This standard specifies the product classification, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of flameproof bolt switches for coal mines. This standard applies to flameproof bolt switches for coal mines (hereinafter referred to as "bolt switches") that are used to connect and disconnect AC asynchronous squirrel cage motors and other electrical equipment infrequently and have corresponding protection measures for them. MT 710-1997 Flameproof bolt switch for coal mines MT710-1997 Standard download decompression password: www.bzxz.net

MT7101997bzxZ.net
The explosion-proof performance requirements of this standard are drafted based on GB3836.1-83 "General requirements for explosion-proof electrical equipment for explosive atmospheres" and
GB3836.2--83 "Explosion-proof electrical equipment for explosive atmospheres Flameproof electrical equipment "d"". The electrical performance requirements of this standard are drafted based on GB/T14048.1-93 "General rules for low-voltage switchgear and controlgear"
GB/T14048.2-94 "Low-voltage switchgear and controlgear low-voltage circuit breakers" and GB/T14048.4-93 "Low-voltage switchgear and controlgear low-voltage electromechanical contactors and motor starters". This standard is proposed by the Science and Technology Education Department of the Ministry of Coal Industry. This standard is under the jurisdiction of the Coal Mine Safety Standardization Technical Committee of the Ministry of Coal Industry. The drafting unit of this standard: Fushun Branch of China Coal Research Institute. The main drafters of this standard are Li Shuanghui, Chen Zaixue and Zhang Derun. This standard is entrusted to Fushun Branch of China Coal Research Institute for interpretation. 393
1 Scope
Coal Industry Standard of the People's Republic of China
Flameproof circuit breaker with plugs and sockets for coal mine
Flameproof circuit breaker with plugs and sockets for coal mineMT 710—1997
This standard specifies the product classification, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage of flameproof plug switches for coal mines.
This standard is applicable to flameproof plug switches for coal mines (hereinafter referred to as "plug switches") that are used to connect and disconnect AC asynchronous squirrel cage motors and other electrical equipment infrequently and have corresponding protection measures for them. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were all valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the following standards. GB156-93 Standard voltage
GB191-90 Pictorial marking for packaging, storage and transportation
GB/T 228—87
Metal tensile test method
Rated current of electrical equipment
GB/T 762--80
GB/T2423.4-93 Basic environmental test procedures for electrical and electronic products, test Db: alternating damp heat test method GB3836.1--83 General requirements for explosion-proof electrical equipment for explosive atmospheres GB3836.2-83 Explosion-proof electrical equipment for explosive atmospheres Flameproof electrical equipment \d" GB/T4942.2--93 Protection grade of low-voltage electrical enclosures GB/T10111-88 Random sampling method using random numbers GB/T14048.1-9 3 General provisions for low-voltage switchgear and controlgear GB/T14048.2-94 Low-voltage switchgear and controlgear Low-voltage circuit breakers
GB/T14048.4—93 Low-voltage switchgear and controlgear Low-voltage electromechanical contactors and motor starters JB4312-86 Flameproof plugs
3 Definitions, symbols and abbreviations
3.1 This standard adopts the following definitions. In addition, the relevant terms and terms in the standards listed in Chapter 2 of this standard shall be complied with. 3.1.1 Reversible phase convertiable plug can be inserted in two directions to change the phase sequence of the connected three-phase circuit or the direction of rotation of the motor. 3.1.2 Irreversible phase unconvertiable plug can only be inserted in one direction.
3. 1.3 Plug switch circuit breaker with plugs and sockets An electrical appliance that combines a plug with a small circuit breaker. Approved by the Ministry of Coal Industry of the People's Republic of China on December 30, 1997 394
Implementation on July 1, 1998
MT 710
3.2 Symbols and abbreviations shall comply with the provisions of GB3836.1~3836.2-83 and GB/T14048.1-93. 4 Product classification
4.1 Type
4.1.1 The explosion-proof type is the mining explosion-proof type (ExdI). 4.1.2 According to the operation mode of the plug, it can be divided into reversible type and irreversible type. 4.1.3 The structural type of the socket and the plug rod is recommended to adopt the type in JB4312. 4.2 Model and meaning
4.3 Basic This parameter
Operation mode characteristic code (N for reversible type) Rated voltage (V)
Rated current (A)
Design serial number (represented by 1, 2, ·, 50 in sequence) Plug switch
Plug-in electrical appliances
4.3.1 Rated voltage 127, 380, 660, 1140V. 4.3.2 Rated current: 10, 16, 20, 25, 31.532), 50, 63A. 4.3.3 Rated frequency: 50 (60) Hz.
4.3.4 The plug switch is an uninterrupted working system. 5 Technical requirements
5.1 The product shall comply with the requirements of this standard and be manufactured in accordance with the drawings and technical documents approved by the prescribed procedures. 5.2 The plug switch should be able to work normally under the following conditions: ambient air pressure: 86kPa ~ 110kPa;
ambient temperature: -20℃ ~ +40℃;
relative humidity of air: not more than 98% (at +25℃), - underground coal mine with methane explosive gas mixture, without significant shaking and severe impact vibration environment; pollution level: level 3;
installation category: 1.
