JB/T 2657.2-1999 Technical requirements for BD and BS series non-contact synchro machines
Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T2657.2
BD BS
1999-08-06
Wa Xian Ji Dong
2000-01-01
JB/T2657.21999
This standard is a revision of JB2658-80 "BD, BS series non-contact self-aligning machine". During the revision, in addition to the editorial changes made to the original standard, the following changes were made: 1. The relevant terms and terms were changed according to national standards; 2. The contents that do not belong to the product technical conditions, such as "the bearings should be coated with good anti-rust lubricating grease", were removed; 3. The technical requirements for winding diagrams and non-excitation friction torque were deleted; 4. The test method for static error of the synchro receiver was added with a note to adapt to the automatic test method that has been adopted recently; 5. The speed of the accelerated life test of the 5500 synchro was increased to be consistent with the requirements of the 404 and 501 types; 6. The temperature and mechanical zero position of the high and low temperature tests were supplemented with appropriate deviations. This standard replaces JB2658-80 from the date of implementation. This standard was proposed and managed by the National Micromotor Standardization Technical Committee. The drafting unit of this standard: Shanghai Shangwei Jinli Motor Co., Ltd. The main chapter authors of this standard: Chen Fen and Chen Enci. This standard was first issued in July 1980.
Jijiakuiluwayixian
BDkeBS
JB/T2657.21999
JB26581980
This standard specifies the classification, requirements, test methods, inspection rules, marking, packaging: transportation, storage and other requirements of BD and BS series non-contact self-synchronous machines.
This standard applies to BD and BS series non-contact self-synchronous machines with a frequency of 50Hz and a frame size of 4 and 5. 2
The non-contact self-synchronous machine has two separate windings: one is a three-phase winding, whose outgoing line is marked with letters T1, T2 and T3; the other is a single-phase winding, whose line is marked with L1 and L2. This series of synchro machines are divided into three categories according to their uses, see Table 1 Table 1 Classification of non-contact synchro machines
Non-contact grid angle transmitter
Non-contact white synchro receiver
Non-contact white synchro transformer
BD-404A, BD-404B, BD-500, BD-501A, BD-501BBS-404A, BS-404B, BS-500, BS-S01A, BS-50IB, DBS--500BS-405
Note: The DRS-501 synchro machine consists of two receivers installed in a housing, which are used to receive instructions from two transmitters on the same dial.
Non-contact type angle receivers are equipped with mechanical dampers. In the synchro system, the synchro transmitter and synchro receiver or synchro transformer should be connected according to Figure 1 or Figure 2. The maximum number of synchro receivers or synchro transformers that can be driven by the synchro transmitter is shown in Table 2. Table 2 Maximum number of synchro matching
RS—404A
BL-404A
BD-—404B
BL—500
BD—501A
BD501B
Usage environment
BS—404B
1999-08-06
BS—405
BS—so0
DBS—S00
B S—501A
BS:501D
2000-01-01 Small cable
JB/T2657.2
This series of synchro motors are allowed to work under the following conditions, and the performance should meet the requirements of this standard: a) Air temperature: -40~+55r (humidity is 60%-70%); b) Relative humidity: 92%-98%
Vibration:
d) Shock:
(air temperature is 20±5%
double amplitude 1.4 ± U.2 mm, frequency 10 Hz: frequency 1.33 Hz, acceleration 70 m/s2. Note: For BD-500, 8S-500, DBS-500, there is no impact requirement. 3.2 Rated data
The rated data of the synchro should meet the values listed in Table 3. 3.3 Appearance quality
3.3.1 The surface of the synchro should be free of rust and mechanical damage. The fasteners should be tightened and sealed with enamel paint as appropriate. 3.3.2 Except for the shaft extension end and the mounting surface for the user to install the dial, the surface of the synchro must have a firm coating to prevent rust and moisture: The shaft end of the machine should be coated with anti-rust grease. 3.3.3 The writing and content of the terminal board and nameplate should be clear and not fall off. 3.4 Overall dimensions and installation dimensions
The overall dimensions and installation dimensions of the household full-angle machine should meet the requirements of Figure 3-Figure 8. Note: Except for the dimensions with tolerances, the other dimensions are for reference. 3.5 Radial runout
