GB 13539.4-1992 Supplementary requirements for low voltage fuses for semiconductor device protection fuses
Some standard content:
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National Standard of the People's Republic of China
Low-voltage fuses
Supplementary requirements for fuse-links for the protection of semiconductor devices Low-voltage fuses
Supplementary requirements for fuse-links for the protectionof semiconductor devices
GB13539.4-92
This standard refers to the international standard IEC269-4 (1986) "Supplementary requirements for low-voltage fuses for semiconductor device protection fuses. This standard should be consistent with GB13539.1 92 "Basic Requirements for Low Voltage Fuses". Unless otherwise stated in this standard, fuse links for semiconductor device protection should also comply with the provisions of GB13539.1. 1 Subject content and scope of application
This standard specifies the ratings of fuses for semiconductor device protection, temperature rise under normal use, power dissipation, time-current characteristics breaking capacity, cut-off current characteristics, It characteristics, Arc voltage characteristics, tests and markings. This standard applies to fuse links used on equipment with semiconductor devices in circuits with an AC rated voltage not exceeding 1200V or a DC rated voltage not exceeding 1500V.
Note: ① In most cases, a part of the combined equipment is used as the base of the fuse link. Due to the wide variety of equipment, it is difficult to make general regulations. Whether the combined equipment is suitable for use as a base for fuse links should be negotiated between the user and the manufacturer. However, when using independent fuse bases or supports, they should comply with the relevant provisions of GB13539.1. ②This kind of fuse is usually called "semiconductor fuse". 2 Reference standards
GB321 priority number and priority number system
GB13539.1 Basic requirements for low-voltage fuses
3 terms, symbols, codes
3.1 terminology||tt| |3.1.1 The basic characteristic of semiconductor device is a device caused by the flow of carriers in the semiconductor. 3.1.2 Semiconductor fuse-link is a current-limiting fuse-link that can break any current value within the range of 7.2 under specified conditions. Note: The terminology in GB13539.1: (fuse-link) usage category\this standard does not apply. 3.2 Symbol
T time constant
4 classifications
The provisions of GB13539.1 are not applicable
Approved by the State Administration of Technical Supervision on 1992-07-0.1 and implemented on 1993-03-01
5 Characteristics
5.1 Fuse link
Arc voltage characteristics.
5.2 rated voltage
GB13539.4-92
If there are special needs, the user can negotiate with the manufacturer and select according to the R5 or R10 series in GB321. 5.3 Rated frequency
Rated frequency refers to the frequency related to performance data. 5.4 Rated power dissipation of the fuse link
In addition to the provisions in GB13539.1, the manufacturer should also specify the functional relationship between the power dissipation and 50% to 100% of the rated current or specify 50%, 63%, 80 % and power dissipation at 100% rated current. Note: If you need to know the resistance value of the fuse link, the resistance value should be determined based on the functional relationship between dissipated power and current. 5.5 Limits of Time-Current Characteristics
5.5.1 Time-Current Characteristics, Time-Current The time-current characteristics of a fuse-link vary with design and, for a given fuse-link, depend on ambient air temperature and cooling Conditions related. The manufacturer should provide time-current characteristics when the ambient air temperature is 20 to 25°C according to the conditions specified in 8.2. The time-current characteristics are the pre-arc time-current characteristic and the fusing time-current characteristic with voltage as parameter at rated frequency. The DC time-current characteristics are based on the time constants specified in Table 4. For some use cases, especially for high expected currents (short time), the It characteristic can be used instead of the time-current characteristic or the It characteristic and the time-current characteristic can be specified simultaneously. 5.5.1.1 Pre-arc time-current characteristics
For AC: pre-arc time-current characteristics should be expressed in terms of AC effective values ??at rated frequency. NOTE: This is particularly important between the time of around 10 cycles at rated frequency and the short time when the device is actually in an adiabatic state. For DC: The part of the pre-arc time-current characteristics that exceeds 15t is particularly important and is the same as the AC pre-arc time current characteristics in this area.
Note: ① Since the range of circuit time constants encountered in actual use is relatively large and the time is shorter than 15t, it is more convenient to express it by the It characteristic. ②The value of 15t is selected to avoid the impact of different current growth rates on the pre-arc time-current characteristics in a shorter time. 5.5.1.2 Fusing time-current characteristics
For AC: fusing time-current characteristics are related to the external voltage under the specified power factor. In principle, the fusing time-current characteristic should be based on the instant at which the current starts leading to the maximum fusing It value. Voltage parameters should include at least 100%, 50% and 25% of the rated voltage. For DC: fusing time-current characteristics do not apply. Because it is unimportant for times greater than 15t (see 5.5.1.1). 5.5.2 Agreed time and agreed current
The provisions of GB13539.1 do not apply.
