Switch with independent release. Application and connection diagram of the independent release RN47. Methodology for checking the operation of circuit breaker releases

Various protective devices are installed in each electrical circuit. Quite often, in addition to them, an independent release is used, connected to the circuit breaker mechanically. If conditions arise that threaten damage to the devices and the line itself, it promptly breaks the electrical circuit. This usually occurs when there is a short circuit, breakdowns and leaks, as well as an increase in current strength above rated limits that are dangerous for cables and wires.

General design of the release and connection diagram

Each independent release is a device that is used to remotely switch off protective equipment. As a rule, it is used in conjunction with various circuit breakers - with one, two, three or four poles. Typically, the release is connected to the input circuit breaker and, in the event of an emergency, completely de-energizes the panel.

The design of the release is made in the form of an electromagnet. When it receives a short-term impulse, the device uses a special lever to influence the mechanism that turns off the automatic protective device. The electromagnetic coils used in the design can be different, designed for alternating or direct current with a voltage of 12-60 V and 110-415 V, in accordance with one or another modification. Attachment to the machine also depends on specific model and is performed on the right or left side.

The correct operation of the entire system depends on the correct connection of the release with the protective device.

The normal operation of both devices largely depends on compliance with all the requirements of the connection diagram. For example, phase conductors must be connected from the lower phase terminals of the machine. If this condition is not met, there is a high probability of failure of an incorrectly connected release. Normally, the circuit breaker with an independent release should turn off and the voltage from the device coil should disappear.

Remote control of the triggering is carried out using the normally open contact of one of the fire alarm devices or by pressing a conventional button with normally open contacts. Using a similar scheme, several tripping devices are switched off at once, distributed into separate groups.

Independent release for circuit breakers

As already noted, this device is an additional protective element of the electrical circuit. It is used to remotely switch off circuit breakers or load switches.

The independent release is most widely used in the design of ventilation systems. In accordance with regulatory documents, in the event of a fire, ventilation must be turned off very quickly. Therefore, an independent release is additionally connected to the input circuit breaker installed in the panel serving the ventilation system.

Modular circuit breakers are installed in electrical panels designed for currents up to 100 amperes. The common input is in most cases protected by a load switch. It is to this that an independent tripping device is connected, which shuts down in emergency situations. If the input current is over 100 A, installation of a more powerful circuit breaker is required. You can also select the most suitable independent release for it.

Using this device, it is possible to disconnect not only single-phase, but also three-phase equipment. In order for the release to start operating, one voltage pulse is applied to its coil. Returning the release to the initial state carried out using the "return" button. Manually pressing it indicates remote tripping rather than tripping due to a short circuit.

Triggering of independent releases can occur due to various reasons. The most widespread are the following:

• Excessive voltage surges either up or down.
• Violation of set parameters, change of state electric current.
• Malfunction of machines, inability to perform their functions.

There are similar disconnecting devices used in conjunction with circuit breakers. They perform the same functions, but according to the principle of operation they are thermal and electromagnetic.

Thermal releases of automatic machines

The main element of thermal tripping devices is a bimetallic plate. It is made of two metals, each of which has its own coefficient of thermal expansion.

Both metals are pressed together and during heating they experience different degrees of expansion, which in turn causes deformation and curvature of the plate. If the current situation does not return to normal over a certain period of time, the plate, under the influence of rising temperature, will touch the contacts of the machine, turning off the electrical circuit.

Thus, the operation of the thermal release is caused by an increase in the temperature of the plate under the influence of excessive load in any area under the protection of the machine. That is, a strictly limited number of devices and equipment can be connected to a wire or cable with a certain cross-section. If you try to turn on another device, the total power of the devices will exceed its permissible value for of this cable. The current will begin to increase and cause the conductor to heat up. Severe overheating often leads to melting of the insulating layer and fire.

This situation is prevented by the operation of a thermal release. The bimetallic plate heats up along with the wire, and after some time its bending, acting on the machine, turns off the current supply. After cooling, the protective device is switched on manually, first turning off the devices that caused the overload. Without this procedure, the machine will turn off again after a while.

The use of a thermal release requires an exact match to the cross-section of the given cable. Failure to comply with this condition will result in trips even under normal loads. And, conversely, if the current is dangerously high, the release will not react and the wiring will fail.

Automatic machines with electromagnetic releases

Switching devices, which include an independent release and a thermal release, are complemented by an electromagnetic device with similar functions.

The need for their use is dictated by the specifics of thermal releases, which cannot operate instantly and perform a shutdown only for one second or more. Therefore, they cannot provide effective short circuit protection. Therefore, in addition to the thermal one, another tripping device is installed - electromagnetic.

