Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T2379
1993-08-21
JB/T23791993
JB23791978
This standard specifies various requirements for metal tubular electric heating elements (hereinafter referred to as elements), including product classification, technical requirements, test methods, inspection rules, ordering and supply, etc. This standard applies to tubular electric heating elements designed and manufactured according to the requirements of Articles 3.1, 4.1 and 4.2, with a working voltage not exceeding 440V and a metal tube as the outer surface.
This standard does not apply to tubular electric heating elements for daily use and similar purposes. For components used in vacuum or in media with an absolute pressure exceeding 1MPa and for components with special requirements, in addition to complying with this standard, they shall also comply with the corresponding standards for special requirements.
2 Terms
The terms used in this standard have the following meanings: 2.1 Metal tubular electric heating element
An electric heating element with a metal tube as the outer shell, an alloy heating wire as the heating element, and a lead rod (wire) at one or both ends. The metal tube is filled with dense magnesium oxide powder insulation medium to fix the heating element. 2.2 Lead rod (wire)
A metal conductive part connected to the heating element for connecting the element to the power supply and between elements. 2.3 Expanded length (L), mm
The sum of the lengths of the straight and curved parts of the metal tube on the element pattern. 2.4 Heating length (t): mm
The length of the heating element on the element sample. 2.5 Heating surface area, cm2
The area of the metal tube on the heating length.
2.6 Surface load, W/cm
Power per unit area on the heating surface.
2.7 Full heating conditions
Working conditions that enable the component to reach the specified working state. 2.8 Rated voltage, V
refers to the voltage connected to the component specified in the design and marked on the component housing. 2.9 Rated power, kW
refers to the component input power specified in the design and marked on the component outer shell. 2.10 Working voltage, V
For a single component connected to the power supply, it refers to the voltage connected to the component specified in the design, that is, the rated voltage. For a group of multiple components connected in series to the power supply, it refers to the voltage connected to this group of components specified in the design. 2.11 Working temperature, ℃
The average temperature of the heating surface of the component under rated power and full heating conditions. 2.12 Maximum temperature, ℃
1993-08-21
1993-10-01
JB/T2379
The temperature of the highest temperature point on the heating length of the optical component under 1.27 times the rated power and full heating conditions. 2.13 Simulation conditions
The working case in which measures are taken to make the operating temperature of the component basically consistent with the specified value under the conditions of each clause of this standard. 2.14 Repair
Refers to the repair of the lead-out rod damage, metal surface coating damage, insulator breakage and sealing failure of the component, and the repair does not affect the performance and normal use of the component.
2.15 Restoration
The process of restoring the electrical insulation performance of the component to the standard value through methods such as oven drying due to the use and long-term storage, which is lower than the standard value, and does not affect the performance and normal use of the component. 2. 16 Damage
No components are considered damaged if any of the following conditions occur: a. The withstand voltage of the component is lower than the standard value, the leakage current value is greater than 5mA, or the insulation resistance value is lower than 1MQ, and it cannot be restored. b. There is flame emission and molten material, severe surface corrosion or other damage that cannot be repaired, c. The actual power of the component exceeds the rated power by 20%. 3 Product classification
3.1 Varieties and specifications
3.1.1 Components are divided into the following four varieties according to their basic structure: L
Components with double leads, one end connected to the shell, structure code B. Its size code and name should be basically consistent with Figure 1. L
Components with double leads, one end connected to the shell, structure code B. Its size code and name should be basically consistent with Figure 2. L
Components with single leads and parallel lead rods, structure code C. Its size code and name should be basically consistent with Figure 3. N
JB/T2379
Single-end lead-out, lead-out coaxial components, structural code D. Its size code and name should be basically consistent with Figure 4. d,
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AA:AtT
Note: The meanings of the serial numbers and symbols shown in Figures 1 to 4 are as follows: L-the expanded length of the component, L-the outer diameter of the component, L-the wall thickness of the component, LdLa-the length of the inner part of the lead-out section: L-the non-heating length of the part: 1-lead-out rod, 2-end sealing material: 3-alloy heating wire, 4-insulating filler magnesium oxide powder, 5-metal tube, 6-metal plug, 3.1.2 Components can be divided into: Ordinary components: mainly used for heating with gas and liquid. b. Embedded components: mainly used for heating metal solids and components with certain requirements for outer diameter size deviation. 3.1.3 Each type of component is divided into multiple specifications according to the outer diameter size. The outer diameter size (diameter, mm) should be selected from the following specifications: 22, 20, 16, 14, 12.10, 8.5 and 6.5. 3.2 Model
The model of the component and its meaning are as follows: 口口口口
Rated voltage, V Rated power, W
Design serial number
Heating medium, heating characteristic code
Structure code (A, B, C, D)
Small category code, G is tubular
Major category code, G is industrial (generally can be omitted) 3. 3 Main parameters
The main parameters of the components are as follows,
a. Power supply voltage, V;
b, Power supply frequency, Hz
c. Rated voltage, V
d. Rated power, kW
e. Working temperature,
1. Outer diameter, mml
g. Expanded length, mm;
