Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T6319-1992
Resistors
Published on 1992-06-26
Basic Technical Requirements
Implemented on 1993-01-01
Published by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Mechanical Industry Standard of the People's Republic of China
Resistors
Subject Content and Scope of Application
Basic Technical Requirements
JB/T6319-1992
This standard specifies the basic technical requirements for resistors, including terms, characteristics; normal working conditions and installation conditions; structural and performance requirements; verification of characteristics and performance; requirements for marking, packaging, and storage, etc. This standard applies to resistors with rated voltages of 50Hz AC, 1140V and below; and 1500V and below DC. Mainly includes resistors used for starting, speed regulation and braking of AC and DC motors; resistors used to adjust circuit parameters (such as current) and energy consumption resistors that convert electrical energy into heat energy, etc.
This standard also applies to resistor elements or components, and can be used as a reference for resistor elements of varistors, but does not include switching devices or resistance value conversion devices for various types of varistors (sliding wire varistors; excitation varistors; liquid oil-immersed starting varistors, etc.). This standard does not include varistors (frequency-sensitive varistors) that use ferromagnetic materials to change the equivalent impedance value with frequency changes to enable the motor to achieve smooth starting, etc.
2 Reference standards
National standards
GB2900.18
GB2423.10
GB1980
GB4207
GB2828
GB2829
GB4026
JB2759
JB3284
3 Terms and symbols
3.1 Terms
General provisions for low-voltage switchgear and controlgear
Degree of protection of low-voltage electrical enclosures
Electrical terms low-voltage electrical appliances
Basic environmental test procedures for electric and electronic products Test Ea: Impact test method Basic environmental test procedures for electric and electronic products Electric and electronic products Basic environmental test procedures Rated frequency of electrical equipment
Test Fc: Vibration (sinusoidal) test method Test Db: Alternating damp heat test method
Determination of tracking index and electrical tracking index of solid insulating materials under humid conditions Batch inspection Count sampling procedure and sampling table Periodic inspection Count sampling procedure and sampling table Identification of electrical terminals and marking terminals with alphanumeric symbols General technical conditions for packaging of electromechanical products
Basic environmental conditions and test methods for transportation and storage of motors and electrical products The terms of this standard, except for the following referenced definitions, can be found in GB2900.18 for related terms and definitions. 3.1.1 Resistor
An electrical appliance used because of its resistance. An electrical appliance used to limit, adjust circuit current or convert electrical energy into heat energy. 3.1.2 Rated value
A value generally specified by the manufacturer for a (switch) electrical appliance or component or equipment under specified working conditions. 3.1.3 Rated working current ratloperationalcurrent Approved by the Ministry of Machinery and Electronics Industry on June 26, 1992 and implemented on January 1, 1993
JB/T 63191992
The current value that ensures the normal operation of (switching) electrical appliances under specified circumstances. 3.1.4 Nominal value nominalvalue
The appropriate approximate value used to mark or identify a (switching) electrical appliance or component and equipment. 3.1.5 Load factor (duration of power-on) on-load factor The ratio of the load time of an electrical appliance to the working cycle (the working cycle is the sum of the load time and the no-load time in each operation), usually expressed as a percentage.
No protection (open) noprotection
No housing or a housing that cannot prevent foreign objects from touching its internal working parts. 3.1.7 Degree of protection The degree of protection of the enclosure to prevent solid foreign matter from entering the enclosure and touching live parts or moving parts, as well as to prevent water from entering the enclosure, according to the specified inspection requirements.
3.2 Symbols
The main symbols used in this standard are as follows; U.—Rated working voltage;
U—Rated insulation voltage;
I—Rated working current;
Ih—Conventional thermal current:
Ih—Conventional closed thermal current
CTI—Comparative tracking index;
IP××—Enclosure protection grade
T——Heating time constant;
Db——Alternating damp heat test;
TD%-Load factor under intermittent cycle duty system. 4
Classification and model
1 Classification
4.1.1 According to the purpose, it can be divided into: for starting and braking of motors; for regulating the speed of motors; for loading; for adjusting circuit parameters; for converting electric energy into heat energy.
