CN86205248U - Mechanical and electric powermeter for asynchronous motors - Google Patents
Mechanical and electric powermeter for asynchronous motors Download PDFInfo
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- CN86205248U CN86205248U CN 86205248 CN86205248U CN86205248U CN 86205248 U CN86205248 U CN 86205248U CN 86205248 CN86205248 CN 86205248 CN 86205248 U CN86205248 U CN 86205248U CN 86205248 U CN86205248 U CN 86205248U
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- asynchronous machine
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Abstract
The utility model relates to a mechanical and electric power meter for asynchronous motors, which is from the retrofit of the common three-phase electric power meter. Three-phase search coils are inserted on the three-phase stators winding (each group as a pole phase group) of the asynchronous motor. The output mechanical power of the asynchronous motor can be read directly on the surface of the power meter, the accuracy of which is between 0.5 and 1.5; the output mechanical power of the asynchronous motor can also be obtained indirectly after simple calculation, the accuracy of which is between 0.5 and 1.0. The face sheet of the utility model is provided with two start-ups, which not only measures the input electrical power of the asynchronous motor but also measures the output mechanical power according to the two means, and calculates the efficiency on the load stabilization. The utility model has the advantages of convenient installation and measurement, low cost, and direct reading in particular to the field monitoring of the asynchronous motor.
Description
The utility model belongs to goes up the easy test instrumentation that motor performance indexs such as output mechanical power, input electric power, efficient are measured to the axle of threephase asynchronous machine.
Output mechanical power and efficient thereof are one of important performance index of motor on the asynchronous machine axle, and the breadboard education experiment of product testing, school in factory all need be made measurement to this.In addition, in the actual production scene, also often need mechanical output, carry out scene and supervise and show and relevant research so that it is dragged object, can utilize the energy and energy savings better to exporting on the operating asynchronous machine measurement axis.At present, more advanced, survey instrument is the digital rotational speed and torque power instrument that torque sensor matches with the secondary Displaying Meter easily, it can directly demonstrate the motor output power with numeral, but must change original motor unit base plate before measuring, install torque sensor additional, this just big leap ahead the axial dimension of motor, for guaranteeing measuring accuracy, also must be strict with three with one heart, the workload of installing, adjusting is very big, needs when accurately measuring to revise sensor coefficient by the instant environment temperature of actual measurement.And cost an arm and a leg, be difficult to use at the scene.
The purpose of this utility model is to seek a kind of relatively simple for structure, and it is convenient to measure, and is economical and practical and the measurement instrument of output mechanical power and input electric power on the motor shaft of enough accuracy arranged.
Design of the present utility model is that the first step installs a spot of test coil additional in motor; Second step was done simple repacking to common three phase electric power table.Read formula or direct-reading dual mode between can adopting and measure the output mechanical power of motor.Wherein: the formula of reading measure only need take the first step and through simple computation get final product the output mechanical power of degree of precision; The direct-reading measurement taked for the one the second steps can directly read output mechanical power on the power meter surface.These two kinds of metering systems are described in detail as follows:
Between to read the formula measurement be the output power relational expression P that draws with new derivation
2=(n)/(n
1) (W-P
Fe)-P
Mech-P
SFor foundation, when we embed respective three-phase test coil (1) respectively on motor threephase stator winding (utmost point of every phase is organized mutually), its space distribution differs 120 ° of electrical angles, and connection is consistent with three-phase stator winding, the number of turn is 1/4 of a former phase winding, and line directly is taken between the 0.2mm to 0.5mm.The voltage terminal of common three phase electric power table is connected to the three-phase test coil, and current coil still is concatenated on the power supply routinely.Then the reading of power meter is W, n, n
1, P
Fe, P
Mech, P
SBe respectively rotating speed, synchronous rotational speed, iron loss, mechanical loss, the load stray loss of asynchronous machine, their all available conventional methods are measured, perhaps more simply under the rated voltage no-load test point make Po'=P
Fe+ P
Mech=Po-3I
2 Or
1, Po is the empty load of motor input electric power in the formula, I
OBe the unloaded phase current of stator, r
1It is the stator phase resistance; Draw the P under the nominal load again
SNAfter, P under other load
SCan determine by linear change.Therefore can calculate output mechanical power by preceding relational expression.This formula does not contain temperature-dependent copper loss item, thereby need not survey motor temperature.