n. Overall dimensions, mm
1. Weight, kg.
4 Technical requirements
4.1 Design requirements
JB/T2379
The design of the components should meet the requirements of use, convenience of replacement, reliability, durability, safety, economy, rationality and energy saving. 4.1.1 Design Standards
The design of components shall comply with the basic standards and general component standards of relevant electromechanical products: such as unit system, mechanical drawing, graphic symbols, tolerance and fit, shape and position tolerance, surface roughness, threaded fasteners, output voltage, power frequency and other standards. If there are special requirements for units, power voltage and output frequency, they can be proposed according to Article 8.2. 4.1.2 Environmental Conditions
Altitude shall not exceed 1000m
Ambient temperature -20~50℃,
Ambient relative humidity shall not exceed 90% (when ambient temperature is 25C); d. There is no conductive dust, explosive gas and corrosive gas that can seriously damage metal and insulating materials in the surrounding area, and there is no obvious impact and vibration. When the user has special requirements, they can be proposed according to Article 8.2. 4.1. 3 Safety and Health
4.1.3.1 For components used for heating in flammable atmosphere, the design should consider avoiding explosion accidents. 4.1.3.2 For components used for heating in pressure medium, the design should consider avoiding pressure relief accidents caused by damage to metal pipes, welds and seals. 4.1.3.3 For components used in toxic and harmful media such as heat, the design should consider avoiding harmful media leakage accidents caused by damage to metal pipes, welds and seals.
4.1.3.4 The shell or coating of components in contact with food and eating utensils must meet the national health standards. 4.1. 4 Materials
The materials used for manufacturing components should be reasonably selected according to their use requirements and should meet the requirements of their quality standards. 4.1.4.1 Common materials and their maximum allowable temperatures for component metal tubes are shown in Table 1. Table 1
Material and its grade
Maximum allowable temperature,
Material and its grade
Stainless steel 0Cr18Ni11 (1Cr1&Ni9TI) Nickel-based alloy steel IncoloyB0o
JB/T2379
Continued Table 1
Maximum allowable temperature,
Note, 1) The main reductions are: 0.04%C, 0.75%Mn, 0.35%Si, 20.5%Cr, 32.00%Ni, 0.30%Cu and remainder Fc. 4.1.4.2 The maximum surface load allowed by common materials of component metal pipes in common media shall comply with the provisions of Table 2. Table 2
Surface load W/em
Heating medium, heating characteristics and codes
Water, boiling of weak acid and weak alkali solution, S
Food oil, lubricating oil, hydraulic oil, Y
Combustion oil,
Water with a pressure greater than IMFa, A
Still air
Air with a velocity not less than 6m/s, L
Component is cast. Embedded and pressed in aluminum, copper, steel and other materials,
Metal pipe materials and grades
Aluminum LI~L4
Carbon steel 10
Stainless steel OCt18Ni11(1Cr1BNi9Ti)Copper T4, Carbon steel 10
Stainless steel OC/18N (1C18N9T)
War steel 10
Stainless steel oCr18Ni11(1Cr18Ni9Ti)Stainless steel 0Cr18Ni11(IC1BNi9Ti)
Carbon steel 10
Stainless steel Steel Cr18Ni11 (1C18Ni9T)
Base alloy steel Ineoloy B00
Carbon steel 10
Stainless steel 0Cr18Ni11 (1Ct18Ni9Ti)
Base alloy steel Incoloy 800
Carbon steel 10
Stainless steel OCr18Ni11 (1C/18Ni9Ti)
4.1.4.3 For components with a maximum temperature of 450°C or a temperature exceeding 450°C during processing, brass lead rods shall not be used. 4.1. 5 Structure
When designing components, the effects of potential expansion, ablation, oxidation, and deformation shall be considered to avoid failures due to deformation during normal operation. 4.1.5.1
4.1.5.2 The design of the internal structure of the component shall ensure that the material used to manufacture the component will not be damaged under the highest temperature or the highest temperature that may be encountered during its processing, and can still work reliably. 4.1.5.3 The design of the welded structure of the component shall comply with relevant standards. The welds of the pressure-bearing component, especially the part inside the container, should be as few as possible. The setting of the welds should be easy to check.