The design of electromagnetic devices consists of an inductor - a solenoid and a core. In normal operating mode of the circuit, electrons pass through the solenoid and form a weak magnetic field that does not affect the overall performance of the network. When a short circuit occurs, the current instantly increases many times. At the same time, a proportional increase in the magnetic field power is observed. Under its influence, an instantaneous shift of the core occurs, affecting the tripping mechanism. This prevents serious consequences from short circuit overcurrents.

How to check the serviceability and functionality of the release

This inspection should only be performed by qualified personnel. The actions are performed in the following order:

• Visual inspection of the surface of the case for chips, cracks and other defects.
• Make a few clicks of the switch. The lever should move easily into all positions.
• At the next stage, you need to perform the so-called loading of the device by creating unfavorable conditions. This will require special equipment and the presence of a qualified electrical technician. The main testing indicator is the time interval from the moment the current increases until the device is completely turned off. Exactly the same procedure is performed on the device with the housing removed.
• When checking the thermal release, it is necessary to set the time required to turn off the device under the influence of increased current.

This is an external type of circuit breaker release - additional device, designed for manual or automatic remote control automatic switch.

Perhaps the most common example of their use today is their use in protection and control circuits for ventilation systems - triggering the operation of a circuit breaker that powers the ventilation system when a fire sensor is activated.

Turning off the machine, in the above example, in the event of a fire, will de-energize the electric motors pumping air into the room.

Structurally, the devices are quite simple. Their main element is a coil (solenoid) with a core (rod) inside. Applying a control signal to a working coil, usually with a fairly wide voltage range, leads to retraction of the core, which affects the automatic circuit breaker mechanically connected (through a special lever) to the external release (or, depending on the design of the machine, built into it).

As you can see, the scheme is not particularly complicated. The device is activated when the contacts of the sensor or button are closed.

Please note that in the proposed circuit, the release coil is powered from the automatic machine in conjunction with which the device operates. It is very important that when the machine is turned off, it breaks the power supply circuit of the independent release coil.

The fact is that voltage applied to the coil for a long time can simply burn it out and the release will fail. Some modern devices have protection in the form of microswitches that open the coil power circuit in the off switching position.

Using the circuit proposed here, you can protect the release from failure: when the machine is turned off, the supply phase voltage will be guaranteed to be removed from the contact of the solenoid coil of the device.

The diagram above shows the possibility of implementing remote shutdown of several machines. In both schemes, the circuit breakers are single-pole, but using independent releases you can also control a three-phase load using three- and four-pole circuit breakers.

", here I want to tell you how to correctly connect the independent release S2C-A1 from ABB. Of course, it is not used at home, since it is not necessary, but you can encounter it at work, in the office, etc. It is used to de-energize panel of air conditioners and other electrical equipment when a "Fire" signal appears from a fire alarm. Therefore, this article may be useful to you. I was prompted to write it by the incorrect connection of this release by installers in our panel. Also, after looking on the Internet, I realized that this problem occurs quite often. On Forums often write that the release does not turn off the input circuit breaker because it does not have enough current. This is fundamentally wrong. This release may not turn off the input circuit breaker only because of the poor competence of the installers in working with these devices.

A few words about the device itself. Shunt release S2C-A1 is designed for remote shutdown of protective devices. It connects to ABB S200 series circuit breakers and DS200 series automatic circuit breakers. Usually it is connected to input circuit breakers to enable remote shutdown of the entire power supply panel.

There are two types of release depending on the voltage level of its coil. These are S2C-A1 and S2C-A2. Their abbreviations differ only in the last digits. To operate the S2C-A1, a DC or AC voltage of 12 to 60 V is required. This voltage is usually taken from fire alarm devices. To operate S2C-A2, you need a constant or alternating voltage from 110 to 415 V. As you can see, the only difference is in the voltage level. These types of releases are connected to circuit breakers only on the right side. If suddenly for some reason you need to connect the independent release to the machine on the left side, then you need to order S2C-A1L or S2C-A2L. This is indicated by the last letter “L” in the designation.

The connection diagram for the independent release is very simple. It has only two contacts to which the wires are connected. But installers often miss one little thing, due to which the circuit does not work and the panels are not de-energized.

I'll tell you about our case. For us, it all started with the fact that when a fire signal was sent to S2C-A1, it did not turn off the input circuit breaker, but something inside the release clicked. One got the feeling that he simply did not have enough strength to move the handle of the machine gun.

