JPS60200743A - Diagnosing method of motor - Google Patents

Abstract

PURPOSE:To accurately judge whether normal or abnormal by quantifying the attenuated vibration state of a motor by utilizing the difference of the amplitude and the phase angle from the waveform of the attenuated variation of the motor to be diagnosed and of normal state, and diagnosing the presence or absence of an interlayer shortcircuit. CONSTITUTION:A pulse is applied through a switch 3 from a pulse generator 2 between two phases of windings U-W phases of a 3-phase induction motor 1. The applied pulse voltage is detected by a detecting resistor 4, and input through an amplifier 5, a recorder 6 and an A/D converter 7 to a calculator 8. Thus, the ratio of the maximum values of waveform signals of the phases, the ratio of peak-to-peak values, the ratio of the phase angles of the maximum values zero potentials, the ratio of the phase angle of the maximum value the minimum value and the percentages of them are calculated, and the average values are obtained. Then, the difference between the average values and the average values of the motor 1 of normal state is obtained to quantitatively judge the displacement (abnormal amount) from the normal state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for diagnosing a three-phase motor, and specifically relates to a method for diagnosing a three-phase motor.
The present invention proposes a motor diagnostic method that can accurately determine the presence or absence of a glabella short circuit or loose winding of a phase motor.

[Prior art]

Layer short circuits or loosening of the windings caused by dielectric breakdown in the three-phase motor windings are directly connected to the life of the motor, so periodically check for their presence and try to detect them early. There is a need.

A method for diagnosing a glabellar short circuit or loose winding of a 3-phase motor is to apply a pulse voltage between each phase of the winding of the 3-phase motor, detect the damped vibration waveform at that time, and perform the same procedure as this detected waveform. Use an oscilloscope to detect the deviation from the waveform of the motor in a positive state where there is no looseness in the 2nd winding, or take a photo of the oscilloscope display and compare the photos visually. However, there was a method of determining the presence or absence of glabellar short circuit based on the comparison results.

That is, the presence or absence of a glabellar short circuit is determined by utilizing the fact that when a glabellar short circuit or the like occurs in the winding, the circuit constants of each phase become unbalanced.

However, when using this method, it is difficult to quantify the criteria for determining the presence or absence of glabellar short circuits or loose windings, and the judgment relies on the experience and intuition of the inspectors. There was an xW point that a proper diagnosis could not be made.

〔the purpose〕

The present invention has been made in view of such circumstances, and it quantifies the damping state by using the difference in amplitude and the difference in phase angle from the damped vibration waveform of the motor to be diagnosed and the motor in the heavy seat state, It is an object of the present invention to provide a method for diagnosing the presence or absence of loosening of the glabellar short circuit 1 winding based on the value.

[Structure of the invention]

The method for diagnosing a motor according to the present invention is to apply a pulse voltage to the windings of each phase of a three-phase motor to be diagnosed, and to calculate the ratio of the maximum value of the vibration that appears first in the damped vibration waveform between each phase,
Determine the peak-to-peak value ratio, the phase angle ratio between the local maximum value and zero potential, and the phase angle ratio between the local maximum value and the local minimum value, then calculate the average value of these ratios, and calculate the average value for each of the average values. The winding is diagnosed based on the difference from a predetermined reference value.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof. FIG. 1 is a block diagram showing the implementation state of the method of the present invention, and FIG. 3 is a flowchart showing the calculation contents of the calculation device.

A pulse generator 2 applies a pulse having a time width of about 20 μsec and a voltage about the rated voltage of the motor to the first two phases of the windings U, V, and W of the three-phase induction motor 1.

For example, the (2) phase is installed via the detection resistor 4, and a pulse voltage is applied to the U and V phases via the switch 3. U-
The current waveform of the pulse voltage applied between the V and W-phases is detected by the detection resistor 4. This detected current signal is amplified to a required level by an amplifier 5 and input to a recorder 6. The recorder 6 temporarily records the detection signals between the UV and WV phases of the damped oscillation waveform as shown in FIGS. 2A and 2B.

Next, by changing the connections between the U, V, and W phase to
--Detect the current waveform when a pulse voltage is applied between the U phase and the V-○ phase, and once record the damped vibration waveform signal on the recorder 6. The detection signal thus recorded on the recorder 6 is reproduced, converted into a digital signal by the A/D converter 7, and inputted to the arithmetic unit 8.

The arithmetic unit 8 samples the first period of the input signal. Then, based on the signal waveform data between the U--V phase and W-■ phase, the calculation shown in the following equation (1) is executed, and
Figure fan, (ratio of the maximum value of the waveform signal between the U-■ phase and the waveform signal between the W-V phase as shown in bl at/b+, peak-to-peak value ratio a2/b2゜between the maximum value and zero potential Phase angle ratio a3/b3 and phase angle ratio a between maximum value and minimum value
4/b 4 respective percentage UWAp-z (%),
UWAp-p (%).

Add UWTp-z (%) and UWTp-p (%).