4.1.5.4 The design of the shell and accessories of the pressure-bearing component must comply with relevant standards. 4.1.5.5 The component (including the end) must be sealed; if there is a design, the end can be temporarily sealed or not sealed, and the sealing performance of the end is not good. 4.1.5. The components used for heating corrosive media must use corrosion-resistant metal pipes or protective sleeves to ensure the working life of the components. 4.1.5.7 When the shell is made of ordinary steel or other alloy materials with better performance than ordinary steel, its wall thickness should not be less than 0.35mm. When the shell is made of copper or steel alloy, it must have the corresponding mechanical strength to adapt to the harsh working environment. 4.1.5.8 The bending radius of the component should not be less than 2.5 times the weight of the tube. 4.1.5.9 The bending shape of the component must ensure that the inner end of the lead sample is on the true line part of the tube, and the distance from the starting point of the bend should not be less than 5
10mm.
JB/T23791993bzxz.net
4.1.5.10 The gap between the two current-carrying parts of the component with a potential difference greater than 40V and the gap between the current-carrying part and the outer wall and the thickness of the insulating filler should not be less than 1mm. The distance between the exposed lead rod and the shell should not be less than 1m. With agreement, the above gap and distance can be less than 1mm, but the design needs to be strengthened and the manufacturing needs to be carefully manufactured to ensure performance and reliability. 4.1.5.11 The length of the lead sample tube of the component should not be less than the provisions of Table 3. Table 3
Outer diameter of lead sample P
Outer diameter of metal tube
The cross-sectional area of the lead rod shall not be less than 7 times the cross-sectional area of the heating wire. 4.1.5.12
4.2 Manufacturing requirements
The manufacturing of components shall comply with the design drawings approved according to the prescribed procedures and meet the requirements of product standards and relevant technical documents. mm
4.2.1 The welding of components shall comply with the provisions of relevant standards. Fusion welding, brazing and soft needle welding are only allowed in places specified in the design, but these processes are not allowed to be used to repair defective components. 4.2.2 The lead rod shall be able to withstand a tensile test lasting 3 minutes without displacement and fracture. The test tensile force is 70% of the lead tensile resistance, but not more than 1000 N.
4.2.3 Components used for heating liquid joints installed below the liquid level shall be able to withstand a hydrostatic pressure test of 0.5 MPa for 5 minutes without full penetration. Components with a pressure of more than 0.1MPa must also undergo a 5-minute water test. There should be no leakage or deformation. The test pressure is twice the design pressure and should not be less than 0.5MPa.
4.2.4 The metal tube of the component shall not have obvious mechanical scars or local expansion, and there shall be no wrinkles, bumps, etc. at the bends. The coating layer, key layer, metal or non-metallic spraying layer, and braided aluminum layer shall be evenly connected and firm, and there shall be no bubbles, peeling or local accumulation. 4.2.5
The outer diameter size deviation of the component shall not exceed the range specified in Table 4. 4.2.6
Ordinary type
4.2.7 The deviation of the expanded length of the component shall not exceed the range specified in Table 5. Table 5
Expanded length E
4.2.8 The deviation of the exposed length of the lead shall not exceed =mml. 4.2.9 The installation dimensions of the components after bending and some geometrical dimension deviations that need to be assessed shall not exceed the range specified in Table 6. 6
Basic size L
500L1000
JB/T2379
4.2.10 The deviation of the length of the lead rod Lal and La2 in the tube shall not exceed ±2% or ±5mm. 4.2.11 The deviation of the non-heating length Lds of the tail shall not exceed ±5mm: 4.2.12 The deviation of the heating length of the single-end lead component shall not exceed ±5% or ±20 mm. 4.2.13 The heating element shall be evenly arranged along the axis of the tube, and the difference in the number of turns of the heating wire per unit length shall not exceed 15%. If there are special requirements for the heating element, it can be proposed according to Article 8.2. 4.3 Performance requirements
4.3.1 Heating time
Under the test voltage, the time for the component to rise from ambient temperature to the test temperature should not exceed 15 minutes. 4.3.2 Rated power deviation
Under full heating conditions, the deviation of the rated power of the component should not exceed the following specified range, for components with a rated power less than or equal to 100W: ±10%. For components with a rated power greater than 100W, it is +5%~-10% or 10W, whichever is greater. 4.3.3 Leakage current
4. 3, 3. 1 The cold leakage current and the leakage current after the water pressure and sealing test should not exceed 0.5 mA. 4.3.3.2 The hot leakage current at the working temperature should not exceed the calculated value of formula (1), but the maximum should not exceed 5 mA. Where: I-hot leakage current, mA#
-heating length, mm;
T-working temperature, ℃.
