Miniature circuit breakers

Publish Time:2015-09-25 Author:admin Views:16

Miniature circuit breaker
MCB (Circuit Breaker or Miniature Circuit Breaker Micro) is the most widely used in the construction of electrical terminal distribution device. For 125A following single-phase and three-phase short circuit, overload, over-voltage protection, including unipolar 1p, diode 2p, tripolar 3P, quadrupole 4P.

chinese  name: xiao xing duan lu qi (小型断路器)
English  name: Circuit Breaker Micro or mini circuit breaker
Jane     said: MCB
Fixed meaning: a kind of terminal protection apparatus

1 Introduction
2 working principle
3 product selection
4 design points
5 Product Introduction
6 construction and installation
7 national standards

Brief introduction
Circuit breaker: the current can be connected, load bearing and the normal circuit condition, also can be connected in the condition of the provision of non normal circuit, bearing a certain time and a mechanical switch.

Working principle
Mini circuit breaker operating mechanism, by contact, protection device (various releases), composed of arc extinguishing system. The main contact is by manual or electric switch. The main contacts are closed, free trip will lock in the closing position on the main contacts. A heat element of the current release of the coil and heat release with the main circuit in series, under voltage tripping coil and power supply in parallel. When the short circuit occurred or severe overload, over current tripping device attracted armature, free tripping mechanism of action and the main contact breaking away from the main circuit. When the circuit is overloaded, the heating element heat release heat bend on the bimetallic sheet, promote free trip action. When the circuit under voltage, under voltage release of the armature release. The free trip action. [1]

Product selection
In civil building design, low voltage circuit breaker is mainly used for the line of overload, short circuit, over current, voltage, under voltage, grounding, leakage, double power automatic switch and the motor is not frequent starting the protection, operation and other basic principles, such as the use of low voltage electrical equipment (see industrial and civil power distribution design manual) should consider the following conditions:

1) the rated voltage of the circuit breaker shall not be less than the rated voltage of the circuit;
2) to calculate the current rated current of the circuit breaker with overcurrent tripping device rated current is not less than the line;
3) the rated short circuit breaking capacity of circuit breaker is not less than the maximum short circuit current in the circuit;
4) the choice of power distribution circuit breaker with short circuit breaking capacity and delay protection level;
5) circuit breaker undervoltage tripping device rated voltage is equal to rated voltage lines;
6) when used in the protection of motors, the choice of circuit breaker should be considered in the starting current of the motor and the starting time of the motor does not act; design and calculation of the industrial and civil power distribution design manual";
7) the choice of circuit breaker should also take into account the circuit breaker and circuit breaker, circuit breaker and fuse.

Design key points
Circuit breaker and circuit breaker with should consider higher breaker's instantaneous release action value should be greater than the lower circuit breaker outlet at the end of the expected maximum short-circuit current, if due to the two-stage circuit breaker short loop impedance value difference is small, the short-circuit current value difference, the higher breaker can choose to take short time delay tripping device.

The current limiting circuit breaker when the short circuit current is greater than or equal to the instantaneous tripping device setting value, will be release in a few milliseconds, so lower protection equipment is not for circuit breaker achieve selective protection requirements.

2-3 with short time delay of the circuit breaker, when the setting time limits on the maximum delay through the breaking capacity decreased. Therefore, in the selective protection circuit, consider selection circuit breaker with short delay on-off capacity should meet the requirements.

The consideration should also be given to the higher-level circuit breaker short-circuit delay return characteristics and lower circuit breaker action time characteristic curve should not intersect, short delay characteristic curve and the instantaneous characteristic curve should not intersect.

The circuit breakers and fuses with the use should be considered subordinate with, the circuit breaker should be an second characteristic curve and fuse second characteristic curve, so that in the event of a short circuit current, with selective protection.

When the circuit breaker for distribution line protection should be selected to with long delay action overcurrent tripping device of circuit breaker, when the single phase grounding short circuit happens in the end of the line, short-circuit current not less than circuit breaker instantaneous or short delay overcurrent tripping device setting current of 1.5 times.

Product introduction
Schneider C65 series miniature circuit breakers
Performance description with a rich array of products, according to the different breaking capacity, c65n, c65h, c65l breaking capacity range covering the 6~15KA, rated current of 1 to 63A, with B / C / D type tripping curves;
Can be assembled with a wealth of electrical accessories, machinery accessories, greatly expand the function of the expansion and operation of the convenience;
The full range of products can be assembled to protect the residual current accessories, to achieve A/AC class of residual current action protection function, rated residual action current including 30mA, 100mA, 100mA delay, 300mA and 300mA delay type. Advantage
C65 series miniature circuit breaker is a kind of breakthrough significance of the digital product was born, after continuous development and improvement, has always been ahead of the market, has become a model for the world's low-voltage terminal power distribution products.

Application range
Can be widely used in the industrial, commercial and civil low-voltage terminal power distribution needs.
Schneider OEM special miniature circuit breaker OSMC65H

Performance description
OSMC65H series of miniature circuit breakers for modular products, 10kA breaking capacity, each product is unified for the 9mm width, and become complex.
International standard DIN guide rail installation.
Tunnel type terminals are connected to effectively reduce the terminal heat and burn caused by the connection.
3C, CE, UL, TUV certification, convenient for the domestic use and design of OEM users