The most complete circuit breaker model and selection principle in history!

Breaker:

Also known as the automatic switch, it is an electrical appliance that has both manual switching and automatic voltage loss, undervoltage, overload, and short circuit protection. It can be used to distribute electric energy, start asynchronous motors infrequently, protect power lines and motors, and automatically cut off circuits when they are severely overloaded or short-circuited or under-voltage faults. Their functions are equivalent to fuse switches and A combination of under-heat relays, etc. Moreover, it is generally not necessary to change parts after breaking the fault current, and it has been widely used.

classification:

According to the operation mode, it is divided into electric operation, energy storage operation and manual operation.

According to the structure: universal and molded shell.

According to the use category: selective and non-selective.

According to the arc extinguishing medium, there are oil immersion, vacuum and air.

According to the speed of action: fast type and normal type.

According to the number of poles: single, second, third and fourth.

According to the installation method: plug-in, fixed and drawer.

Circuit breaker model interpretation

At present, China's circuit breaker models are generally composed of text symbols and numbers in the following manner according to the provisions of national technical standards. Its representative meaning is:

Product letter code, with the following letters: S - less oil circuit breaker;

D—multi-oil circuit breaker;

K-air circuit breaker;

L-sulfur hexafluoride circuit breaker;

Z-vacuum circuit breaker;

Q—gas circuit breaker;

C—magnetic blow breaker.

Device location code:

N—indoors;

W—outdoor.

Design sequence code:

Expressed by the numbers 1, 2, 3, ....

Rated voltage, KV.

Other supplementary work characteristic signs: G-improved;

F—phase separation operation.

Rated current, A.

Rated breaking current, KA.

Special environmental code.

supplement:

GW-110(III)W-630

G------Isolation switch

W------ outdoor use

110---------Applicable to systems with a rated voltage of 110KV

(III)-------Type III (design number)

630---------Applicable to systems with rated current below 630A

GN22-10/2000

G------------Isolation switch

N------------ indoor use

22-----------Design serial number

2000-----------Applicable to systems with rated current below 2000A

SW2-110II

S-------------Low oil circuit breaker

W-------------Outdoor use

2------------Design serial number

110----------Applicable to systems with rated voltage of 110KV

II-----------Type II switch in this series of switches

Low voltage circuit breaker:

DWX15, DWX15C series universal current limiting circuit breaker;

DW17 (ME) series universal circuit breaker;

DZ15 series plastic case circuit breaker;

DZ20 series plastic case circuit breaker;

DZ25 series plastic case circuit breaker;

High voltage circuit breaker:

DW series high voltage outdoor installation multi-oil circuit breaker;

SW series high pressure outdoor installation less oil circuit breaker;

SN series high-voltage indoor installation of oil-less circuit breakers;

ZW series high voltage outdoor installation vacuum circuit breaker;

ZN series high voltage indoor installation vacuum circuit breaker;

LW series high voltage outdoor installation SF6 circuit breaker;

SF6 circuit breakers are installed in LN series high voltage indoors;

Common circuit breaker description

DZ5 series plastic case circuit breakers are suitable for AC 50hz, 380v, rated current from 0.15 to 50a. The circuit breaker for protecting the motor is used to protect the overload and short circuit of the motor. The circuit breaker for distribution is used for distributing electric energy and for overload and short circuit protection of the line and power equipment in the power distribution network, and can also be used as the infrequent starting of the motor respectively. Infrequent conversion of lines.

DZ12 series plastic case circuit breakers are small in size, novel in structure and excellent in performance. Mainly installed in the lighting Distribution Box, used in hotels, apartments, high-rise buildings, plazas, airports, railway stations and industrial and commercial enterprises to exchange 50hz single-phase 230v, three-way 00v and below lighting lines, as the line overload Short-circuit protection and, as a normal case, infrequent conversion of the line.

DZ15 series plastic case circuit breaker is suitable for on-off operation in AC 50hz, rated voltage 380v, rated current up to 63a (100), and can be used to protect line and motor overload and short circuit protection, or as a line Infrequent conversion and infrequent starting of the motor.

DZ20 series plastic case circuit breaker is suitable for AC 50hz, rated insulation voltage 660v, rated working voltage 380v (400v) and below, its rated current to 1250a. Generally used as a power distribution, the rated current 200a and 400y type circuit breaker can also be used as a protection motor. Under normal conditions, the circuit breaker can be used as an infrequent line switching and infrequent starting of the motor.

The four-pole circuit breaker is mainly used in AC 50hz, rated voltage 400v and below, rated current 100 to 630a three-phase five-wire system, it can ensure that the user and power supply are completely disconnected, to ensure safety, so that any other circuit breaker can not be solved. The drawback of overcoming the neutral pole current is not zero.

Distribution breakers are used to distribute electrical energy in distribution networks and can be used as overload, short-circuit and undervoltage protection for line and power equipment. The circuit breaker for protecting the motor is used as a start and break of the squirrel cage motor in the power distribution network and as an overload, short circuit and under voltage protection for the motor.

DZ47 series miniature circuit breaker is mainly used in AC 50hz/60hz, rated working voltage is 240v/415v and below, rated current to 60a circuit, the circuit breaker is mainly used for overloading and short circuit protection of electrical lines and equipment of modern buildings. Also applicable to infrequent operation and isolation of lines.

SCM1 (cm1) series circuit breakers are suitable for infrequent conversion and infrequent starting of motors in AC 50hz, 60hz, 500v and below circuits. The circuit breaker has overload, short circuit and under voltage protection devices to protect the line and power equipment from damage. This open circuit can be installed vertically or horizontally.

DW15 series universal air circuit breaker is suitable for AC 50hz, rated current up to 4000a, rated working voltage to 1140v (shell rated current 630a or less) 80v (shell rated current 1000a and above) in the distribution network, used Allocate power, power supply lines and power supply equipment for overload, under voltage, short circuit protection. Circuit breakers with rated frame currents of 630a and below can also be used for overload, undervoltage and short circuit protection of motors in AC 50hz and 380v networks.

DW17(me) series universal air circuit breaker is suitable for AC 50hz, voltage 380v, 660v or DC 440v, current to 4000a power distribution network, used to distribute power and protect lines and power equipment overload, under voltage, short circuit, etc. Under normal conditions, it can be used as an infrequent conversion of the line. Circuit breakers below 1250a can be used to protect the motor from overload and short circuit in a network of 50hz and 380V. Under normal conditions, it can also be used as an infrequent start of the motor.

DZ20l series leakage circuit breaker is a current-operating electronic residual current action protection device. It is mainly used in the distribution network with AC 50 Hz, rated voltage of 380 volts and rated current up to 630a. It is also used for personal electric shock protection. It can be used to prevent fire hazard caused by grounding fault current caused by equipment insulation damage, and can be used to distribute electric energy and protect overload and short circuit of line and power equipment, and can be used as infrequent conversion of lines.

DZL18-20 series household leakage switch is suitable for personal electric shock protection in single-phase circuit with AC 50hz, voltage 220v and rated current up to 20a. It can also be used as overload protection and overvoltage protection for lines and equipment and to prevent insulation due to equipment. Damage, fire hazard caused by ground fault current, when connected in series with rl1 fuse, can be short-circuit protected.

DZL25 series leakage circuit breakers for AC 50hz, rated voltage, rated current circuits 200a through 380v to the, for shock, leakage protection. It may overload and short circuit protection for the circuit and motor as well as infrequent start with frequency conversion and the line of the motor.

H series molded case circuit breaker is suitable for AC 50hz~60hz, rated working voltage to 690v, DC 250v, rated current to 1200a. It is used to distribute electrical energy and to protect the overload and undervoltage and short circuit of line and source equipment, as well as to infrequently disconnect and connect power lines under normal conditions.

TO, TG series circuit breakers are suitable for rated current 600a and below, AC 50hz, rated working voltage 690v and below, DC 230v and below are generally used for power distribution, and circuit breakers with rated current 225a and below can be used as line and infrequent conversion respectively. And infrequent conversion and infrequent starting of the motor.

DZ108 (3ve) series plastic case circuit breakers are suitable for AC 50-60hz, voltage to 660v, rated current 0.1 to 63a. As the overload and short circuit protection of the motor. It can also be used as a full-voltage starter for starting and breaking motors under ac-3 load, and can also be used for overload and short-circuit protection of line and power equipment in the distribution network.

DZ30 (dpn), dz30k (dpnk), dz23 circuit breakers are suitable for AC 50hz or 60hz, single-phase residential lines with rated voltage of 220v, as leakage protection, and for single-phase residential lines of civil electrical lines, as For leakage protection, the fire line of the civil electrical line is cut off at the same time, and the leakage can still be protected if the fire is reversed.

The filtering device in the electronic leakage overvoltage protection circuit breaker can prevent the tripping of the malfunction caused by the instantaneous voltage (illumination, line interference of other equipment) and the instantaneous current (such as the capacitive load line).

DZ302 (dpnl), DZ23l leakage circuit breaker is suitable for AC 50hz or 60hz, single-phase residential line with rated voltage of 220v, protects the overload and short circuit of electric circuit. The product has high breaking capacity, small volume and width of 36mm. Zero and fire lines are cut off at the same time, which eliminates the personal and fire hazard caused by the live line, neutral line or zero line to ground potential. It is the most ideal power distribution protection switch in the field of residential buildings.

AC30 series modularized socket is the supporting electrical component of the modularized terminal combination electrical appliance installed indoors. It can also be installed in other complete electrical equipment boxes to connect the electrical equipment.

DZ47 leakage tripping circuit breaker has the function of shunt tripping. It is suitable for AC 50hz or 60hz, rated working voltage is 230v, rated current to 63a, long-distance control breaking or automatic signal control breaking of line, at the same time The function of overload and short circuit protection can also be used as an infrequent operation conversion of the line.

DZ47LE series leakage circuit breaker is suitable for AC 50hz, rated voltage to 400v, rated current to 50a, for leakage protection. When someone is shocked or the circuit leakage current exceeds the specified value, the leakage circuit breaker can automatically cut off the power supply in a very short period of time to ensure personal safety and prevent accidents caused by leakage current.

DZ47LE-63 series leakage circuit breaker is suitable for AC 50hz rated voltage 380v and below, rated current to 63a for leakage protection. When someone gets an electric shock or the circuit leakage current exceeds the specified value,

The electromagnetic leakage protection switch is mainly used for leakage, electric shock, overload and short circuit protection of AC 50hz and voltage 250v lines. The product has the characteristics of reliable operation, beautiful appearance and convenient use.

How to choose the circuit breaker (low voltage) correctly?

(1) The rated current of the circuit breaker is determined by the calculated current of the line;

(2) Verify the breaking capacity of the low-voltage circuit breaker according to the maximum short-circuit current of the line;

(3) Verify the sensitivity of the circuit breaker according to the minimum short-circuit current of the line, that is, the minimum short-circuit current of the line should not be less than 1.3 times of the short-circuit setting current of the circuit breaker;

(4) The short-circuit setting current of the circuit breaker should avoid the normal working starting current of the line;

(5) According to the short-circuit inrush current on the line (ie, the maximum instantaneous value of the short-circuit full current), the rated short-circuiting capability of the circuit breaker (the expected peak value of the maximum current) is verified, that is, the latter should be larger than the former.

For the selection of low-voltage circuit breakers, select the type of use according to the specific conditions of use, select the rated working voltage, rated current, tripping setting current and voltage and current of the shunt and undervoltage release, refer to the protection characteristics provided by the product sample. The curve selects the protection characteristics and the short-circuit characteristics and sensitivity coefficients are verified. When there is a requirement for cooperation with another circuit breaker or other protective device, a selective circuit breaker should be used.