When multiple components are connected in series to the power supply, the leakage current test should be carried out on this group of components as a whole. 4.3.4 Insulation resistance
4.3.4.1 The cold insulation resistance during factory inspection should be no less than 50M01. 4.3.4.2 The insulation resistance after sealing test, long-term storage or use should be no less than 1M0. 4.3.4.3 The hot insulation resistance at working temperature should be no less than the value calculated by formula (2), but the minimum should be no less than 1MQ. R=10-0. 01ST×10
Where; R—hot insulation resistance, Mo;
t—heating length, mm
Tworking temperature,.
4.3.5 Insulation withstand voltage
The components should be kept under the specified test conditions and test voltage for 1 min without internal shunting and breakdown. 4.3.6 Ability to switch on and off
The component should be able to undergo 2000 power-on and power-off tests under the specified test conditions without damage. 4.3.7 Overload capacity
The component should be able to withstand 30 cycles of overload tests under the specified test conditions and input power without damage. 4.3.8 Heat resistance
The component should be able to withstand 1000 cycles of heat resistance tests under the specified test conditions and test voltage without damage. m
5 Test method
5.1 General requirements
JB/T23791993
5.1.1 The power-on test of the component should be carried out under the following conditions: + The ambient temperature is 20±5℃, there is no wind and no strong heat radiation, the relative humidity is not more than 85%, b, the power supply voltage deviation does not exceed 1%:
C, the component is in full heating conditions or simulated conditions. 5.1.2. The leakage current measurement, insulation resistance measurement and insulation withstand voltage test of the double-terminal lead-out component with one end connected to the shell should be carried out when one end is still connected to the shell, and the type inspection of these items is not carried out. If an arbitration test is required, the connected part shall be peeled off mechanically, but the body shall not be damaged, and then the component shall be further processed according to Figure 1, and then all items or required items shall be tested. 5.2 Lead-out rod tensile test (Article 4.2.2) Fix the component, and then hang the set weight (including the accessories required to hang it on the lead-out rod) vertically on the lead-out rod for 3 minutes, and then inspect it.
5.3 Sealing test (Article 4.1.5.5)
5.3.1 Component shell sealing test
Immerse the component in the molten water (2% to 3% hydrochloric acid, sulfuric acid or nitric acid in water) for 3 hours, and take measures to expose the end face of the component to the surface by 5 to 10mm, and then carry out insulation resistance measurement, leakage current measurement and insulation pressure test in sequence. Note: This item is not required for components undergoing water pressure test. 5.3.2 Component end sealing test
5.3.2.1 Requirements for test chamber (room)
and. A humidity sensor should be installed in the effective working space of the test chamber (room) to monitor the test conditions. b. The temperature at each location in the effective working space of the test chamber (room) should be consistent with the temperature of the temperature control point as much as possible, and should be maintained at 40±2℃, and the relative humidity should be maintained within the range of (93-3%). Note: ±2. Its temperature difference includes the measurement error and the uniformity and passivity of the temperature in the effective working space. In order to maintain the required humidity, the temperature fluctuation of the control point should be kept within ±0.5. The condensed water in the test chamber should be continuously discharged, and the discharged condensed water shall not be used as a moisture source before purification. d. The resistivity of water directly used to generate humidity shall not be less than 500·m. e. The resistance and electrical load of the component shall not significantly affect the operation in the test chamber (room). f. The condensed water on the wall and top of the test chamber (room) shall not drip onto the component. 5.3.2.2 Test method
. The component shall be placed in the test chamber without packaging, without power, "ready to use" and normal working position or in accordance with the relevant standards. First, preheat the components in the chamber for 40°C, and then humidify when the component temperature stabilizes to prevent condensation on the components. b. Test time 48 h.
