CN108872890B - Device and method for measuring performance of annular iron core of motor - Google Patents
Device and method for measuring performance of annular iron core of motor Download PDFInfo
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- CN108872890B CN108872890B CN201810284889.9A CN201810284889A CN108872890B CN 108872890 B CN108872890 B CN 108872890B CN 201810284889 A CN201810284889 A CN 201810284889A CN 108872890 B CN108872890 B CN 108872890B
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R33/12—Measuring magnetic properties of articles or specimens of solids or fluids
- G01R33/1253—Measuring galvano-magnetic properties
Abstract
A performance measuring device and method for an annular iron core of a motor. The large-section cylindrical conductive core of the device penetrates through the tested annular iron core and generates voltage drop at two ends of the conductive core when the conductive core is electrified; the upper and lower conductive connectors are respectively connected with one end of the conductive core, and one of the upper and lower conductive connectors is detachable; the adjustable power supply is connected with the upper and lower conductive connectors through the large current measuring circuit; two ends of a wire penetrating through the tested annular iron core output low voltage induced by the tested annular iron core; the conversion unit converts the large current, the low voltage or the voltage drop for the operation unit to operate and display by hardware or a built-in program, wherein the operation unit obtains an active power value based on the large current, the low voltage or the voltage drop value or obtains an iron core performance value based on the values. And in the measuring step, after the magnetic circuit parameters of the yoke part of the sample are determined, the power supply is adjusted to a selected large current to measure low voltage or a selected low voltage to measure active power. The measuring device and the measuring method can measure the performance of the iron core by a software and hardware circuit with lower cost, and are convenient to operate.
Description
Technical Field
The invention relates to a device and a method for measuring the performance of an annular iron core of a motor, and IPC classification belongs to G01R 33/12.
Background
The quality control of the performance of the motor core is traditionally carried out by measuring the performance of a raw material steel sheet for manufacturing the motor core or the no-load performance of a product motor, and the operation is troublesome or the measurement result is not direct.
For terms and general knowledge, reference is made to "circuit foundation" (1979, 1 st edition of the national defense industry press) and "handbook of electric machine engineering", except where the specification indicates otherwise.
Disclosure of Invention
The invention aims to solve the technical problem of providing a device and a method for measuring the performance of an annular iron core of a motor, which are simple compared with the traditional measuring device and method, direct in measuring result and high in testing efficiency.
The invention solves the technical scheme that the performance measuring device for the annular iron core of the motor is characterized by comprising a signal detection part and a signal processing part; the signal detection section includes:
the large-section cylindrical conductive core is used for penetrating through the tested annular iron core and generating voltage drop at the cylindrical bottom end and the cylindrical top end when current passes through the large-section cylindrical conductive core;
the upper conductive joint and the lower conductive joint are respectively connected with two cylindrical ends of the conductive core, and one of the upper conductive joint and the lower conductive joint is detachably connected;
-a single phase adjustable low voltage high current power supply, the output of which is connected via a high current measurement circuit to the upper and lower conducting contacts;
two ends of the wire penetrating through the tested annular iron core output low voltage induced by the tested annular iron core;
the signal processing section includes a conversion unit, an arithmetic unit, and a display unit, and:
the conversion unit converts the signal output by the signal detection part into a signal for processing by the arithmetic unit or/and displaying by the display unit;
the arithmetic unit calculates the signal output by the conversion circuit into a value for display by the display unit by using hardware or a built-in program, wherein the value comprises the large current, low voltage or voltage drop value, an active power value obtained on the basis of the large current, low voltage or voltage drop value, or an iron core performance value obtained on the basis of the values;
the device is simple, can realize the quality detection to this iron core performance with lower software and hardware circuit, and the operation is more convenient.
One of the further designs of the technical scheme is as follows: the wire penetrating through the tested annular iron core is a wire turn penetrating through the tested annular iron core for multiple times. The design can improve the measurement accuracy of the low voltage.