5.5.3 threshold
The provisions of GB13539.1 do not apply.
5.5.4 Overload curve
5.5.4.1 Overload capacity
The manufacturer should mark several sets of coordinate points along the time-current characteristics. These points have been specified in 8.3.2.3 The program has been verified. The number and location of coordinate points for verifying overload capability can be selected by the manufacturer. The time coordinate point for verifying overload capability should be selected in the range of 0.01~60s.
If you need to increase the number of coordinate points, the user can negotiate with the manufacturer. 5.5.4.2 Agreed overload curve
Agreed overload curve is composed of straight line segments drawn from coordinate points that have been verified according to the procedure specified in 8.3.2.3. Two straight lines are drawn from each set of coordinate points:
GB13539.4-92
One line starts from the verified coordinate points and goes along the points where the current coordinate is constant and the time coordinate decreases. connected straight lines. The other starts from the verified coordinate point and follows the straight line connecting the points where It is constant and the time coordinate is increasing. These straight segments end at the straight line representing the rated current, forming an agreed overload curve (see Figure 1). Note: In actual use, only a few verified overload capability points are sufficient. As the number of points increases, the agreed overload curve becomes more accurate. 5.6 Breaking capacity range and usage category
The provisions of GB13539.1 do not apply.
5.7 Rated breaking capacity
For AC: The rated breaking capacity is based on the type test conducted in a circuit containing only linear impedance, with a constant sinusoidal voltage applied at the rated frequency. The rated breaking capacity is at least 50kA. For DC: The rated breaking capacity is based on type tests conducted in a circuit containing only linear impedance with an applied average voltage. The rated breaking capacity is at least 8kA.
Note: In practical applications, increasing nonlinear impedance and voltage DC component may have a significant impact on the severity of breaking. (9) 2
.
Fore-arc characteristics
It constant line
Conventional overload curve
I,(A)
Fig. 1 Agreed overload curve (schematic diagram)
Note: X and Y are coordinate points where the overload capability has been verified. 5.8 Cut-off current characteristics and It characteristics
5.8.1 Cut-off current characteristics
The manufacturer should provide cut-off current characteristics expressed in double logarithms according to the example in Figure 3 in GB13539.1, with the abscissa Indicates the expected current, if necessary, with external voltage and/or frequency as parameters. For AC: The cut-off current characteristics shall represent the maximum current values ??that may occur in operation. They shall be related to the corresponding test conditions in this standard. For example: given voltage, frequency and power factor, etc. The cut-off current characteristics are verified according to the test specified in 8.5. For DC: The cut-off current characteristic should represent the maximum current value that may occur during operation in a circuit with a time constant of 15~20ms. In circuits with smaller time constants, these values ??will be exceeded. The manufacturer should provide relevant information that can determine the characteristics of the larger cut-off current. GB13539.4—92
Note: The cut-off current characteristics change with time constant. The manufacturer should provide information to determine the change of characteristics with time constant. At least relevant information that can determine the change of characteristics with time constants of 5ms and 10ms should be provided. 5.8.2I\t Characteristics
5.8.2.1 Pre-arc 1t Characteristics
For AC: Pre-arc It characteristics should be expressed in terms of the AC effective value at rated frequency. For DC: The pre-arc It characteristic should be expressed as the DC effective value when the time constant is 15~20ms. Note: For some fuse links, the pre-arc I\t characteristics change with the time constant in the circuit. The manufacturer should provide information to determine the change of characteristics with time constant, at least relevant information that can determine the change of characteristics with time constants of 5ms and 10ms. 5.8.2.2 Fusing It characteristics
For AC: Fusing It characteristics are related to the external applied voltage under the specified power factor. In principle, the fusing I\t characteristic should be based on the instant at which the current leading to the maximum fusing 1t value begins. Voltage parameters should include at least 100%, 50% and 25% of the rated voltage. For DC: The fuse I2t characteristic should be the external voltage as a parameter and correspond to a certain time constant in 15~20ms. Voltage parameters should include at least 100% and 50% of rated voltage. The fusing 1\t characteristics at lower voltage can be determined according to the test in Table 4. 5.9 Arc voltage characteristics
The arc voltage characteristics provided by the manufacturer should give the maximum value (peak value) of the arc voltage as a function of the applied voltage of the circuit where the fuse link is located.