According to the manufacturing method of the resistance element structure of the resistor: wire wound:
tape wound;
cast;
stamped.
According to the temperature coefficient of resistance of the material:
high temperature coefficient (temperature coefficient ≥300
low temperature coefficient (temperature coefficient <300
4.1.4 According to the protection level of the shell
1/℃, such as cast iron and other materials);
1/℃ such as electrical alloys such as Kanggang, iron-alloy aluminum). If the resistor needs to be protected by an enclosure, the enclosure protection level is shown in Table 1 (see GB4942.2 for details). According to the pollution level, the pollution level is 3; the pollution level is 4: 4.2 Model JB/T 63191992 The resistor is composed of a resistor element and other accessories. The model of the resistor and the meaning of the model of the resistor element are as follows: a. Model and meaning of the resistor Basic specification code Design code Resistor Code and meaning of resistor element Serial number of resistor element Design code of resistor element XX type resistor element Second characterization number First characterization number Characteristic number Overview of characteristics The resistor can be described by the following characteristics or values: a.
Types and types of resistors:
Nominal resistance value of resistors;
Rated working voltage;
Common housing protection level
Rated insulation voltage and (or) rated impulse withstand voltage; Conventional heating current (or convention closed heating current》): 2
Protection level
IP××
JB/T6319—1992
Rated working current of different TD% under a certain working cycle level; f.
Overload current tolerance;
When the convention heating current (or convention closed heating current) is passed through the resistor Heating time constant. Types and models of resistors
The types of resistors include their uses and structures, such as: resistors for starting wire-wound motors; number of boxes;
types of current (AC including frequency);
assembly method:
cooling medium and method;
wiring diagram of resistors (wiring method); specifications and parameters of resistor elements,
5.3 Rated working system of resistors
【Eight-hour working system
The eight-hour working system is a working system in which a resistor is passed with a stable current and the power-on time is long enough to achieve thermal equilibrium, but the power can be turned off after 8 hours.
|The eight-hour working system is the basic working system. The agreed heating current and agreed closed heating current of the resistor are determined by this basic working system. 5.3.2 Intermittent cycle working system.
Intermittent cycle working system is a working system in which a stable current is passed through the resistor, and its power-on time and power-off time are cyclically alternated and have a specified ratio. Both times are too short for the resistor to reach thermal equilibrium. The intermittent cycle working system uses three parameters: current value, number of cycles of on and off current per hour, and load factor to express its characteristics. a.
The standard values of load factor are 4.4%, 6.25%, 8.8%, 12.5%, 15%, 17.5%, 25%, 35%, 40%, 50%, Resistors can be divided into the following levels according to the number of power-on and power-off cycles per hour (working cycle): 12 levels
120 levelswww.bzxz.net
300 levels
5.3.3 Short-time working system
12 times/h
30 times/h
60 times/h
120 times/h
300 times/h
Short-time working system is a working system in which the power-on time of the resistor is not enough for the resistor to reach thermal equilibrium, the power-on time is separated by the power-off time, and the power-off time is enough for the resistor temperature to return to the temperature equal to the cooling medium temperature. The standard value of the power-on time of the short-time working system is 3, 5, 10, 15, 20, 30s, 1, 3, 10min. 5.4 Rated voltage
Common rated voltages are as follows:
220, 380, 660, 1140V
110, 220, 400, 550, 750, 1000; 1500V Note: The voltage of the resistor installed in the rotor circuit for motor starting can be increased to 2 times. The rated voltage of the resistor installed at the end of the power supply equipment is specified by the specific product standard. 5.4.1
Rated working voltage (U.)
The working voltage value that ensures the normal operation of the resistor under specified conditions. 5.4.2 Rated insulation voltage (U.)
