GB 5959.11-2000 Safety of electric heating equipment Part 11: Special requirements for equipment for electromagnetic stirring, conveying or pouring of liquid metal

This standard applies to: - Low-frequency electromagnetic (induction) stirring or conveying equipment for liquid metal; - Equipment that affects the pouring process with electromagnetic fields; - Components directly affected by electromagnetic stirring, conveying or pouring equipment. Application examples: - Electromagnetic stirring device for continuous pouring machines, which is adjacent to electric arc furnaces, ladle furnaces, etc., or is part of them; - Liquid metal transportation, used for emptying and filling of liquid metal in furnaces, troughs or molds; - Quantitative conveying device for liquid metal, such as for filling of die casting machines; Use electromagnetic fields to affect the surface of the ingot or the pouring flow during continuous casting to enhance the crystallization process. This standard should be used in conjunction with GB 5959.1-1986. GB 5959.11-2000 Safety of electric heating equipment Part 11: Special requirements for electromagnetic stirring, conveying or pouring equipment for liquid metal GB5959.11-2000 Standard download decompression password: www.bzxz.net

GB5959.11—2000
IEC Foreword
EC Introduction
Referenced Standards
Inductors
Capacitors
Power frequency power supply
Electronic frequency conversion device
Ferromagnetic frequency multiplier
Switchgear
Cables, wires and busbars….
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Liquid cooling (see 4.6 of GB5959.1—1986) Nameplate (see Chapter 6 of GB5959.1—1986)…
Electrical clearance and creepage distance·
14 Protection against electric shock (see Chapter 10 of GB5959.1—1986) 15 Radio interference
16 Operation details Appendix A (Appendix to the standard) Special requirements for electromagnetic pouring equipment
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Appendix B (Appendix to the standard) Special requirements for electromagnetic devices with furnace lining..2
GB5959.11—2000
This standard is equivalent to IEC60519-11:1997 "Safety of electric heating equipment Part 11: Special requirements for liquid metal electromagnetic stirring, conveying or pouring equipment".
This standard should be used in conjunction with GB5959.1-1986 "Safety of Electric Heating Equipment Part 1: General Requirements". This standard shall be implemented from July 1, 2001, and all relevant products shall comply with the requirements of this standard from October 1, 2001. Appendix A and Appendix B of this standard are appendices to the standard. This standard was proposed by the State Machinery Industry Bureau. This standard is under the jurisdiction of the National Technical Committee for Standardization of Industrial Electric Heating Equipment. The drafting unit of this standard is Xi'an Electric Furnace Research Institute of the State Machinery Industry Bureau. The main drafter of this standard is Ge Huashan.
This standard is entrusted to the Secretariat of the National Technical Committee for Standardization of Industrial Electric Heating Equipment for interpretation. I
GB5959.11-2000
IEC Foreword
1) IEC (International Electrotechnical Commission) is a worldwide standardization organization composed of national electrotechnical committees (IEC National Committees). The goal of IEC is to promote international cooperation on all standardization issues related to the electrical and electronic fields. For this goal and other purposes, IEC publishes international standards. Standards are entrusted to technical committees; any IEC National Committee interested in the subject may participate in the preparation of the subject. International, governmental and non-governmental organizations in contact with the IEC may also participate in the preparation. The IEC and the International Organization for Standardization (ISO) work closely together in accordance with rules agreed upon by the two organizations. 2) Formal decisions or agreements on the subject, drawn up by technical committees in which all national committees with a particular interest in the technical subject are represented, express as far as possible the international consensus on the subject. 3) These decisions or agreements are published in the form of recommended standards, technical reports or guidelines for international use and are recognized by the National Committees in this sense.
4) In order to promote international unification, the IEC National Committees explicitly commit themselves to adopt IEC International Standards as far as possible in their national and regional standards. Any inconsistencies between IEC standards and corresponding national or regional standards shall be clearly indicated in the national or regional standards. 5) IEC does not provide any explicit procedure for indicating its agreement with, and does not assume any responsibility for, any equipment claiming to comply with an IEC standard.
6) Please note that some parts of this International Standard may involve patent rights. IEC assumes no responsibility for identifying any or all such patent rights.