In the second design of the technical scheme, the conducting wire penetrating through the tested annular iron core is the conducting core. The large cross-section of the conductive core is sufficient to make its resistance influence negligible, thus simplifying the structure. The voltage drop signal is led out from the cylindrical surfaces of two ends of the cylindrical conductive core, and the design can avoid the influence of contact resistance at two ends of the cylindrical conductive core, which are connected by the upper conductive joint and the lower conductive joint.
The solution of the invention and its typical design will be further explained in the detailed description.
Drawings
Fig. 1 is a top view of a ring core measurement sample of a motor according to an embodiment of the present invention.
Fig. 2 is a front view of a measuring sample of the annular iron core of the motor according to the embodiment of the invention.
Fig. 3 is a circuit diagram of a device for measuring the performance of a toroidal core of a motor according to embodiment 1 of the present invention.
Fig. 4 is a circuit diagram of a device for measuring the performance of the toroidal core of the motor according to embodiment 2 of the present invention.
Detailed Description
Measurement sample of embodiment of the invention as shown in fig. 1 and 2, the measurement device of the embodiment of the invention measures the performance of the magnetic circuit at the yoke part of the sample.
The structure of the measuring device according to embodiment 1 of the present invention is shown in fig. 3, and mainly includes two parts, signal detection and signal processing. The signal detection part mainly comprises the following components:
a cylindrical conductive core 6 with a diameter approximately equal to the inner circle radius of the core, which in use penetrates the annular core 8 to be measured and generates a voltage drop at the cylindrical bottom and top ends thereof when a current passes through the conductive core;
an upper conductive connecting plate 4 and a lower conductive connecting plate 5. The cylindrical bottom end of the conductive core 6 is welded or connected with the lower conductive connecting plate 5 by a screw, after the conductive core 6 is sleeved by the tested annular iron core 8 from top to bottom, a butterfly screw penetrates through a through hole of the upper conductive connecting plate 4 and is screwed in a threaded hole at the cylindrical top end of the conductive core 6, and the upper conductive connecting plate 4 is tightly pressed at the top end of the conductive core 6;
a single-phase autotransformer 1, a step-down transformer 2 and a current transformer 3. The primary of the single-phase autotransformer 1 is connected to a 220V single-phase power supply of a power grid, the adjustable secondary of the single-phase autotransformer is connected with the primary of the step-down transformer 2, the end 1 of the secondary of the step-down transformer 2 is connected with the upper conductive connecting plate 4 through the primary of the current transformer 3, and the other end of the secondary is directly connected with the lower conductive connecting plate 5;
the wire turns 7 penetrate through the tested annular iron core 8 for 2 times, and the wire end outputs the low voltage induced from the tested annular iron core 8.
The signal processing part is a circuit board 9 which mainly comprises chips 91-95 and a liquid crystal display 96. The chips 91 and 92 have the function of true effective value conversion, and the model is AD 536; the chips 93 and 94 have the function of AD conversion, and the model is MC 7135; the chip 95 mainly functions as an operation, adopts a single chip microcomputer, and selects the model W77E 58; the liquid crystal display 96 is selected as model 2402 (produced by Shenzhen Xingyusan electronics Limited) and works as follows:
the voltage signal from the secondary of the current transformer 3 reflecting the large current supplied to the conductive core 6 is input into the circuit board 9, and the signal is input into the chip 95 after being subjected to true effective value conversion by the chip 91 and AD conversion by the chip 93 in sequence;
the low voltage signals from the two wire ends of the wire turns 7 and sensed by the tested annular iron core 8 are input into the circuit board 9, and the signals are sequentially subjected to true effective value conversion by the chip 92 and AD conversion by the chip 94 and then input into the chip 95;
the CPU of the chip 95 converts the signals received from the chips 93, 94 into values for the display 96, either directly or by calculation, according to its built-in program: the low voltage value measured from the wire turn 7 and the large current value measured from the current transformer 3 are directly displayed, and simultaneously, the phase difference between the low voltage value and the large current value is measured and calculated according to the electrical engineering principle to obtain the power factor, and further multiplication is carried out to obtain the active power value for display.
