Circuit Breaker Common Type Introduction and Differences

Update date:2018-05-01 Source:MAXGE

Circuit Breaker Common Type Introduction and Differences

Miniature Circuit Breaker / Miniature Circuit Breaker / Small Air Circuit Breaker

(English name: Miniature Circuit Breaker), the electrical industry is abbreviated as MCB, is suitable for AC 50/60Hz rated voltage 230/400V, rated current to 63A line overload and short circuit protection, can also be used as a line in normal circumstances Frequent operating conversions.

Residual current protection circuit breaker

The residual current protection device (short for RCD in the electrical industry), also known as the “leakage switch”, is a measure of the phase-to-earth leakage current or the electric shock current that occurs within the protected grid and acts as an action trip signal and is completed. Trip protection task protection appliances. In a low-voltage power network equipped with a leakage protector, under normal conditions, the leakage current from the phase-to-ground phase of the power grid (unbalanced leakage current in a three-phase power network) is small, and the operating current value of the leakage protector cannot be reached. Leakage protector does not operate. When a fault such as a leakage or personal electric shock occurs in the protected power grid, when the current of the leakage protection device detects the component reaches its leakage or electric shock action current value, the leakage protection device will cause an action trip command to make it control the master. The circuit switching action trips, cuts off the power, thus completes the electric leakage or the electric shock protection duty. RCD has overload and short-circuit protection functions, which can be used to protect the overload or short circuit of the line or motor, and can also be used as an infrequent conversion of the line under normal conditions.

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What are the similarities and differences between miniature circuit breakers and residual current circuit breakers (leakage switches)?

Both have line overload protection. A miniature circuit breaker is a switch that controls the electrical circuit. If air is used as an arc extinguishing medium, it is referred to as an air switch. It is generally selected as the rated current (load) and used as the main switch of the electrical circuit. Leakage switch is a set of overload, short circuit and leakage protection in one, can be installed independently, equivalent to leakage protection device plus small circuit breaker or leakage accessories plus small circuit breakers.

Can be simply understood as when a small circuit breaker with leakage protection, it is called leakage protection switch. If it is an electrical device that is used solely for leakage protection, it is called a leakage protector.

What are the differences in the trip characteristics of miniature circuit breakers B, C and D? How to apply?

The instantaneous trip current of the class is 3-5In (rated current), suitable for resistive loads; the instantaneous trip current of class C is 5-10In, suitable for general loads; the instantaneous trip current of class D is 10-20In, Suitable for large inductive loads.

Miniature circuit breakers are not in place. Why?

First check the output circuit of the miniature circuit breaker for short circuit or overload conditions. If so, troubleshoot can be done; if not, replace the miniature circuit breaker.

What is the difference between "1P+N" miniature circuit breakers and "2P" miniature circuit breakers?

The rated voltage of the "1P+N" miniature circuit-breaker is 230VAC, which can only divide the single-phase circuit, and the phase and neutral lines cannot be connected incorrectly. The rated voltage of the "2P" miniature circuit-breaker is AC 400V, and can be broken and doubled. Phase / single-phase circuit.

What are the main technical parameters of the leakage protector?

The main performance parameters include: rated leakage current, rated leakage operation time, and rated leakage current. Other parameters include: power frequency, rated voltage, rated current, etc.

1 Rated leakage operating current The current that causes the leakage protector to operate under specified conditions. For example, a 30mA protector, when the input current reaches 30mA, the protector will act to disconnect the power.

2 Rated leakage operating time This is the time from when the rated leakage operating current suddenly applied to when the protection circuit is cut off. For example, a 30mA×0.1s protector, from the current value up to 30mA, to the main contact separation time does not exceed 0.1s.

3 Rated leakage current without operating current Under the specified conditions, the current value of the leakage protection device does not operate, generally one half of the leakage current operating current value should be selected. For example, a leakage protector with a leakage action current of 30 mA, the protector should not operate when the current value is less than 15 mA. Otherwise, the sensitivity is too high and it is easy to malfunction, affecting the normal operation of the electrical equipment.

4 other parameters such as: power frequency, rated voltage, rated current, etc., in the selection of leakage protection device, should be used with the line and electrical equipment to adapt. The operating voltage of the earth leakage protector must adapt to the rated voltage of the normal fluctuation range of the electric network. If the fluctuation is too large, it will affect the normal operation of the protector. Especially for electronic products, the action will be rejected if the supply voltage is lower than the rated operating voltage of the protector. The rated operating current of the leakage protector must also be the same as the actual current in the circuit. If the actual operating current is greater than the rated current of the protector, overload is caused and the protector malfunctions.

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How to use the leakage protector?

After installing the wiring, press the Leakage Test button of the Leakage Protector to create a short-term manual leakage condition to verify that the Leakage Protector can operate. The test button should be tested once a month to verify the function of the leakage protector. In case of ground leakage, the leakage protector automatically trips. Before the fault is cleared, even if the handle is pushed to the “ON” position, the circuit cannot be reconnected, thus avoiding the human error connecting the faulty circuit.

How to use leakage accessory

Used in conjunction with miniature circuit breakers to provide overload, short circuit and leakage protection. After installing the wiring, press the leakage test button of the leakage accessory to create a temporary artificial leakage condition to check whether the leakage attachment can operate. The test button shall be tested once a month to verify the function of the leakage accessory. When an overload or short circuit occurs, the miniature circuit breaker handles and the leakage accessory handle does not operate. When a leakage trigger occurs, both handles act. When resetting, the leakage attachment handle must be reset. Until the cause of leakage has not been eliminated, the handle of the miniature circuit breaker and the handle of the leakage accessory cannot be reset.

What are the differences between leakage switches and leakage accessories?

Both have leakage protection. However, the leakage switch can be installed independently, and the leakage accessory must be used with a miniature circuit breaker.

Why do you need to install a leakage protector after protective zero-crossing (grounding)? No matter if the protection is connected to zero or grounding, the protection range is limited. For example, “protection to zero” is to connect the metal housing of the electrical equipment with the neutral wire of the power grid and install a fuse on the power supply side. When a collision occurs with a power device (a certain phase touches the enclosure), a single-phase short circuit occurs relative to the neutral line. Since the short-circuit current is large, the fuse is quickly disconnected and the power is cut off for protection. Its working principle is to change the "collision fault" to "single-phase short-circuit fault" to obtain a large short-circuit current cut-off insurance. However, the electrical faults at the construction site are not frequent, and leakage faults often occur, such as equipment leakage, excessive load, long lines, and insulation aging. These leakage currents are relatively small and cannot quickly cut off the insurance. Therefore, the failure will not be automatically eliminated and it will exist for a long time. However, this leakage current poses a serious threat to personal safety. Therefore, it is also necessary to install a more sensitive leakage protector for supplementary protection.

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What is the safety of the leakage switch "30mA?s"?

The human body's perceived current----1.1mA for females is 0.7mA for males; 10.5mA for females with 16mA from currents; and children are smaller than adults; currents that are life-threatening in a relatively short period of time are caused by currents from two Understand that ---- First, the current up to 50mA will cause ventricular fibrillation, life-threatening, and the current of more than 100mA will be the center of the death toll, 30mA below no temporary danger.

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