Below is a photo of the input circuit breaker of our air conditioner power supply panel. This is a 3-phase circuit breaker with an independent release S2C-A1 connected to the right side.

It was decided to dismantle this entire facility to find an answer to the question: what could be the matter?

S2C-A1 is disconnected from the machine with little effort. To do this you need to pull them in different directions. To help, insert a slotted screwdriver between them.

It turned out that this independent release acts on the machine only through a thin metal pin that connects their control handles. This is not enough to remotely turn off the machine. Have you tried turning off a 3-pole circuit breaker by hand? This requires strength. Therefore, the machine must be influenced by something else that is not here.

It turns out everything is simple. As people say: “It wasn’t the reel.” There was a small, harmless plastic fork missing. Against the background of these powerful devices, she looks somehow helpless.

Its length is about 16 mm.

This fork must be inserted into both devices into special grooves. On the machine, this groove is initially sealed with a round plug. It can be easily removed with a screwdriver.

I cocked the machine and lightly pressed the mechanism with a screwdriver through the open hole and the machine immediately turned off. Hooray! All that remains is to find such a fork.

As it turned out, it is not sold separately and you only need to buy a new release S2C-A1, which costs about 1250 rubles. It was useless to look for the old one, since it had been in the trash for several months. Where to go - bought it.

The independent release S2C-A1 from ABB is sold in plastic packaging. The fork we need is in the same package, but in a special compartment. Be careful!

You can clearly see it in the bottom photo.

When the installers open the package, the fork flies away and no one has any problems. Something like this! These are our installers!

I don't understand why during development of this device it was impossible to provide for its initial attachment to the release. That is, make it so that it is one with this fork and it does not disconnect from it. It already has three pins sticking out. They would have done the fourth one and there would have been no problems. Or at least write a warning on the package in large letters: “Attention! There is a small thing inside! Don’t lose it!”

Everything is ready for assembly...

This fork has a triple fork on one and a double fork on the other. So, the triple plug needs to be inserted into the machine itself. She sits there well. And the double plug must go into the S2C-A1 release.

It looks something like this...

Snap it on and you're done!

Repeated testing of the independent release with the plug installed showed that the S2C-A1 very easily and quickly trips a powerful three-phase circuit breaker. As you can see, more current is not needed here, as is advised on some forums.

Thank you for your attention!

Let's smile:

Strange people - electricians!
They are standing on the ground and looking for land!

The independent release is an addition to the protective device for the electrical network. It is mechanically connected to the circuit breaker. An independent release performs the function of breaking the circuit when factors are detected that can lead to damage to the line and the devices included in it. These include an increase in current strength above the limit that the cable can withstand, a breakdown of electric current to the ground or the body of a device connected to the circuit, as well as a short circuit. This material will help you understand what circuit breaker releases are, what types of this device there are and what the operating principle of each of them is. In addition, we will tell you how to check the functionality of these elements.

Automatic safety switch with independent release

The independent release, as mentioned, is an additional element of the circuit protection device. It allows you to turn off the AV at a distance when voltage is applied to its coil. To return it to its original state, press the button on the device that says “Return”.

Circuit breaker releases of this type can be used in single-phase and three-phase networks.

The independent release is most often used in electrical circuits and automatic switchboards of large objects. Energy supply control in these cases, as a rule, is carried out from the operator’s console.

An example of an independent release triggering in the video:

What causes an independent type tripping element to trip?

An independent release can trip for various reasons. We list the most common of them:

• Excessive decrease or, on the contrary, increase in tension.
• Change given parameters or electrical current conditions.
• Malfunction of circuit breakers, malfunction for an unknown reason.

In addition to independent tripping devices, there are similar elements included in circuit breakers. Built-in circuit breaker releases are divided into thermal and electromagnetic. These devices also help protect the line from excessive loads and short circuits. Let's look at them in more detail.

Thermal release of circuit breaker

The main element of this device is a bimetallic plate. In its manufacture, two metals with different coefficients of thermal expansion are used.

Being pressed together, they expand to varying degrees when heated, which leads to curvature of the plate. If the current is not normalized for a long time, then upon reaching a certain temperature the plate touches the AB contacts, interrupting the circuit and de-energizing the wiring.

The main reason for excessive heating of the bimetallic plate, due to which the thermal release is triggered, is too high a load on a certain section of the line protected by the circuit breaker.

For example, the cross-section of the AB output cable going into the room is 1 square meter. mm. It can be calculated that it is capable of withstanding the connection of devices with a total power of up to 3.5 kW, while the strength of the current passing in the line should not exceed 16A. Thus, you can easily connect a TV and several lighting fixtures to this group.