3.5.1 The radial runout of the outer circle of the housing installation mating surface to the rotor axis should not exceed 0.09min. 3.5.2 The radial runout of the shaft end mating surface should not exceed 0.09min. The radial runout of the shaft axis should not be greater than 0.05mm. However, the radial runout of the hollow shaft extension of BD-500, BS-500 and DBS-500 should not be greater than 0.02mm: the radial runout of the solid shaft extension of DBS-500 should not be greater than 0.08mm. 3.6 Flange end face runout
The end face runout of the flange end face to the rotor axis at the installation of the self-synchronous machine should not be greater than 0.1mm, and for BD-500, BS-500 and DBS-500, the radial runout of the hollow shaft extension should not be greater than 0.02mm: the radial runout of the solid shaft extension of DBS-500 should not be greater than 0.08mm. S—500 should not be greater than 0.15mml
3.7 Axial clearance
The axial clearance of the synchro should be within the range of 0.05-0.15mm. 3.8 Excitation static friction torque
The excitation static friction torque of the synchro should comply with the provisions of Table 4. 2
JB/T2657.2
Vlosaa
Z--00s—Na
[00s-Na
士Y±
(。 ）uN
FIOS—E
Vios-sa
2—00S—s
2—005
- 00-
1005·8
HS-404A, BS--404B
BS—500、DBS-500（hollow shaft and solid shaft）BS—501A.BS-501B
BD—404ABD—404B、HS—405
BD-500
BD-501A. ED -501B
3.9 DC resistance
JB/T2657.21999
Table 4 Excitation static friction torque
The DC resistance of the synchro winding shall comply with the value specified in the product drawing. 3.10 Insulation resistance
The insulation resistance of all windings of the synchro to the housing and between the windings shall be: The magnetostatic torque shall not exceed
a) When the ambient temperature is 20±5℃ and the relative humidity is 60 %~70% is not less than 100M0; 6) when the ambient temperature is 55±2℃ and the relative humidity of the air is 60%~70% at a stable temperature rise, it is not less than 50M0; d) place the self-synchronous angle machine in an environment with a temperature of 20±s℃ and a relative humidity of 92%-98%, take it out after 20 days, place it for 25min and measure it within 5min, it is not less than 1M; then apply the rated medium voltage to the single-phase winding, measure it immediately after 6h±15minl, it is not less than 5M beans.
3.11 Rotation direction
When the self-synchronous angle transmitter, the self-synchronous angle receiver or the self-synchronous angle transformer is connected to the standard transmitter specified in Table 3 according to Figure 1 (for the self-synchronous angle transmitter, it is connected to the standard transmitter of the same model), the rotation direction of the two should be the same when viewed from the direction of the wiring board. The standard transmitter should be regularly checked for its rotation direction using a D-511 standard transmitter meter. At the same time, the zero position error of the standard transmitter should not exceed 0.15°.
3.12 Damping time
When the auto-sync receiver and the transmitter are adjusted from 177\±2° to coordination, the damping time of the receiver should comply with the provisions of Table 3.13 Accuracy
All synchro receivers are classified into accuracy grades according to their static errors, while synchro transmitters and synchro transformers are classified into accuracy grades according to their zero position errors, see Table 5.
Table 5 Error and accuracy grades
BD—404A, BD404B, BD-500, BS—405BD—501A, BD50IB
BS—404A.BS—404P, BS—500, DBS500.BS--501A. BS—501E
3.14 Insulation dielectric strength
Error name
Zero error
Standard error
Maximum half mean error\【）
>0.25-0.5
>0.35-0.5
>0.75~1.5
The insulation of the conductive part of the rectifier to the casing should be able to withstand a 50Hz, 1000V stop-sine wave voltage for 1min without breakdown. 4
JB/T2657.2
The insulation dielectric strength test shall not be repeated more than once, and the test voltage during the retest is 750V. 3.15 Temperature rise
When the excitation voltage increases by 4% of the rated value and works for a long time, the winding temperature rise shall not exceed 55K. 3.16 Shock and vibration
The door synchro should be free from mechanical damage, loose fasteners and loss of synchronization under the following test conditions. Its accuracy level should remain unchanged after the test,
a) Under the condition of vibration with a frequency of 10Hz and a double amplitude of 1.4±0.2mm for 2 hours; b) Under the condition of a shock acceleration of 70m/s= and a shock frequency of 1.33I1z for 10 minutes (for BD-500, BS-500 and DBS-500 white synchro, there is no such shock requirement. 3.17 Low temperature
When the synchro receiver is placed at a temperature of -40±2℃ for 2 hours and operated at the same temperature for 30 minutes, its static error is allowed to increase by 0.75°.
3.18 High temperature
BS-500 and DBS- When the 500 synchro is placed at a temperature of 55±2°C for 2h, its static error is allowed to increase by 0.5°. 3.39 Dynamic error
When the transmitter rotates at a speed of 60r/min, the dynamic error of the synchro receiver with a damper is not more than 5°; when driven by a sine wave with a vibration of 720° and a period of 6s, it is not more than 7°. BS-500 and DBS-500 synchro receivers do not have this requirement. 3.20 Life
When the average operating speed is 10 r/min, the synchro should be able to run synchronously for 300Xh, and the error after running is allowed to exceed the range of its initial value.
Table 6 Allowable increase in error after life test
BS--404A.BS404, BS-501A.B5-501BBS-500,13BS-500
BD-500
BD-404A,BD404B, BS-405.BD-501A,BD-5DIB3.21 Noise
The error increase value is not more than ()
The noise of the synchro should not exceed 65B for BS-405, BS-500, DBS-500, BD-500; it should not exceed 70 for other models. dB.
3.22 Changes in voltage and frequency
When the changes in the grid voltage and frequency reach the deviation given in Table 7 compared with the rated value, it should not affect the normal operation of the self-synchronous receiver. In this case, check its static error. Compared with the error obtained at the rated voltage and frequency, the allowed increase value is shown in Table 7.
JB/T2657.2
Table 7 Voltage and frequency change values,
Error allowable increase value
Deviation from rated value%
BS—404A, BS—404B, BS—501A, BS—501BBS—500. DBS-500
3.23 Mechanical zero position
Error increase value is not greater than
Except for BD-500, BS—500, DBS-500 In addition. There should be a mechanical zero position mark hole on the thrust ring and end cover or bearing cover of the rotor of other types of synchro motors: when the synchro transmitter, receiver or synchro transformer and the standard transmitter are connected according to Figure 1, the two mark holes of the standard transmitter are exactly the same, and the deviation between the two mark holes of the tested synchro motor should not exceed 20°. The mechanical zero position of the synchro transmitter is checked with a standard transmitter of the same model. 3.24 Electrical zero position
There should be an "electrical zero position mark" on the thrust ring and front cover of the BD-500 synchro rotor. When checked according to the prescribed method, the deviation between the two marks should not exceed 20°. 3.25 High-speed synchronous speed
When the speed of the synchro transmitter increases from 0 to 500 r/min, the synchro receiver should not lose synchronization. 3.26 Tilt
For BS-500D and DBS-500 For self-grid angle machines, when the center line of the axis is tilted 45° in any direction from the horizontal position, its static error compared with the static error in the horizontal position should exceed 0.5°3.27 Weight
The weight of the self-grid angle machine should not exceed the values listed in Table 8. Table 8 Weight
BD--404A, BD404B, BS—405
BS—404A, BS—404B
BD501A, BD50LB|| tt||BS—501A,BS—501B
BD—500
BS—500
DBS-500
4 Test Methods
4.1 Test Conditions
All tests shall be conducted under the following conditions unless otherwise specified: a) Ambient temperature is 20±5°C; b) Relative humidity is 60%~70%; c) Pressure is 96~104 kPa:
d) The accuracy of the air measuring instrument shall not be lower than Class 1; 6
Weight kg
e) The angle machine shall be installed horizontally. wwW.bzxz.Net
4.2 Appearance quality
JB/T2657.21999
Visually inspect the external quality of the angle machine, which shall comply with the provisions of 3.3. 4.3 Overall dimensions and installation dimensions
Use a measuring instrument or special measuring instrument that can ensure the dimensional accuracy requirements of the product drawing to inspect the overall dimensions and installation dimensions of the angle machine, which shall comply with 3.4
4.4 Radial runout and flange end runout 4.4.1 Fix the self-synchronous machine and use a dial indicator to measure the radial runout of the housing mounting surface and the radial runout of the flange end. Measure each three times. The average value should meet the requirements of 3.5.1 and 3.6. 4.4.2 Fix the housing of the self-synchronous machine and use a dial indicator to measure the radial runout three times at different positions of the shaft extension and the flange end when the shaft is rotated. The average value should meet the requirements of 3.5.2. 4.5 Axial clearance
Fix the self-synchronous machine on a special device and rotate it. Two axial thrusts in opposite directions are applied to the shaft (or housing) one after another, 50N thrust for the No. 4 machine base and 100N thrust for the No. 5 machine base, so that the shaft (or housing) moves back and forth along the axis. The movement value is the axial clearance. The measurement is made 3 times in total, and the average value should meet the requirements of 3.7. Invitation magnet static friction torque
The white angle machine is applied with rated pressure, a wheel with a diameter of 2-5cm is fixed at the end of the shaft, and the load (base weight) is hung on the pulley with a thin line, and its weight
In the formula: M—the friction torque allowed by 3.8, mN·m; R——pulley radius. cin.
