CN202075392U - Electromotor comprehensive state monitoring system - Google Patents

Abstract

A comprehensive state monitoring system for electric motors is used for timely and accurate diagnosis of generator faults. Its technical scheme is: it is made up of electrical signal sensor, vibration signal sensor, signal conditioning circuit, data acquisition card and computer, described electrical signal sensor comprises three-phase current transformer and three-phase voltage transformer, and described vibration signal sensor comprises Acceleration sensors, displacement sensors and rotational speed sensors installed on the monitored motor, the signal output terminals of each sensor are connected to different input terminals of the data conditioning circuit, the output terminals of the signal conditioning circuit are connected to the input ports of the data acquisition card, and the data The acquisition card is connected with the computer through the Ethernet interface. Compared with the traditional monitoring device, the utility model can not only diagnose various faults of the generator more accurately, but also greatly reduce the operating cost.

Description

A comprehensive state monitoring system for electric motors

technical field

The utility model relates to a device for on-line monitoring of electrical faults and mechanical faults of a motor, which belongs to the technical field of monitoring.

Background technique

The state monitoring and fault diagnosis of the motor is generally based on the monitoring of its fault signal, using various analysis methods to analyze the fault signal, and using the characteristic signal to judge the operating state and fault type of the motor.

The common faults of motors are mainly divided into two categories: electrical faults and mechanical faults. For example, single-phase grounding, overcurrent, and inter-turn short circuit are electrical faults, while motor rotor imbalance, misalignment, shaft bending, and bearing faults are Mechanical failure. Therefore, electrical signals (three-phase current, voltage signals) and mechanical vibration signals (vibration displacement parameters, vibration velocity parameters, vibration acceleration parameters, etc.) have always been the two major types of signals to be monitored and analyzed by the motor equipment condition monitoring system. At present, the monitoring of these two types of signals is often completed by two independent monitoring systems, which not only increases the cost of the monitoring system, but also has a multi-point correspondence between the motor fault and its representative signal, such as the electrical fault of the motor in the electrical parameter The change also causes the vibration of the mechanical system, so only a comprehensive analysis of the two types of signals can accurately diagnose the fault of the motor. However, because the two types of data collected by the traditional independent monitoring system are not synchronized, the two types of analysis results cannot correspond, resulting in inaccurate diagnosis.

Utility model content

The purpose of the utility model is to provide a motor comprehensive state monitoring system to accurately diagnose motor faults and reduce the operating cost of the monitoring equipment.

Problem described in the utility model is realized with following technical scheme:

A motor comprehensive state monitoring system is composed of an electrical signal sensor, a vibration signal sensor, a signal conditioning circuit, a single-chip microcomputer and a computer, the electrical signal sensor includes a three-phase current transformer and a three-phase voltage transformer, and the vibration signal sensor includes Acceleration sensors, displacement sensors and speed sensors installed on the monitored motor, the signal output terminals of each sensor are connected to different input terminals of the data conditioning circuit, the output terminals of the signal conditioning circuit are connected to the analog input port of the data acquisition card, and the data The acquisition card is connected with the computer through the Ethernet interface.

In the motor comprehensive state monitoring system described above, the signal conditioning circuit is composed of a plurality of signal conditioning units corresponding to the electrical signal sensors and vibration signal sensors, and each signal conditioning unit is composed of an operational amplifier, a resistor and a capacitor. The non-inverting input terminal of the operational amplifier is connected to the output terminal of an electrical signal sensor or vibration signal sensor through the first resistor, the inverting input terminal is grounded through the second resistor and connected to the output terminal through the third resistor, and the output terminal is connected to one channel of the data acquisition card An analog input port, one end of the capacitor is grounded, and the other end is connected to the non-inverting input end of the operational amplifier.

In the motor comprehensive state monitoring system described above, four acceleration sensors are provided, two are installed on the two bearings of the generator, and the two acceleration sensors on the same bearing are perpendicular to each other; three displacement sensors are provided, all of which are non- Contact eddy current displacement sensor, in which two displacement sensors are installed vertically near the motor shaft, and the other displacement sensor is installed at one end of the motor shaft.

The utility model uses the electrical signal sensor and the vibration signal sensor to synchronously collect the three-phase current, voltage signal and mechanical vibration signal of the monitored generator, and transmits the processed signal to the computer by the single chip microcomputer, and the computer comprehensively analyzes these signals, Determine the operating condition of the generator. Compared with the traditional monitoring device, the utility model can not only diagnose various faults of the generator more accurately, but also greatly reduce the operating cost.

Below in conjunction with accompanying drawing, the utility model is further described.

Description of drawings

Fig. 1 is the electric principle block diagram of the present utility model;

Fig. 2 is electrical schematic diagram;

FIG. 3 is an electrical schematic diagram of the signal conditioning unit;

Fig. 4 is a schematic diagram of the installation of the vibration signal sensor.

