ohmic resistance.

An engine system according to any one of the preceding claims, characterized in that a safety switch (12) is arranged between the relay (7) and the neutral wire (3).

An engine system according to any one of the preceding claims, characterized in that the relay switch in a first position connects the phase line and the third assembly (10) via a fourth assembly (14) and the engine system further comprises a second safety switch (15), which is placed between the fourth assembly and the third assembly.

An engine system according to any one of the preceding claims, characterized in that a PTC (17) is arranged between the first assembly (8) and the phase line (2).

An engine system according to any one of the preceding claims, characterized in that a first safety switch (12) is arranged between the auxiliary winding (5) and the neutral wire (3).

An engine system according to claim 8, characterized in that the relay contact in a first position connects the phase line and the third assembly (10) via a fourth assembly (14) and the motor system comprises an additional capacitor (18) disposed between it. the fourth collection and the third collection. DK 177646 B1 3

An engine system according to any one of the preceding claims, characterized in that an operating capacitor (Cr) is arranged between the second assembly (9) and the phase line (2).

An engine system according to any one of the preceding claims, characterized in that a PTC (19) is inserted between the third assembly (10) and the neutral wire (3).

An engine system according to claims 1 and 11, characterized in that the element (11) supplying an impedance is interposed between a seventh assembly (20) and the second assembly (9) where PTC (19) extends. between the seventh assembly (20) and the zero lead (3).

A motor system according to any one of the preceding claims, characterized in that the voltage relay comprises an anchor which is mechanically moved by a magnetic field supplied by a coil.

A motor system according to any one of the preceding claims, characterized in that the motor system is part of a compressor for a refrigeration system.

A power supply system for supplying a motor component with a rotor driven by a main winding connected between a phase line and a zero line for connecting the motor component to a single-phase power supply, and which is started by providing auxiliary winding with power via a starting capacitor, which causes a phase shift of the single phase from the power supply, whereby the power supply a voltage relay, such as the controller relay contact, which can be connected to the motor component in such a way that it deactivates the starting capacitor when a control voltage across the relay exceeds a limit whereby the relay is positioned to the relay contact, that a movement of the relay contact between a second and a first position DK 177646 B1 4 switches between a state where the control voltage depends on the voltage across the auxiliary winding of a connected motor component and a state where the control voltage is independent of the voltage across the auxiliary winding in it. connected motor component, characterized in that the starting capacitor (Cs) is arranged between a first assembly (8) and a second assembly (9), the auxiliary winding (5) is arranged between the second assembly (9) and the zero wire (3), the control voltage being determined between a third assembly (10) and the zero wire, wherein the second and third assemblies are electrically connected by an element (11) supplying an impedance, and the relay contact (7) alternates between a first and a second position, position connects the phase line (2) and the third joint (10), and in the second position connects the phase line and the first joint (8).

A method for controlling a single-phase compressor motor with a rotor driven by a main winding connected between a phase line and a zero line for connecting the motor to a single-phase power supply, and which is started by means of an auxiliary winding supplied via a starting capacitor, which causes a phase shift of the single phase from the power supply, where the starting capacitor (Cs) is disposed between a first assembly (8) and a second assembly (9), the auxiliary winding (5) is disposed between the second assembly (9) and the zero wire (3 ), the control voltage is determined between a third junction (10) and the zero wire, whereby the second and third junctions are electrically connected by an element (11) supplying an impedance and whereby the relay contact (7) alternates between a first and a second position. wherein in the first position it connects the phase conduit (2) and the third joint (10) and in the second position the phase conduit and the first joint (8), characterized in that the method comprises switching the relay contact between a second and a first position, thereby deactivating the starting capacitor on the basis of a control voltage

5 DK 177646 B1 between control assemblies where the relay contact is arranged in relation to the control assemblies such that the switching of the relay contact between the second and the first position switches between a state where the control voltage depends on a voltage across the auxiliary winding and a state where the control voltage is independent of the voltage. over the auxiliary winding.