JPH04355381A - Method for inspecting connection of winding of rotary electric machinery - Google Patents

Abstract

PURPOSE:To easily and certainly inspect the quality of the winding connection in a three-phase rotary electric machinery by low voltage. CONSTITUTION:The respective end parts considered to be on the side of a neutral point of windings 1, 2, 3 to be measured are temporarily subjected to star-connection 4. An AC power supply 5 is connected, for example, to the windings 1, 2 to be measured using measuring connection 10 to measure the synthetic impedance between the windings 1, 2 to be measured. The same measurement is also performed between the windings 2, 3 to be measured and between the windings 3, 1 to be measured and the measured impedances are compared. Since the synthetic impedance containing the winding 1, 2 or 3 of inverse connection in polarity is lowered by about half in its value as compared with the synthetic impedance in the case of regular connection, the quality of connection can be certainly inspected.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

[Industrial Application Field] The present invention relates to a rotating electrical machine winding connection verification method for determining the quality of the winding connection in a three-phase rotating electrical machine, and particularly to verifying the quality of the connection by measuring the combined impedance of the windings. Regarding how to.

0002

2. Description of the Related Art Generally, when manufacturing a rotating electrical machine such as an electric motor, it is necessary to check internal connections once the connections of stator windings or rotor windings are completed.

[0003]Furthermore, when the assembly of the rotating electric machine is completed and the inside is not visible, if the terminal symbol is unknown during periodic inspection or the like, it is necessary to clarify this. Also, depending on the manufacturer, there are no terminal symbols from the time of new manufacture, and in the case of three-phase rotating electric machines, the lead wires on the neutral point side and the power source side are 6.
There are also machines that only have a main line, and in this case as well, it is necessary to identify the lead line.

[0004] Conventionally, therefore, when manufacturing a rotating electrical machine, after the windings have been connected, a direct current resistance measurement, a measurement of the magnetic center in direct current flow, and a visual inspection by comparison with a design drawing have been carried out.

[0005] After assembly is completed, for example, in a three-phase electric motor, first check the conductivity of the six lead wires using a resistance meter and tentatively color code them as U-X phase, V-Y phase, and W-Z phase.
After temporarily connecting these to the star connection, try applying high voltage. Then, if the rotor does not rotate, the power supply side and neutral point side of one phase are connected in reverse, and if the rotor still does not rotate, the other phase is connected in reverse. In this way, the connections for two phases are changed in the worst case, and the lead wires are identified on the power supply side and the neutral point side.

[0006]

Problem to be Solved by the Invention In the conventional method for verifying the winding connection of a rotating electric machine, there is a problem in that the verification method at the time of manufacturing cannot verify when the windings are connected with reverse polarity.

[0007] In addition, in the verification method after assembly is completed, high voltage is actually applied, so there is no normal approx. There is a problem in that twice as much starting current flows, which adversely affects not only the rotating electric machine but also the grid.

The present invention has been made in consideration of the above-mentioned circumstances, and it is possible to easily verify whether the connection of the three-phase winding is good or not, and there is no risk of adversely affecting the rotating electrical machine or the system. The purpose is to provide a winding connection verification method. [Structure of the invention]

[0009]

[Means for Solving the Problems] In order to solve the above-mentioned problems, a winding connection verification method for a rotating electric machine according to the present invention is a winding connection verification method for a rotating electric machine that verifies the connection state of three-phase windings in the rotating electric machine. In the wire connection verification method, the composite impedance between each phase is measured, and the quality of the winding connection is verified based on the difference in the values.

0010

[Operation] In a three-phase rotating electric machine, the combined impedance between each phase is significantly lower when one phase is connected in reverse than when the phases are connected normally. Therefore, by comparing the combined impedance between each phase, the quality of the winding can be verified. Moreover, since the composite impedance can be easily measured using a commercial frequency power source of approximately 50 to 100 V, a voltage regulator, a voltmeter, and an ammeter, there is no fear of adversely affecting the rotating electric machine or the system.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the principle of the verification method in the present invention will be explained with reference to FIGS. 2 and 3. As shown in Figure 2,
When two coils 11 and 12 are connected in series with the same polarity 13, the self-inductance of the coil 11 is L1 (H
), the self-inductance of the coil 12 is L2 (H),
If the mutual inductance of the coils 11 and 12 is M(H), the combined inductance La of the coils 11 and 12 is: La=L1 +L2 +2M(H)
...(1). On the other hand, as shown in FIG. 3, when one coil 12 is connected in series with the opposite polarity 14, the combined inductance Lb of the coils 11 and 12 is Lb=L1 +L2 -2M(H
) ...(2).

[0013] Here, if each coil 11, 12 is replaced with one phase of stator winding of a rotating electric machine, the impedance is as follows.
It consists of resistance and inductance, so the resistance is R (Ω).
, the inductance is L(H), the impedance Z12 in the case of series with the same polarity is Z12=2R
+jw2(L+M)...
(3) becomes. In addition, the impedance Z21 in the case of reverse polarity series is Z21=2R+jw2(L-M)
...(4).