If the owner of the house decides to include additional power in the sockets of this room washing machine, electric fireplace and vacuum cleaner, then the total power will be much higher than what the cable can withstand. As a result, the strength of the current passing through the line will increase, and the conductor will begin to heat up.

Overheating the cable can cause the insulating layer to melt and catch fire.

To prevent this from happening, a thermal release is activated. Its bimetallic plate heats up along with the metal of the wire, and after some time, bending, turns off the power to the group. When it has cooled down, the protective device can be turned on again manually, after first unplugging the power cords of the devices that caused the overload. If this is not done, after a while the machine will turn off again.

An example of using a release in fire protection in the video:

It is important that the AB rating matches the cable cross-section. If it is less than required, then operation will occur even under normal load, and if it is more, then the thermal release will not respond to a dangerous excess of current, and as a result the wiring will burn out.

In order to protect electric motors from prolonged overloads and phase failure, thermal release relays can also be installed on these units. They are several bimetallic plates, each of which is responsible for a separate phase of the power unit.

Automatic network protection switch with electromagnetic release

Having figured out how a machine with a thermal release works, let's move on to the next question. The protective device, the operation of which we have just analyzed, does not operate immediately (it takes at least a second), so it is not able to effectively protect the circuit from short circuit overcurrents. To solve this problem, an electromagnetic release is additionally installed in the AV.

Electromagnetic type circuit breaker releases include an inductor (solenoid) as well as a core. When the circuit is operating normally, the flow of electrons passing through the solenoid creates a weak magnetic field that is unable to influence the function of the network. When a short circuit occurs, the current instantly increases tens of times, and the magnetic field power increases in proportion to it. Under his influence ferromagnetic core instantly moves to the side, affecting the shutdown mechanism.

Since the process of strengthening the magnetic field during a short circuit occurs in a fraction of a second, the electromagnetic release under its influence is triggered instantly, turning off the power to the network. This allows you to avoid serious consequences associated with short-circuit overcurrents.

Checking the functionality of releases

Quite often, amateur electricians are interested in whether it is possible to independently check the serviceability of circuit breaker releases. It should be said that such testing cannot be carried out on your own, and if it is carried out by a novice installer, then the work should be supervised by an experienced specialist. We present step by step instructions to complete this procedure:

• First of all, the surface of the box should be inspected visually to ensure the integrity of the body part.
• Then you need to click the switch lever several times. It should be easy to install in either the on or off position.
• After this, the device is loaded. This is the name for checking the quality of equipment operation under adverse conditions. This stage requires the presence of specialized equipment, and a qualified electrician must be present when performing it. During testing, the time that passes from the moment the current begins to increase until the release is turned off is recorded.

• Finally, a similar test is performed on the device from which the housing has been removed.
• During testing for the operation of a thermal release, the time required to turn off the device under the influence of an increased electric current is recorded.

Functionality check protective devices in accordance with the requirements of the PUE, it is performed only in special clothing. As mentioned above, this procedure should be supervised by an experienced specialist.

The video shows the process of installing an independent release in a circuit breaker:

Conclusion

In this article, we dealt with the topic of tripping devices, talked about what they are and how independent releases, as well as those built into the circuit breaker, work. Now you know what principle they work on Various types of this equipment, and what function each of them performs.

A circuit breaker release (automatic) is an electrical device that turns off the network if a large electric current occurs in it. This device is used to ensure that if the wires overheat, there is no fire in the house, and expensive household appliances do not fail.

Types of switches

All machines are divided according to the type of release. They are divided into 6 types:

• thermal;
• electronic;
• electromagnetic;
• independent;
• combined;
• semiconductor.

They very quickly recognize emergency situations, such as:

• the occurrence of overcurrents - an increase in the current strength in the electrical network that exceeds the rated current of the circuit breaker;
• voltage overload – short circuit in the circuit;
• voltage fluctuations.

At these moments, the contacts in the automatic releases open, which prevents serious consequences in the form of damage to wiring and electrical equipment, which very often leads to fires.

Thermal switch

It consists of a bimetallic plate, one of the ends of which is located next to the release device of the automatic release. The plate is heated by the current passing through it, hence the name. When the current begins to increase, it bends and touches the trigger bar, which opens the contacts in the “machine”.

The mechanism operates even with slight excesses of the rated current and an increased response time. If the load increase is short-term, the switch does not trip, so it is convenient to install it in networks with frequent but short-term overloads.

Advantages of a thermal release:

• absence of contacting and rubbing surfaces;
• vibration stability;
• budget price;
• simple design.

