What is a residual current circuit breaker? What are the models of residual current circuit breakers

In our lives, we will use a lot of large electrical appliances, so if we don't pay attention to it, there may be a hidden danger of electric shock, in order to protect our safety, the leakage circuit breaker was invented. So what is a leakage circuit breaker? How to choose a leakage circuit breaker?

What is a residual current circuit breaker?

Leakage circuit breaker is a kind of safety protection device against leakage, generally the main role is that when we have an electric shock, the leakage circuit breaker can quickly cut off the power supply, protect our personal safety, and prevent electric shock accidents. In addition, some leakage circuit breakers also have protection functions against overload or short circuits in the line, which can protect our home appliances.

How the leakage circuit breaker works.

The working principle of the leakage circuit breaker is based on the circuit, generally speaking, when the line is working normally, the sum of the three-phase current phasor of our main circuit through the zero sequence current transformer is equal to zero, and the leakage protector works in a closed state. When a leakage or electric shock accident occurs, the sum of the three-phase current is no longer equal to zero, but equal to a certain current value will form a loop through the human body, the earth, and the neutral point of the transformer, so that the secondary side of the zero-sequence current transformer generates the induced electromotive force corresponding to IS, which is added to the tripper, and when the IS reaches a certain value, the tripper acts, pushes the lock of the main switch, and breaks the main circuit, so that it can play a role in power-off and ensure our personal safety.

How to choose a leakage circuit breaker?

There are many kinds of leakage circuit breakers, and we need to choose them according to the purpose of use and operating conditions. According to the purpose of use, in order to prevent people from being electrocuted, we can choose a high-sensitivity and fast leakage circuit breaker. However, if it is a branch line that is used to ground the equipment for the purpose of preventing electric shock, you can choose a medium-sensitivity, fast leakage circuit breaker.

If it is a trunk line for the purpose of preventing fire caused by leakage and protecting lines and equipment, a medium-sensitivity, time-delay leakage circuit breaker should be selected. According to the power supply mode, when we are protecting a single-phase line, we can choose a single-pole two-wire or two-pole leakage circuit breaker; When we protect three-phase lines, we can choose three-pole products. When there are both three-phase and single-phase on the line, three-pole, four-wire or four-pole products are selected.

Leakage circuit breaker: A switch that can automatically operate when the leakage current in the circuit exceeds a predetermined value.

There are 6 types of leakage circuit breakers:

1. CDL7 series leakage circuit breaker: suitable for household and similar places with AC 50Hz, rated voltage to 400V, rated current to 63A, and action performance independent of line voltage.

2. DZL18 series leakage circuit breaker: suitable for line circuits with AC 50Hz, rated working voltage of 220V and rated current of 32A and below.

3. DZ20L series leakage circuit breaker: mainly suitable for AC 50Hz, rated working voltage of 380V, rated current to 630A in the distribution network.

4. DZL25 series leakage circuit breaker: mainly suitable for AC 50Hz, rated working voltage of 380V, rated current to 200A distribution network.

5. DZ15LE series leakage circuit breaker: suitable for AC 50Hz, rated working voltage to 380V, rated current to 100A line.

6. DZ47LE leakage circuit breaker: suitable for AC 50Hz, rated voltage 230V or 400V, rated current to 63A and below lines.

Leakage circuit breaker wiring

1. The power supply and load signs on the leakage circuit breaker should be wired, and the two should not be reversed.

2. The protection line shall not pass through the zero sequence current transformer, and when the three-phase five-wire system or single-phase three-wire system is adopted, the protection wire must be connected to the protection trunk at the inlet end of the leakage circuit breaker, and shall not pass through the zero sequence current transformer halfway.

3. Single-phase lighting circuits, three-phase four-wire distribution lines and other lines or equipment that use the working neutral line, the neutral line must pass through the zero-sequence current transformer.

4. In the system where the neutral point of the transformer is directly grounded, once the leakage circuit breaker is installed, the working zero line can only be used as the working zero line after passing through the zero sequence current transformer, and cannot be repeatedly grounded, nor can it be connected to the working zero line of other lines.

5. The electrical equipment can only be connected to the load side of the leakage circuit breaker, and one end is not allowed to be connected to the load side and the other end to the power supply side.

6. In the line where the single-phase and three-phase load are mixed under the three-phase four-wire system or the three-phase five-wire system, the three-phase load should be balanced as much as possible.

There are many specifications and models of air switches, and the most commonly used ones are the air switches of the DZ series. The specifications and models of several common air switches are C16, C40, C32, C80, C60, C100, C120 and so on.

In addition, in addition to the specifications and models of air switches for this household device, there are also air switches used in industry, the more commonly used ones are DZ and DW series, and their specifications and models are 32A, 80A, 100A, 160A, 250A, 400A, 800A, 1000A, etc., and there may be higher air switch models.

Meaning of the parameters of the specifications and models of the empty opening.

dz47-60 c60。

400v--4000a。

DZ: Miniature Air Circuit Breaker 47: Design serial number.

63: The largest model of this specification C: For general lighting 40: Model --A.

220V 380V: Rated voltage 50Hz: Rated frequency.

6000: Rated operating short-circuit breaking capacity --a.

At present, the types of leakage protection circuit breakers used in households are usually divided into AC type, A type, F type, and B type. For example, the AC leakage protection circuit breaker is more suitable for electric heaters, incandescent lamps, ovens, water heaters and other electricity scenarios; Type A leakage protection circuit breaker is more suitable for induction cooker, microwave oven, dishwasher, computer and other electricity scenarios; F-type leakage protection circuit breaker is matched with air conditioners, inverter washing machines, etc.; Type B leakage protection circuit breaker is matched with charging piles, elevators, etc.

For detailed example: A-type leakage protection circuit breaker, Schneider's ACTI 9 is a A-type leakage protector, this product has overload protection, short-circuit protection, leakage protection and other functions, is an integrated leakage protection circuit breaker, and the electricity is safer. Secondly, it is a small "core" tight-fitting design, and the volume after upgrading is only half of the original, which is very space-saving for installation.

And it does not need to be assembled, and it will not bring quality problems caused by poor assembly wiring. In general, to buy a leakage circuit breaker, pay attention to the two major issues of product quality and installation. Are you satisfied with my mastery?

If you're satisfied, let's do it.

The main component of the leakage protector is a magnetic ring inductor, and the live wire and the neutral wire are wound several times on the magnetic ring by parallel winding, and there is a secondary coil on the magnetic ring.

When the live and neutral wires of the same phase are in normal operation, the magnetic flux generated by the current is exactly offset, and the voltage is not induced in the secondary coil. If there is leakage on a certain line, or the neutral wire is not connected, the current of the live wire and the neutral wire passing through the magnetic ring will be unbalanced, and the magnetic flux through the magnetic ring will be generated, and the voltage will be induced in the secondary coil, and the tripper will be tripped through the electromagnet.

Selection principle. Because the harm of direct contact with electric shock is relatively large, the consequences are serious, so it is necessary to choose a leakage circuit breaker with high sensitivity, and a leakage circuit breaker with an action current of 30mA and an action time within the range should be installed in the circuit for power tools, mobile electrical equipment and temporary lines. For residential houses with a large number of household appliances, it is best to install them behind the household energy meter.

If the electric shock is easy to cause secondary injury (such as high-altitude work), a leakage circuit breaker with an action current of 15mA and an action time within US should be installed in the circuit. For electrical and medical equipment in hospitals, leakage circuit breakers with an operating current of 6mA and an operating time within US should be installed.

The principle of the circuit breaker is that when there is a short circuit, the magnetic field generated by the high current (generally 10 to 12 times) overcomes the reaction spring, the tripper pulls the operating mechanism to act, and the switch trips instantaneously. When overloaded, the current becomes larger, the heat generation intensifies, and the bimetal sheet deforms to a certain extent to push the mechanism to act (the larger the current, the shorter the action time).

Its function is to cut off and turn on the load circuit, as well as cut off the fault circuit, to prevent the expansion of the accident, and to ensure safe operation. The high-voltage circuit breaker should break the arc of 1500V and the current is 1500-2000A, which can be stretched to 2m and continue to burn without extinguishing. Therefore, arc extinguishing is a problem that must be solved by high-voltage circuit breakers.

Introduction] Circuit breaker refers to a switchgear that can close, carry and break the current under normal circuit conditions, and can close, carry and break the current under abnormal circuit conditions within a specified time. Circuit breakers are divided into high-voltage circuit breakers and low-voltage circuit breakers according to their scope of use, and the division of high and low voltage boundaries is relatively blurred, and generally more than 3kV is called high-voltage electrical appliances.

The circuit breaker can be used to distribute electric energy, start the asynchronous motor infrequently, protect the power supply line and the motor, and automatically cut off the circuit when they have serious overload or short circuit and undervoltage and other faults, and its function is equivalent to the combination of fuse switch and over/underheat relay. In addition, it is generally not necessary to change the parts after the fault current is switched off. At present, it has been widely used.

In the generation, transmission and use of electricity, power distribution is an extremely important link. The power distribution system includes transformers and various high and low voltage electrical equipment, and the low voltage circuit breaker is a kind of electrical appliances that are widely used.

The leakage protection part of the leakage circuit breaker is composed of a zero-sequence current transformer (sensing part), an operation controller (control part) and an electromagnetic tripper (action and execution part).

All phases and neutral lines of the protected main circuit pass through the core of the zero-sequence current transformer to form the primary side of the zero-sequence current transformer.

According to the Kirchhoff current, at any time, the current flowing into any node is always equal to the current flowing out of this node, that is, at any time, the sum of the current vectors flowing into (outgoing) a node is zero.

The working principle of the zero-sequence current transformer is: whether the vector sum of the instantaneous current in the primary side is zero, when the protected circuit has an insulation fault, the load side has a discharge current to the ground, that is, the vector sum of the zero-sequence current transformer is not zero, and the mutual inductance voltage is generated in the secondary winding of the zero-sequence current transformer, and the signal is calculated by the operation controller, when the leakage current reaches the setting action value, the thyristor is driven, the power supply of the electromagnetic tripper is turned on, and the electromagnetic tripper is engaged, so that the circuit breaker trips. So as to achieve the role of leakage protector.

According to the working principle of the leakage circuit breaker, it can be seen that the leakage circuit breaker cannot protect the two-phase electric shock that is in contact with two phases at the same time.

Both the live wire and the neutral wire are wound around the coils, and when there is no leakage, the two coils are equal in current and in opposite directions, and the magnetic force cancels out.

When there is leakage, the current is unequal, and the magnetic force is generated, and the electromagnet works to disconnect the gate knife to achieve leakage protection.

Friends upstairs posted a lot, but the main thing was not said. The principle of ordinary household leakage protector is very simple, that is, by detecting whether the input current and the output current are completely equal, equal, the circuit is in a balanced state, the induction coil has no current output, and the lock does not move; On the contrary, if the input current and the output current are not equal, there must be a leakage phenomenon, and the internal relay of the leakage protector is engaged, released and the power supply is cut off. This leakage current is generally controlled within 15mA and operates within seconds.

An air switch is a type of switch that trips as long as there is a short circuit and the switch forms a loop.

There are three types of tripping methods: thermal, electromagnetic and duplex.

When the general overload occurs in the line, although the overload current can not make the electromagnetic tripper move, it can make the thermal element generate a certain amount of heat, promote the bimetal sheet to bend upwards when heated, push the lever to disconnect the hook and the lock, break the main contact, and cut off the power supply.

When the line is short-circuited or seriously overloaded, the short-circuit current exceeds the instantaneous tripping setting current value, and the electromagnetic tripper generates a large enough suction force to suck the armature and hit the lever, so that the hook rotates upward around the shaft seat and disengages the lock, and the lock breaks the three main contacts under the action of the reaction spring to cut off the power supply.

The tripping mechanism of the switch is a set of connecting rod devices. When the main contact is closed by the operating mechanism, it is locked in the closing position by the latch. If a fault occurs in the circuit, the relevant tripper will act to disengage the locking hook in the trip mechanism, so that the main contact is quickly disconnected by the release spring.

According to the different protection functions, the tripper can be divided into overcurrent trippers and loss-of-voltage trippers.

Under normal conditions, the armature of the overcurrent tripper is released; In the event of a serious overload or short circuit fault, the coil connected in series with the main circuit will generate a strong electromagnetic attraction to attract the street railway down and jack the lock hook, so that the main contact is disconnected. The undervoltage tripper works on the contrary, when the voltage is normal, the electromagnetic suction pulls the armature and the main contact is closed. In the event of a severe voltage drop or power failure, the armature is released and the main contact is disconnected.

When the power supply voltage returns to normal, it must be re-closed before it can work, and the voltage loss protection is realized.

Because there are many ways of insulation, there are oil switches, vacuum switches and other inert gas (sulfur hexafluoride gas) switches. An air switch is a switch that uses air arc extinguishing, so it is called an air switch. Air is used to extinguish the arc generated during the switching process.

That's why it's called an air switch.