The labels in the figure are: U1, data acquisition card; U2, Ethernet; M, motor; TL1~TL14, signal conditioning unit; F, operational amplifier; CT1~CT3, current transformer; PT1~PT3, voltage transformer; a1～a4, acceleration sensor; V1～V3, displacement sensor; n, rotational speed sensor; C, capacitance; R1～R3, resistance; PC, computer.

Detailed ways

Referring to Fig. 1 to Fig. 4, the utility model uses the electrical signal and mechanical vibration signal of the motor as the monitoring object of the motor state monitoring and fault diagnosis system. Its hardware consists of sensors, signal conditioning circuits, data acquisition cards and PCs. There are six electrical signals and eight mechanical vibration signals. The implementation steps of this system are as follows:

1) First connect the current transformers CT1~CT3 and voltage transformers PT1~PT3 to the generator circuit, and collect the three-phase voltage signals and three-phase current signals of the generator.

2) Next, install two mutually perpendicular non-contact eddy current displacement sensors (V1 and V2) near the rotating shaft of the motor M to measure the radial vibration of the motor rotor; A vertical acceleration sensor (a1 is perpendicular to a3, a2 is perpendicular to a4) is used to measure the radial vibration of the motor rotor; a non-contact eddy current displacement sensor V3 is installed on the shaft end of the motor to measure the shaft of the motor rotor vibration; install a speed sensor n near the motor shaft, the speed sensor n is a photoelectric sensor, and record the number of pulse signals through the counter provided by the data acquisition card U1, so as to monitor the speed of the motor. A spare analog input channel. The connection between the vibration sensor and the motor M is shown in Figure 4.

3) Connect 6 electrical signals and 14 signals picked up by 8 vibration sensors to the input terminals of 14 signal conditioning units (TL1~TL14) of the signal conditioning circuit, and the signal conditioning unit preprocesses the signals.

4) Connect the conditioned signal to the data acquisition card U1, and the data acquisition card U1 communicates with the host computer through the Ethernet interface to start collecting data and monitoring.

The working principle of this system is: first, the electrical signals from PT and CT and the mechanical vibration signals picked up by the vibration sensor are sent to the signal conditioning circuit of the monitoring system, and the signal conditioning circuit adjusts the above signals to adapt to the data acquisition card U1 In addition, the signal conditioning circuit also has a simple filtering function. Then send the conditioned signal to the single-chip microcomputer U1, and the data acquisition card U1 completes the AD conversion of the analog signal, converts the analog signal into a digital signal, and completes the data communication with the upper computer through the communication chip, and the data acquisition card U1 Parameters (sampling frequency, data length, etc.) are set by software installed on the host computer. Finally, the analysis software installed in the host computer performs real-time display, storage, and analysis of the received collected data, including calculation and monitoring of the peak-to-peak value and effective value of the vibration signal, and real-time display of electrical and mechanical vibration signals. Historical data query, trend analysis, fault data waveform display, spectrum analysis, correlation analysis, etc. At the same time, the analysis software is used to set the alarm value. When a certain monitoring data exceeds the alarm value, the computer will alarm.

The data acquisition card can use UA505 network port data acquisition card (produced by Beijing Youcai Measurement and Control Technology Co., Ltd.).

Claims (3)

1. general motor condition monitoring system, it is characterized in that, it is by electrical sensor signal, vibration signal sensor, signal conditioning circuit, data collecting card (U1) and computing machine (PC) are formed, described electrical sensor signal comprises threephase current transformer and threephase potential transformer, described vibration signal sensor comprises the acceleration transducer that is installed on the monitored motor, displacement transducer and speed probe (n), the signal output part of each sensor connects the different input ends of data conditioning circuit, the input port of the output termination data collecting card (U1) of described signal conditioning circuit, the TXD0 of described data collecting card (U1) is connected with computing machine (PC) through Ethernet interface with the RXD0 port.

2. according to the described general motor condition monitoring system of claim 1, it is characterized in that, described signal conditioning circuit is made up of the signal condition unit identical with the corresponding a plurality of structures of vibration signal sensor with each electrical sensor signal, each signal condition unit is by operational amplifier (F), resistance and electric capacity (C) are formed, the in-phase input end of described operational amplifier (F) connects the output terminal of an electrical sensor signal or vibration signal sensor through first resistance (R1), inverting input connects output terminal through second resistance (R2) ground connection and through the 3rd resistance (R3), an input port of output termination data collecting card (U1), described electric capacity (C) end ground connection, the in-phase input end of a termination operational amplifier (F).

3. according to claim 1 or 2 described general motor condition monitoring systems, it is characterized in that described acceleration transducer is provided with four, respectively install two on two bearings of generator (M), two acceleration transducers that are positioned on the same bearing are vertical mutually; Described displacement transducer is provided with three, is the non-contact turbulent flow displacement transducer, and wherein two displacement transducers are installed near motor (M) rotating shaft mutual vertically, and another displacement transducer is installed in motor (M) rotating shaft one end.

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