SYSTEM WITH ELECTRIC MOTOR AND SENSOR DATA TRANSMISSION

Description

[0001] The invention relates to a system, in particular a plant, with an electric motor.

[0002] It is generally known that an electric motor designed as a three-phase motor can be powered via a three-phase cable.

[0003] From the DE 199 57 064 A1 A cover for a motor connection box is known.

[0004] From the DE 10 2016 113 028 A1 A system for monitoring energy consumption in industrial plants is known.

[0005] From the WO 2009 / 109 245 A1 A motor system with a sensor and evaluation unit is known.

[0006] From the DE 10 2008 045 476 A1 A drive unit is known.

[0007] From the WO 2012 / 113 496 A2 An arrangement for determining the angular position of a shaft is known.

[0008] From the DE 10 2013 007649 A1 The closest known state of the art is a method for operating a system.

[0009] From the DE 10 2007 052445 A1 An electric motor with a junction box is known.

[0010] The XP055467154 is known to contain a Ferraris accelerometer.

[0011] The invention is therefore based on the objective of operating a three-phase motor in a simple manner with increased safety.

[0012] According to the invention, the problem is solved in the system according to the features specified in claim 1. Furthermore, the problem is solved by a method according to claim 13.

[0013] Important features of the invention in the system, in particular the installation, with electric motor are that the electric motor has a terminal box into which a three-phase cable is inserted and in which the stator winding, in particular the wire ends of the winding wire of the stator winding, of the electric motor is electrically connected to electrical conductors of the three-phase cable. wherein a data collector is arranged in the terminal box of the electric motor, which has a data storage device and which is electrically connected to at least one sensor arranged in and / or on the electric motor, wherein the data collector has an electronic circuit for modulating and demodulating voltage components.

[0014] The advantage here is that data acquired in, on, or near the electric motor can be modulated and evaluated and / or monitored by a computer connected via the internet to the signal electronics located in the control cabinet. Thus, the electric motor does not require a powerful computer; instead, it relies on a computer connected via the internet.

[0015] The advantages of the invention are therefore that no separate power supply to the motor is necessary, that only low costs are incurred for installation and / or maintenance, that simple installation is possible, that high system availability can be achieved, that the probability and / or number of defects and / or failures is reduced, and / or that the availability of operating data can be achieved.

[0016] According to the inventionThe sensor's measured values ​​of a physical quantity can be stored in the data memory and transmitted via modulation over the electrical conductors of the three-phase cable. The advantage here is that no separate additional lines are required to transmit the measured values ​​of the physical quantities to a powerful computer, which then evaluates and monitors the data using computationally intensive operations.

[0017] In an advantageous embodiment, values ​​of a physical quantity detected by the sensor can be stored in the data memory and transmitted via the electrical conductors of the three-phase cable to signal electronics located in a control cabinet. These electronics also include an electronic circuit for modulating and demodulating voltage components. The advantage of this is that contactless data transmission is possible, thus enabling simple condition monitoring.

[0018] In an advantageous embodiment, the signal electronics arranged in the control cabinet are comprised of a converter which is arranged in the control cabinet and is powered from an AC power supply network. wherein the signal electronics generate pulse-width modulated control signals for controllable semiconductor switches of the inverter, in particular wherein the inverter supplies the electric motor with three-phase current via the three-phase cable, wherein the frequency of the three-phase current is lower than the frequency of the voltage components, in particular lower than 1 kHz. It is advantageous that the signal electronics of an inverter can also be used to operate condition monitoring, wherein the recorded values ​​are first stored in the data memory of the data collector (6) and then the evaluation of the data is carried out.

[0019] According to the invention finds the modulation and demodulation of voltage components takes place in one or more first time periods, wherein the electric motor is not supplied in the first time period(s) and the data collector is supplied from an energy storage device of the data collector (6), wherein the inverter supplies the electric motor with three-phase current in one or more second time periods, where the first time interval(s) do not overlap with the second time interval(s). An advantage of this is that interference sources can be reduced in the first time intervals, since no motor current is present.