For AC: the power factor is as specified in Table 5. For DC: the time constant is 15~20ms. 6. Normal working conditions
6.1 Voltage
6.1.1 Rated voltage
For AC: the rated voltage of the fuse is related to the external applied voltage, which is represented by the effective value of the sinusoidal AC voltage. And it is assumed that the applied voltage remains constant during the entire melting process of the fuse link. All tests to verify the rated values ??are based on this. Note: In many applications, the applied voltage is fairly close to a sine wave during most of the fusing time. But there are many occasions where this condition is not met. The characteristics of the fuse link under non-sinusoidal applied voltage can be approximately estimated by comparing the arithmetic mean of the non-sinusoidal applied voltage with that under sinusoidal applied voltage.
For DC: The rated voltage of the fuse link is related to the applied voltage, which is expressed as an average value. If DC is obtained by AC rectification, its pulsation should not cause the voltage (instantaneous value) to be greater than 105% of the average value or less than 91% of the average value. 6.1.2 Externally applied voltage during operation
In the working state, the externally applied voltage refers to the voltage that increases the current in the fault circuit to the point where the fuse will melt. For AC: The applied voltage of a single-phase circuit is usually the same as the power frequency recovery voltage. For non-sinusoidal AC voltages, the time function of the applied voltage must be known.
The main data of pulsating DC voltage are:
a. The average value of the entire melting time of the fuse link; b. The instantaneous value close to the end of arcing.
For DC: The applied voltage is generally basically the same as the average value of the restored voltage. 6.2 Current
The rated current of the fuse is expressed in terms of the effective value of the sinusoidal alternating current at the rated frequency. For DC, the effective value of the current is considered not to exceed the effective value of sinusoidal AC at rated frequency. Note: The thermal reaction time of the melt may be so short that the melting of the melt under these non-sinusoidal current conditions cannot be estimated based only on the effective value of the current. This situation occurs especially when the frequency is lower and the current has more prominent peaks, and a small current appears for a long time between the peaks. For example: in frequency conversion and traction applications.
: 6.3 Frequency, power factor and time constant 6.3.1 Frequency
GB13539.492
The rated frequency refers to the frequency of sinusoidal current and voltage in type testing. Note: When the operating frequency is greatly different from the rated frequency, the user should negotiate with the manufacturer. 6.3.2 Time constant (T)
The actual required time constant should comply with the provisions of Table 4. Note: The requirements for time constants in some applications may exceed those specified in Table 4. In this case, the user should consult with the manufacturer or the fuse link should be tested and proven to meet the requirements and should be marked accordingly.
6.4 Shell temperature
The rating of the fuse link is based on the specified conditions. When the specified conditions cannot meet the conditions of the installation site (including local air conditions), the user should negotiate with the manufacturer Whether the rating needs to be re-specified. 6.5 Category of use and selectivity
The provisions of GB13539.1 do not apply.
7 Standard conditions for design
7.1 Temperature rise and power dissipation of fuse links
The temperature rise shall not exceed the temperature rise limit of the hottest metal part of the upper part of the fuse link specified by the manufacturer. The power dissipation of the fuse link shall not exceed the power dissipation specified by the manufacturer. 7.2 Protection performance
The fuse link should be designed to continuously carry any current up to and including the rated current. The fuse link should be able to break any current between the current when the pre-arc time is not greater than 30s and the rated breaking capacity. Note: After consultation between the user and the manufacturer, a shorter time can be selected for special use occasions. 7.3 Breaking capacity
The fuse link shall be able to break any expected current specified in 7.2 when the voltage specified in 8.4 and the following power factor or time constant are not exceeded:
For AC: corresponding to the expected current The power factor shall not be lower than specified in Table 3. For DC: the time constant corresponding to the expected current is not greater than the range of 15~20ms. 7.4It characteristics
The fusing I\t value determined according to 8.6 should not exceed the manufacturer's specifications. The fore-arc I\t value determined in accordance with 8.6 shall not be less than the manufacturer's specifications. 7.5 Arc voltage characteristics
The arc voltage value measured according to the provisions of 8.6.5 shall not exceed the manufacturer's regulations. 7.6 Special working conditions
For special working conditions, such as large gravity acceleration, the user should negotiate with the manufacturer. 8 Test
8.1 General
8.1.1 Arrangement of fuse links
The fuse link should be opened and installed in a non-ventilated place. Unless otherwise specified, the fuse link should be installed vertically. Examples of test setups are shown in Figures 2 and 3.