JB/T 6319—1992
Under specified conditions, the nominal voltage value used to measure the insulation strength, electrical spacing and creepage distance of different potential parts of the resistor and its components. In any case, the maximum rated working voltage should not exceed this value. 5.4.3 Rated impulse withstand voltage (Um)
Under specified conditions, it can withstand the peak value of impulse voltage with specified waveform and characteristics without failure. The rated impulse withstand voltage is related to the electrical space, etc.
The rated impulse withstand voltage of the resistor should be equal to or greater than the specified value of the overvoltage that may be generated in the circuit where the appliance is located. 5.5 Rated frequency
The rated frequency of the resistor is the power supply frequency of the power supply network used to design the resistor. The rated frequency should comply with the provisions of GB1980. 5.6 Nominal resistance value
The resistor should give the cold resistance nominal value at +20°C, and provide the temperature correction coefficient of the resistor material. 5.7 Current
The resistor should determine the current as follows
5.7.1 Conventional heating current (I)
The conventional heating current is the maximum value of the test current used for temperature rise test of unenclosed electrical appliances in the atmosphere. Atmospheric conditions are understood as normal indoor air conditions without ventilation and external radiation.
The agreed thermal current shall be at least equal to the rated working current of the non-enclosed electrical appliance in the eight-hour working system. The temperature rise of each component of the resistor shall not exceed the allowable temperature rise value under this rated working current and in the eight-hour working system. 5.7.2 Agreed enclosed thermal current (Iae) The agreed enclosed thermal current is specified by the manufacturer and is used to perform temperature rise tests on resistors installed in specified enclosures. The agreed enclosed thermal current shall be at least equal to the rated working current of the resistor with the corresponding enclosure in the eight-hour working system. If it is marked as an enclosed resistor in the product sample and it is usually expected to be used in one or several enclosures of specified types and sizes, a verification test shall be mandatory. The verification of the agreed enclosed thermal current shall be tested using the specified minimum size enclosure. If the resistor is not usually used in the specified enclosure and the agreed thermal current has been verified by test, the agreed enclosed thermal current is not mandatory to be tested, but the manufacturer shall provide the enclosed thermal current or current reduction factor and its use guide. 5.7.3 Rated working current (I.) or rated power The rated working current of a resistor is the normal working current determined by (rated working voltage), rated frequency, rated working system and housing protection type. The rated power (I'R) is the power consumed by the resistor when the rated working current is passed. 6 Normal working conditions and installation conditions 6.1 Normal working conditions 6.1.1 Ambient air temperature The maximum ambient air temperature shall not exceed +40℃; e. The average value of the ambient air temperature for 24 hours shall not exceed +35℃; b. c. The lower limit of the ambient air temperature shall be -25℃. Note: When the ambient air temperature exceeds +40℃, the manufacturer shall make reasonable recommendations on capacity reduction (current reduction coefficient) to the user. 6.1.2 Altitude The altitude of the installation site shall generally not exceed 2000m. 6.1.3 Atmospheric conditions
The relative humidity of the atmosphere shall not exceed 50% when the ambient maximum temperature is +40℃. It can have a higher relative humidity at a lower temperature. When the monthly average minimum temperature of the wettest month is 25℃, the monthly average maximum relative humidity shall not exceed 90%. Measures must be taken for condensation on the product due to temperature changes.
