JPH0458721A - Motor controlling device - Google Patents

Abstract

PURPOSE:To recognize an abnormal state without a substantial modification to detecting means even when the capacity of a motor is changed by always monitoring such physical states of the motor as temperature, vibration, rotating speed, etc., with the detecting means and receiving the data detected by the detecting means at a receiving section, and then, discriminating the presence/ absence of abnormality at a logical operation circuit. CONSTITUTION:The temperature, vibration, and rotating speed of a motor 2 are always detected with each sensor 17-19. The data detected by the sensors 17-19 are transmitted to the carrier input circuit 24 of a receiving section from a transmitting section 23 through a main circuit 3 and further given to a logical operation circuit 9. A comparator circuit 27 successively executes abnormality presence/absence discriminating operations by comparing the detected data inputted to the circuit 9 with reference values for discriminating abnormality stored in a storage circuit 14 and always monitors the status of the motor 2. Therefore, the actual status of abnormality can be recognized directly and, even when the capacity of the motor is changed, the extent of change to be given to the constitution of the sensors and controlling section can be made smaller.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to control and protection performed by opening and closing a switch such as an electromagnetic contactor interposed in a main circuit between a power supply bus and a motor. , and a motor control device having a monitoring function.

(Prior Art) As an example of this type of motor control device, a control center having a motor control and protection function is known. That is, in the control center, a plurality of units in which main circuit devices such as molded circuit breakers, electromagnetic contactors, and current converters are grouped into unit circuits are housed in multiple stages.
Each unit is provided with a display/operation panel including a start/stop indicator lamp, a start operation switch, a stop operation switch, etc. In addition, in recent years, in order to easily deal with changes in unit specifications,
By employing electronic application technology, configurations have also been created in which necessary functions among a plurality of control and protection functions can be set, added, or changed as appropriate.

In such conventional motor control devices, a current transformer is installed in the main circuit to detect the main circuit current, and a logical operation is performed to constantly compare the detected pressure signal with a reference value for abnormality determination. overloaded by.

When an abnormality such as an open phase is determined, a protective operation is performed to open the electromagnetic contactor, and at the same time, an abnormal state is displayed.

(Problem to be solved by the invention) However, in conventional devices, the electric motor is installed far away from the control device, so abnormal phenomena such as vibration, heat generation, or a drop in rotation speed caused by the electric motor are directly detected. It is difficult to accurately grasp the actual state of the abnormality because it cannot be confirmed and the abnormality in the main circuit current is indirectly determined. Furthermore, in the conventional device, when the capacity of the motor is changed, there is a problem in that the current transformer, which is the main circuit current detector, must also be changed to match the capacity.

Therefore, an object of the present invention is to directly monitor the state of the motor without detecting the state of the main circuit current, so that abnormal conditions can be accurately grasped, and even if the motor capacity is changed, the detection means can be exceptionally changed. The objective is to provide a motor control device that never fails.

[Configuration of the Invention (Means for Solving the Problems) A motor control device according to the present invention includes an electromagnetic contactor that opens and closes a main circuit between a power bus and a motor, and a control system that controls the operation and stopping of the electromagnetic contactor. An input circuit for inputting operation signals, a setting circuit for setting protection, monitoring and control functions to open the electromagnetic contactor in the event of an abnormality such as overload of the motor, and calculations necessary for performing these protection, monitoring and control functions. a logical arithmetic circuit that performs the following: a detection means attached to the electric motor to detect its physical conditions such as temperature and vibration; and a transmission that converts the detection data from the detection means into a high frequency and conveys it to the main circuit. and from the main circuit,
The receiving section receives the conveyed detection data, demodulates it, converts it into a digital signal, and supplies it to the logical operation circuit as data for determining the presence or absence of an abnormality.

(Operation) Normal operation and stop control of the electric motor is performed by inputting operation and stop operation signals to the input circuit using the operation switch. On the other hand, while the electric motor is in operation, physical conditions of the electric motor such as temperature, vibration, rotation speed, etc. are constantly monitored by the detection means, and the detected data is transmitted by the transmitter via the main circuit. The conveyed detection data is received by the receiver, converted into a digital signal, and given to the logical operation circuit, where an operation to determine the presence or absence of an abnormality is performed.If an abnormality occurs, a command signal is issued to open the electromagnetic contactor, and the details of the abnormality are sent. Outputs a display signal indicating.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG.

That is, this figure 1 shows the outline of the circuit configuration for one unit of the control center, and the three-phase power supply bus 1
The main circuit 3 between the motor 2 and the load is provided with a molded circuit breaker 4 and an electromagnetic contactor 5, which are main circuit devices, respectively. An operating transformer 6 is installed on the load side of the molded circuit breaker 4.
The primary side of the transformer 6 is connected to the transformer 6, and the control buses 7a and 7b are connected to the secondary side of the transformer 6.

The control section 8, which is supplied with power from the control buses 7a and 7b via a DC power supply circuit (not shown), is mainly composed of a logic operation circuit 9 composed of a microcomputer. This logic operation circuit 9 includes starting operation switches 10. Each ON signal from the stop operation switch 11 and the normally closed auxiliary contact 5a of the electromagnetic contactor 5 is received as a start and stop operation signal via the input circuit 12, and the operation coil 5b of the electromagnetic contactor 5 is connected to an output circuit. Power on/off control is performed via 13. The storage circuit 14 stores a control program and functional data for executing control operations such as instantaneous power failure restart and 1-time restart, and reference values for abnormality determination.