GB13539.4-92
Figure 2 Example of agreed test device (dimensions in the picture are approximate) Note: 1) Matte black coated copper bar. 2) Insulating base plate (such as 16mm laminate). 3) Thermocouple placement point (specified by the manufacturer), the thermocouple is fixed at the hottest point of the upper metal of the fuse link. 4) Determine the voltage measurement point selected for dissipated power. 5) Tighten the bolts.
6) Tinned contact surface.
7) Insulating plywood.
8) Insulating blocks (such as wood blocks).
8.1.2 Test of fuse links
8.1.2.1 Full set of type tests
GB13539.4-92
Figure 3 Agreed test device with fuse base (schematic diagram )? Temperature rise test point ③ Dissipation power test point
The complete set of type tests for the fuse link is specified in Table 1. The resistance value of the fuse link shall be recorded in the test report. Table 1 Full set of type test items
Serial number
2
3
5
6
8.2
8.3. 2.1
For communication:
8.4
Test items and corresponding terms
Dimensions
Resistance
Temperature rise and dissipated power|| tt||Rated current
No.2a breaking capacity\)
Breaking capacity\
No.2
No.1 breaking capacity\)
Number of fuse links tested
3
All test samples
1
1
1
3
3
Serial number
8
9
10
11
12
13
14|| tt||15
16
8.5
8.3.2.3
For DC:
8.4
GB13539.4—92|| tt||Continued Table 1
Test items and corresponding terms
No.10 Fusing characteristics 3)
Fusing characteristics 2
No.9
No .8
No.7
fuse characteristics\
fuse characteristics”
No.6 fuse characteristics\
overload\
break Capacity and fusing characteristics
No.12a
No.12
Breaking capacity and fusing characteristics
Breaking capacity and fusing characteristics
No.11
Note: 1) If the ambient air temperature is 20±5℃, then The arc front\t feature is valid. 2) Effective for cut-off current characteristics, I\t characteristics, arc voltage and arc t characteristics. 3) The number of points to verify overload capability is specified by the manufacturer. 8.1.2.2 Number of fuse links tested in the fuse type test of the same fuse group
2
2
2
2
2|| tt||1
1
3
3
If the fuse-link with the maximum rated current in the same fuse group has been tested in accordance with 8.1.2.1, the minimum The fuse links with rated current shall be tested according to the provisions of Table 2, and the test of fuse links with other intermediate rated currents may be exempted from the test. Table 2 Minimum rated current fuse type test item table serial number
1
2
3
4
5
8.2| |tt||For AC
8.5.2
For DC:
8.5.2
Test items and corresponding terms
Dimensions||tt| |Resistance
Temperature rise and power dissipation
No.6
Cut-off current characteristics
No.11
Temperature rise and power dissipation|| tt | | 8.2 | | tt | tt||1
2
3
The test only requires one fuse link, which should be installed vertically on the agreed test device shown in Figure 2 or Figure 3. The current density of the copper conductor as part of the agreed test device shall be not less than 1A/mm\ and not greater than 1.6A/mm. These values ??should be based on the rated current of the fuse link. The ratio of the width to thickness of the copper conductor shall comply with the following provisions: not greater than 10 for rated current less than 200A, and not greater than 5 for rated current equal to or greater than 200A. The ambient air temperature during the test should be within the range of 10 to 30°C. During the temperature rise test, the cross-section of the wire connecting the agreed test device and the power supply is very important. The cross-section should be selected according to the provisions of Table 11 in GB13539.1, and the length of the wire should be at least 1m. | |tt | Provisions for selection. In other cases, testing must be carried out in accordance with the above requirements. For special fuse links or special use occasions, when the agreed test device is not applicable, the manufacturer may specify another test device and record all relevant data in the test report.
8.2.2 Power dissipation of fuse link
The measurement points of power dissipation of fuse link are specified in Figure 2 or Figure 3. In addition to the provisions of 8.3.4.2 in GB13539.1, the dissipated power should be measured at least at 50% of the rated current. 8.2.3 Judgment of test results
The temperature rise limit and power dissipation of the fuse should not exceed the manufacturer's regulations. After the test, the characteristics of the fuse link should not change significantly.
