Release the circuit breaker

Each circuit breaker is equipped with one or more releases that are designed to perform:

• automatic opening of the main contacts in case of overload in the main circuit breaker;

• automatic opening of the circuit breaker in case of voltage drop or change in other characteristics of electrical circuits and electrical equipment connected to it;

• remote circuit breaker tripping, etc. Release the circuit breaker. In the International Electrotechnical Dictionary (IEC) (in IEC 60050-441 [2, 3]) the term "release (of a mechanical switching device)" is defined as: a device mechanically connected to a mechanical switching device which releases the device and allows opening or closing the switching device. The cited definition is implemented in the current standard IEC 60947-1 2007 [4] and was also used in its previous edition (1999) — and supplemented with a note where the release may have instantaneous operation, time-delayed, etc. n. .

GOST R 50030.1 [5] (developed on the basis of IEC 60947-1 1999) uses the term "release (contact switching device)", defined as follows: "A device mechanically connected to a contact switching device which releases the detents and thus allows the switching device to open or close. » A note to the definition says that "Snap action releases, delay time releases, etc. are possible."

IEC 61992-1 [6] also uses the definition of the term "release (mechanical switching device)" from MEC, which is supplemented by the following three notes. Here, the term "release" refers to any mechanical device used to actuate when certain conditions are present in the input electrical circuit of the device. A circuit breaker may have several releases, each of which operates according to certain conditions. The release can be assembled from mechanical, electromagnetic or electronic parts.

In standards IEC 62271-100 [7], IEC 62271-105 [8], IEC 62271-107 [9] and IEC 62271-109 [10] the term "release" is defined in the same way as the term "release" (mechanical switching device) «in the standard IEC 60050-441.

In IEC 60077-4 [11], the term «releasing» is defined as follows: a device that releases the holding device and allows the circuit-breaker to be opened or closed. The notes on the definition of this term clarify that a circuit breaker can be operated by several releases, each of which operates according to certain conditions.These releases can be mechanically or electrically connected to the switching device.

In IEC 60898-1 2003 [12] and its previous edition, IEC 60898 1995 [13], the term "release" is defined as: a device mechanically connected (or incorporated) in a circuit-breaker which releases the holding device and allows automatic opening of the circuit-breaker .

In GOST R 50345 (developed on the basis of the standard IEC 60898 1995), this term has the same name — «release» and a similar definition: «A device mechanically connected to a circuit breaker (or built into it), which releases a holding device in a mechanism circuit breaker and causing the circuit breaker to operate automatically. »

IEC 61009-1 2006 [14] and its previous edition (1996 [15]) also define the term "release": a device mechanically connected (or incorporated) in an RCBO [1] that releases the restraint device and enables the RCBO to automatically open (the note shows that the MES definition [2] also refers to closure).

In GOST R 51327.1 [16] (developed on the basis of IEC 61009-1 1996) the term "release" is defined in a similar way: "A device mechanically connected to (or built into) the RCBO which releases the retaining mechanism and allows automatic opening of RCBO «(the note states that» In the definition given in MES, reference is also made to closure «).

GOST 17703 [17] defines the term «switching device of the contact device (release)» — «a device designed to act mechanically on the retaining device of the contact device to release its movable parts in order to change the switching position» ( note says, that «depending on the principles of action of the release, use the terms:» electromagnetic release «,» thermal release «, etc.»).

For national regulatory documents, the following definition of the term in question can be recommended: release - a device mechanically connected to or incorporated in the circuit breaker that releases the detent device in the circuit breaker mechanism, initiating its automatic opening.

For automatic opening of the main contacts in case of overload in electrical circuits protected by a circuit breaker, turn off the electrical circuits when the voltage drops at any point, remote control of the circuit breaker, as well as other actions, each circuit breaker is equipped with one or more releases. A release is a device mechanically connected or incorporated into the circuit breaker that acts on the detent in the circuit breaker mechanism and initiates its automatic opening. The opening of a circuit breaker under the action of a release is called tripping.