[0020] In an alternative, advantageous design, The modulation and demodulation of voltage components in the range of one or more zero crossings of a motor phase current takes place. An advantage of this is that at least on the motor phase supply line used for modulating the voltage components, no source of interference is present.

[0021] In an advantageous embodiment, the frequency of the voltage components is higher than the frequency of the three-phase current transmitted via the three-phase cable and / or higher than 1 kHz. An advantage of this is that data can be transmitted on the same electrical line on which power can also be supplied.

[0022] In an advantageous embodiment, the electric motor can be connected by means of the three-phase cable. directly from the AC power supply network provided wherein a switch, in particular a contactor, is arranged between the three-phase cable and the AC power supply network, wherein the signal electronics arranged in the control cabinet modulate voltage components onto the electrical lines or demodulate them from the electrical lines by means of the electronic circuit for modulating and demodulating voltage components and are connected to a computer for data exchange via a network, in particular the Internet, wherein the computer is suitable for evaluating the data stored in the data storage. It is advantageous that an electric motor directly powered by the supply network, i.e., not speed-controllable but operated at a constant speed, can be equipped with condition monitoring, in particular, can be monitored.

[0023] In an advantageous configuration, the frequency of the voltage components is higher than the frequency of the three-phase current supplied by the AC power grid. This is advantageous because interference is avoided, as a sufficiently large band gap can be achieved.

[0024] In an advantageous embodiment, the terminal box is formed integrally with a housing part of the electric motor, i.e., as a single unit, or is detachably connected. An advantage of this is that the data logger can be arranged in a protected location.

[0025] In a preferred embodiment, a further sensor, arranged outside the electric motor and the junction box, is connected to the data collector. The advantage here is that additional physical quantities can be monitored.

[0026] In an advantageous design, the data storage of the data collector the value of the temperature detected by a sensor arranged in the stator winding, the value of the mains frequency of the AC power supply network, in particular which is detected by a sensor arranged in the data collector for voltage detection, and / or a value representing the operating hours, in particular which is detected by a timer device that determines the time of the non-vanishing motor voltage supplied via the three-phase cable, The data is stored. An advantage of this is that operational data can be collected and analyzed, particularly monitoring for exceeding a specific threshold. Therefore, if the voltage supplied via the three-phase cable from the AC power supply network exceeds a threshold, an overvoltage can be detected, and a warning can be displayed, forwarded, or issued, especially by the computer connected via the network.

[0027] In a preferred embodiment, the additional sensor is an acceleration sensor. The advantage here is that it allows for simple monitoring of excessively high axial accelerations occurring on the rotor shaft.

[0028] Further advantages arise from the dependent claims. The invention is not limited to the combination of features of the claims. For those skilled in the art, further meaningful combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent, in particular from the problem statement and / or the problem arising from a comparison with the prior art.

[0029] The invention will now be explained in more detail with reference to schematic illustrations: In the Figure 1 The oblique view shows a schematically sketched system, in particular a plant, according to the invention.

[0030] As in Figure 1As shown, an electric motor 3 has a connection box, in particular a terminal box, to which a three-phase cable 7 is led, which is electrically connected to the stator winding inside the connection box.

[0031] The electric motor 3 is designed as a three-phase motor, in particular the stator winding is designed as a three-phase winding.

[0032] Furthermore, sensors 4, which are located outside the electric motor 3 and its terminal box 5, are connected by means of a respective cable to a data collector 6, which is located inside the terminal box 5.

[0033] The data collector 6 is designed as the first signal electronics, which has a data storage and an electronic circuit for modulating and demodulating voltage components whose frequency is higher than the frequency of the three-phase voltage supplied by the public supply network via a switch 8, in particular a contactor, and the three-phase cable 7.

[0034] Thus, data is transmitted by modulation from the data collector 6 via the three-phase cable 7 to a signal electronics unit 2 located in the control cabinet in which the switch 8 is also located.

[0035] The signal electronics 2 also features an electronic circuit for modulating and demodulating the higher frequency voltage components and additionally includes an interface connected to the Internet.