Driven by the base weight, the white angle machine is rotated in the positive and negative directions for 2~3 turns at a speed of 2-3T/min. If there is no stop phenomenon, it is considered that the excitation magnet static friction torque is sufficient. 4.7 DC resistance
Put the rectifier at room temperature for more than 2 hours, and use a bridge or ohmmeter to measure the DC toe of each winding. The measurement results should meet the requirements of 3.9.
4.8 Normal insulation resistance
According to the requirements of a) in 3.10, use a 500V megohmmeter to measure the insulation resistance. The time for each measurement shall not be less than 3$, and the measurement results shall meet the requirements of a) in 3.10.
4.4 Insulation dielectric strength
According to the requirements of 3.14, when the capacity is not less than 0.5kVA test equipment is used for the insulation dielectric strength test. During the test, all windings of the synchro can be connected in parallel.
The time for the test output voltage to increase from the full value slowly and evenly or step by step (each level does not exceed 50V) to the full value shall not be less than 10s. Keep it at the full value for 1min, then reduce it evenly and slowly to zero value and disconnect the power supply. If no insulation breakdown is found during the test and the normal insulation resistance after the test is not less than 100M2, the test is qualified. 4.10 Excitation current, excitation power, and output voltage JB/T2657.21999
Connect the synchro according to Figure 9, and apply the rated voltage of 50Hz to the single winding of the synchro to check the excitation current, excitation power, output voltage and their difference. The measurement results should comply with the relevant provisions in 3.2. When the output winding is open, use an ammeter to measure the excitation current; use a power meter to measure the excitation power. When measuring the maximum output voltage, use a voltmeter with an internal resistance of 1800~2000 for BD-404A, BS-404A, BD-501, ABS-501A, BL-500, BS-500, and DBS-500; use a voltmeter with an internal resistance of 1000/V or a vacuum tube voltmeter (but the reading of the vacuum tube voltmeter needs to be corrected by the calibration method) for BD-404B, BS-404B, BV-501B, BS-501B, and BS-405, and connect it to each pair of line ends of the three-phase winding in sequence for measurement (eight times in total), slowly rotate the rotor of the measured concave rectifier until the pointer of the voltmeter has a large deflection, read the maximum output voltage, and calculate the difference of the maximum output voltage based on this result. 4.11 Direction of rotation
According to the requirements of 3.1I, connect the standard transmitter and the tested auto-synchro according to Figure 1. If the tested auto-synchro itself is correctly connected, when the standard transmitter rotates, the tested auto-synchro should rotate in the same direction as the standard transmitter when viewed from the wiring board. 4.12 Damping time
Connect the standard transmitter and the standard transmitter according to the figure, and install the auto-synchro in the test frame. The connected standard transmitter is selected according to Table 3 in 3.2.