The more detailed principle and design can refer to the user manual or instruction of the chip of the model and the common electric quantity measuring singlechip program.
For the measured values of the large current, the low voltage and the active power, the indexes of the values can be set according to the calculation or verification condition of a specific iron core product to directly control the quality; the magnetic permeability of the yoke part of the annular iron core and the iron loss can be converted into numerical values, and the quality is controlled according to the indexes of the steel sheet standard of the specific raw material of the iron core, and the specific method comprises the following steps:
when the product standard gives a continuous curve or complete table of properties:
1. determining magnetic circuit parameters of a yoke part of a sample, and mainly comprising the following steps:
yoke magnetic path length ljAnd average height hj(ii) a The dimensions of the patterned core shown in fig. 1 and 2 can be calculated according to the formula in motor design (1 st edition 1982 of mechanical industry Press) or/and micro special motor design program (1 st edition 1997 of Shanghai science and technology Press), or obtained by running a specific motor electromagnetic design computer program (note: the length of the yoke magnetic path obtained by the electromagnetic calculation is usually 1 pole, and the calculated length l of the yoke magnetic path is 1 polejMultiplying the length of the magnetic path of the yoke part obtained by the electromagnetic calculation by the number of poles, namely calculating the whole circle perimeter of the circle where the magnetic path is located on the yoke part);
average yoke section Sj，Sj＝L*KFe*hj(ii) a In the formula, L: length of iron core, KFe: the lamination coefficient is about 0.95-0.97;
yoke mass Gj，Gj＝7.8*lj*Sj。
2. Selecting B for simultaneously measuring magnetic permeability and iron lossm,
The method is selected according to the indexes of the product standard of the steel sheet of the specific raw material and the working range of the magnetic circuit of the motor of the specific product. In general BmTake 0.5, 1.0, 1.5 and 1.7T.
3. According to selected BmDetermining the corresponding measurement voltage U
U＝4.44fNΦm
In the formula: f is the power frequency;
n is the number of times the wire turns 7 of the measuring device cross the iron core ring, which is 2 in this embodiment;
Φmmagnetic flux of yoke part, phim＝Bm*Sj，SjSee item 1.
4. Measurement of selected BmMagnetic permeability and iron loss of
Adjusting the single-phase autotransformer 1 to make the display value of the turn 7 be the measurement voltage U determined in item 3, reading the current value I and the active power value P of the measurement device at the moment, and respectively and directly comparing the current value I and the active power value P with the indexes of a standard performance curve or a table of a specific iron core product to judge the quality, or:
a) h calculated according to the following formulamComparing with the standard performance curve or table index (such as H) of specific raw material steel sheet product0.5、H1.0、H1.5And H1.7) Judging the quality:
Hm＝1.414ξ*I/lj
in the formula: xi is a correction coefficient related to the iron core material and the saturation degree, about 0.7-1.5, B can be selectedmFrom Chapter 4 of the "Circuit Foundation" (1 st edition 1979 of the national defense industry Press).
ljSee item 1.
b) P calculated according to the following formulatComparing with the standard performance curve or table index (such as P) of specific raw material steel sheet product10/50、P15/50And P17/50) Judging the quality:
Pt＝P/Gj
in the formula: gjSee item 1 for yoke mass.
The measurement and quality control steps can be performed in the order of the above 6 items, or can be adjusted. For example: the items a) and b) in the item 4 can be in no sequence, and the items 1 to 3 can be omitted in the repeatability measurement.
Secondly, when the product standard gives a performance characteristic value:
1. determining magnetic circuit parameters of sample yoke
The same as item 1 of the first point.
