RU97014U1 - MOTOR PROTECTION DEVICE - Google Patents

Abstract

 1. A motor protection device, including current sensors installed on a power supply line of an electric motor, to which input circuits, an analog-to-digital converter, a block of protection algorithms, a block for calculating the current values of currents, a memory for settings, an indication and control unit are connected to a single circuit , a data exchange interface, characterized in that it further comprises at least a unit for measuring the starting characteristic of the electric motor and at least a unit for calculating settings for shield. ! 2. The device according to claim 1, characterized in that it is configured to connect at least to a computer for joint image on a computer screen in graphical form of the measured starting characteristic of the motor and protection thresholds at their current settings, as well as the ability to adjust thresholds protection from the computer while displaying the result of the adjustment.

Description

The utility model relates to the field of electrical engineering, namely to devices and components for protecting electric motors.

Currently, electrical protection devices for electric motors are known and used, consisting of a set of current sensors, an electronic protection circuit for signal processing of sensors that detect emergency situations, an actuator for turning off the electric motor in the event of an emergency, and means for setting protection parameters.

The well-known "Universal protection blocks of asynchronous motors UBZ-301", designed to constantly monitor the parameters of the mains voltage and the operating values of phase / linear currents of three-phase electrical equipment 380 V / 50 Hz, primarily asynchronous electric motors (ED) with power from 2.5 kW to 315 kW , including networks with isolated neutral. Three modifications of the device are available in current ratings: UBZ-301 5-50A; UBZ-301 10-100A; UBZ-301 63-630A, (see http: //www.novatekelektro.com/production_ubz.htm), a photocopy of the page is attached to the application materials, Appendix No. 1 (1).

Also known is the “Relay of control and protection (RCH)” (see http://rele.tomsk.ru/menu/product.html), (2).

Before use, the data of the UBZ-301 and RKZ devices must be configured in accordance with the parameters of the protected motor.

A common drawback of these devices and the technical solutions used in them is the inability to determine the best settings for the protection, since when setting them up there is no necessary information about the starting characteristics of a particular motor with a specific load. And this can lead to a false or untimely response of the defenses.

The goal to which the claimed technical solution is directed is to ensure the most reliable, accurate and timely detection of emergency situations when the motor is running.

The specified goal and technical result are implemented as follows. The proposed motor protection device includes, like the well-known UBZ-301 analogue, a set of current sensors installed on the electric power supply line of the electric motor, to which input circuits, an analog-to-digital converter, a block of protection algorithms, a block for calculating the effective values of currents are connected, settings memory unit, indication and control unit, data exchange interface and actuator.

But unlike the analogue, it additionally includes, for example, a block for measuring the starting characteristics of the electric motor and, for example, a block for calculating the settings of the protections.

The proposed motor protection device is configured to connect, for example, to a computer and a joint image on a computer screen in graphical form of the measured starting characteristic of the motor and protection thresholds at their current settings, as well as the ability to adjust settings from the computer while displaying the result of the correction.

The proposed motor protection device has the ability to connect, for example, to a specialized control panel for a joint image on the screen of the remote control in graphical form of the measured starting characteristic of the motor and protection thresholds at their current settings, as well as adjusting the protection thresholds from the remote control while displaying the result of the correction.

As the closest analogue to the proposed device, you can take the UBZ-301 electric motor protection device according to the source of scientific and technical information (1).

The list of figures in the drawings.

Figure 1 shows the structural diagram of the proposed device.

Figure 2 shows a typical starting characteristic of an electric motor and thresholds of motor protection algorithms.

The proposed motor protection device (figure 1) includes the following blocks and assemblies.

A set of current sensors 2, DT1, DT2, DT3, is connected to the electric power supply line of electric motor 1, which are connected via input circuits 3 to an analog-to-digital converter (ADC) 4. The ADC 4 is connected to a block of protection algorithms 5, to which a block for calculating the effective values of currents is connected 6. A block of settings memory 7 is connected to the block of protection algorithms 5, to which a block of calculation of protection settings 8 is connected, designed to automatically calculate the parameters of protection algorithms. The block of protection algorithms 5 is connected to the actuator 9, for example, a relay.

An indication and control unit 10 and a data exchange interface 11 are connected to a block for calculating the effective values of currents 6, and a measurement unit for starting characteristics of the electric motor 12 is connected to it. A block of protection algorithms 5 is also connected to an indication and control unit 10 and a data exchange interface 11, which in turn, they are connected with the protection settings calculation unit 8 and the settings memory unit 7.

The proposed motor protection device via the data exchange interface 11 can be connected, for example, to a computer or to an automated control system (ACS). Also, the proposed device can be connected to a dedicated control panel.

The proposed motor protection device operates as follows. The currents consumed by the electric motor 1 are measured using a set of current sensors 2 - DT1, DT2, DT3 and through the input circuit 3 are then transferred to the ADC 4 in digital code. Then, in digital form, the effective values of the currents in block 6 are calculated and the block of protection algorithms 5 controls the presence of currents within acceptable limits in terms of the magnitude and duration of the current flow of a given value. If the current consumed by the electric motor 1 is outside the permissible limits, then a command is generated by the block of protection algorithms 5 to turn off the electric motor, and the indication and control unit 10 indicates the presence of an emergency by the LED or the display.

To ensure the most accurate correspondence between the protection thresholds and the start mode and the operation mode of the electric motor 1, at each start, the starting characteristic of the electric motor is measured by block 12, based on which, as necessary, the automatic and automatic settings of the protection parameters are made.

Automated setting of protection parameters is carried out by connecting the proposed device to a computer or to a specialized console. Moreover, the proposed motor protection device allows you to visually see the starting characteristic of the electric motor on the computer screen or a specialized console in graphical form (figure 2), where line 1 is the measured starting characteristic of this electric motor; I _n - rated current of the electric motor; line 2 - these are the characteristics formed by the thresholds for protection against overload and against idling; arrows ↔ show the process of setting protection characteristics.

Thus, the proposed device, in contrast to the analogue, provides increased reliability of motor protection due to the possibility of setting protection thresholds in full accordance with the actual start-up and operation of a particular motor. Additionally, it becomes possible to analyze the process of starting the electric motor by the user of the proposed device.

Information sources.

1. "Universal protection blocks for asynchronous electric motors UBZ-301", (see http://www.novatekelektro.com/production_ubz.htm).

2. “Relay control and protection (RCH)” (see http://rele.tomsk.ru/menu/product.html).

Claims (2)

1. The motor protection device, which includes current sensors mounted on the electric motor power line, to which input circuits, an analog-to-digital converter, a block of protection algorithms, a block for calculating the current values of currents, a memory for settings, an indication and control unit, are connected to a single circuit , a data exchange interface, characterized in that it further comprises at least a unit for measuring the starting characteristics of the electric motor and at least a unit for calculating settings for shield. 2. The device according to claim 1, characterized in that it is configured to connect at least to a computer for joint image on a computer screen in graphical form of the measured starting characteristic of the motor and protection thresholds at their current settings, as well as the ability to adjust thresholds protection from the computer while displaying the result of the adjustment.