The direct-reading measurement is with output power relational expression P
2≈ (n)/(n1) (W-(p
Fe+ p
Mech))-P
S=(n)/(n
1) W '-P
SP
2≈ ((n)/(n
1)-P
S) W '=(1-
) W ' is foundation, respectively measures implication in the formula with preceding identical, the connection of electric power meter is with preceding identical, and different is to utilize fixed loss compensator transformer (2) and loss balancing coil (3) to compensate (P on the current coil of table
Fe+ P
Mech) after W ', utilize rotating speed compensated line (4) compensate for variable loss again, can be on power meter direct-reading P
2House transformer all requires short-circuit impedance little in fixed loss compensator transformer and the rotating speed compensated line, and no-load current is little.Can select the high-quality ring-shaped core for use for this reason.Unshakable in one's determination unsaturated in operating voltage range, coil close around.Its design can be according to a conventional method, and wiring is referring to accompanying drawing one, figure two.Being wrapped in the offset current that the loss balancing coil of table on the current coil passed through determines by following formula: I
b=(1.15～1.25) * (P ' o)/(Vx) * (Wc)/(Wb), as if Current Transformer, Po ' should be divided by no-load voltage ratio substitution again when measuring in the formula, and Vx is a motor lines voltage, and Wc is the former electric power meter current coil number of turn, and Wb is the loss balancing coil turn.With reference to electric power meter current coil institute power taking current density, can determine the wire gauge of loss balancing coil.The rotating speed compensated line is by the additional resistance R of string on the power meter current coil
f, transformer, bridge rectifier, two-level operating amplifier and one-level triode amplifying circuit form.R
fSize depend on and can make 2～3 volts of voltages of rectifier output.The enlargement factor of two-level operating amplifier is determined by following formula: (y-
(I1n)/(I10))/(y-1)=(X-(I
1n)/(I
10))/(X-1), after arrangement, can get y=a(x+b), wherein x is that stator current is (with stator no-load current I
10Be base value) per unit value, y is the per unit value of rotating speed offset current (with zero load time required offset current be base value), and then a is enlargement factor, and x takes from the component voltage of rectifier output among the figure, b takes from and adds fixed voltage, and x, b all import from first order operational amplifier superposition.Remainder can design according to a conventional method, adjust and obtain.Must notice that the rotating speed compensation is all to show (the connecing the cell list of c phase often) of carrying out on that cell list of positive by zero load to being fully loaded with, should calibrate a point (nominal load point) simultaneously, method is mobile x point, making | x| is gradually by equaling | and b| is to greater than | b|, till variable power loss balancing amount is suitable.So through twice compensation, the common electrical power meter can show the output mechanical power of asynchronous machine.
An offset current size that reometer can be observed fixed loss has been installed on the utility model panel, adjustable rheostat adjustable compensation electric current has been arranged to adapt to the needs of different size motor.There is a detection hole can measure the rotating speed compensation rate, also have two switches on the panel, make the power meter gauge outfit both can measure the input electric power of motor and (compensate excision entirely, the voltage terminal of table takes back power line voltage) can measure the output mechanical power of motor by reading formula (not adding compensation) or direct-reading (adding compensation) again, and can calculate load efficiency of motor when stablizing, one table number usefulness provides convenience to the user.
The utility model has the advantages that simple in structurely, need not increase axially and radial dimension; Measure easy, quick; Degree of accuracy is higher, reads formula in the middle of it and reaches the 0.5-1.0 level, direct-reading 0.5-1.5 level; A-table-multi-purpose, and range extension is convenient; Cheap.Be particularly useful for occasion and the on-the-spot power monitoring of asynchronous machine operation that the electric machine assembly compact conformation is not easy to measure with other gimmicks power.Make also not only can be used as power machinery but also can make measurement of power machinery of general asynchronous machine, enlarged the usable range of product.
Figure one is the connection line synoptic diagram of test coil (1), fixed loss compensator transformer (2) and compensating coil (3), and figure two is the synoptic diagram of rotating speed compensated line (4).
The installation adjustment of implementing model machine as mentioned above, its data are as follows: the fixed loss compensator transformer adopts the ring-shaped core of current transformer, cross section 2.75cm
2, the former limit number of turn 1900, line footpath 0.31mm pays the limit number of turn 14, line footpath 0.96mm.Loss balancing coil turn 8, line footpath 0.96mm.The rotating speed compensator transformer also adopts ring-shaped core, cross section 2.75cm
2, the former limit number of turn 200, line footpath 0.96mm pays the limit number of turn 200, line footpath 0.96mm.Additional resistance R
f=0.7 Ω, operational amplifier model LM324N.The output mechanical power value that adopts direct-reading to measure is compared with the performance number that digital rotational speed and torque power instrument is measured, at motor (Y90L-4,1.5KW) (0.15～1.33) P
NIn the scope, the phase difference is no more than 15W, and precision is in 1.0 grades.