2. Selected measurement BmH of (A) to (B)mAnd B for measuring iron lossmOr measuring core loss B simultaneouslym,
Characteristic value according to the product standard of a specific raw material steel sheet, usually H＝Taking 10, 25, 50, 100 and 300A/cm, BmTake 1.0, 1.5 and 1.7T.
3. According to selected H＝Determining the corresponding measuring current I
I＝0.707H＝*lj/ξ
In the formula: xi is a correction coefficient related to the iron core material and the saturation degree, and is about 0.7-1.5, see chapter 4 in "circuit foundation" (1979, 1 st edition of the national defense industry press). The precision measurement can be carried out by first selecting one of the values empirically and measuring B as described in item 5 belowmAnd (5) reexamining the curve, adjusting and then measuring, and circularly correcting to be consistent in the above way. The engineering measurements are selected empirically and then no cyclic corrections are made.
ljSee item 1.
4. According to selected BmDetermining the corresponding measurement voltage U
U＝4.44fNΦm
In the formula: f is the power frequency;
n is the number of times the wire turns 7 of the measuring device cross the iron core ring, which is 2 in this embodiment;
Φmmagnetic flux of yoke part, phim＝Bm*Sj，SjSee item 1.
5. Measure selected HmB of (A)m
Adjusting single-phase autotransformer 1 to make the display value of large current be the measuring current I determined in item 3, reading the low voltage value U of the turn 7 of the measuring device at the moment, and judging the quality by directly comparing the low voltage value U with the index of the standard characteristic value of the specific iron core product, or calculating according to the following formula to obtain BmComparing with indexes (such as B) of standard characteristic values of specific raw material steel sheet products10、B25、B50、B100And B300) Judging the quality (taking the measured value not less than the index value as qualified):
Bm＝U/4.44fN/Sj
in the formula: f is the power frequency;
N＝1；
Sjsee item 1.
6. Measurement of selected BmIron loss of
Adjusting the single-phase autotransformer 1 to make the display value of the turn 7 be the measurement voltage U determined in item 4, reading the active power value P of the measurement device at the moment, and judging the quality by directly comparing the active power value P with the index of the standard characteristic value of the specific iron core product, or calculating the obtained value P according to the following formulatComparing with the standard characteristic value index (such as P) of specific raw material steel sheet product10/50、P15/50And P17/50) Judging the quality (taking the measured value not more than the index value as qualified):
Pt＝P/Gj
in the formula: gjSee item 1 for yoke mass.
The measurement and quality control steps can be performed in the order of the above 6 items, or can be adjusted. For example: items 5 and 6 can be omitted, and the repetitive measurement items 1 to 4 can be omitted.
The structure of the measuring device of the 2 nd embodiment of the invention is shown in fig. 4, and the difference from the 1 st embodiment is mainly that: the wire turns 7 are eliminated, and the input of the chip 92 is connected to the posts of the conductive core 6 on the top and bottom cylindrical sides of the column by the connecting wires 71 and 72 instead, namely, the voltage drops at the bottom and top of the column are measured; the difference from the measurement method of embodiment 1 is mainly that N is 1 in item 3 of method one and item 4 of method two. The device outputs low voltage or has low voltage drop, needs high measurement precision, and has a simplified signal detection structure.
The above embodiment may be modified as follows:
-replacing the chips with one chip in the circuit board 9. For example, the chips 91, 93 of the current measuring circuit are replaced by CS7005B or CS5463 used in current electronic watt-hour meters, and the direct output is used for the display 96 to display the value of the active power. CS7005B or CS5463 is characterized by combining conversion function of voltage and current measurement and operation function, and the operation unit is provided with a hardware circuit multiplier without a software multiplication program. For more detailed principles and design reference may be made to the user manual thereof;
for embodiment 1, the number of times the turns 7 cross the core toroid can be increased, improving the accuracy of the low voltage measurement, and if sufficient, can be reduced to a minimum of 1 turn;
the high-precision variable-frequency variable-voltage test power supply commonly used in the laboratory at present can also be used for directly supplying power to replace the single-phase self-coupling voltage regulator;
the large current measurement can also adopt a Hall current sensor.