Here, since R, L, and M differ depending on the machine, the ratio of the impedances Z12 and Z21 cannot be determined unconditionally, but at least the impedance Z21
It can be easily estimated that the value of is expressed as a difference greater than the impedance variation.

[0015] The present inventors conducted actual measurements using actual equipment, and found that
As will be described in detail later, it was confirmed that the combined impedance when connected in a one-phase reverse manner is approximately 1/2 of the value when connected normally. Therefore, the combined impedance when one phase is connected in reverse is significantly reduced, and it becomes possible to easily and reliably verify the quality of the winding connection. Next, an actual verification method for a three-phase AC motor will be explained with reference to FIG.

In FIG. 1, reference numerals 1, 2, and 3 indicate windings to be measured of a three-phase AC motor, and each of these windings 1, 2
, 3, each terminal considered to be on the neutral point side is
It is assumed that the wires are connected in a star pattern 4.

On the other hand, as shown in FIG.
This measuring device is equipped with an AC power supply 5 of AC 50 to 100 V of 0 to 60 Hz, a switch 6, a voltage regulator 7, an AC ammeter 8, and an AC voltmeter 9.
It is connected between the phases of the windings 1, 2, and 3 to be measured. The voltage applied between the phases is adjusted by the voltage regulator 7, and the current flowing through the circuit can be read by an AC ammeter 8, and the voltage can be read by an AC voltmeter 9.

In the above configuration, when verifying the three-phase AC motor, first, as shown in FIG.
are connected to the windings to be measured 1 and 2, respectively, and current is applied between these phases to measure the voltage and current at that time. Similar measurements are sequentially performed on the windings 2 and 3 to be measured and the windings 3 and 1 to be measured. The voltage measured in this way is E(V)
, the current is I (A), the combined impedance between phases Z (Ω) is

[0019]

[Math 1] It can be found by

[0020] Therefore, the combined impedance Z (
Ω). At this time, if there is a phase with reversed polarity, the combined impedance Z (Ω) between the phases including that phase is much lower than the combined impedance Z (Ω) between the phases of the normal connection. The value will be approximately half. Therefore, by checking whether there is an extremely low value of composite impedance Z (Ω), it is possible to verify whether the windings are connected with opposite polarity.

[0021] The inventors of the present invention have developed a
P, A three-phase induction motor stator winding with four parallel star connections is used, and the polarity of the windings is connected correctly and the polarity of a given winding is connected in the opposite direction. The difference in composite impedance was measured for each case, and the power supply was AC 50 Hz, 100 V, 1φ. As a result, when the polarities of all the windings were connected correctly, the results were as shown in Table 1, and when the polarities of the winding 2 were connected, the results were as shown in Table 2.

[0022]

[Table 1]

[0023]

[Table 2] As is clear from the results in Tables 1 and 2, it is possible to easily and reliably identify the winding 2 whose polarity is reversed.

[0024] The inventors of the present invention have proposed that the winding 1 and the winding 3
Similarly, measurements were made with reverse connections, but the results were similar to those for winding 2, and it was found that any winding could be verified.

[0025] By performing a simple check at the time when winding connections are completed during the manufacture of rotating electric machines, it is possible to extremely easily verify reverse phase connections, which is extremely difficult with conventional direct current tests and visual inspections. Can be done. When the neutral point is not exposed as a terminal, and considering the damage caused by correcting the connection when it is discovered after assembly is completed, the practical effect of this is extremely large.

[0026] Furthermore, when a rotating electrical machine is brought in for a periodic inspection after assembly has been completed, if the terminal symbol for the neutral point terminal is missing or has fallen off,
By identifying the terminals using the verification method according to the present embodiment, it is possible to prevent overcurrent from flowing due to mixed reverse phase connections when checking rotation under high voltage energization. Therefore, the rotating electric machine can be protected, and electricity can be supplied with confidence without adversely affecting the power supply system.

[0027]

[Effects of the Invention] As explained above, the present invention measures the composite impedance between each phase of a three-phase winding, and verifies the quality of the winding connection based on the difference in value. The quality can be easily verified, and there is no risk of adversely affecting the rotating electric machine or the system.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a circuit for implementing a winding connection verification method for a rotating electric machine according to an embodiment of the present invention.

FIG. 2 is a circuit diagram for explaining the basic principle of the winding connection verification method for a rotating electrical machine according to the present invention.

FIG. 3 is a circuit diagram similar to FIG. 2;

[Explanation of symbols]

1, 2, 3 Winding under test 4 Star connection 5　AC power supply 6 Switch 7 Voltage regulator 8 AC ammeter 9 AC voltmeter 10 Connection for measurement

Claims (1)

[Claims] Claim 1: In a rotating electrical machine winding connection verification method that verifies the connection state of three-phase windings in a rotating electrical machine, the combined impedance between each phase is measured, and the quality of the winding connection is determined based on the difference in the value. A rotating electric machine winding connection verification method characterized by verifying.