C. After the test, take the component out of the test box (indoor) and place it in an environment with an ambient temperature of 20 ± 5 °C, no wind, no strong heat radiation, and a relative humidity of not less than 60°C. Then, perform insulation resistance measurement, leakage current measurement, and insulation withstand voltage test accordingly. The total time from taking out the component to the end of the insulation withstand voltage test shall not exceed 10 minutes. 5.3.2.3 After the sealing test, the component is allowed to be restored. 5. 1X X-ray inspection
For single-ended lead-out, lead-out rod parallel components, the distance between the two leads (Article 4.1.5.10), the internal lead-out rod length deviation (Article 4.2.10), the non-heating length deviation (Article 4.2.11), the single-ended heating length deviation (Article 4.2.12) and the number of heating wire turns per unit length deviation (Article 4.2.13) are measured by X-ray machine display. According to the design drawings of the components, a 100mm long lead strip is placed close to the tube at the connection between the lead-out rod and the heating element, and a 50mm long lead strip is placed every 200mm in the middle, but at least one 50mm long lead strip is placed. The lead strip length is used as the reference during the test, and the lead strip length deviation should be less than ±0.5mm, the component is allowed to be measured after compression and before bending. The distance between the leads should be measured 8
JB/T23791993
single, two leads must be clearly seen from the light source, and the distance between the two leads shown on the X-ray film is the largest. The non-heating length of the tail is usually measured after the tail X-ray film is fully displayed.
The deviation of the number of heating wire turns per unit length is calculated according to formula (3), and the calculation must include the number of heating wire turns in the 50n1m section from the lead-out sample in the 100mm long lead strip.
A=max(1-mi)
Where: △——deviation of the number of heating wire turns per unit length, i——measurement with 50 mm long lead strip number, i=1, 2 -.k, ni—number of heating wire turns on the length of the ith 50 mm long lead strip; k—total number of 50 mm long lead strips, including the lead-out rod end; v—average number of heating wire turns on the 50 mm length calculated by measurement. Note: When the X-ray film can fully display the components, the actual size displayed can be multiplied by the proportional coefficient for calculation. 5.5 Measurement of the heating time (Section 4.3.1 5.5.1 Test temperature determination: Use a surface thermometer or thermocouple to measure the temperature at the specified temperature measuring points on the component housing, and take the average temperature measured at each temperature measuring point as the measured temperature. The temperature measuring points are located at 1/4, 1/2 and 3/4 of the heating length of the component. 5.5.2 For components whose heating time is estimated to meet the requirements, the power supply voltage should be lowered for testing during measurement. If qualified, it is considered qualified this time. Otherwise, the voltage should be increased and the power-on test should be conducted after the component is completely cooled until the specified test voltage is reached. 5.6 Rated power measurement (Article 4.3.2) 5.6.1 The rated power should be measured with a power meter, voltmeter or ammeter after the component is under full heating conditions or simulated conditions and reaches the working temperature of 10mrm. The accuracy of the measuring instrument should not be lower than Class 1.5. The working temperature of the component shall be determined by the following method: Under sufficient heating conditions, use a surface thermometer or thermocouple to measure the temperature at the specified temperature measuring points on the component shell: the average temperature measured at each temperature measuring point is the working temperature. Three temperature measuring points are selected, which are located at the highest temperature point, the lowest temperature point and the middle temperature point on the heating surface of the component.
5.6.2 When multiple components are connected in series to the power supply, the power of each component shall be measured separately. 5.6.3 During factory inspection, it is allowed to measure the cold DC resistance value of the component and convert the power according to formula (4): Power, kw:
Wu Zhong: P—
U——Rated voltage, V,
R. Cold DC resistance, Q;
Ct——Operating temperature coefficient of the heating wire. (4)
Cold DC resistance and its deviation as well as the temperature coefficient of the heating wire must be clearly specified in the technical documents. The accuracy of the instrument used to measure the cold DC resistance shall not be lower than Class 1.
5.7 Leakage current measurement (Article 4.3.3) The accuracy of the milliammeter used in this test should not be less than Class 1.5. For a group of components with multiple components connected in series to the power supply, the component housings should all be connected in parallel to the milliammeter when measuring the leakage current. 5.7.1 The leakage current measurement test after the cold state and sealing test should be carried out when the component is not energized. Insulate the component housing from the ground, then apply the test voltage between any lead of the component and the housing, and the current measured by the milliammeter mA connected in the connection is the leakage current. The test voltage Us is 1.1 times the rated voltage.