Claims (6)
1, by reading formula asynchronous machine machine merit electric work tester between the repacking of three phase electric power table, it is characterized in that,
A) the voltage terminal of electric power meter is received on the three-phase test coil [1],
B) motor output mechanical power P
2=(n)/(n
1) (W-P
Fe)-P
Mech-P
S, W receives the three-phase test coil for the voltage terminal in the formula, and current coil is concatenated into the power meter reading on the motor power, n, n
1, p
Fe, p
Mech, p
sBe respectively the assorted consumption of rotating speed, synchronous rotational speed, iron loss, mechanical loss, load of asynchronous machine,
2, asynchronous machine machine merit electric work tester according to claim 1, it is characterized in that the utmost point that the three-phase test coil is embedded in the threephase stator winding is respectively organized mutually and its space distribution differs 120 ° of electrical angles, connection is consistent with three-phase stator winding, line is directly got 0.2mm to 0.5mm, and the number of turn is 1/4 of a former phase winding.
3, by the direct-reading asynchronous machine machine merit electric work tester of three phase electric power table repacking, it is characterized in that,
A) fixed loss compensator transformer (2) and compensating coil (3) are arranged,
B) rotating speed compensated line (4) is arranged,
C) reading is motor output mechanical power P on the table
2≈ ((n)/(n
1)-P
S) (W-p
Fe-p
Mech), respectively measure implication in the formula with preceding identical, P
SBe p
S/ P
2,
4, according to the described asynchronous machine machine of claim 3 merit electric work tester, the former limit that it is characterized in that the fixed loss compensator transformer is attempted by on the voltage terminal of power meter, pay the limit and be attempted by on its compensating coil, the former limit of transformer in the rotating speed compensated line is attempted by the current coil and the R of table
fOn, pay the edge joint rectifier, this two transformer all requires no-load current little, short-circuit impedance is little, and is unshakable in one's determination unsaturated in operating voltage range, coil close around,
5, according to claim 3,4 described asynchronous machine machine merit electric work testers, it is characterized in that being wrapped in the electric current that the loss balancing coil on the table current coil passes through is (1.15～1.25) (P'
0)/(V
X) (W
C)/(W
b), Po ' in the formula=p
Mech+ p
Fe=Po-3I
2 Or
1, V
XBe motor lines voltage, W
c, W
bBe respectively the number of turn of table current coil and compensating coil, refer again to the used current density of table current coil, determine the wire gauge of compensating coil,
6, according to claim 3,4,5 described asynchronous machine machine merit electric work testers, it is characterized in that rotating speed compensated line (4) is by the additional resistance R that is serially connected on the power meter current coil
f, transformer, rectifier, two-level operating amplifier and one-level transistor amplifier form, R wherein
fSize depend on and can make 2～3 volts of voltages of rectifier output that the enlargement factor of secondary transport and placing device is determined by following formula: (Y-
(I
1n)/(I
10))/(Y-1)=(X-(I
1n)/(I
10))/(X-1), can get Y=a(X+b through arrangement), then a is enlargement factor, and b takes from and adds fixed voltage, and X takes from the component voltage of rectifier output, and b, X are all from the input of first order transport and placing device superposition, P
SBe p
S/ P
2
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86205248 CN86205248U (en) | 1986-07-18 | 1986-07-18 | Mechanical and electric powermeter for asynchronous motors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 86205248 CN86205248U (en) | 1986-07-18 | 1986-07-18 | Mechanical and electric powermeter for asynchronous motors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN86205248U true CN86205248U (en) | 1987-06-17 |
Family
ID=4808125
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 86205248 Withdrawn CN86205248U (en) | 1986-07-18 | 1986-07-18 | Mechanical and electric powermeter for asynchronous motors |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN86205248U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110412466A (en) * | 2019-09-02 | 2019-11-05 | 无锡康沃特变频电机有限公司 | Measure the structures and methods of high revolving speed permanent magnet motor operating parameters |
-
1986
- 1986-07-18 CN CN 86205248 patent/CN86205248U/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110412466A (en) * | 2019-09-02 | 2019-11-05 | 无锡康沃特变频电机有限公司 | Measure the structures and methods of high revolving speed permanent magnet motor operating parameters |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C15 | Extension of patent right duration from 15 to 20 years for appl. with date before 31.12.1992 and still valid on 11.12.2001 (patent law change 1993) | ||
| RN01 | Renewal of patent term | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |