Some standard content:
Mechanical Industry Standard of the People's Republic of China
Marine low-voltage air circuit breakers
JB57961991
This standard refers to IEC92 "Marine Electrical Equipment" and IEC947-2 (1989) "Low-voltage switchgear and control equipment Part 2: Circuit breakers".
1 Subject content and scope of application
This standard specifies the classification, technical requirements, test methods and inspection rules of marine low-voltage air circuit breakers (hereinafter referred to as circuit breakers). This standard applies to marine low-voltage air circuit breakers with DC, AC 50Hz or 60Hz and rated voltage of 1000V and below, including circuit breakers with fuses.
2 Reference standards
GB1497
GB2423.16
GB2423.17
GB2900.18
GB3321
GB3783
GB4026
GB4205
GB7094
JB1284
Basic test methods for low-voltage electrical appliances
Basic standards for low-voltage electrical appliances
Basic environmental test procedures for electric and electronic products Test Db: Alternating damp heat test method Basic environmental test procedures for electric and electronic products Test J: Long test method Basic environmental test procedures for electric and electronic products Star test Ka: Salt spray test method||tt| |Electrical terminologyBasic terminology
Electrical terminologyLow-voltage electrical appliances
Short-circuit calculation of shipboard AC power system
Basic standards for marine low-voltage electrical appliances
Identification of electrical terminals and marking of terminals with alphanumeric symbolsGeneral rules for operating control electrical equipmentDirection of motionVibration (sinusoidal) test method for marine electrical equipmentLow-voltage circuit breakers
General requirements for control circuit appliances and switching elements3 Terms, terms, symbols and codes
3.1 Terms, terms
In addition to the following terms and terms, this standard also refers to terms, terms and definitions related to this standard in GB2900.1, GB2900.18, GB1497, GB3783 and JB1284. 3.1.1 Integrally-fused circuit-breaker A single electrical appliance composed of a circuit breaker and a fuse, each phase of which is composed of a fuse and one pole of the circuit breaker in series. 3.1.2 Plug-in circuit-breaker In addition to the disconnecting contacts, it also has a set of plug-in contacts to facilitate the installation and protection of the circuit breaker. 3.1.3 Withdrawable circuit-breaker Approved by the Ministry of Machinery and Electronics Industry on 1991-16-15 and implemented on 1992-10-01 JB5796-1991 It is a plug-in circuit breaker. In addition to the disconnecting contacts, it also has a set of isolation contacts. When in the withdrawn position, the contacts can disconnect the circuit breaker from the main circuit and ensure the required isolation distance. Drawer-type circuit breakers generally have three positions: connected, tested, and removed (withdrawn).
3.1.4 Moulded case circuit breaker
moulded case circuit-breaker A circuit breaker with a housing made of molded insulating material that assembles all components into an integral whole. 3.1.5 Frame circuit breaker
frame circuit-breaker
A circuit breaker with a frame structure base with insulating pads that assembles all components into an integral whole and has a variety of structural variations and uses.
3.1.6 Air circuit breaker
air circuit-breaker
A circuit breaker whose contacts are opened or closed in free air. 3.1.7 Ultimate short-circuit breaking capacity
ultimate short-circuit breaking capacity refers to the breaking capacity under specified conditions, and after the specified test sequence, the circuit breaker is not considered to continue to carry its rated current. 3.1.8 Service short-circuit breaking capacity refers to the breaking capacity under specified conditions. After the specified test sequence, it is necessary to consider that the circuit breaker continues to carry its rated current. 3.1.9 Conventional tripping current refers to the specified current value that can cause the relay or release to operate within the specified time. 3.1.10 Conventional non-tripping current refers to the specified current value that can cause the relay or release to not operate within the specified time. 3.1.11 Selectivity limit current (Is) Selectivity limit current (Is) Selectivity limit current is the handover and coordination of the time-current characteristics of the protection device close to the load end and the arcing (for fuses) or tripping (for circuit breakers) time-current characteristics of other protection devices. Selectivity limit current is a current limit value 8. When it is lower than this value:
When two overcurrent protection devices are connected in parallel, the protection device close to the load end completes its disconnection action in time to prevent other protection devices from starting to operate (i.e., selectivity is guaranteed). b. When it is higher than this value:
When two overcurrent protection devices are connected in parallel, the protection device close to the load end cannot complete its disconnection action in time to prevent other protection devices from starting to operate (i.e., selectivity cannot be guaranteed). 3.1.12 Capacitor tripping device
condenser tripping device
When the control power supply voltage disappears, through the discharge effect of the capacitor, the shunt release can still disconnect the circuit breaker once within a specified period of time.
3.2 Symbols and codes
3.2.1 Symbols
Symbols appearing in this standard:
Rated working voltage
Rated insulation voltage
Rated control circuit voltage
Rated control power supply voltage
Breaking voltage (steady-state recovery voltage)
Rated current of circuit breaker
Rated current of circuit breaker frame grade
Current setting value of release
Conventional thermal current
Conventional closed thermal current
Rated short-circuit breaking capacity (current)
Rated operating short-circuit breaking capacity (current) Rated ultimate short-circuit breaking capacity (current)|| tt||Rated short-time withstand current
Continuous current
Rated working current
Selective limiting current of combination electrical appliances
Transfer current of combination electrical appliances
Rated current of generator
Time for current to rise to 95% of stable value
Ambient air temperature
Alternating damp heat test
Comparative tracking index
AC alternating current
DC direct current
3.2.2 Code
The main use category codes adopted in this standard are shown in Table 1. Current type
According to the use category:
Class A (non-selective);www.bzxz.net
Class B (selective).
Use category code
JB5796—1991
Control capacity (closed state) of electromagnet load less than 72VAControl capacity (closed state) of electromagnet load greater than 72VAControl DC electromagnet load
Control DC electromagnet load with economic resistor in the circuitNon-selective protection
Selective protection
4.2 According to the structural type:
Frame type;:
JB5796—1991
Plastic case type (including plastic case circuit breaker with fuse). 4.3 According to the operation mode:
Related human operation;
Unrelated human operation;
Related power operation;
Unrelated power operation;
Energy storage operation.
4.4 According to the number of poles:
single pole;
two poles;
three poles.
4.5 According to whether it is suitable for isolation:
suitable for isolation;
unsuitable for isolation.
4.6 According to whether it needs maintenance:
needs maintenance;
no maintenance.
4.7 According to the installation method:
Fixed type;
Plug-in type;
Drawer type.
4.8 According to the degree of enclosure protection:
According to the provisions of Table 9 in Article 6.7 of GB3783.
Technical requirements
Characteristics of circuit breakers Overview
Characteristics of circuit breakers must be described by the following items: a.
Type of circuit breaker (see Article 5.2);
Rated value and limit value of main circuit (see Article 5.3): Use category (see Article 5.4);
Control circuit see Article 5.5);
Auxiliary circuit (see Article 5.6):
Releaser (see Article 5.7);
Composed fuse (circuit breaker with fuse) (see Article 5.8): Ability to withstand environmental climate and environmental mechanical forces (see Article 5.10). 5.2 Type of circuit breaker
The type of circuit breaker can be described by the following items: number of poles;
b. Type of current (AC or DC) and rated frequency (AC). 5.3 Rated values and limit values of main circuit
The rated values of circuit breakers shall be in accordance with the provisions of 5.3.1 to 5.3.5, but it is not necessary to specify all the listed rated values. 5.3.1 Rated voltage
5.3.1.1 Rated working voltage (U.)
JB5796—1991
The rated working voltage refers to the voltage value related to the breaking capacity and the use category. For single-phase circuits, this voltage refers to the voltage between the upper and lower ends of single-pole circuit breakers, and for multi-phase circuits, it refers to the phase-to-phase voltage. An electrical appliance can have different combinations of rated working voltages and rated working currents corresponding to different working systems and different use categories. The rated working voltage of the circuit breaker can be selected according to the provisions of Table 2. Table 2
Current type
Note: The voltage value in brackets is not recommended. 5.3.I.2 Rated insulation voltage (U,)
Rated working voltage
(24), (36), (110), 220, 660
(12), 24, (36), 110, 220, 440, 750 Rated rate
50 or 60
The rated insulation voltage of the circuit breaker is related to the dielectric performance test and the creepage distance height. In any case, the maximum rated working voltage should not exceed the rated insulation voltage.
If the rated insulation voltage of the circuit breaker is not clearly specified, the maximum rated working voltage can be regarded as the rated insulation voltage. 5.3.1.3 Rated impulse withstand voltage
See 5.3.1.3 of GB1497.
5.3.2 Current
5.3.2.1 Conventional thermal current (I)
The conventional thermal current of a circuit breaker is the maximum fire test current value of an unenclosed circuit breaker when it is subjected to a temperature rise test in free air. Strictly speaking, I is not a rated value and may not be marked on the circuit breaker. An unenclosed circuit breaker is one for which the manufacturer does not provide a housing, or, although a housing is provided, this housing is a component of the circuit breaker and is generally not used as a protective housing for the circuit breaker.
5.3.2.2 Conventional enclosed thermal current (1) See 5.5.2.2 of GB1497.
5.3.2.3 Rated current
B. Rated current of circuit breaker (I.)
For circuit breaker, rated current is the current that the overcurrent release can pass for a long time. b. Frame grade rated current of circuit breaker (I.) The frame grade rated current of circuit breaker is expressed by the maximum rated current of the release that can be installed in a frame or plastic casing of the same size and structure.
Unless otherwise specified in the product technical documents, the rated current of the frame grade is 6, 10, 20, 32, 40, (60), 63, 100, (150), 160, 200, (225), 250, 315, 400, (600), 630, 800, 1000, 1250, (1500), 1600, 2000, 3000), 3150, (3200), 4000, 5000, (6000), 6300, 8000, 10000, 12500A. Note: The values without brackets are preferred. 5.3.2.4 Current setting value of overcurrent release (I,) The current setting value of the overcurrent release is expressed as the current value or as a multiple of the circuit breaker rated current I. 5.3.3 Rated frequency
Unless otherwise specified in the product technical documents. Rated frequency is 50IIz or 60Hz5.3.4 Rated working system, installation category, pollution level JB5796-1991
Unless otherwise specified in the product technical documents, the rated working system of the circuit breaker is long-term working system, the installation category is I, and the pollution level is 3.5.3.5 Short-circuit characteristics
5.3.5.1 Rated short-circuit making capacity (I.) The rated short-circuit making capacity refers to the short-circuit making current value of the circuit breaker at the rated working voltage, specified frequency and power factor (AC) or time constant (DC), expressed as the maximum expected current peak value, which is specified in the product technical documents. For AC, the rated short-circuit making capacity of the circuit breaker should not be less than the rated limit breaking capacity multiplied by the coefficient n. The value of II is listed in Table 7 of Article 6.6.1 of GB3783.
For DC, assuming that the steady-state short-circuit current is constant, the rated short-circuit making capacity of the circuit breaker shall not be less than the rated ultimate short-circuit breaking capacity. The rated short-circuit making capacity is the current value that the circuit breaker can connect when the power supply voltage is 105% (not exceeding 110%) of the rated working voltage.
5.3.5.2 Rated short-circuit breaking capacity (I.) The rated short-circuit breaking capacity refers to the short-circuit breaking current value of the circuit breaker under the rated working voltage and specified conditions. This value should be specified in the product technical documents.
The rated short-circuit breaking capacity requires that the circuit breaker can break any current at or below the rated short-circuit breaking capacity when the power frequency recovery voltage is equal to 105% of the rated working voltage. When the three-phase average value of the power frequency recovery voltage is greater than 110% of the rated working voltage, the rated short-circuit breaking capacity is not guaranteed.
The power factor and time constant of the rated short-circuit breaking capacity are in accordance with Table 3. Table 3
Rated short-circuit breaking capacity
1≤10
10<1,≤20
Power factor
Time constant
For rated short-circuit breaking capacity with power factor lower than the value listed in Table 3, it can be converted according to the method described in Appendix B of GB3321 for the calculation of short-circuit breaking capacity of circuit breakers. The arcing distance of the circuit breaker at the rated breaking capacity must be limited to a safe range, and the specific value is specified in the product technical documents. The rated short-circuit breaking capacity is indicated in the following ways: a. Rated ultimate short-circuit breaking capacity Ia;
b. Rated operating short-circuit breaking capacity Ia;
For circuit breakers used for protection of important equipment and generators, Ia and Ia are used; for circuit breakers for non-important equipment, only Ia or Ia can be used. 5.3.5.2.1 Rated ultimate short-circuit breaking capacity (I.) The rated ultimate short-circuit breaking capacity is the ultimate short-circuit breaking current value of the circuit breaker under the specified rated working voltage and other specified conditions. This value is expressed by the manufacturer as the expected breaking current value (in the case of AC, it is the effective value of the symmetrical short-circuit current). 5.3.5.2.2 Rated operating short-circuit breaking capacity (I) The rated operating short-circuit breaking capacity is the operating short-circuit breaking current value of the circuit breaker under the specified rated working voltage and other specified conditions. This value is expressed by the manufacturer as the expected breaking current value. The rated operating short-circuit breaking capacity is a percentage of the rated ultimate short-circuit breaking capacity and is rounded to the nearest integer. 1. The ratio of I to I is in accordance with Table 4.
Application category A
JB5796—1991
Application category B
When the rated operating short-circuit breaking capacity is equal to the rated short-time withstand current, the rated operating short-circuit breaking capacity may be specified as this value, provided that this value is not less than the minimum ratio listed in Table 4. If the I of the application category A circuit breaker exceeds 200kA or the I of the application category B circuit breaker exceeds 100kA, the manufacturer may specify I as 50kA.
5.3.5.3 Rated short-time withstand current (I) The rated short-time withstand current of the circuit breaker refers to the current value that the circuit breaker withstands for a short time under the test conditions of 6.1.6.2. For AC, this current value is the symmetrical short-circuit current effective value of the prospective short-circuit current (remains constant during the short delay period). The short delay related to the rated short-time withstand current is at least 0.05s, and the preferred values are: 0.05, 0.1, 0.25, 0.5, 1s. The rated short-time withstand current is not less than that specified in Table 5. Table 5
Frame grade Rated current I.
≤2500
5.4 Use category
5.4.1 Utilization category A
Minimum value of rated short-time withstand current Ic
121 or 5kA, whichever is greater
In the case of a short circuit, the circuit breaker is not used as a selective protection for another short-circuit protective device connected in series on the load side, that is, there is no artificial short delay, and therefore there is no requirement for the short-time withstand current specified in 5.3.5.3. Except for the short-circuit condition, the circuit breaker of utilization category A may have a short-time withstand current less than the value specified in Table 5 to provide a selective artificial short delay. In this case, the test includes a sequential test N (see 6.1.6) at this short-time withstand current. 5.4.2 Utilization category B
In the case of a short circuit, the circuit breaker is clearly used as a selective protection for another short-circuit protective device connected in series on the load side, that is, there is an artificial short delay (which may be adjustable), and therefore there is a requirement for the short-time withstand current rating specified in 5.3.5.3. In order to ensure the selective short-time withstand current rating, it is not necessary to reach the ultimate short-circuit breaking capacity of the circuit breaker (for example, when there is an instantaneous release action), but it must at least reach the value specified in Table 5. 5.5 Control circuit
Control circuit characteristics
Current type:
Rated frequency (AC):
Rated control circuit voltage, U. :
d. Rated control power supply voltage, U.
U. is the voltage appearing on the normally open contact of the control circuit electrical appliance in the control circuit; U. is the voltage applied to the input end of the control circuit of the electrical appliance. Due to the connection of transformers, rectifiers, resistors, etc., the control circuit voltage may be different from the control power supply voltage. JB5796—1991
Rated control circuit voltage U. and rated frequency are parameters that determine the working and temperature rise characteristics of the control circuit. The correct working condition is that the control power supply voltage value should neither be less than 85% of the rated value (when the control circuit passes the maximum current) nor greater than 110% of the rated value.
Unless otherwise specified in the product technical documents, generally, the rated control power supply voltage U of the circuit breaker is its main circuit voltage. If the control power supply voltage is different from the main circuit, or the main circuit voltage is 500V and above, the control power supply voltage should be limited to 250V and below. 5.6 Auxiliary circuits
The characteristics of auxiliary circuits refer to the number, type and characteristics of auxiliary contacts in these circuits. The characteristics and rated values of auxiliary contacts should comply with the requirements of JB4013.1.
Generally, the rated voltage of the auxiliary contacts is the same as the voltage of the main circuit. If the rated voltage of the auxiliary contacts is different from the main circuit voltage, or the main circuit voltage is 500V and above, the rated voltage of the auxiliary contacts should be limited to 250V and below. The number of auxiliary contacts depends on the size of the circuit breaker and is specifically specified in the product technical documents. 5.7 Types and characteristics of releases
5.7.1 Type
5.7.1.1 Shunt release
a. General;
With capacitor release.
5.7.1.2 Undervoltage release
Instantaneous;
Delayed.
5.7.1.3 Overcurrent release
5.7.1.3.1 Instantaneous
5.7.1.3.2 Definite time
Long delay;
b. Short delay.
5.7.1.3.3 Inverse time
a. Long delay
Not related to the original load;
Related to the original load (such as thermal release). b. Short delay.
5.7.1.4 Other releases
5.7.2 Characteristics of releases
5.7.2.1 Shunt and undervoltage releases
Rated control circuit voltage;
Current type;
Rated smoothness (AC);
Time delay.
5.7.2.2 Overcurrent releases
Rated current;
Current type;
Rated rate (AC):
Current setting value (or range of setting values); Time setting value (or range of setting values). The rated current of the overcurrent release is the maximum current setting value that the release must be able to carry under the test conditions specified in Article 6.1.2.5 and the temperature rise must not exceed that specified in Table 13.
5.7.3 Current setting value of overcurrent release JB57961991
For circuit breakers equipped with adjustable overcurrent releases, the current setting value or the range of current setting values shall be specified in the product technical documents and marked on the release or its scale. The mark can be directly expressed as the current value A or as a multiple of the current value marked on the release. For circuit breakers equipped with non-adjustable releases, it can be marked on the circuit breaker; if the action characteristics of the overload release meet the requirements of Table 7 or Table 8, only the rated current (I.) of the circuit breaker can be marked. For overcurrent releases operated by current transformers, the primary current of the current transformer or the current setting value of the overcurrent release can be marked. In both cases, the change of the current transformer should be indicated. Unless otherwise specified in the product technical documents, the action value of the overcurrent release, except for the thermal release, is independent of the ambient air temperature within the range of -5 to +45°C. If relevant, the manufacturer shall explain the effect of changes in ambient air temperature on the characteristics. 5.7.4 Tripping time setting of overcurrent release. a. Time-limited overcurrent release
The time delay of the release does not depend on the magnitude of the overcurrent. If the time delay is not adjustable, the tripping time setting value is expressed in seconds using the disconnection time of the circuit breaker; if the time delay is adjustable, it is expressed in terms of the maximum and minimum values of the disconnection time. b. Inverse time overcurrent release
The time delay of the release depends on the magnitude of the overcurrent. The manufacturer shall provide the time-current characteristics in the form of a curve. The curve shall show the relationship between the disconnection time from the cold state and the current change within the operating range of the release, and the manufacturer shall indicate the tolerance for the use of these curves in an appropriate manner.
These curves correspond to the maximum and minimum current setting values. If the current setting value is set, it is recommended to give the maximum and minimum time setting values.
The time-current curve shall comply with the requirements of Article 5.8 of GB1497. 5.7.5 Requirements for current setting value and time setting value of overcurrent release 5.7.5.1 Definite time overcurrent release
Unless otherwise specified in the product technical documents, the current, setting value and time setting value of the short-delay definite time overcurrent release are listed in Table 6, and the return coefficient is specified in the product technical documents. Returnable coefficient = returnable time
Delay time
Application occasion
Generator protection
Current setting value
3~61.or
5.7.5.2 Inverse time overcurrent release
Time setting value
Ambient air reference temperature
Unless otherwise specified in the product technical documents, all poles of the overcurrent release are energized at the same time, and the inverse time disconnecting action characteristics of the circuit breaker are as follows: a.
The current setting value of the circuit breaker for generator protection is I,=Ic, and its disconnecting action characteristics are shown in Table 7. The returnable coefficient is not less than 0.5. Table 7
Agreed non-tripping current
Agreed tripping current
1.25~1.35lc
Agreed tripping time
Current setting value of distribution circuit breaker I, II., and its disconnection action characteristics are shown in Table 8. b.
Ambient air reference temperature
Agreed non-tripping current
1.051.(I.≤63A)
1.05I.(1,>63A)
5.7.5.3 Instantaneous overcurrent release
Agreed tripping current
JB 57961991
Agreed tripping time
Zhou Guo air reference temperature
The current setting value of the instantaneous overcurrent release 1, can be selected from 3~7, 5~10, 8~20I. (or I) according to the needs. The instantaneous action release of the circuit breaker with a rated current below 100A can select an appropriate value from 3~50I. according to the needs. 5.8 Circuit breakers with breakers
According to the provisions of Article 5.8 of GB1497, the manufacturer shall provide the necessary data. 5.9 Switching overvoltage
The maximum allowable overvoltage generated by the circuit breaker during connection and disconnection shall not exceed the rated impulse withstand voltage peak value specified in Article 5.9 of GB1497.
5.10 Normal working conditions and installation conditions
5.10.1 Normal working conditions
5.10.1.1 Ambient air temperature
The upper limit of the ambient air temperature is +45℃:
b, the lower limit of the ambient air temperature is -5℃ or -25℃ (for open decks). 5.10.1.2 Altitude
The altitude of the installation site is generally not more than 2000m. 5.10.1.3 Environmental climate impact
There are the effects of humid sea air, salt spray, bacteria and oil mist. 5.10.1.4 Environmental mechanical force impact
There is a tilt of no more than 22\30 degrees from the vertical line of the sea level, and there are swaying and vibration effects. 5.10.2 Installation conditions
Normal installation conditions should be in accordance with the manufacturer's installation instructions. 5.11 Structural requirements
5.11.1 Materials
The materials used to manufacture circuit breakers should meet the relevant requirements on structure and performance. Insulating materials should generally be durable, oil-resistant, flame-retardant, and resistant to gradual changes, and non-toxic materials and materials that do not release toxic gases should be used as much as possible. In addition to having good corrosion resistance, metal materials should have a reliable anti-corrosion layer. 5.11.2 Current-carrying parts and their connections
Current-carrying parts should have sufficient mechanical strength and sufficient current-carrying capacity. The contact pressure of the electrical connection shall not be transmitted through the insulating material (except ceramic or insulating material with performance not inferior to ceramic) unless there is sufficient elasticity in the metal parts to compensate for the deformation and contraction of the insulating material. 5.11.3 Electrical clearance and creepage distance
For the calculation and measurement of electrical clearance and creepage distance, please refer to Appendix A of GB1497 5.11.3.1 Electrical clearance
The minimum electrical clearance of the circuit breaker shall not be less than the value listed in Table 9 137
JB57961991
Rated working voltage relative to ground (AC effective value or DC voltage) V
50
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