The schematic diagram of the test circuit is shown in Figure 5.
5.7.2 Hot leakage current measurement
JB/T2379
The test should be carried out when the component is energized and reaches the operating temperature. The operating temperature can be determined by referring to the method specified in Article 5.6.1. Connect the component to the voltage; adjust the test voltage Us so that the input power is equal to 1.15 times the rated power, and start the leakage current measurement 10 minutes after the component reaches the operating temperature. During the measurement, the switch K should be turned on, and the leakage current should be measured at the two lead rods respectively, and the larger value should be taken as the standard for assessment.
The schematic diagram of the test circuit is shown in Figure 6.
5.8 Insulation resistance measurement (Article 4.3.4) This test is measured with a 500V megohmmeter. During the test, the component housing and the megohmmeter shall not form a loop through the ground to avoid affecting the measurement accuracy. At the same time, the impact of the environment on the measurement accuracy should be considered. The megohmmeter should be connected between any lead rod and the housing of the component. 5.8.1 Cold insulation resistance and insulation resistance measurement after sealing test 5.8.1.1 Cold insulation resistance measurement should be carried out 24 hours after the component is provided. During the test, it is allowed to use a megohmmeter higher than 500V but not more than 2000V for measurement.
5.8.1.2 The insulation resistance measurement after the sealing test shall be completed within 30 seconds after the sealing test. 5.8.2 The hot insulation resistance measurement test shall be carried out when the component is at the working temperature. The working temperature can be determined by referring to the method specified in Article 5.6.1. Turn on the power to allow the component to reach the working temperature and keep it for 10 minutes, then turn off the power. The measurement shall be completed within 1 minute after the power is turned off. No forced cooling method shall be used to cool the component within this 1 minute. 5.9 Insulation withstand voltage test (Article 4.3.5) 5.9.1 Test piece
5.9.1.1、The recommended test circuit is shown in Figure 7T1-
Voltage transformer
Voltage transformer:
KM-Contactor
JB/T2379
Test transformer:
Fuse circuit:
The test circuit should meet the following basic requirements:R
Protective resistor:
Signal lamp:
Contact!
SB1, SB2
Specimen:
Button:
Door limit switch!
The capacity of the test transformer should ensure that the secondary rated current is not less than 0.1A+b.
Voltage measurement ball:
Overcurrent relay:
Power switch.
The test power supply should be a 50Hz sine wave, and the test transformer output voltage crest factor is V2±7%: The resistance of the protection resistor is calculated based on 0.2~0.5α per volt of high voltage. The voltage regulator should be able to adjust evenly. Its capacity is the same as that of the test transformer. The overcurrent relay should have sufficient sensitivity to ensure that the current is cut off within 0.1 when the component breaks down. The operating current should be selected with an appropriate value. e.
Avoid failure to operate after breakdown or malfunction when no breakdown occurs: 1 The voltage on the high-voltage side is measured with an electric meter with an accuracy of not less than 1.5, a ball gap, or a voltage transformer with an accuracy of not less than 0.5. The voltage on the low side is measured by a voltmeter with an accuracy of not less than 0.5 level, and the measurement error shall not exceed ±4%. 5.9.1.2 The test voltage is specified as follows: 1500V for components with a working voltage not greater than 250V, and 2000V for components with a working voltage greater than 250V but not less than 440V.
5. 9.2 Test method
First, set the operating current, and then increase the test voltage between the lead-out rod and the external light of the component to the specified value at a rate of 0.5kV per second and maintain it for 1 minute.
5.9.2.1 The operating current is determined by the following formula:
Where: In—operating current, mA
U——test voltage, V
RH——120 kO;
The operating current should be rounded to an integer value.
5.9.2.2 When multiple components are connected to a power supply, the group of components should be tested as a whole. (5)
When the components are inspected before leaving the factory, it is allowed to test each component individually at the same test voltage. For example, if four components with a rated voltage of 95V are connected in series to a 380V power supply, the four components should be connected in series to a 2000V insulation withstand voltage test during type inspection, while each component can be subjected to a 2000V insulation withstand voltage test during factory inspection. 5.9.2.3 During factory inspection, it is allowed to increase the test voltage by 25%, and the operating current remains unchanged, and an insulation withstand voltage test is carried out. 5.9.2.4 When a group of multiple components is connected to a power supply, the operating current should be halved when a single component is inspected before leaving the factory. 5.10 Power on/off test (Article 4.3.6) 11
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