6.1.4 Pollution level
JB/T63191992
Resistors are generally used in occasions with the pollution level specified in Article 4.1.5. 6.1.5 Impact and operating conditions
Resistors should be installed in places where the impact and vibration do not exceed the conditions specified in 7.1.7. Installation cases
6.2.1 Resistors are generally installed in places with installation category. Note: Installation in the installation category should be negotiated with the manufacturer when ordering. 6.2.2 The limit deviation of the working position of the resistor in any direction shall not exceed 5. Note: When the position deviation is greater than 5\, the user should negotiate with the manufacturer to solve the problem. Structural and performance requirements
Structural requirements
7.1.1 Material requirements
The materials used for resistors should be suitable for the relevant use requirements and be able to pass the corresponding tests satisfactorily. The resistor materials and other current-carrying parts should have sufficient mechanical strength and current-carrying capacity. The insulating materials should have sufficient mechanical strength. And according to the actual use and installation location, they can withstand high temperature resistance, low temperature resistance, damp heat resistance, fire resistance and other assessments. In addition to all materials must meet their respective corresponding material standards, other technical requirements should be specified in the specific product standards. Condensation resistance
7. 1. 1. 1
The resistor should have the ability to adapt to the humidity that may occur under normal working conditions, and should be able to withstand the alternating damp heat test of GB2423.4 test Db with a high temperature of 40℃ and a cycle of 6 cycles. 7.1.1.2 Resistance to abnormal heat and fire hazards
Insulating materials may be subjected to thermal stress due to electrical effects, and insulation aging may impair the safety of resistors. These components should not fail or endanger safety when subjected to abnormal heat and fire. The test method for verifying resistance to abnormal heat and fire hazards is shown in 8.2.1.1. 7.1.2 Clearance and creepage distance
7.1.2.1 Clearance
The clearance value of resistors shall meet the requirements of low-voltage insulation coordination. In the range of 0-2000m above sea level, the creepage distance of resistors shall meet the requirements of Table 2.
Table 2 Minimum clearance in air
Minimum clearance value
Maximum relative voltage to ground obtained from the rated voltage of the system (AC effective value or DC)
U≤50
50U100
1003 Rated impulse withstand voltage (Um)
Under specified conditions, it can withstand the peak value of impulse voltage with specified waveform and characteristics without failure. The rated impulse withstand voltage is related to the electrical space, etc.
The rated impulse withstand voltage of the resistor should be equal to or greater than the specified value of the overvoltage that may be generated in the circuit where the appliance is located. 5.5 Rated frequency
The rated frequency of the resistor is the power supply frequency of the power supply network used to design the resistor. The rated frequency should comply with the provisions of GB1980. 5.6 Nominal resistance value
The resistor should give the cold resistance nominal value at +20°C, and provide the temperature correction coefficient of the resistor material. 5.7 Current
The resistor should determine the current as follows
5.7.1 Conventional heating current (I)
The conventional heating current is the maximum value of the test current used for temperature rise test of unenclosed electrical appliances in the atmosphere. Atmospheric conditions are understood as normal indoor air conditions without ventilation and external radiation.
The agreed thermal current shall be at least equal to the rated working current of the non-enclosed electrical appliance in the eight-hour working system. The temperature rise of each component of the resistor shall not exceed the allowable temperature rise value under this rated working current and in the eight-hour working system. 5.7.2 Agreed enclosed thermal current (Iae) The agreed enclosed thermal current is specified by the manufacturer and is used to perform temperature rise tests on resistors installed in specified enclosures. The agreed enclosed thermal current shall be at least equal to the rated working current of the resistor with the corresponding enclosure in the eight-hour working system. If it is marked as an enclosed resistor in the product sample and it is usually expected to be used in one or several enclosures of specified types and sizes, a verification test shall be mandatory. The verification of the agreed enclosed thermal current shall be tested using the specified minimum size enclosure. If the resistor is not usually used in the specified enclosure and the agreed thermal current has been verified by test, the agreed enclosed thermal current is not mandatory to be tested, but the manufacturer shall provide the enclosed thermal current or current reduction factor and its use guide. 5.7.3 Rated working current (I.) or rated power The rated working current of a resistor is the normal working current determined by (rated working voltage), rated frequency, rated working system and housing protection type. The rated power (I'R) is the power consumed by the resistor when the rated working current is passed. 6 Normal working conditions and installation conditions 6.1 Normal working conditions 6.1.1 Ambient air temperature The maximum ambient air temperature shall not exceed +40℃; e. The average value of the ambient air temperature for 24 hours shall not exceed +35℃; b. c. The lower limit of the ambient air temperature shall be -25℃. Note: When the ambient air temperature exceeds +40℃, the manufacturer shall make reasonable recommendations on capacity reduction (current reduction coefficient) to the user. 6.1.2 Altitude The altitude of the installation site shall generally not exceed 2000m. 6.1.3 Atmospheric conditions
The relative humidity of the atmosphere shall not exceed 50% when the ambient maximum temperature is +40℃. It can have a higher relative humidity at a lower temperature. When the monthly average minimum temperature of the wettest month is 25℃, the monthly average maximum relative humidity shall not exceed 90%. Measures must be taken for condensation on the product due to temperature changes.