International Standard IEC 60519-11 was prepared by IEC Technical Committee 27: "Industrial Electrothermal Equipment". The content of this standard is based on the following documents: Final Draft International Standard (FDIS)
27/181/FDIS
Voting Report
27/191/RVD
Details of the voting on this standard can be found in the voting reports listed in the table above. This part of IEC 60519 should be used in conjunction with the following standards: IEC 60519-1: 1984 Safety of electrothermal equipment Part 1: General requirements IEC 60519-3: 1988 Safety of electrothermal equipment Part 3: Particular requirements for induction and conduction heating equipment and for induction melting equipment
Annexes A and B form an integral part of this standard. N
GB5959.11—2000
IEC Introduction
Equipment for electromagnetic stirring, conveying or pouring of liquid metal has, to a large extent, the same technical characteristics as the induction heating or induction melting devices covered in EC60519-3. The numbering of the chapters of this standard is consistent with that of IEC60519-3. Under normal operating conditions, these devices contain high-temperature liquid or partially solidified materials, so they require safety rules similar to those of electric heating equipment. Therefore, the safety rules formulated for electric heating equipment are applicable even to those equipment that are not intended for heating. This standard consists of the following parts:
General requirements for equipment for electromagnetic stirring, conveying or pouring of liquid metal; Appendix A and Appendix B give special requirements for electromagnetic pouring devices and electromagnetic devices with furnace linings respectively. V
National Standard of the People's Republic of China
Safety of electroheating equipment
Part 11: Particular requirements for installations foelectromagnetic stirring, transport or pouring of metal liquids 1 Overview
1.1 Scope
This standard applies to:
- low-frequency electromagnetic (induction) stirring or conveying equipment for liquid metal;- equipment that uses electromagnetic fields to influence the pouring process; parts that are constantly affected by electromagnetic stirring, conveying or pouring equipment. Application examples:
GB5959.11—2000
idtIEC60519-11:1997
- Electromagnetic stirring device for continuous casting machine, which is adjacent to electric arc furnace, ladle furnace, etc., or is part of them; liquid metal transportation, used for emptying and filling of liquid metal in furnace, launder or mold;- quantitative delivery device of liquid metal, such as for filling of die casting machine; use of electromagnetic field to affect the casting surface or pouring flow during continuous casting to enhance the crystallization process. This standard should be used in conjunction with GB5959.1—1986. Note: When GB5959.1-1986 is used in conjunction with this standard, the term "electric heating equipment" or "electric heating device" should be replaced by the term "liquid metal electromagnetic stirring, conveying or pouring equipment".
1.2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T2900.23-1995 Electrical terminology Industrial electric heating equipment (negIEC60050 (841): 1983) GB5959.1-1986 Safety of electric heating equipment Part 1: General requirements (neqIEC60519-1: 1984) GB5959.3-1988 Safety of electric heating equipment Part 3: Special requirements for induction and conductive heating equipment and induction melting equipment (eqvIEC60519-3: 1985) GB14821.1-1993 Protection against electric shock of electrical installations in buildings (eqvIEC60364-4-41: 1992) 2 Definitions
The definitions given in GB5959.1-1986, GB5959.3-1988, GB/T2900.23-1995 and the following definitions apply to this standard.
2.1Equipment for electromagnetic stirring, transport or pouring of liquid metalsApproved by the State Administration of Quality and Technical Supervision on October 17, 2000, and implemented on July 1, 2001
pouring of liquid metals
GB5959.11—2000
Equipment for electromagnetic stirring, transport or pouring of liquid metals, consisting of sensors, electrical and mechanical devices. 2.2Electromagnetic stirring of liquid metalsElectromagnetic stirring of liquid metalsThe process of using a moving, rotating or any other electromagnetic field to achieve stirring in liquid metal. 2.3Electromagnetic transport of liquid metalsThe process of using a moving electromagnetic field to move liquid metal in a specified direction. 2.4 Electromagnetic casting of liquid metals The process of using electromagnetic fields to shape the liquid metal flow or affect its surface quality after pouring. 2.5 Enhancing crystallization of liquid metal in electromagnetic fields
The process of metal grains forming and composing in an electromagnetic field. 2.6 Inductor of
A component of liquid metal electromagnetic stirring, conveying or pouring equipment used to generate an electromagnetic field to provide the required electric power. 3 Inductor
3.1 When the inductor or its components need to be replaced due to damage or to meet new production requirements, the manufacturer's instructions should be followed. 3.2 If the cooling effect of the inductor deteriorates, endangering the safety of the staff or causing damage to the key components of the device, an alarm signal should be given and the heating power should be automatically cut off. bzxZ.net
3.3 Avoid cooling the inductor below the dew point, as this will cause condensation on the inductor coil and its lead terminals and may cause a short circuit.
3.4 ​​For electromagnetic stirring, conveying and pouring equipment with forced cooling inductors, and the inductor contains high heat capacity charge and/or lining (shell), it is recommended to provide a backup cooling source to cool the coil and conveyor (if any) until the hot charge has been removed and the lining (shell) has been cooled to a safe temperature.
3.5 Depending on the circuit design and frequency used, the current and voltage of the inductor should not exceed the maximum value given by the manufacturer. 3.6 The design of the inductor should take into account the concentrated electromagnetic force that can cause vibration and the local electromagnetic field concentration generated by the low-frequency high current in the coil.
3.7 The design of the power cord connection should ensure safe connection under normal environmental and working conditions, such as moisture, metal dust, high temperature and vibration.
3.8 The design and manufacture of the inductor should meet the requirements of severe operating conditions and environments, such as water splashing, steam and heat radiation. 3.9 Influence range of the inductor
When designing components located near the inductor, the influence of the electromagnetic field should be considered. In addition to using appropriate materials and shapes, other measures such as shielding, insulation, forced cooling and avoiding the formation of closed metal loops can be taken to limit the electromagnetic and thermal influences to the allowable range. Note: Mobile electromagnetic fields used for stirring or conveying can be realized by multi-phase or several single-phase inductors. These two types of inductors can be powered by multi-phase or several single-phase power supplies with different phases. 4 Capacitors
4.1 All necessary measures should be taken to quickly discharge capacitors that are still dangerous to touch after disconnection. A warning sign should be placed in a conspicuous location: "Discharge must be carried out before touching the capacitor" 4.2 For capacitors that are fixedly connected in parallel with the inductor coil or transformer, the discharge device can be omitted. For capacitors connected in parallel with an inductor or transformer and disconnected only under load removal, the discharge device may be omitted if there is sufficient discharge time between disconnection of the power supply and opening of the capacitor switch. Note: If there is a risk of DC charging, the discharge device cannot be omitted. 4.3 Capacitors operated under load or connected through external fuses should have discharge facilities. 2
GB5959.11—2000
4.4 The discharge device cannot replace the short circuit or grounding before contacting the capacitor terminals. Note: Even after the discharge device has been operated, there may sometimes be residual charge on the internal connections of the series capacitor due to the burning of the fuse, the disconnection of the internal connection, the difference in capacitance value or the recharging of the dielectric caused by the DC component of the previous charge. 4.5 Low-frequency capacitors should be connected through protective devices. When internal protective devices such as fuses are used, external protective measures can be omitted. The connection of medium-frequency capacitors may not be equipped with protective devices. 4.6 For liquid-cooled capacitors, their temperature should be monitored by a device with automatic alarm function. If the cooling systems of several capacitors are connected in series, it is sufficient to monitor the temperature of the capacitor at the outlet. When the capacitor groups are switched one by one, the last capacitor group connected in series with the cooling circuit should be fixedly connected to the circuit or the last to be disconnected. 4.7 The temperature of the coolant at the outlet, the flow rate of each cooling circuit or the pressure in each capacitor shell can also be monitored to replace the monitoring of the capacitor temperature.
