JB/T 5811-1991 Test methods and limits for interturn insulation of AC low-voltage motor formed windings
Some standard content:
Machinery Industry Standards of the People's Republic of China
AC low-voltage motor formed windings
Inter-turn insulation test methods and limits
1 Subject content and scope of application
This standard specifies the AC Test methods, test parameters and test limits for inter-turn insulation of motor formed windings, JB/T 5811: 91
This standard is suitable for inter-lung insulation testing of formed windings of small and medium-sized AC motors with rated voltages of 1140V and below. 2 Reference standards
GB 755
Basic technical requirements for rotating electrical machines
GB 8170
Numerical rounding rules
JB/Z293 AC high-voltage motor stator winding turns Inter-turn insulation test specification Inter-turn insulation test method for AC low-voltage motor loose-embedded windings JB/Z2941
A method of testing the insulation between turns of motor windings (or coils) using impulse voltage. The principle is to directly apply impulse voltage waves with specified peak values ??and wave front times to the designed test product and reference product windings (or coils) alternately (or at the same time), and use the impulse voltage to convert the two. There is a difference in the attenuated oscillation waveform caused by the motor winding (or coil) to detect whether the insulation between turns of the motor winding (or coil) is good.
3.2 Winding
A group of turns or coils with specified functions in a motor 3.3 Coil
A group of turns in series, usually coaxial and with common insulation 3.4 Reference Product winding (or coil)
The motor winding (or coil) used to compare with the tested winding (or coil) when using the impulse waveform comparison method to detect the inter-turn insulation of the motor winding (or coil).
The parameters of the winding (or coil) of the reference product must be the same as the winding (or coil) of the product under test. The reference winding (or coil) can be selected in the same motor, or in a motor with different specifications. The reference winding (or coil) can be a winding (or coil) whose inter-turn insulation is confirmed to be normal or assumed to be normal. ; 1992-05-01 Implementation
5 Test instruments and requirements
IBT 5811-91
5.1 The two sets of impulse voltage waves output by the instrument should be symmetrical, with a tolerance of ±3.2. The peak voltage of the instrument should be continuously adjustable and have an indication, with a tolerance of ±3% or ±3%. It is recommended to use a maximum value of ±3% and a digital display peak voltmeter
5.3. The peak value of the impulse voltage should be able to meet the maximum test voltage requirement of the sample. 5.4 The wavefront time of the first impulse voltage wave output by the instrument is 0.1.0.5 and 1.2us, with a tolerance of ±30%. The preferred wavefront time is 0.5μs.
5.5 instruments should be able to clearly display and distinguish waveforms. The water sampling frequency should not be less than 25Hz. If the same level of clarity and stability can be achieved, other frequencies are allowed
5.6 instruments should have dedicated wiring for testing. Ground terminal and necessary safety warning facilities, and can be configured with automatic alarm and microcomputer connection 6 Test methods
6.1 Preparation
6.1.1 The instrument shell should be reliably grounded
6.1.2 Inspection test If the waveforms overlap, connect the two sets of measuring wires of the instrument to the same winding respectively. The two oscillation waveforms should completely overlap. 6.2 Trap test
The insulation test between coils can be performed before and/or after wire embedding. 6.2.1 Before each coil is embedded in the iron core slot, take two coils as the reference product and the test product, and draw out the wires at the beginning and end of the two coils. Apply an impulse voltage wave with specified peak value and wave front time, and compare the similarities and differences between the two attenuated oscillation waveforms. For the test wiring, see Figure 1. HiHz!
Qoo
Figure 1 Schematic diagram of coil test wiring| | tt | Take two coils as the reference product and the test product respectively, apply an impulse voltage wave with specified peak value and wave front time between the lead wires of the two coils, and compare the similarities and differences between the two attenuated oscillation waveforms. The test wiring diagram is the same. 1.
Note: If the core is grounded during measurement, the insulation to ground will also withstand the same surge voltage at the same time as the test.
For the motor winding, according to the test There are three test methods for indirect wiring of windings: 6.3.1 Φ (phase) connection
Choose one phase winding (for example, U phase) as the reference product, and the other phase winding (for example, V phase) as the reference product. The test object is to alternately (or simultaneously) apply impulse voltage waves with specified peak values ??and front times to the U-phase and V-phase, compare the similarities and differences between the two attenuated oscillation waveforms, and then convert in sequence, repeat the test times: test wiring Referring to Figure 2, after each test, the windings not participating in the test should be discharged. 137
6.3.2Y (line) connection
HH
888
JB/T 5811
91
U||tt ||y
Figure 2Φ (phase) connection diagram example
H,, H2—high potential terminal: L—low potential terminal Qw
ow
For motor windings that have been connected in Y connection, choose one (two-phase series) winding (for example, UW) as the reference product, and the other (two-phase series connection) winding (for example, VW) as the test product. Between UW and VW Apply impulse voltage waves with specified peak value and wave front time alternately (or simultaneously), and compare the similarities and differences between the two attenuated oscillation waveforms. Then convert in turn and repeat the test · times. See Figure 3 for wiring diagram. HHz | |tt | ||For the motor windings that have been connected in △ connection, choose one (two-phase winding in series and the third-phase winding in parallel) winding (for example, UW) as the reference product, and the other (two-phase winding in series and the third-phase winding in parallel) Windings in parallel) windings (for example, VW) are used as the test object, and impulse voltage waves with specified peak values ??and wave front times are alternately (or simultaneously) applied to UW and VW, and the similarities and differences between the two attenuated oscillation waveforms are compared. Convert again and try again. See Figure 4 for wiring diagram.