8.3 Protection performance
8.3.1 Fuse arrangement
When verifying the protection performance, the fuse arrangement shall be in accordance with the provisions of 8.1.1 and 8.2.1. 8.3.2 Test method and judgment of test results 8.3.2.1 Rated current
fuse shall be carried out according to the test conditions specified in 8.2.1. The fuse link needs to withstand 100 cycles of test cycles. Each cycle should include "power on" for 0.1 times the agreed time and "power off" for 0.1 times the agreed time under the rated current. After the test, the characteristics of the fuse link should not be Significant changes. The agreed time shall be as specified in Table 1 of GB13539.1.
8.3.2.2 Time-current characteristics
The time-current characteristics can be verified by the oscilloscope data in the test in 8.4. The following time is determined during verification:
a, from the moment the circuit is connected to the moment the voltage measuring device indicates the arc appears; b. From the moment the circuit is connected to the moment the circuit is completely disconnected. The pre-arc time and fusing time determined above should be within the time-current band provided by the manufacturer. For AC: the actual pre-arc time is within the range of the expected current of 10 cycles of the rated frequency to the current value of adiabatic melting, so that the expected current does not contain non-periodic components.
For DC: The time-current characteristics determined under AC current greater than 15t can be used for DC. For fuse links in the same fuse group, the full set of type tests in 8.4 is only applicable to the fuse links with the maximum rated current. For fuse links with the minimum rated current, only the pre-arc time needs to be verified. Prearc time-current characteristics can be measured at any voltage and on any linear circuit. The fusing time-current characteristics need to be measured at specified voltage and circuit characteristics. 8.3.2.3 Overload
fuse-link shall be tested according to the test conditions specified in 8.2.1. The fuse link needs to withstand 100 cycles of load cycles. The total time of each cycle is 0.2 times the agreed time. The "power on" time and test current of each cycle are the time and current at the coordinate point to verify the overload capability; the remaining times are There should be no significant change in the characteristics of the fuse-link after the "off" time after the test. The agreed time shall be as specified in Table 1 in GB13539.1. Note: For pre-arc times greater than 15r, these tests can be used to verify the overload capability of the DC fuse link. 8.3.2.4 The action of the fuse indicator and fuse striker (if these devices are present). The characteristics and characteristic verification of the fuse indicator and fuse striker shall be determined by the manufacturer in consultation with the user. 8.4 Breaking capacity
8.4.1 Fuse link arrangement
In addition to the provisions of 8.1.1 and 8.2.1, the following supplements are made:Select according to the provisions of Table 11 in 1. In other cases, testing must be carried out in accordance with the above requirements. For special fuse links or special use occasions, when the agreed test device is not applicable, the manufacturer may specify another test device and record all relevant data in the test report.
8.2.2 Power dissipated by the fuse
The measurement points of the power dissipated by the fuse are as specified in Figure 2 or Figure 3. In addition to the provisions of 8.3.4.2 in GB13539.1, the dissipated power should be measured at least at 50% of the rated current. 8.2.3 Judgment of test results
The temperature rise limit and power dissipation of the fuse should not exceed the manufacturer's regulations. After the test, the characteristics of the fuse link should not change significantly.
8.3 Protection performance
8.3.1 Fuse arrangement
When verifying the protection performance, the fuse arrangement shall be in accordance with the provisions of 8.1.1 and 8.2.1. 8.3.2 Test method and judgment of test results 8.3.2.1 Rated current
fuse shall be carried out according to the test conditions specified in 8.2.1. The fuse link needs to withstand 100 cycles of test cycles. Each cycle should include "power on" for 0.1 times the agreed time and "power off" for 0.1 times the agreed time under the rated current. After the test, the characteristics of the fuse link should not be Significant changes. The agreed time shall be as specified in Table 1 in GB13539.1.
8.3.2.2 Time-current characteristics
The time-current characteristics can be verified by the oscilloscope data in the test in 8.4. The following time is determined during verification:
a, from the moment the circuit is connected to the moment the voltage measuring device indicates the arc appears; b. From the moment the circuit is connected to the moment the circuit is completely disconnected. The pre-arc time and fusing time determined above should be within the time-current band provided by the manufacturer. For AC: the actual pre-arc time is within the range of the expected current of 10 cycles of the rated frequency to the current value of adiabatic melting, so that the expected current does not contain non-periodic components.