5 Power frequency power supply
According to the requirements of Chapter 6 of GB5959.3-1988. 6 Motor generator type frequency conversion unit
According to the requirements of Chapter 7 of GB5959.3-1988. 7 Electronic frequency conversion device
7.1 The electronic frequency conversion device should be protected at its input to prevent overvoltage that may be generated during the switch operation on the power supply side to ensure safety. 7.2 The electronic frequency conversion device should be equipped with fast-acting overvoltage and overcurrent protection devices. 7.3 Additional measures should be taken to avoid the generation of dangerous transient voltages caused by rapid changes in load power. 8 Ferromagnetic frequency multiplier
According to the requirements of Chapter 9 of GB5959.3-1988. 9 Switching device
9.1According to the requirements of 10.1 of GB5959.3-1988. 9.2 The design of the switchgear for no-load operation shall take into account the discharge characteristics of the system composed of the frequency conversion device or frequency conversion unit, transformer, reactor and capacitor.
9.3 The design of the switchgear shall take into account the discharge characteristics of the system composed of the frequency conversion device or frequency conversion unit, transformer, reactor and capacitor.
9.4 When switching capacitors with load, the following points shall be considered in particular when selecting the switching device or switching mode: - When connected, a high-frequency high current peak will be generated; - When disconnected, dangerous overvoltage caused by the re-arcing of the switching device shall be avoided. 10 Cables, wires and busbars
10.1 The cross-sectional dimensions of cables, wires and busbars shall take into account the magnitude and frequency of the current carried to avoid excessive heating. Note: The power frequency (50Hz/60Hz) current carrying value of the cable is usually not applicable to equipment with higher operating frequencies. In the case of parallel connection, care should be taken to avoid overheating of individual conductors due to uneven current distribution. 10.2 For cables, wires and busbars with strong cooling, the requirements of 4.2.8, 4.6.1 and 4.6.2 of GB5959.1-1986 should be followed. 10.3 When the internal connections between frequency converters or frequency converters, transformers, capacitors, switch devices and inductors are equipped with short-circuit and ground leakage protection structures, the respective overcurrent protection devices can be omitted. Note: This is the case when cables or rigid conductors are arranged with sufficient clearance, or when spacers or insulating washers are used, or when the conductors are laid in separate 3
GB5959.11—2000
ducts made of insulating material, or when cables or wires designed to prevent short circuits are used, contact between them (including contact with grounding fittings) can be avoided.
For medium frequency equipment, if the design of the frequency conversion device (such as an electronic frequency conversion device) can provide adequate short-circuit protection, the above-mentioned measures to prevent short circuits can be omitted.
10.4 Cables and wires located in the heating area usually contain insulating materials that are resistant to high mechanical and thermal stresses. In most cases, this insulating material is not sufficient for electric shock protection. Therefore, when the contact voltage exceeds the allowable value (see 14.1.1), measures should be taken to prevent inadvertent contact with these cables and wires during operation. 10.5 When selecting cables or lead-in conductors to power the inductor, the effects of thermal radiation and the presence of water or water vapor should be considered. To protect them, special measures may need to be taken, such as shielding, forced cooling or an outer cover. 11 Liquid cooling (see 4.6 of GB5959.1-1986) 11.1 The requirements of 12.1 in GB5959.3-1988 do not apply. 11.2 According to the requirements of 12.2 in GB5959.3-1988. 11.3 Some water-cooled components (such as inductors with water-cooling jackets) are very sensitive to pressure. Unlike the requirements of 4.6.4 of GB5959.1-1986, these water-cooled components only need to be designed according to their rated pressure, and their water pipe joints should allow 1.5 times the rated pressure. 11.4 The water used to cool the live parts and magnetic cores should be of particularly high quality and should not contain impurities and/or ferromagnetic particles. 11.5 When the cooling circuit is opened, such as when replacing the inductor, care should be taken to avoid any contamination caused by the water. 11.6 When water cooling is used to remove the heat generated by electrical losses and to protect the inductor and/or cables or lead wires from the influence of heat radiation from the charge, the water flow should be maintained even after the power supply is cut off until there is no longer a danger of heating. 12 Nameplate (see Chapter 6 of GB5959.1-1986) The main components of electromagnetic stirring, conveying and pouring equipment (such as inductors) should have separate nameplates. 13 Clearances and creepage distances
Clearances and creepage distances for medium frequency equipment do not have to be the same as those for power frequency (50Hz/60Hz). When smaller clearances and creepage distances are used, such as for medium frequency converters or frequency converters, measures should be taken to prevent arcing that endangers safety.
14 Protection against electric shock (see Chapter 10 of GB5959.1-1986) 14.1 Protection against direct contact (see Chapter 412 of GB14821.1-1993) 14.1.1 Relationship between the voltage and frequency of the permissible contact The voltage limit of the permissible contact is a function of the frequency, and the limit voltage increases with the increase of the frequency. The recommended value is under consideration and can be based on the existing national standards.
Note: Attention should be paid to the situation where the voltage of a higher frequency is modulated by a certain low frequency. 14.1.2 All electrical devices of electromagnetic stirring, conveying and pouring equipment, such as capacitors, reactors, transformers, inductor coils, switchgear, cable and busbar connectors, shall be installed in the enclosure, otherwise there shall be adequate protection against direct contact. It shall not be possible to open the cabinet door or remove the cover to access these electrical devices belonging to the 2nd and 3rd voltage zones without using tools such as wrenches or keys. Only authorized personnel can open the cabinet door and remove the cover.
14.1.3 Live conductors of the 2nd and 3rd voltage zones shall be inaccessible, except where the following conditions are met: For the 2nd voltage zone, only authorized personnel may access. For the 3rd voltage zone, its design shall prevent unintentional contact by authorized personnel engaged in fault finding, testing and maintenance work. This can be achieved by adopting one or more of the following methods: a) Use of screwed covers
Access is only possible when the power is disconnected.
GB5959.11—2000
b) When using a hinged lockable door or hinged inner shield, a reliable, non-resettable safety switch should be used to ensure that the door is closed before power is restored, and facilities should be provided to lead the lead wires of appropriate specifications to the external connection test instrument. c) Internal shielding and insulation
A fixed shield or insulation should be used to cover the voltage test point. The shield or insulation should have a hole or slot of a size that can be inserted into the test probe.
14.1.4 Accessible plugs and sockets for DC, low-frequency or medium-frequency AC with a voltage higher than 500V should not be interchangeable and should be automatically disconnected before or when the equipment is used to avoid personal safety accidents. This can be achieved by mechanical interlocking. 14.2 Protection against indirect contact (see Chapter 413 of GB14821.1-1993) 14.2.1 Relationship between the allowable contact voltage and the contact duration and frequency As described in 14.1.1, the allowable contact voltage increases with the increase of frequency. The limit values ​​of the allowable contact voltage for power frequency, direct current and the second voltage band are given in Table 41A and Figure 41B of 413.1.1.3 of GB14821.1-1993. When using these values, the frequency factor should be considered. The allowable contact voltage related to frequency for continuous contact is the same as the allowable contact voltage for direct contact (see 14.1.1). For the third voltage band and non-power frequency conditions, the limit values ​​of the allowable contact voltage are under consideration. 14.2.2 Due to temperature changes, the electrical insulation resistance of the components of the electromagnetic stirring, conveying and pouring equipment changes throughout the process cycle. The insulation resistance of electrical insulation materials, furnace linings and electrical components such as capacitors and water-cooled windings depends on the temperature and quality of the water used. The minimum value of electrical insulation resistance is usually not given. Therefore, it is necessary to take these changes into account when setting the action value of the protection device, such as when setting the ground leakage current detection device when the equipment is delivered for production. The leakage current of electromagnetic stirring, conveying and pouring equipment is usually large. This may require consideration of electrical isolation from the power supply network. 14.2.3 Protection measures such as star point grounding or protective grounding should be adopted. 14.3 Special requirements
14.3.1 Metal rings and bracelets should not be worn near low-frequency and medium-frequency strong magnetic fields (such as near sensors). 14.3.2 If the electromagnetic field strength or exposure time in the electromagnetic field leakage area of ​​the sensor exceeds the permissible limit value, the personnel should not enter the area.
People with electronic or metal implants (such as pacemakers or metal spinal connectors) should not enter the vicinity of the sensor during operation of the equipment and warning signs should be displayed.