6.1.4 Pollution level
JB/T63191992
Resistors are generally used in occasions with the pollution level specified in Article 4.1.5. 6.1.5 Impact and operating conditions
Resistors should be installed in places where the impact and vibration do not exceed the conditions specified in 7.1.7. Installation cases
6.2.1 Resistors are generally installed in places with installation category. Note: Installation in the installation category should be negotiated with the manufacturer when ordering. 6.2.2 The limit deviation of the working position of the resistor in any direction shall not exceed 5. Note: When the position deviation is greater than 5\, the user should negotiate with the manufacturer to solve the problem. Structural and performance requirements
Structural requirements
7.1.1 Material requirements
The materials used for resistors should be suitable for the relevant use requirements and be able to pass the corresponding tests satisfactorily. The resistor materials and other current-carrying parts should have sufficient mechanical strength and current-carrying capacity. The insulating materials should have sufficient mechanical strength. And according to the actual use and installation location, they can withstand high temperature resistance, low temperature resistance, damp heat resistance, fire resistance and other assessments. In addition to all materials must meet their respective corresponding material standards, other technical requirements should be specified in the specific product standards. Condensation resistance
7. 1. 1. 1
The resistor should have the ability to adapt to the humidity that may occur under normal working conditions, and should be able to withstand the alternating damp heat test of GB2423.4 test Db with a high temperature of 40℃ and a cycle of 6 cycles. 7.1.1.2 Resistance to abnormal heat and fire hazards
Insulating materials may be subjected to thermal stress due to electrical effects, and insulation aging may impair the safety of resistors. These components should not fail or endanger safety when subjected to abnormal heat and fire. The test method for verifying resistance to abnormal heat and fire hazards is shown in 8.2.1.1. 7.1.2 Clearance and creepage distance
7.1.2.1 Clearance
The clearance value of resistors shall meet the requirements of low-voltage insulation coordination. In the range of 0-2000m above sea level, the creepage distance of resistors shall meet the requirements of Table 2.
Table 2 Minimum clearance in air
Minimum clearance value
Maximum relative voltage to ground obtained from the rated voltage of the system (AC effective value or DC)
U≤50
50U100
1003 Rated impulse withstand voltage (Um)
Under specified conditions, it can withstand the peak value of impulse voltage with specified waveform and characteristics without failure. The rated impulse withstand voltage is related to the electrical space, etc.
The rated impulse withstand voltage of the resistor should be equal to or greater than the specified value of the overvoltage that may be generated in the circuit where the appliance is located. 5.5 Rated frequency
The rated frequency of the resistor is the power supply frequency of the power supply network used to design the resistor. The rated frequency should comply with the provisions of GB1980. 5.6 Nominal resistance value
The resistor should give the cold resistance nominal value at +20°C, and provide the temperature correction coefficient of the resistor material. 5.7 Current
The resistor should determine the current as follows
5.7.1 Conventional heating current (I)
The conventional heating current is the maximum value of the test current used for temperature rise test of unenclosed electrical appliances in the atmosphere. Atmospheric conditions are understood as normal indoor air conditions without ventilation and external radiation.