[0036] Within the electric motor 3, specifically within the stator winding, another sensor is arranged which detects temperature and is connected to the data collector via an electrical conductor. Furthermore, other sensors arranged within the electric motor 3 can also be connected to the data collector 6. In this way, a torque value and / or lateral force value and / or a rotational speed and / or an angular position of the rotor shaft of the electric motor 3 can also be detected and their values ​​transmitted to the data collector 6.

[0037] The data collector 6 can also perform an evaluation of the sensor signals. Naturally, the data collector 6 cannot perform computationally intensive evaluations, as it does not contain a powerful computer. However, simple operations are possible, such as averaging, calculating a moving average, low-pass filtering, and / or calculating differences and / or difference quotients. For example, a current angular velocity can be determined from the recorded angular position values ​​and then transmitted via modulation to the signal electronics 2 of the control cabinet, or via the signal electronics 2 to the internet 9, i.e., to an internet server.

[0038] Thus, a simple electric motor 3, which is powered directly from the public supply network, in particular not by an inverter or converter, can be equipped with condition monitoring, whereby further evaluation or at least essential parts of the evaluation and / or monitoring of the data can be carried out in a server of the Internet or a computer connected to it.

[0039] Thus, the computationally intensive evaluation of the physical quantities recorded by the sensor(s) can be easily performed on a powerful computer.

[0040] The data collector 6 is also electrically supplied from the three-phase power cable 7. Therefore, a separate power supply line for the data collector 6 is not necessary.

[0041] Preferably, the data collector 6 has a winding inductively coupled to at least one electrical conductor of the three-phase cable 7, wherein the voltage induced on the winding by the electrical conductor is supplied on the one hand to a low-pass filter and / or rectifier to generate a DC voltage which supplies the data collector 6, and on the other hand to a band-pass filter or high-pass filter whose characteristic frequency is above ten times the frequency of the public AC power grid, to extract a voltage component modulated onto the electrical conductor.

[0042] In this way, the data collector 6 can be supplied with a DC electrical voltage and data reception can be carried out, for example, above 1 kHz and demodulated by the three-phase cable 7.

[0043] Similarly, data is modulated onto the winding, whereby the data can then be received by the signal electronics 2 and transmitted from the same to a server of the Internet 9.

[0044] Alternatively, instead of galvanic isolation, a direct galvanic supply to the data collector 6 is also possible by supplying the data collector 6 directly from the electrical lines of the three-phase cable 7, which are laid in a terminal block and to which the stator winding of the electric motor 3 is also connected.

[0045] In further embodiments of the invention, the motor 3 is not supplied directly from the public AC power supply network via the three-phase cable 7, but via an inverter which is supplied from the public AC power supply network. The signal electronics 2 preferably function as the signal electronics of the inverter and generate pulse-width modulated control signals for controllable semiconductor switches of the inverter, wherein the signal electronics 2 is also connected to an internet server.

[0046] Thus, the recorded values ​​of physical quantities, such as temperature and / or torque, can be directly taken into account.

[0047] Preferably, the voltage components are not modulated onto the three-phase cable 7 at the same time as the power supply to the electric motor 3, but separately in time. Reference symbol list

[0048] 1 Control cabinet 2 Signal electronics 3 Electric motor 4 External sensors 5 Junction box 6 Data logger 7 Three-phase cable 8 Switch 9 Internet 10 Temperature sensor

Claims

1. System, in particular a facility, comprising an electric motor (3), the electric motor (3) having a junction box (5) into which a three-phase cable (7) is led and in which the stator winding, in particular the wire ends of the winding wire of the stator winding, of the electric motor (3) is electrically connected to electrical lines of the three-phase cable (7), a data collector (6) being arranged in the junction box (5) of the electric motor (3), said data collector having a data store and being electrically connected to at least one sensor (4) arranged in and / or on the electric motor (3), the data collector (6) having an electronic circuit for modulating and demodulating voltage components onto the electrical lines of the three-phase cable (7), the system being suitably configured such that values of a physical variable that are acquired by the sensor (4) are stored in the data store and are transmitted via the electrical lines of the three-phase cable (7) by means of the modulation, characterised in that the voltage components are modulated and demodulated in one or more first time intervals, the electric motor (3) not being powered in the first time interval(s) and the data collector (6) being powered from an energy store of the data collector (6), the converter being configured to supply the electric motor (3) with the three-phase current in one or more second time intervals, the first time interval(s) not overlapping with the second time interval(s).