For DC: The time-current characteristics determined under AC current greater than 15t can be used for DC. For fuse links in the same fuse group, the full set of type tests in 8.4 is only applicable to the fuse links with the maximum rated current. For fuse links with the minimum rated current, only the pre-arc time needs to be verified. Prearc time-current characteristics can be measured at any voltage and on any linear circuit. The fusing time-current characteristics need to be measured at specified voltage and circuit characteristics. 8.3.2.3 Overload
fuse-link shall be tested according to the test conditions specified in 8.2.1. The fuse link needs to withstand 100 cycles of load cycles. The total time of each cycle is 0.2 times the agreed time. The "power on" time and test current of each cycle are the time and current at the coordinate point to verify the overload capability; the remaining times are There should be no significant change in the characteristics of the fuse-link after the "off" time after the test. The agreed time shall be as specified in Table 1 in GB13539.1. Note: For pre-arc times greater than 15r, these tests can be used to verify the overload capability of the DC fuse link. 8.3.2.4 The action of the fuse indicator and fuse striker (if these devices are present). The characteristics and characteristic verification of the fuse indicator and fuse striker shall be determined by the manufacturer in consultation with the user. 8.4 Breaking capacity
8.4.1 Fuse link arrangementwwW.bzxz.Net
In addition to the provisions of 8.1.1 and 8.2.1, the following supplements are made:Select according to the provisions of Table 11 in 1. In other cases, testing must be carried out in accordance with the above requirements. For special fuse links or special use occasions, when the agreed test device is not applicable, the manufacturer may specify another test device and record all relevant data in the test report.
8.2.2 Power dissipated by the fuse
The measurement points of the power dissipated by the fuse are as specified in Figure 2 or Figure 3. In addition to the provisions of 8.3.4.2 in GB13539.1, the dissipated power should be measured at least at 50% of the rated current. 8.2.3 Judgment of test results
The temperature rise limit and power dissipation of the fuse should not exceed the manufacturer's regulations. After the test, the characteristics of the fuse link should not change significantly.
8.3 Protection performance
8.3.1 Fuse arrangement
When verifying the protection performance, the fuse arrangement shall be in accordance with the provisions of 8.1.1 and 8.2.1. 8.3.2 Test method and judgment of test results 8.3.2.1 Rated current
fuse shall be carried out according to the test conditions specified in 8.2.1. The fuse link needs to withstand 100 cycles of test cycles. Each cycle should include "power on" for 0.1 times the agreed time and "power off" for 0.1 times the agreed time under the rated current. After the test, the characteristics of the fuse link should not be Significant changes. The agreed time shall be as specified in Table 1 in GB13539.1.
8.3.2.2 Time-current characteristics
The time-current characteristics can be verified by the oscilloscope data in the test in 8.4. The following time is determined during verification:
a, from the moment the circuit is connected to the moment the voltage measuring device indicates the arc appears; b. From the moment the circuit is connected to the moment the circuit is completely disconnected. The pre-arc time and fusing time determined above should be within the time-current band provided by the manufacturer. For AC: the actual pre-arc time is within the range of the expected current of 10 cycles of the rated frequency to the current value of adiabatic melting, so that the expected current does not contain non-periodic components.
For DC: The time-current characteristics determined under AC current greater than 15t can be used for DC. For fuse links in the same fuse group, the full set of type tests in 8.4 is only applicable to the fuse links with the maximum rated current. For fuse links with the minimum rated current, only the pre-arc time needs to be verified. Prearc time-current characteristics can be measured at any voltage and on any linear circuit. The fusing time-current characteristics need to be measured at specified voltage and circuit characteristics. 8.3.2.3 Overload
fuse-link shall be tested according to the test conditions specified in 8.2.1. The fuse link needs to withstand 100 cycles of load cycles. The total time of each cycle is 0.2 times the agreed time. The "power on" time and test current of each cycle are the time and current at the coordinate point to verify the overload capability; the remaining times are There should be no significant change in the characteristics of the fuse-link after the "off" time after the test. The agreed time shall be as specified in Table 1 of GB13539.1. Note: For pre-arc times greater than 15r, these tests can be used to verify the overload capability of the DC fuse link. 8.3.2.4 The action of the fuse indicator and fuse striker (if these devices are present). The characteristics and characteristic verification of the fuse indicator and fuse striker shall be determined by the manufacturer in consultation with the user. 8.4 Breaking capacity
8.4.1 Fuse link arrangement
In addition to the provisions of 8.1.1 and 8.2.1, the following supplements are made:
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