Executes protection operations and control operations based on functional data and various input signals. The setting unit 15 is composed of a large number of selection switches (not shown) so that the function data to be stored in the storage circuit 14 can be selected as desired at the installation site of the control center.

Next, to explain the parts directly related to the object of the present invention, the electric motor 2 is provided with a detection means 16, which consists of a temperature sensor 17, a vibration sensor 18, and a rotation speed sensor 19, which are directly attached to the electric motor 2. , among them, the temperature sensor 17 detects the winding temperature of the electric motor 2, the vibration sensor 18 detects the vibration of the electric motor 2, and the rotation speed sensor 19
is composed of, for example, a tacho generator, and is adapted to detect the rotational speed of the electric motor 2. These sensors 17-19
The analog state detection data output from the main circuit 3
The signal is then converted into a high frequency signal by a conversion circuit 21 of a receiving section 23 which is supplied with power via a transmission transformer 20. The detection data converted by the conversion circuit 21 is conveyed from the carrier wave output circuit 22 to the control section 8 via the main circuit 3. The transmitter 23 having the conversion circuit 21 and the carrier wave output circuit 22 is housed in a terminal box of the electric motor 2. On the other hand, the control unit 8 includes a carrier wave input circuit 24 as a receiving unit that receives the detection signal conveyed via the main circuit 3, a conversion circuit 25, and an A/D converter circuit 24.
A conversion circuit 26 is provided, which demodulates and digitizes the detected data and supplies it to the logic operation circuit 9. The control unit 8 is also provided with a comparison circuit 27 that compares the detection data input to the logical operation circuit 11 with a reference value, and an auxiliary output circuit 28 that outputs the comparison result to the outside for purposes such as alarms. . Here, although the carrier wave output circuit 22 and the carrier wave input circuit 24 for transmitting and receiving the carrier wave signal are not shown, they are connected to the conductor of the main circuit 3 via a capacitor or a high frequency transformer, and high voltage is applied to the electronic circuit. Care has been taken to ensure that it is not applied directly.

Next, the operation of the above configuration will be described. First, to describe the general control of the electric motor 2, when the start operation switch 10 or the stop operation switch 11 is operated, the logic operation circuit 9
receives these operation signals via the input circuit 12, performs judgment processing using logical operations, and outputs the excitation coil 5b to the output circuit 1.
Power supply/disconnection control is performed via 3. This opens and closes the electromagnetic contactor 5, thereby starting and stopping the electric motor 2.

Now, while the electric motor 2 is operating, the temperature condition, vibration condition, and rotation speed of this electric motor are constantly detected by each sensor 17 to 19, and the detected data is transmitted from the transmitting section 23 to the carrier wave input circuit 24 of the receiving section through the main circuit 3. Further, this detection data is given to the logical operation circuit 9. The comparison circuit 25 sequentially compares the detection data input to the logic operation circuit 9 with the reference value for abnormality determination stored in the storage circuit 14 to determine the presence or absence of an abnormality. The status is constantly monitored. In this monitoring state, motor 2
When an abnormality occurs, such as an abnormal rise in temperature due to an overload or the like, the comparator circuit 25 determines that the detected data value exceeds the abnormality determination reference value, and outputs the output circuit 13.
An open command signal is outputted to energize the operating coil 5b to open the electromagnetic contactor 5. At the same time, the auxiliary output circuit 2
An alarm signal is output to the outside via 6. Even when abnormal vibration or abnormally low rotational speed occurs in the electric motor 2, the electromagnetic contactor 5 is opened by the same operation as described above.

[Effects of the Invention] According to the present invention, as described above, the physical conditions such as the temperature and rotation speed of the electric motor are detected and used as detection data for monitoring the presence or absence of an abnormality, so that the actual state of the abnormality can be monitored. It is possible to directly understand and accurately understand the causes of abnormalities, making it easier to investigate the cause of the abnormality, and even if the capacity of the motor changes, the changes to the configuration of the sensor and control section are minor. An effective motor control device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram showing an embodiment of the present invention. In the figure, 2 is a motor, 3 is a main circuit, 5 is an electromagnetic contactor, 9 is a logic circuit, 12 is an input circuit, 14 is a memory circuit, 17 is a temperature sensor, 18 is a vibration sensor, 19 is a rotation speed sensor, 2
2 is a carrier wave output circuit, 24 is a carrier wave input circuit, and 27 is a comparison circuit.

Claims (1)

[Claims] 1. An electromagnetic contactor that opens and closes the main circuit between the power bus and the motor, an input circuit that inputs operation and stop operation signals to open and close the electromagnetic contactor, and an electromagnetic contactor that opens and closes the main circuit between the power bus and the motor, and an input circuit that inputs operation and stop operation signals to open and close the electromagnetic contactor, and when an abnormality such as overload of the motor occurs, the electromagnetic contactor A setting circuit that sets protection, monitoring, and control functions that open the circuit; a logical operation circuit that performs the calculations necessary to perform these protection, monitoring, and control functions, and a circuit that is attached to the motor and controls physical a detection means for detecting a state; a transmission section for converting detection data from the detection means into high frequency and transmitting it to the main circuit;
A motor control device comprising: a receiving section that receives detected data conveyed from the main circuit, demodulates it, converts it into a digital signal, and supplies it to the logical operation circuit as data for determining the presence or absence of an abnormality.