HH
98
A
Figure 4 △ (angle) connection diagram illustration
HH high potential terminal; L.·Low potential terminal 7 Test waveform and display
7.1 Display of test waveform
The test waveform should be displayed on the oscilloscope screen for observation and comparison. 7.2 Test display waveform
The test display waveform can be a voltage waveform or a current waveform. While observing and comparing the voltage waveforms, the peak value of the impulse test voltage can be read from the displayed waveform; the current waveform meter is used for observing and comparing the test waveforms.
.138
8 Test method selection principles
8.1 Coil test
JB/T 5811—1
91
8.1.1 Testing each wire one by one before embedding wires can prevent coils with poor insulation between turns from being embedded in the iron core. The test sample has the smallest impedance. 8.1.2 After wire embedding (before wiring), conduct tests on coils one by one to check the impact on the insulation between turns during the wire embedding process. The impedance of the test sample increases, which expands the capacity range of the instrument's test motor. bZxz.net
8.2 Winding test
8.2.1Φ (phase) connection method
Suitable for testing windings with lead-out terminals at both ends of each phase winding, or Y connection method with lead-out midpoint N The winding, or the person who unties the connection point connects the winding. The impedance of the test sample is medium.
Φ (phase) connection method is the basic method for judging insulation faults between winding turns. 8.2.2Y (line) connection method
is suitable for detecting Y connection motor windings. The impedance of the test sample is maximum. For motor windings with larger power, Y (line) connection is recommended. 8.2.3 △ (angle) connection
is suitable for detecting A connection motor windings. The test sample has the smallest impedance. 9 Test judgment
This standard uses test waveforms as the main basis for judgment. The fault waveform automatic identification device designed using the waveform difference principle can be used as an auxiliary identification method. The fault waveform display is often accompanied by discharge sound. Even discharge sparks and film to ozone (()) can be seen. These signals can help identify the fault type and location
9.1 Fault-free waveform
9.1.1 Coil test
If the displayed If the waveform and the insulation between the coils are confirmed to be normal, the waveforms of the reference product coil basically coincide with no significant difference (referred to as coincidence), then the waveform shown in this test is a fault-free waveform. 9.1.2 Winding test
If the attenuated oscillation waveforms displayed in the two tests are basically significantly different (hereinafter referred to as coincidence) and are normal waveforms, then the waveform shown in this test is a fault-free waveform
9.2 Fault waveform
During the coil or winding test, if there is a situation that does not meet the fault-free waveform, the insulation between the turns of the tested coil or winding is faulty (see Appendix A of JB/Z29487 for details).
9.3 Fault identification
9.3.1 Coil test
If the test shows a difference in waveform, the insulation between the turns of the tested coil is faulty. 9.3.2 Winding test
Make fault diagnosis according to different wiring methods. If one of the two test waveforms shows a difference, there is a fault in the one-phase winding: If the two test waveforms show a difference, a third test is required; if the third test waveforms show overlap, then the --phase winding If there is still a difference, it means there is a fault in the windings of two phases and above. For the second and third tests, you only need to choose one wiring method, which is called judgment. 9.3.2.1Φ(phase) connection method
1 3
sequence
JB/T5811---91
For examples of fault identification of heavy (phase) connection method, see the table 1. The rest are analogous to Φ (phase) connection method and enemy obstacle identification example (see Figure 2 for wiring) Table 1
at
t
bin experience and difference
2| |tt||2
3
Note:
9. 3.2.2
1-1
U
U2|| tt||V
U
U2
U
U
V
U
waveform overlap, X-
Y (line) connection
Instrument terminal wiring
H
V
W
W.
V
W
W
V2
w.
W
W
W
L| |tt||U and V
U and w
V. and W.
Li and V
U, and W
Vi and W
U, and V
' and w
V, and w
and W
w, and
waveforms are different ,
Y (line) connection fault identification examples are shown in Table 2, and by analogy, the waveform shows
X
x
X
X| |tt|| Test level
2
H
U
V
U
U
U
V
U
V
Instrument terminal wiring
1
w
w
W
W
V
W
w
w
-waveform overlap: ×
Note.
The waveforms are different.
!