The agreed thermal current shall be at least equal to the rated working current of the non-enclosed electrical appliance in the eight-hour working system. The temperature rise of each component of the resistor shall not exceed the allowable temperature rise value under this rated working current and in the eight-hour working system. 5.7.2 Agreed enclosed thermal current (Iae) The agreed enclosed thermal current is specified by the manufacturer and is used to perform temperature rise tests on resistors installed in specified enclosures. The agreed enclosed thermal current shall be at least equal to the rated working current of the resistor with the corresponding enclosure in the eight-hour working system. If it is marked as an enclosed resistor in the product sample and it is usually expected to be used in one or several enclosures of specified types and sizes, a verification test shall be mandatory. The verification of the agreed enclosed thermal current shall be tested using the specified minimum size enclosure. If the resistor is not usually used in the specified enclosure and the agreed thermal current has been verified by test, the agreed enclosed thermal current is not mandatory to be tested, but the manufacturer shall provide the enclosed thermal current or current reduction factor and its use guide. 5.7.3 Rated working current (I.) or rated power The rated working current of a resistor is the normal working current determined by (rated working voltage), rated frequency, rated working system and housing protection type. The rated power (I'R) is the power consumed by the resistor when it passes the rated working current. 6 Normal working conditions and installation conditions 6.1 Normal working conditions 6.1.1 Ambient air temperature The maximum ambient air temperature shall not exceed +40℃; e. The average value of the ambient air temperature for 24 hours shall not exceed +35℃; b. c. The lower limit of the ambient air temperature shall be -25℃. Note: When the ambient air temperature exceeds +40℃, the manufacturer shall make reasonable recommendations on capacity reduction (current reduction coefficient) to the user. 6.1.2 Altitude The altitude of the installation site shall generally not exceed 2000m. 6.1.3 Atmospheric conditions
The relative humidity of the atmosphere shall not exceed 50% when the ambient maximum temperature is +40℃. It can have a higher relative humidity at a lower temperature. When the monthly average minimum temperature of the wettest month is 25℃, the monthly average maximum relative humidity shall not exceed 90%. Measures must be taken for condensation on the product due to temperature changes.
6.1.4 Pollution level
JB/T63191992
Resistors are generally used in occasions with the pollution level specified in Article 4.1.5. 6.1.5 Impact and operating conditions
Resistors should be installed in places where the impact and vibration do not exceed the conditions specified in 7.1.7. Installation cases
6.2.1 Resistors are generally installed in places with installation category. Note: Installation in the installation category should be negotiated with the manufacturer when ordering. 6.2.2 The limit deviation of the working position of the resistor in any direction shall not exceed 5. Note: When the position deviation is greater than 5\, the user should negotiate with the manufacturer to solve the problem. Structural and performance requirements
Structural requirements
7.1.1 Material requirements
The materials used for resistors should be suitable for the relevant use requirements and be able to pass the corresponding tests satisfactorily. The resistor materials and other current-carrying parts should have sufficient mechanical strength and current-carrying capacity. The insulating materials should have sufficient mechanical strength. And according to the actual use and installation location, they can withstand high temperature resistance, low temperature resistance, damp heat resistance, fire resistance and other assessments. In addition to all materials must meet their respective corresponding material standards, other technical requirements should be specified in the specific product standards. Condensation resistance
7. 1. 1. 1
The resistor should have the ability to adapt to the humidity that may occur under normal working conditions, and should be able to withstand the alternating damp heat test of GB2423.4 test Db with a high temperature of 40℃ and a cycle of 6 cycles. 7.1.1.2 Resistance to abnormal heat and fire hazards
Insulating materials may be subjected to thermal stress due to electrical effects, and insulation aging may impair the safety of resistors. These components should not fail or endanger safety when subjected to abnormal heat and fire. The test method for verifying resistance to abnormal heat and fire hazards is shown in 8.2.1.1. 7.1.2 Clearance and creepage distance
7.1.2.1 Clearance
The clearance value of resistors shall meet the requirements of low-voltage insulation coordination. In the range of 0-2000m above sea level, the creepage distance of resistors shall meet the requirements of Table 2.