5.3 The electrical clearance and creepage distance between live parts of different potentials in the plug switch and between live parts and grounding bodies such as the shell should not be less than the provisions in Table 1.
wiring chamber
rated voltage
MT 710—1997
electrical clearance and creepage distance
minimum electrical clearance
Note: ! , I, Ia are groups divided according to the comparative tracking index (CTI) of insulating materials. Minimum creepage distance, mm
The insulating parts of the latch switch shall not have breakdown and flashover during the power frequency withstand voltage test. 5.4
The temperature rise of the latch switch terminals and conductive contact parts shall not exceed the values ​​specified in Table 2. 5.5
Table 2 Limit temperature rise
Terminals
Bare copper
Bare brass
Tin-plated steel (or brass)
Silver-plated or inlaid copper (or yellow pot)
Other metals
Conductive contact parts
Operating handle
Non-metallic
5.6After the alternating damp heat test, the insulation resistance value of the latch switch shall not be less than that specified in Table 3, and it shall be able to withstand the power frequency withstand voltage test specified in this standard, and there shall be no rust on the flameproof surface. Table 3 Insulation resistance value
Rated insulation voltage U
Minimum insulation resistance value
Ui≤60
60500cm, L≥25.0, b≤0.60. bmm
Net volume of housing (V), cm2
V≤100
5.10 Standard parts should be used for the wiring terminals in the bolt switch, and they should not rotate or be damaged during the torsion test. V>100
5.11 The minimum effective length Lo of the flameproof joint surface of the bolt switch, the minimum effective length L1 from the edge of the bolt through hole to the inner edge of the flameproof joint surface and the maximum gap (or diameter difference) 6 of the flameproof joint surface must comply with the provisions of Table 6. 5.12 The roughness Ra of the flameproof joint surface of the bolt switch should not exceed 6.3μm, and anti-rust measures should be taken on the flameproof joint surface, but paint shall not be applied.
5.13 Anti-loosening measures should be taken for the fasteners of the flameproof housing of the bolt switch. When anti-loosening washers are used, the thread margin greater than 2 times the thickness of the anti-loosening washers should be left after the bolts and the non-penetrating screw holes are tightened. The fastening screw hole shall not penetrate the shell wall, and the thickness around and at the bottom of the screw hole shall not be less than 1/3 of the bolt diameter, but at least 3.0mm. Bolts and nuts are not allowed to be made of light alloy materials. 5.14 When the parts of the bolt switch flameproof enclosure are subjected to water pressure test, water shall not drip continuously. 5.15 After the impact test (except for steel enclosures with a wall thickness greater than 3mm), the bolt switch flameproof enclosure shall not produce deformation or damage that affects the explosion-proof performance.
5.16 The protection level of the bolt switch flameproof enclosure shall not be lower than IP54. 5.17 After the clamping test of the introduction device, the displacement of the test rod shall not be greater than 6mm, and its structure shall not be damaged. 3 After the sealing test, the introduction device shall not drip or be damaged. 5.18
9 The Shore hardness of the rubber sealing ring in the introduction device is 45 to 60 degrees. After the aging test, the change in its Gunner hardness shall not exceed 5.19
20%.
MT 710—1997
5.20 The flameproof housing of the bolt switch used in non-mining working faces or with a housing volume not exceeding 2000cm3 can be made of cast iron with a tensile strength not less than HT250.
5.21 After the strength test, the bolt switch shall not produce deformation and damage that affects the flameproof performance; when conducting the flameproof performance test, it shall not transmit explosion. 5.22 The grounding terminal of the bolt switch shall be made into a dedicated plug rod and socket, and it is not allowed to replace the grounding terminal with the housing grounding. The grounding plug rod must be contacted before the main plug rod and then the power is cut off, except for those using the grounding core wire as the control line. 5.23 The inner and outer surfaces of the bolt switch made of metal shall first be coated with anti-rust primer, and then the inner surface shall be evenly coated with arc-resistant paint; the outer surface shall be coated with magnetic paint.
5.24 Anti-corrosion measures shall be taken for all ferrous metal parts on the bolt switch. 5.25 The bolt switch shall be provided with mechanical or electrical interlock to ensure that the bolt cannot be separated after the contact is energized, and the contact cannot be energized after the bolt is separated. The bolt switch without interlock shall be fixed together with the special fasteners specified in GB3836.1, and a warning sign with the words "plug and unplug after power off" shall be set.
5.26 When the rated voltage is lower than 250V and the current is less than 16A, if a slow-motion device is used to prevent sudden unplugging, or a delayed release is used to extinguish the arc, and the plug assembly still has flameproof performance during the arc extinguishing period, after the plug rod is separated from the socket, the socket assembly has a protective cover with IP44 protection level, then the provisions of 5.25 can be an exception. 5.27 The bolt switch shall ensure that it cannot loosen by itself during use. After the plug rod is pulled out, no exposed live parts are allowed in the socket; a protective cover that is easy to open shall be set at the entrance of the socket assembly. However, the structure specified in 5.26 can be an exception. 5.28 The making and breaking capacity of the latch switch according to the use category shall meet the requirements of Table 7 and Table 8. Table 7 Making and breaking conditions of making and breaking capacity for different use categories Use category
Note: Among the number of operation cycles, the last 5 are disconnected by the protection element. Disconnection
cos@±0.05
cos@±0.05
Power-on time, s
Power-on time, s
Interval time, s
See Table 8
See Table 8
Interval time, s
Table 8 Relationship between breaking current 1. and interval time when verifying the rated making and breaking capacity Breaking current I. .A
1≤100
1001≤200
2001300
Interval time, s
Breaking current IA
3001.≤400
4001≤600
600
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.