Each circuit breaker is equipped with overcurrent switches that initiate its opening (with or without a time delay) in cases where the electrical current in the circuit breaker's main circuit exceeds a predetermined value. The overcurrent release may have an inverse time delay, where the tripping time is inversely related to the amount of overcurrent flowing in the main circuit of the breaker.At high overcurrent values, the response time of such a release is minimal. This release is called the reverse time overcurrent release.

Overcurrent releases of circuit breakers are aimed at protection against overload currents (overload release) and short circuit currents (short circuit release). Overload release is usually an inverse time delay. Releasing a short circuit causes the circuit breaker to trip without a time delay.

Circuit breakers on household circuit breakers are usually direct-acting releases that operate directly from the electric current that flows in the main circuit of the circuit breaker through these releases.

Circuit breakers are sometimes equipped with shunt releases that allow them to be remotely controlled (triggered). They can also be equipped with undervoltage releases, which turn them off when the voltage at certain points in the building's electrical installation drops below certain values. Retaining device. In the IEC definitions of the term "release" quoted above and in the standards IEC 60077-4, IEC 60898-1 and IEC 61009-1, mention is made of a so-called "holding device" which prevents the switching device from being actuated and on release allows it to run. National standards GOST R 50345, GOST R 51327.1, developed on the basis of IEC standards, and GOST 17703 call this device a holding device and a holding mechanism.

GOST 17703 defines the term «device for holding a contact device» — «a device designed to prevent the movement of moving parts of the contact device from one position to another».

For national regulatory documents, it is recommended that the term in question be referred to as a retaining device, as it is part of the switching device mechanism. This term can be defined as follows: arresting device — a device that prevents the main contacts of a circuit breaker from moving from the closed position to the open position.

When triggered, the overcurrent release acts on the circuit breaker's holding device, which prevents the moving parts of the closed main contacts from moving, i.e. prevents the main contacts from opening. The detent device releases the main contacts which begin to open due to the energy stored in the tensioned (compressed) springs of the circuit breaker mechanism when it is closed. The holding device is also affected by other releases—shunt release and undervoltage release, the tripping of which will open the breaker.

Instant release. In the IEC 60050-441 standard, the term «instantaneous release» is defined as: a release that operates without an intentional time delay.

In IEC 62271-100 the term «instantaneous release» is defined in the same way as this term is defined in IES.

IEC 60947-1 2007 and its previous edition (1999) define the term «instantaneous relay or release»: a relay or release that operates without an intentional time delay.

GOST R 50030.1 uses the term «momentary relay or release», defined as «Relay or release, actuation without a specified time delay».

In IEC 61992-1, the term «momentary relay or instantaneous release» is defined as: a relay or release that operates without intentional delay.

In IEC 60077-4, the term «(instant) overcurrent release» is defined as: a device that causes a tripping operation without an intentional time delay when the current reaches a certain value.

The IEC standard definitions of the instantaneous release period presented here characterize a release that operates without an intentional time delay. For national regulatory documents, it is recommended to refer to the term in question as instantaneous release and define it as follows: instantaneous release — release , which operates without a time delay.

Any instantaneous release will cause the circuit breaker to trip instantaneously — with no predetermined time. If the instantaneous release is an overcurrent release, it will initiate an instantaneous opening of the circuit breaker when the overcurrent in its main circuit exceeds a certain value. The household circuit breaker is equipped with overcurrent disconnectors, which include electromagnetic short-circuit releases that operate without any time delay, that is, their operation is completely consistent with the operation of the instantaneous release.

Shunt release. In the IEC 60050-441 standard, the term «shunt release» is defined as: a release fed by a voltage source.The definition note states that the voltage source can be independent of the main circuit voltage.

In IEC 60947-1 2007, as well as in its previous edition (1999), in standards IEC 62271-100, IEC 62271-105, IEC 62271-107, IEC 62271-109 and IEC 60694 [18] the term "Shunt release" is defines in the same way as the term is defined in IEC 60050-441.

In GOST R 50030.1, the term in question is given the name «shunt release» and the following definition: «Controlled release from a voltage source». The definition note says that "The voltage source may be independent of the main circuit voltage."

IEC 61992-1 defines the term «shunt relay or shunt release»: a relay or release supplied by an independent voltage source.

The IEC standard definitions of the term «shunt release» presented here describe a release that is energized by a voltage source. For national regulatory documents, it is recommended to refer to the term in question as shunt release and define it as follows: shunt release — release excited by a voltage source.

A shunt release is used in the circuit breaker control circuit. It is designed for remote control of a circuit breaker, it is used in cases where it is necessary to remotely disconnect some electrical circuits using a circuit breaker.

After energizing the shunt release control circuit, its electromagnetic mechanism acts on the circuit breaker's holding device to initiate the opening of its main circuit contacts.The control signal to release the shunt may be generated manually, for example, by means of a push-button with a normally closed contact switch, or it may be generated by some switching or electronic device acting as a sensor, upon fulfillment of some predetermined condition, for example, a timer at the arrival of a certain hour.

Switching on the household circuit breaker after its remote shutdown using a shunt release is done manually.

Shunt releases manufactured for household circuit breakers may have an AC control circuit with a voltage of 12–415 V and a DC voltage of 12–220 V. To protect the shunt release control circuit against short circuits, fuses or circuit must to use circuit breakers with rated current, the value of which is specified by the manufacturer.

The width of the shunt release (Fig. 1) is usually the same as the width of a single-pole circuit breaker with a rated current of up to 63 A (one module-17.5 or 18 mm). The other sizes of the shunt release correspond to the dimensions of the circuit breaker. The shunt release is attached to the circuit breaker on the right or left side using spring clamps or screws. The design of the release shunt may allow one or more auxiliary contacts to be attached to it (Fig. 2).

Low voltage relief. In the IEC 60050-441 standard, the term «under-voltage release» is defined as: a shunt release that allows a mechanical switching device to open or close with or without a time delay when the voltage across the release terminals falls below a predetermined value. ..In IEC 62271-100 the definition of the term «undervoltage release» is the same.

In IEC 60947-1 2007 and its previous edition (1999), the term «undervoltage relay or release» is defined as a relay or release that allows a mechanical switching device to open or close with or without a time delay. In cases where the voltage at the relay or release terminals falls below a predetermined value.

In GOST R 50030.1, the term receives the name "relay for undervoltage or undervoltage release" and the following definition: "Relay or release allowing opening or closing of a contact switching device with or without a time delay when the voltage of the relay or the release terminals fall below a predetermined value «…

In IEC 61992-1, the term «undervoltage relay or undervoltage release» is defined as a relay or release that opens a switching device when the voltage appearing at the terminals of the switching device falls below the selected value.

In GOST 17703, the term «minimum release» is defined — «a release that causes the device to work at values ​​of the influencing quantity less than a certain value» «etc.»).

The IEC standard definitions of the term undervoltage release presented here describe a release that allows the switching device to open or close when the voltage at the release terminals falls below a predetermined value.The name "undervoltage release" used in the national regulations has a logical error. The release in question must respond to a voltage drop below the specified value. Therefore, it is advisable to call it an undervoltage release and define it as follows: undervoltage release — a release that initiates the opening of the circuit breaker with or without a time delay when the voltage at its terminals falls below a predetermined value.

Low voltage release is used in the circuit breaker control circuit. Its main purpose is to cause a circuit breaker to turn off electrical circuits when the voltage in them decreases, which is unacceptable for electrical equipment. Low voltage release can initiate the opening of the circuit breaker when the voltage in its control circuit drops to 70% of its rated value (e.g. equal to 230 V AC) or less, and also allows the circuit breaker to close if the voltage in this circuit is at least 85% of nominal.

Low voltage releases, usually manufactured for household circuit breakers, have a control circuit of 230-400 V AC and 24-220 V. DC. circuit-breaker with rated current up to 63 A. The other dimensions of the low-voltage release correspond to the dimensions of the circuit-breaker. The low-voltage release is attached to the circuit-breaker on the right or left side by means of spring clamps or screws. One or more auxiliary contacts may be fitted to the low voltage release (see Fig. 2).

The low voltage release may have make and break contacts which are used for auxiliary circuits and circuit breaker control circuits. Some versions of the low voltage release have a short time delay and allow adjustment of the cut-off voltage.

The low voltage release can also be used as a shunt release if a button with an NC contact is connected in series in its control circuit. If this contact opens briefly, the low voltage release will trip the circuit breaker.

Closing a household circuit breaker after opening with de-energization is also usually done manually.

Rice. 1. Shunt disconnection or voltage release

Rice. 2. Installation of additional devices on automatic switches: 1 — shunt disconnection or undervoltage release of a single-pole automatic switch; 2 — disconnection of the shunt or release of reduced voltage of a three-pole automatic switch; 3 — shunt disconnection or undervoltage release and two auxiliary contacts of a four-pole automatic switch

Bibliography

1. GOST R 50345–99 (IEC 60898–95). Small electrical equipment. Circuit breakers for overcurrent protection for household and similar purposes. M.: IPC Publishing House for Standards, 2000.

2. International standard IEC 60050-441. International Electrotechnical Dictionary. Part 441: Switchgear, controlgear and fuses. Second edition. — Geneva: IEC, 1984-01.

3. International standard IEC 60050-441-am1. International Electrotechnical Dictionary.Part 441: Switchgear, controlgear and fuses. Second edition. Amendment 1. — Geneva: IEC, 2000‑07.

4. International standard IEC 60947-1. Distribution and control devices for low voltage. Part 1: General rules. Fifth edition. — Geneva: IEC, 2007‑06.

5. GOST R 50030.1-2000 (IEC 60947-1-99). Low voltage distribution and control equipment. Part 1. General requirements and test methods. M.: IPC publishing house for standards, 2001.

6. International standard IEC 61992-1. Railway applications. Fixed installations. DC switchgear. Part 1: General. Second edition. — Geneva: IEC, 2006-02.

7. International standard IEC 62271-100. High voltage switchgear and controlgear. Part 100: High voltage AC circuit breakers. Release 1.2. — Geneva: IEC, 2006-10.

8. International standard IEC 62271-105. High voltage switchgear and controlgear. Part 105: AC fuse combinations. First edition. — Geneva: IEC, 2002‑08.

9. International standard IEC 62271-107. High voltage switchgear and controlgear. Part 107: Alternating current fused circuit breakers for rated voltages above 1 kV up to and including 52 kV. First edition. — Geneva: IEC, 2005-09.

10. International standard IEC 62271-109. High voltage switchgear and controlgear. Part 109: AC series capacitor bypass switches. First edition. — Geneva: IEC, 2006‑08.

11. International standard IEC 60077-4. Railway applications. Electrical equipment for rolling stock. Part 4: Electrotechnical components. Rules for AC circuit breakers. First edition. — Geneva: IEC, 2003-02.

12.International standard IEC 60898-1. Electrical accessories. Circuit breakers for overcurrent protection of household and similar installations. Part 1: Breakers for a. ° C. operation. Release 1.2. — Geneva: IEC, 2003‑07.

13. International standard IEC 60898. Electrical accessories. Circuit breakers for overcurrent protection of household and similar installations. Second edition. — Geneva: IEC, 1995-02.

14. International standard IEC 61009-1. Residual current operated circuit breakers with built-in overcurrent protection for household and similar applications (RCBO). Part 1: General rules. Release 2.2. — Geneva: IEC, 2006‑06.

15. International standard IEC 61009-1. Residual current operated circuit breakers with built-in overcurrent protection for household and similar applications (RCBO). Part 1: General rules. Second edition. — Geneva: IEC, 1996-12.

16. GOST R 51327.1-99 (IEC 61009-1-96). Residual current operated circuit breakers for household and similar purposes with built-in overcurrent protection. Part 1. General requirements and test methods. M.: IPC Publishing House for Standards, 2000.

17. GOST 17703–72. Electrical switching devices. Basic concepts. Terms and definitions. M.: Publishing House for Standards, 1972.

18. International Standard IEC 60694. General specifications for high-voltage switchgear and controlgear. Release 2.2. — Geneva: IEC, 2002‑01.