14.4 Grounding precautions (see 10.4 of GB5959.1-1986) 14.4.1 If live parts are grounded through resistors, impedances or dischargers in equipment electrically isolated from the power grid, the size of the grounding connection should be determined from the aspects of heat generation and electromotive force based on the maximum current in the event of an accident. The current flowing in these grounding connections should be monitored. If it exceeds the maximum allowable value, an alarm should be issued and the power supply to the equipment should be automatically cut off. When the grounding connection is used to release static charges, it is not necessary to monitor it. 14.4.2 When protective grounding is used, the relationship between the impedance and frequency of the loop composed of the current source, the live conductor and the grounding system should be considered. 14.4.3 Sometimes it is possible to operate metal parts that are directly affected by electromagnetic fields without grounding. In order to avoid the formation of metal closed loops and keep the electromagnetic and thermal effects and contact voltages within the allowable values, other protective measures should be provided. See 10.3 of GB5959.1-1986.
When the voltage on these metal parts exceeds the permissible contact voltage (see 14.2.1), the operator shall not approach them. If this cannot be done due to the limited space or the operating method of the equipment, other measures given in the operating instructions shall be taken to ensure the safety of the personnel.
14.4.4 All metal armored cables, conduits or pipes shall be grounded at the point where they pass through the enclosure containing the high-voltage circuit belonging to the third voltage band.
14.5 Protective wire
14.5.1 For low-frequency devices, the material of the protective (grounding) wire is allowed to be copper, aluminum or galvanized steel strip; for medium-frequency devices, it should be copper or aluminum. 5
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When determining the cross-sectional size of the conductor, the discharge current of the capacitor shall also be appropriately considered. When determining the cross-sectional size of the protective wire, the factor that the current penetration depth decreases with increasing frequency shall be considered. 14.5.2 Due to different operating modes, the inductor may need to be replaced frequently, so special consideration should be given to the safe and reliable connection between the metal shell parts of the inductor and its protective wire.
14.5.3 Due to the effect of the operating leakage current, the protective wire has a constant current load, which should be taken into account when determining its size. If possible, it is recommended to monitor the leakage current.
5 Radio interference
When electromagnetic stirring, conveying and pouring equipment is in operation, care should be taken to avoid radio interference. Some guidelines can be given by national or international standards.
Operation details
16.1 If the operating frequency of the electromagnetic stirring, conveying or pouring equipment for liquid metal is adjustable, appropriate measures should be taken to ensure that the operating frequency does not exceed or fall below the permitted frequency range. 16.2 If the electromagnetic stirring, conveying or pouring equipment for liquid metal is allowed to operate at different maximum currents (for example, depending on its operating frequency), monitoring devices should be provided separately to ensure safety. 16.3 For ingot stirring equipment, it should be ensured that during the start-up operation, the stirring device is powered only when the cold casting mold is not affected by the electromagnetic field.
For the operation of low-frequency equipment without intermediate DC circuit, special effects on the power supply system, such as power pulsation, should be considered. 6
GB5959.11—2000
Appendix A
(Standard Appendix)
Special requirements for electromagnetic pouring devices
A1 In the event of an accident that endangers personnel, equipment or the production process, protective measures should be provided, alarm signals should be issued and the power supply to the equipment should be cut off.
Failure of the electromagnetic pouring system may be caused by metal overflow that is not controlled by electrical measures. For this reason, other non-electrical measures should be taken to ensure personal safety.
Appendix B
(Standard Appendix)
Special requirements for electromagnetic devices with furnace lining B1 Furnace lining
B1.1 Liquid metal penetrating the inductor lining is very dangerous to personnel and equipment. During the entire working life of the lining, its thickness is constantly changing. In addition, sudden damage to the lining caused by thermal and mechanical shocks may also be encountered. B1.2 The condition of the inductor lining should be checked regularly. The inspection methods can be: a) measuring the electrical operating parameters of the equipment; b) visual inspection; c) checking the lining conditions at different locations; d) monitoring the temperature of the sensor housing and coolant. B1.3 In order to ensure the safety of the staff and reduce the damage to the electromagnetic device, it is recommended to provide an alarm device and a measure to cut off the power supply to the electromagnetic device when the refractory lining is penetrated.
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