1. Rated working voltage and rated current The rated working voltage Ue of the low-voltage circuit breaker. And rated current Ie. Should be no less than the line, the equipment's normal rated operating voltage and operating current or calculated current. The rated working voltage of the circuit breaker is related to the on-off capability and the type of use. The same circuit breaker product can have several rated operating voltages and corresponding switching capacity usage categories.

2. Long-delay tripping setting current Ir1 The long-delay tripping setting current of the selected circuit breaker Ir1 should be greater than or equal to the calculated load current of the line, which can be determined by calculating the load current by 1~1.1 times; It is greater than 0.8-1 times of the long-term allowable current of the line conductor.

3. The setting current of the instantaneous or short-delay trip unit Ir2 The instantaneous or short-delay trip setting current Ir2 of the selected circuit breaker should be greater than the line peak current. The distribution circuit breaker can be determined according to the principle of not less than 1.35 times of the peak current. When the action time is greater than 0.02s, the motor protection circuit can be determined according to the principle of not less than 1.35 times of starting current. If the action time is less than 0.02s, it should be increased. It is not less than 1.7-2 times the starting current. These coefficients are added in consideration of factors such as setting error and possible change in motor starting current.

4. Short-circuit breaking capacity and short-time withstand capability The rated short-circuit breaking capacity and rated short-circuiting capability of the low-voltage circuit breaker shall not be lower than the expected short-circuit current at its installation position. When the operation time is greater than 0.02s, may be considered non-periodic component of the short circuit current, i.e., the short-circuit current periodic component rms as the maximum short-circuit current; when the operation time is less than 0.02s, should be considered non-periodic components, i.e., the first short-circuit current The full current in the cycle acts as the maximum short circuit current. As verification results show that the circuit breaker breaking capacity is not enough, the following measures should be taken.

a) addition of other protective device (fuse) the power supply side of the circuit breaker as backup protection.

b) The current-limiting circuit breaker can be used to select the corresponding product according to the let-through current characteristic or current limiting coefficient provided by the manufacturer (ie, the ratio of the actual breaking current peak value to the expected short-circuit current peak value).

c) The circuit breaker of larger capacity can be selected. Various short circuit protection circuit breakers must be capable of carrying unrestricted short circuit current transients in the closed position and must be capable of carrying short circuit currents within the specified delay range. The short-term carrying short-circuit current value should not exceed the rated short-time withstand capability of the circuit breaker, otherwise measures should be taken or the circuit breaker specifications should be changed. The rated peak withstand current and rated short-time withstand current (1s current) of the product are generally given in the circuit breaker product sample. When it is an alternating current, the short-time withstand current should be based on the effective value of the unrestricted short-circuit current period component.

5, the sensitivity calibration coefficients shall be further selected circuit breaker short-circuit current sensitivity coefficient calibration. The sensitivity coefficient is the ratio of the minimum short-circuit current in the line (generally taking the two-phase or single-phase short-circuit current at the motor terminal or the end of the distribution line) and the setting current of the circuit breaker instantaneous or time-delay trip. The sensitivity coefficient of the two-phase short circuit should not be less than 2, the sensitivity coefficient of the single-phase short circuit can be 1.5 for the DZ type circuit breaker, and 2 for the other type circuit breaker. If the calibration sensitivity coefficient does not meet the above requirements, in addition to adjusting the setting current, the time delay release can also be used as backup protection.

6. Parameters of the shunt and undervoltage release determine that the rated voltage of the shunt and undervoltage release should be equal to the rated voltage of the line. The power supply category (AC, DC) should be determined according to the control line conditions. The rated power supply voltage series specified by the national standard are DC (24), (48), 110, 125, 220, 250V; AC (24), (36), (48), 110, 127, 220V, the data in parentheses is not Recommended.