The disadvantages include the fact that its operation largely depends on the temperature regime. It is better to place such machines away from heat sources, otherwise there is a risk of numerous false alarms.

Electronic switch

Its components include:

• measuring devices (current sensors);
• Control block;
• electromagnetic coil (transformer).

At each pole of the electronic circuit breaker there is a transformer that measures the current passing through it. The electronic module that controls the trip processes this information, comparing the obtained result with the specified one. In the event that the resulting indicator is greater than the programmed one, the “machine” will open.

There are three trigger zones:

1. Long delay. Here, the electronic release serves as a thermal release, protecting the circuits from overloads.
2. Short delay. Provides protection against minor short circuits that usually occur at the end of the protected circuit.
3. The working area “instantly” provides protection against high-intensity short circuits.

Pros - a large selection of settings, maximum accuracy of the device to a given plan, the presence of indicators. Cons: sensitivity to electromagnetic field, high price.

Electromagnetic

This is a solenoid (a coil of wound wire), inside of which there is a core with a spring that acts on the release mechanism. This is an instant action device. As the supercurrent flows through the winding, a magnetic field is generated. It moves the core and, exceeding the force of the spring, acts on the mechanism, turning off the “automatic machine”.

Pros: resistance to vibration and shock, simple design. Cons – forms a magnetic field, triggers instantly.

This is an additional device to automatic releases. With its help, you can turn off both single-phase and three-phase circuit breakers located at a certain distance. To activate the independent release, voltage must be applied to the coil. To return the machine to its original position, you must manually press the “return” button.

Important! The phase conductor must be connected from one phase from under the lower terminals of the switch. If it is connected incorrectly, the independent switch will fail.

Basically, independent automatic machines are used in automation panels in highly ramified power supply devices of many large facilities, where control is transferred to the operator’s console.

Combination switch

It has both thermal and electromagnetic elements and protects the generator from overloads and short circuits. To operate the combined automatic release, the current of the thermal circuit breaker is indicated and selected: the electromagnet is designed for 7–10 times the current, which corresponds to the operation of heating networks.

The electromagnetic elements in the combination switch provide instantaneous protection against short circuits, and the thermal elements protect against overloads with a time delay. The combined machine is switched off when any of the elements is triggered. During short-term overcurrents, none of the types of protection are triggered.

Semiconductor switch

It consists of alternating current transformers, magnetic amplifiers for direct current, a control unit and an electromagnet that functions as an independent automatic release. The control unit helps set the selected contact release program.

Its settings include:

• regulation of the rated current in the device;
• setting the time;
• triggered when a short circuit occurs;
• protective switches against overcurrent and single-phase short circuit.

Pros - a large selection of regulation for different power supply schemes, ensuring selectivity to series-connected circuit breakers with fewer amperes.

Cons: high cost, fragile control components.

Installation

Many home-grown electricians believe that installing a machine is not difficult. This is fair, but certain rules must be followed. Circuit breaker releases, as well as plug fuses, must be connected to the network so that when the plug of the circuit breaker is turned out, its screw sleeve is without voltage. The connection of the supply conductor for one-way power supply to the machine must be made to the fixed contacts.

Installation of an electric single-phase two-pole circuit breaker in an apartment consists of several stages:

• securing the switched-off device to the electrical panel;
• connecting wires without voltage to the meter;
• connecting voltage wires to the machine from above;
• turning on the machine.

Fastening

We install a DIN rail in the electrical panel. We cut it to the required size and fasten it with self-tapping screws to the electrical panel. We snap the automatic circuit breaker onto the DIN rail using a special lock, which is located on the back of the machine. Make sure that the device is in shutdown mode.

Connection to the electricity meter

We take a piece of wire, the length of which corresponds to the distance from the meter to the machine. We connect one end to the electric meter, the other to the terminals of the release, observing the polarity. We connect the supply phase to the first contact, and the neutral supply wire to the third. Wire cross-section – 2.5 mm.

Connecting voltage wires

From the central electrical distribution panel, the supply wires are connected to the apartment panel. We connect them to the terminals of the machine, which must be in the “off” position, observing the polarity. The wire cross-section is calculated depending on the energy consumed.

Turning on the machine

Only after all the wires have been installed correctly can the automatic current release be put into operation.

It happens that the constant shutdown of the machine becomes a big problem. Do not try to solve this by installing a trip unit with a large rated current. Such devices are installed taking into account the cross-section of the wires in the house, and, perhaps, a large current in the network is unacceptable. The problem can only be solved by inspecting the electrical supply system of the apartment by professional electricians.