Brake the rotor of the auto-synchro transmitter, and install a pointer for measuring the damping time (made according to Figure 10) on the shaft extension end of the tested auto-synchro receiver. Then disconnect the power supply and rotate the receiver 177°+2° relative to the rotor of the lower transmitter. Then connect the power supply again and turn on the switch while the voltage is applied. From the time the power is turned on to the time the receiver is The time required for the rotor to return to the position coordinated with the transmitter is the damping time. Measure three times in total, and the average value should meet the relevant provisions in 3.2. Calculation: When the movement of the pointer does not exceed ±0.25. It can be considered that the coordinated position has been reached. 4.13 Accuracy
4.13.1 For the self-synchronous angle receiver, use the line with the standard transmitter to measure the static error and determine the accuracy level. Connect the measured angle receiver and the standard transmitter (selected according to Table 3 in 3.2) as shown in Figure 1. Wiring: The transmitter and receiver are installed in the test frame respectively. , a dial with a diameter of 250-300mm and concentric with the axis is fixed on the frame, and the dial scale is evenly divided into 360°. The transmitter and receiver axes are equipped with overbalanced vernier pointers (Figure 11). After the rated voltage is applied to the single-machine windings of the transmitter and receiver, the transmitter and receiver pointers are aligned to zero. Then, evenly rotate the transmitter rotor clockwise for one circle, and then rotate it counterclockwise for one circle without re-adjusting the fog: during the rotation process, fix the transmitter rotor every 10° and start from The angle of rotor deflection is read on the dial of the receiver. The error of the receiver can be obtained based on the difference in the rotor angles of the transmitter and the receiver. This error can be positive or negative. Half of the sum of the absolute values of the maximum positive and negative errors of the receiver when the transmitter rotates clockwise and counterclockwise is the static error, and the accuracy level is determined according to this error value. Note
1 The full amplitude of the pointer swing is allowed to not exceed 0.5°. When the self-regulating receiver has the right to move, 1/2 of the pointer probe value should be excluded from the error during swing when determining its accuracy level.
2 From the time of sending the positioning. The time for the receiver and the transmitter to achieve coordination should not exceed 1.3. When the self-regulating receiver is inspected, only its static error and accuracy are measured, while during the type inspection, an error curve needs to be drawn. 4 It is allowed to be measured by other methods that can ensure the test accuracy. 4.13.2 For the self-synchronous angle transmitter, the zero position error is measured by the zero voltage method and the accuracy grade is determined. The self-synchronous angle transmitter is installed in the test channel for testing the static error in 4.13.1, and the axis is equipped with a vernier pointer that has been calibrated for balance. 8
JB/T2657.21999
Apply the rated voltage to its single-phase winding, and the three pairs of terminals TI-T2, T2-13, and T3-TI of the three-phase winding are connected to the vacuum arm voltmeter or cathode ray oscilloscope in turn (see Figure 12 for wiring). When any pair of terminals is connected to the vacuum tube voltmeter or cathode ray oscilloscope: slowly rotate the rotor, and the position where the meter or instrument indicates the minimum voltage is the zero position. Six zero positions can be obtained within one rotation of the rotor.
For each self-synchronous angle machine under test, any zero position can be selected from the six zero positions to start measurement. The rotor angle of the first zero position is taken as the reference. The difference between the actual angle values of the other five zero positions and the first zero position and the theoretical 60°, 120°, 180°, 240° and 30° is the error of each point. Half of the sum of the absolute values of the maximum positive and negative errors is the position error, and the accuracy level of the self-synchronous angle transmitter is determined accordingly.
4.13.3 For the self-synchronous angle transformer, the zero position reading difference is measured by the zero voltage method to determine the accuracy level. Install the self-synchronous angle transformer in the test stand for testing static errors in 4.13.1, and install a vernier pointer for overbalancing on the shaft. First connect the wires according to Figure 13. The power supply is 35 V. The three pairs of terminals T1-T2, T2-T3, T3-T1 of the three-phase winding are connected to the power supply in turn, and the single-phase winding is connected to the empty tube voltmeter or cathode ray oscilloscope. When any pair of terminals is connected to the power supply, it rotates slowly. The position when the meter or instrument indicates the minimum voltage is the zero position. According to this wiring diagram, six zero positions can be obtained within the range of one rotation. For each self-commutating transformer under test, any zero position can be selected from the six zero positions to start measurement. The rotor angle of the first zero position measured is used as the reference, and the difference between the actual angle values of the other five zero positions and the first zero position and the theoretical 60°, 120°, 180°, 240° and 300° is the difference between the actual angle values of the first zero position and the theoretical 60°, 120°, 180°, 240° and 300°, which is the difference between the actual angle values of the first zero position and the theoretical 60°, 120°, 180°, 240° and 300°, ... Six more zero positions are available in China.
The rotation angle of the first position selected when measuring the circuit according to Figure 13 is still used as the basis. The difference between these six zero positions and the actual angle values of the position and the theoretical 30°, 90°, 150°, 210°, 270° and 330° respectively is the error of the customer point. There are eleven error values in total. Half of the sum of the absolute values of the maximum positive and negative errors is the position error, and the accuracy level of the angle transformer is determined accordingly.