Claims (1)
1. A performance measuring device for an annular iron core of a motor is characterized by comprising a signal detection part and a signal processing part; the signal detection section includes:
the large-section cylindrical conductive core is used for penetrating through the tested annular iron core and generating voltage drop at the cylindrical bottom end and the cylindrical top end when current passes through the large-section cylindrical conductive core;
the upper conductive joint and the lower conductive joint are respectively connected with two cylindrical ends of the conductive core, and one of the upper conductive joint and the lower conductive joint is detachably connected;
-a single phase adjustable low voltage high current power supply, the output of which is connected via a high current measurement circuit to the upper and lower conducting contacts;
a lead penetrating through the tested annular iron core is arranged, and two ends of the lead output low voltage induced by the tested annular iron core; or the low voltage induced from the tested annular iron core is directly output from the bottom end and the top end of the conductive core column;
the signal processing section includes a conversion unit, an arithmetic unit, and a display unit, and:
the conversion unit converts the signal output by the signal detection part into a signal for processing by the arithmetic unit or/and displaying by the display unit;
the arithmetic unit calculates the signal output by the conversion circuit into a value for display by the display unit by using hardware or a built-in program, wherein the value comprises the large current, low voltage or voltage drop value, an active power value obtained on the basis of the large current, low voltage or voltage drop value, or an iron core performance value obtained on the basis of the values;
the use method of the motor annular iron core performance measuring device comprises the following working step one or working step two;
the working step one:
a. determining the magnetic circuit parameters of the yoke part of the tested annular iron core sample, comprising the following steps:
yoke magnetic path length ljAnd average height hj；
Average yoke section Sj，Sj＝L*KFe*hj(ii) a In the formula, L: length of iron core, KFe: stacking and pressing coefficients;
yoke mass Gj，Gj＝7.8*lj*Sj；
b. Selecting the maximum magnetic induction B for simultaneously measuring excitation and iron lossm,
Selecting according to indexes of standard performance curves or tables of specific raw material steel sheet products and the working range of a magnetic circuit of a specific product motor;
c. according to the selected maximum magnetic induction BmDetermining the corresponding measurement voltage U
U＝4.44fNΦm
In the formula: f-supply frequency;
n, when a wire penetrating through the tested annular iron core is arranged and two ends of the wire output low voltage induced by the tested annular iron core, the value of N is equal to the number of turns of the wire penetrating through the annular iron core; when two ends of the conductive core column directly output low voltage induced by the tested annular iron core, the value of N is equal to 1;
Φmmagnetic flux of yoke, phim＝Bm*Sj，SjSee item a;
d. measuring the selected maximum magnetic induction BmMagnetic conductance and iron loss of
Adjusting the single-phase adjustable low-voltage large-current power supply to enable the display value of the low voltage to be the measurement voltage U determined by the item c, reading the large-current value I and the active power value P at the moment, and judging the quality by directly comparing indexes of a standard performance curve or a table of a specific iron core product with the large-current value I and the active power value P respectively, or:
a) the maximum value H of the magnetic field intensity is calculated according to the following formulamAnd judging the quality by contrasting indexes of standard performance curves or tables of specific raw material steel sheet products:
Hm＝1.414ξ*I/lj
in the formula: ξ is a correction factor related to the core material and the degree of saturation;
ljsee item a;
b) p calculated astAnd judging the quality by contrasting indexes of standard performance curves or tables of specific raw material steel sheet products:
Pt＝P/Gj
in the formula: p is the active power value;
Gjthe mass of the yoke part is shown as item a;