Next, in the same manner, the percentage of the ratio of the respective maximum values VUAp-z is determined based on the waveform data between the V-W phase and the U--W phase, and between the W-U phase and the V-U phase.

WVAp-z, percentage of peak-to-peak value ratio VUAp
-p, WVAp-p, percentage of phase angle ratio between maximum value and zero potential VUTp-z, WVTp-z and maximum value ~
Percentage of the ratio of phase angles between local minima V U Tp-p.

Add WVTp-p.

Next, the calculation shown in the following equation (2) is executed, and the percentage of the ratio of the maximum value, the percentage of the peak-to-peak value ratio, the percentage of the phase angle ratio between the maximum value and zero potential, and the ratio between the maximum value and the minimum value are calculated. Average value of each percentage of phase angle ratio (Ap-z) a, (
Ap-p) a, (Tp-z) a, (Tp-p
) Add a.

(Left below) 3 Next, calculate the difference between each of these average values and the average value (100%) of the motor in normal condition, and further calculate the common logarithmic values LAZ, LAP as shown in equation (3) below. .

Add LTZ and LTP.

Note that the index such as (A9-Z) a of the electric motor in the compacted state is not limited to 100.

Next, execute the calculation shown in equation (4) below, and LAZ and LAP
Calculate the average value XA of the sum of and the average value YT of the sum of LTZ and LTP.

XA and YT indicate the deviation of the amplitude and phase angle from the normal state, respectively. In other words, XA.

A relationship is established in which the deviation of the amplitude and phase angle from the consolidated state (field lightning amount) increases as YT increases. Thereby, the degree of foreignness can be determined quantitatively by measuring XA and YT.

Next, the arithmetic unit 8 outputs these to the printer 9 to display them on a two-dimensional scale with XA as the horizontal axis and YT as the vertical axis.

〔effect〕

Next, the effects of the present invention will be explained based on Examples. Ten electric motors were tested, all of which had a rated output of 3 kW, and their characteristics were as shown in Table 1.

(Margin below) Volume 1 Table 4 shows XA on the horizontal axis and YT on the vertical axis.
This is a graph plotting the detection results of each motor. The white circles in the graph are the motors in the heavy seating area (NO, 1 to 4), and the black circles are the motors in the caution area (NO, 5, 8, 9, 10).
, △ indicates the motor (NO, 6, 7) in the abnormal area.

As is clear from this graph, the region where both XA and YT are small, specifically the region where XA is less than 10 and YT is less than 12, is the positive electric region where there is no interlayer short circuit or loosening in the 2nd winding of the motor. , and 10≦XA<30°12≦YT<30
The areas requiring attention are areas where the windings are loose and moisture absorption is occurring,
and XA>30. The area where YT>30 can be distinguished as an abnormal area where glabellar shorting occurs.

When XA and YT are determined in this manner, it becomes possible to quantitatively determine whether the glabella short-circuited first winding of the motor is loose or moisture is absorbed. Further, from FIG. 4, it can be determined that the abnormality progresses as the plot moves from left to right or from bottom to top within the normal region, and it is good to take this into consideration in diagnosis by monitoring changes over time.

In the case of the method of the present invention as described above, since the amplitude deviation XA and the phase angle deviation YT can be quantified, the normal region as shown in Fig. 4 obtained through experiments and actual results is determined in advance as a judgment standard. The normality of the motor can be determined by plotting the actual measurement results of the motor to be measured, or quantifying these values during consolidation, and directly comparing the actual measurement values and the values when the motor is stopped. Abnormalities can be determined accurately.

In the above embodiment, the method of the present invention is applied to a three-phase induction motor, but it goes without saying that the method of the present invention can also be applied to other motors such as a three-phase synchronous motor.

As detailed above, the motor diagnosis method according to the present invention determines the difference in amplitude and phase angle from the damped vibration waveforms of the motor to be measured and the motor in a normal state. The present invention has excellent effects, such as being able to quantitatively determine whether there is a short circuit between the eyebrows of the wire or loosening of the winding, allowing accurate diagnosis.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the implementation state of the method of the present invention, and FIG.
FIG. 3 is a signal waveform diagram for explaining the operation, FIG. 3 is a flowchart showing the calculation contents of the arithmetic unit, and FIG. 4 is a graph plotting the experimental results of the motor under test. 1...3-phase induction motor 2...Pulse generator 8.
...Arithmetic device patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono

Claims (1)

[Claims] 1. A pulse voltage is applied to the windings of each phase of a three-phase motor to be diagnosed, and the ratio of the maximum value of the vibration that appears at the beginning of the damped vibration waveform between each phase. Determine the peak-to-peak value ratio, the phase angle ratio between the local maximum value and zero potential, and the phase angle ratio between the local maximum value and the local minimum value, then calculate the average value of these ratios, and calculate a predetermined value for each of the average values. A method for diagnosing an electric motor, characterized by diagnosing a winding based on a difference from a reference value.