4.14 Mechanical zero position
Check the mechanical zero position according to 3.23. Install the standard transmitter and the test self-synchronous machine in the test frame of 4.13.1 and connect them according to Figure 1. When the end cover of the standard transmitter Or when the marked hole on the bearing cover coincides with the marked hole on the rotor thrust ring, brake its rotation. When compared, the deviation between the marked hole on the end cover or bearing cover of the test angle machine and the marked hole on the rotor thrust ring should not exceed 20°. 4.15 Air zero position
Perform an electrical position check on the BD-500 angle transmitter according to 3.24, connect the wires according to Figure 15, and apply a rated frequency medium voltage at this time. The rotor of the auto-synchro should rotate to the position where the deviation between the marked hole on the rotor thrust ring and the marked hole on the front cover is no more than 20°. 4.16 Maximum step torque and relative step torque According to the requirements of 3.2, check the maximum step torque and relative step torque of the auto-synchro receiver. During the measurement, clamp the auto-synchro on In the test stand with a dial as described in 4.13.1. Fasten the error measuring indicator (Figure II) and a pulley with a diameter of 2~5cm to the receiver shaft, and obtain the torque by hanging the base code as the load through a wire wrapped around the wheel rim. This wire is wrapped around the wheel 2~3 times. The self-synchronous machine is connected according to Figure 1, and the rotor of the transmitter is braked during the test. The model of the standard transmitter is selected according to Table 3 of 3.2 9
JB/T2657.21999
The maximum full-step torque is determined by gradually increasing the load until it starts to fall. The maximum full-step torque is the product of the code weight (g) and the wheel radius (cm) at the beginning of the fall, multiplied by 0.098. This value should meet 3.2. The full-step torque can be calculated according to the full-step torque measured when the adjustment angle is 5°±1 according to the following formula. The calculated value should meet the relevant provisions of Table 3 in 3.2.
ma=M/[mN·m/()]
Where: M=0.098GR—full-step torque, mNm; H misalignment angle, (°);
G load weight, g;
R——pulley radius, cm.
4.17 Humidity source
After applying anti-rust grease on the shaft extension end of the self-synchronous machine and the matching surface without painting, place it in a constant humidity chamber with a temperature of 20°C and a relative humidity of 92%~98%. The volume of the constant humidity chamber should be twice the total volume of all the self-synchronous machines tested at the same time. The water level in the box is not less than 40m: the surface area of the liquid should be more than 20% larger than the projected area of the water surface of the tested synchro. The tested synchro is placed on a support channel so that the bottom of the synchro is about 200mm away from the liquid surface. The condensed water on the inner wall of the box is not allowed to drip onto the tested synchro. This lasts for 20 days. The temperature in the box is measured with a thermometer. Once every night, there should be an air stirring device in the box. The agitation is measured with a dry mixing ball. The humidity is placed about 300mm from the bottom: after 20 days, the synchro is taken out of the box, placed for 25min, and the insulation resistance is measured within 5min; then, the tested synchro is installed in a metal bracket, and the rated voltage is applied to the single-phase winding. After 6-15min, the insulation resistance is measured again. If the insulation resistance of the winding to the housing and the windings to each other meets the requirements of c) in 3.10, it is qualified. 4.18 Temperature rise
The synchro to be tested is installed in the metal bracket shown in Figure 16, and the bracket is fixed on a metal plate of 150×t90×10 (in mm). The temperature rise test is carried out in a constant humidity chamber at a temperature of 552℃. Only the BS-405 synchro transformer shall be connected to the BD-404A transmitter according to Figure 2 during the test. The transmitter is fed by a 50Hz113V power supply. The rotor of the synchro transformer is braked at a position where the misalignment angle is 5° different from the transmitter, and a load resistor of 800? is connected in its single winding.
For other types of synchro transformers, an AC current with a rated frequency and positive voltage increased to 4% higher than the rated value is applied to its single-phase winding, and the three-pole winding is open-circuited.
The test shall be carried out until the actual stable temperature is reached, but not less than 2h. If the temperature change does not exceed 1° within 1h, it is considered that the actual stable temperature has been reached. The temperature rise of the winding is calculated by the resistance method as follows: R1 -Ri (234.5+t)+ti - t
-winding temperature rise, K;
or: 6
R1-winding resistance before the test, :
R2-winding resistance in hot state, :
-ambient temperature at the beginning of the test, tr
-ambient temperature at the end of the test, °C. t
Note: The thermometer used to measure the ambient temperature is placed 0.35Ⅲ away from the measured white angle machine. 10
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