and a second working step:
a. determining the magnetic circuit parameters of the yoke part of the tested annular iron core sample, comprising the following steps:
yoke magnetic path length ljAnd average height hj；
Average yoke section Sj，Sj＝L*KFe*hj(ii) a In the formula, L: length of iron core, KFe: stacking and pressing coefficients;
yoke mass Gj，Gj＝7.8*lj*Sj；
b. Selecting and measuring maximum magnetic induction BmMaximum value of magnetic field intensity HmAnd measuring the maximum magnetic induction B of the iron lossmSelecting according to the standard characteristic value of a specific raw material steel sheet product and the working range of a specific product motor magnetic circuit;
c. at a selected maximum H of magnetic field strengthmDetermining the corresponding measuring current I
I＝0.707Hm*lj/ξ
In the formula: ξ is a correction factor related to the core material and the degree of saturation;
ljsee item a;
d. according to the selected maximum magnetic induction BmDetermining the corresponding measurement voltage U
U＝4.44fNΦm
In the formula: f-supply frequency;
n, when a wire penetrating through the tested annular iron core is arranged and two ends of the wire output low voltage induced by the tested annular iron core, the value of N is equal to the number of turns of the wire penetrating through the annular iron core; when two ends of the conductive core column directly output low voltage induced by the tested annular iron core, the value of N is equal to 1;
Φmmagnetic flux of yoke, phim＝Bm*Sj，SjSee item a;
e. measuring the maximum value H of the selected magnetic field strengthmMaximum magnetic induction Bm
Adjusting the single-phase adjustable low-voltage large-current power supply to enable the display value of the large current to be the measuring current I determined by the item c, and reading the low-voltage value U of the measuring device at the moment1At the low voltage value U1 Directly comparing with the standard index of specific iron core product to judge quality, or calculating according to the following formula to obtain maximum magnetic induction BmAnd judging the quality by contrasting indexes of standard characteristic values of specific raw material steel sheet products:
Bm＝U1/4.44fN/Sj
in the formula: f-supply frequency;
n, when a wire penetrating through the tested annular iron core is arranged and two ends of the wire output low voltage induced by the tested annular iron core, the value of N is equal to the number of turns of the wire penetrating through the annular iron core; when two ends of the conductive core column directly output low voltage induced by the tested annular iron core, the value of N is equal to 1;
Sj-see item a;
f. measuring the selected maximum magnetic induction BmIron loss of
Adjusting the single-phase adjustable low-voltage large-current power supply to enable the display value of the low voltage to be the measurement voltage U determined by the item d, reading the active power value P at the moment, directly comparing the active power value P with the index of the standard characteristic value of the specific iron core product to judge the quality, or calculating the obtained P according to the following formulatAnd judging the quality by contrasting indexes of specific raw material steel sheet product standards:
Pt＝P/Gj
in the formula: p is the active power value;
Gjsee item a for the yoke mass.
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| CN1235058C (en) * | 2003-06-12 | 2006-01-04 | 国家磁浮交通工程技术研究中心 | Long-stator iron core electric performance testing device |
| WO2011010325A1 (en) * | 2009-07-23 | 2011-01-27 | Indian Institute Of Technology, Bombay | An on-line diagnostic method for health monitoring of a transformer |
| CN202126495U (en) * | 2011-06-29 | 2012-01-25 | 刘中阳 | Iron core property comprehensive tester |
| CN203376353U (en) * | 2013-07-03 | 2014-01-01 | 衢州三源汇能电子有限公司 | Tool clamp of annular iron core automatic detection system |
| CN203376415U (en) * | 2013-07-03 | 2014-01-01 | 衢州三源汇能电子有限公司 | Control unit of annular iron core automatic detection system |
| CN205539419U (en) * | 2016-01-19 | 2016-08-31 | 郑州三晖互感器有限公司 | Semi -automatic testing arrangement of circle troidal core magnetic property |
| CN206311655U (en) * | 2016-11-30 | 2017-07-07 | 武汉朗德电气有限公司 | A kind of high-tension cable shield circulating current monitoring and compensating device |
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