9. 3. 2. 3
Eight (corner) connection
L
W
U
W||tt ||U
V
w
u
C
Waveform display
x
X||tt ||X
X
V
|tt||Phase failure
Do the first test
U orange failure
Two phases and above failure
V phase failure
Two phases and Above fault
Do
Judgment
W-phase fault
U grid fault
V and fault
Do the: test|| tt||V-tree fault
Two-phase and above fault
L: Phase barrier
Two-material and above fault
JB/T 5811-
91
See Table 3 for examples of fault identification for the eight (corner) connection method, and analogy for the rest (see Figure 4 for wiring) Table 3
Test identification
1
2
1
2
2
3
1
2
3| |tt||3
H
U
V
U
V
u
U||tt ||U
V
V
Instrument terminal wiring
H2
y
W
W||tt ||W
w
w
W
W
W
W
U
w
V
U
V
w
V
U
u
waveform display
X
X
x
X
X
Fault identification
U phase fault
W and fault
Do the ··th test
W phase fault
Two phases or more have faults
Do the ··· test
V phase Fault
Two phases or more are faulty
V phase fault
Note:)
The waveforms overlap; X
The waveforms are different
②U phase refers to the winding between UV terminals: V phase refers to the winding between VW terminals; W phase refers to the winding between WU terminals. 10 Test parameters and comparison parameters
10.1 Test parameters
The test parameters are the impulse test voltage peak value, wave front time, test number and test time. 10.2 Comparison parameters
The comparison parameters during the test are the amplitude and oscillation frequency of the test display waveform. 11 Test Limits
11.1 Impact Test Voltage Peak Value
11.1.1 Impact Test Voltage Peak Measurement
Any of the following methods can be used for the impact test voltage, in the motor coil or winding ( Measurement on the terminal): calculated based on the amplitude and magnification of the voltage waveform: a.
b.
c.
Pointer peak voltmeter;
digital display Digital peak voltmeter;
It is preferred to use a digital peak voltmeter for measurement. 11.1.2 Accuracy of impulse voltage peak measurement The accuracy of impulse test voltage peak measurement is ±5.0% or ±3.0%. It is preferred to use ±3.0%.
11.1.3 Impact test voltage peak value
11.1.3.1 Impact test voltage peak calculation formula The motor winding or coil inter-turn insulation impact test voltage peak value should not be lower than calculated using formula (1), and According to the provisions of (GB8170), round the value to the hundreds (hundred volts)
where:
JB/T 5811
91
U=,XK, xU
Motor winding or coil inter-turn insulation breakout test voltage peak value, V; K
Voltage coefficient;
K.
[Sequence coefficient;||tt| |(1)
The power frequency withstand voltage test value (effective value) of the stator or rotor winding to ground insulation, V. U is selected according to G13755 or product standard U
value.
11. 1. 3. 2
Voltage coefficient Kl
Electrical coefficient K, flaw 2.
11.1.3.3 Process coefficient K2
The process coefficient K takes different values ??according to the tested coil or winding before and after insulation treatment (see Table 4). Table 4 Process coefficient K |
1. [-1. 2
The wave front time of the impulse test voltage wave can be 0.1us, 0.5us and 1.2us. The tolerances are all above 30%. The priority recommended wave front time is .5us
11.3 Test time
The impulse electric bed test time for each (conversion) wiring is 1~3s.Adoption is allowed for longer periods of time. 11.4 Number of tests
11.4.1 Number of coil tests
Only one impulse voltage test is required for each coil. 11.4.2 Number of winding tests
For the motor winding, select one of the test connection methods in 6.3, and follow each possible connection force type and the input direction of the impulse test voltage when the motor winding is working. The impulse voltage test should be repeated at least once. 12 Repeated tests and test procedures
12.1 Repeated tests
For each coil in the motor winding, multiple impulse voltage tests are allowed to be carried out in different process centers, and the test voltage peak value remains unchanged.
12.2 Test procedure
The motor shall undergo inter-turn (insulation) impulse withstand voltage test in accordance with GB755. Tests can be performed in each sequence. You can also select only a few of the processes for testing. The inspection process is determined by the manufacturer. It is allowed to conduct separate tests on the wound rotor winding and stator winding before assembly instead of the motor inter-turn (insulation) impulse withstand voltage test: If the motor inter-turn (insulation) can withstand the impulse withstand voltage test specified in Article 11, it will be tested before leaving the factory. During the (inspection) test, it is also allowed to test the coil or winding after wire embedding and before immersion in place of the motor inter-turn (insulation) impulse withstand voltage test. Additional notes:
This standard is proposed and managed by the Shanghai Electrical Apparatus Research Institute of the Ministry of Mechanical and Electronics Industry. This standard was drafted by the Shanghai Electrical Apparatus Research Institute of the Ministry of Mechanical and Electronic Industry, with Nanjing Turbine Motor Factory, Jiangxi Electric Machinery Factory, and Shenyang Electric Machinery Guang participating in the drafting.
The main drafters of this standard are Chen Lanqiu and Qin Xiaoxiao. .
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