2. System according to claim 1, characterised in that values of a physical variable that are acquired by the sensor (4) can be stored in the data store and can be transmitted, via the electrical lines of the three-phase cable (7) by means of the modulation, to signal electronics (2) which are arranged in a switchgear cabinet (1) and which likewise have an electronic circuit for modulating and demodulating further voltage components.

3. System according to claim 2, characterised in that the signal electronics (2) arranged in the switchgear cabinet (1) are comprised by a converter which is arranged in the switchgear cabinet (1) and which is fed from an AC voltage power grid, the signal electronics (2) being configured to generate pulse-width-modulated actuation signals for controllable semiconductor switches of the converter, the converter in particular being configured to supply the electric motor (3) with a three-phase current by means of the three-phase cable (7), the frequency of the three-phase current being less than the frequency of the voltage components, in particular less than 1 kHz.

4. System according to any of the preceding claims, characterised in that the frequency of the voltage components is higher than the frequency of the three-phase current transmitted by means of the three-phase cable (7) and / or higher than 1 kHz.

5. System according to any of the preceding claims, characterised in that the electric motor (3) is powered directly from the AC voltage power grid by means of the three-phase cable (7), a switch (8), in particular a mains contactor, being arranged between the three-phase cable and the AC voltage power grid, the signal electronics (2) arranged in the switchgear cabinet (1) modulating voltage components onto the electrical lines or demodulating voltage components from the electrical lines by means of the electronic circuit for modulating and demodulating voltage components, and being connected, over a network, in particular the internet (9), to a computer for data exchange, the computer in particular being suitably configured for evaluating the data stored in the data store.

6. System according to any of the preceding claims, characterised in that the frequency of the modulated or demodulated voltage components is greater than the frequency of the three-phase current made available by the AC voltage power grid.

7. System according to any of the preceding claims, characterised in that the junction box (5) is formed in one piece, i.e. in one part, with a housing part of the electric motor (3), or is detachably connected thereto.

8. System according to any of the preceding claims, characterised in that a further sensor (4) arranged outside the electric motor (3) and the junction box (5) is connected to the data collector (6).

9. System according to any of the preceding claims, characterised in that - the value of the temperature acquired by a sensor (4) arranged in the stator winding, - the value of the grid frequency of the AC voltage power grid, which in particular is acquired by a voltage acquisition sensor (4) arranged in the data collector (6), - a number of revolutions of the rotor shaft and / or - a value representing the operating hours, which in particular is acquired by a time determination means that determines the duration of the non-negligible motor voltage made available by means of the three-phase cable, is / are stored in the data store of the data collector (6).

10. System according to claim 9, characterised in that the number of revolutions of the rotor shaft, in particular since the electric motor (3) began to operate, is determined by evaluating the signal of a sensor (4) that acquires the number of periods of the voltage powering the electric motor (3), in particular since the electric motor (3) began to operate.

11. System according to claim 9, characterised in that the number of revolutions of the rotor shaft, in particular since the electric motor (3) began to operate, is determined from the counter status of a counter that counts the zero crossings of a phase current or of the motor current of the electric motor (3).

12. System according to any of claims 8 to 11, characterised in that the further sensor (4) is an acceleration sensor.

13. Method for operating a system, in particular a facility, comprising an electric motor (3) according to any of the preceding claims, characterised in that voltage components are modulated and demodulated in one or more first time intervals, the electric motor (3) being supplied, in one or more second time intervals, with electric power for generating mechanical torque, the first time interval(s) not overlapping with the second time interval(s).