Table 2 Minimum clearance in air
Minimum clearance value
Maximum relative voltage to ground obtained from the rated voltage of the system (AC effective value or DC)
U≤50
50U100
1001 Resistors are generally installed in occasions with installation category . Note: When installing in the installation category, the manufacturer should be consulted when ordering. 6.2.2 The limit deviation of the working position of the resistor in any direction is not greater than 5. Note: When the position deviation is greater than 5\, the user should consult with the manufacturer to solve it. Structure and performance requirements
Structural requirements
7.1.1 Material requirements
The materials used for resistors should be suitable for relevant use requirements and can pass the corresponding tests satisfactorily. The resistance materials and other current-carrying parts should have sufficient mechanical strength and current-carrying capacity. The insulating material should have sufficient mechanical strength. And according to the actual use and installation location, it can withstand high temperature resistance, low temperature resistance, damp heat resistance, fire resistance and other assessments. In addition to meeting the corresponding material standards for all materials, other technical requirements should be specified in the specific product standards. Condensation resistance
7.1.1.1
The resistor shall be able to adapt to the humidity that may occur in normal working conditions and shall be able to withstand the alternating damp heat test of GB2423.4 test Db at a high temperature of 40℃ for 6 cycles. 7.1.1.2 Resistance to abnormal heat and fire hazards
The insulating material may be subjected to thermal stress due to electrical effects, and insulation aging may damage the safety of the resistor. These components shall not fail or endanger safety when subjected to abnormal heat and fire. The test method for verifying resistance to abnormal heat and fire hazards is shown in 8.2.1.1. 7.1.2 Clearance and creepage distance
7.1.2.1 Clearance
The clearance value of the resistor shall meet the requirements of low-voltage insulation coordination. The clearance value of the resistor shall meet the requirements of Table 2 in the range of 0-2000m above sea level. Table 2 Minimum electrical clearance in air Minimum electrical clearance value Maximum relative voltage to ground obtained from the system rated voltage (AC effective value or DC) U≤50 50U100 1001 Resistors are generally installed in occasions with installation category . Note: When installing in the installation category, the manufacturer should be consulted when ordering. 6.2.2 The limit deviation of the working position of the resistor in any direction is not greater than 5. Note: When the position deviation is greater than 5\, the user should consult with the manufacturer to solve it. Structure and performance requirements
Structural requirements
7.1.1 Material requirements
The materials used for resistors should be suitable for relevant use requirements and can pass the corresponding tests satisfactorily. The resistance materials and other current-carrying parts should have sufficient mechanical strength and current-carrying capacity. The insulating material should have sufficient mechanical strength. And according to the actual use and installation location, it can withstand high temperature resistance, low temperature resistance, damp heat resistance, fire resistance and other assessments. In addition to meeting the corresponding material standards for all materials, other technical requirements should be specified in the specific product standards. Condensation resistance
7.1.1.1
The resistor shall be able to adapt to the humidity that may occur in normal working conditions and shall be able to withstand the alternating damp heat test of GB2423.4 test Db at a high temperature of 40℃ for 6 cycles. 7.1.1.2 Resistance to abnormal heat and fire hazards
The insulating material may be subjected to thermal stress due to electrical effects, and insulation aging may damage the safety of the resistor. These components shall not fail or endanger safety when subjected to abnormal heat and fire. The test method for verifying resistance to abnormal heat and fire hazards is shown in 8.2.1.1. 7.1.2 Clearance and creepage distance
7.1.2.1 Clearance
The clearance value of the resistor shall meet the requirements of low-voltage insulation coordination. The clearance value of the resistor shall meet the requirements of Table 2 in the range of 0-2000m above sea level. Table 2 Minimum electrical clearance in air Minimum electrical clearance value Maximum relative voltage to ground obtained from the system rated voltage (AC effective value or DC) U≤50 50U100 100
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