Some standard content:
National Standard of the People's Republic of China
Basic technical requirements for flameproof motors
General specification for flameproof electrical machines
1 Subject content and scope of application
GB 15703-1995
This standard specifies the types and classifications of flameproof motors, technical requirements, inspection rules and marking requirements. This standard is applicable to flameproof motors for various purposes. If there are additional requirements for flameproof motors for various purposes that are not specified in this standard, supplementary provisions should be made in the standard of the motor. If there are special requirements for the clauses of this standard for flameproof motors for certain purposes, special provisions should be made in the standard of the motor. Those not specified in this standard should comply with the provisions of GB3836.2 and GB755. 2 Reference standards
GB3836.1 General requirements for explosion-proof electrical equipment for explosive gas atmospheres GB3836.2 Explosion-proof electrical equipment for explosive gas atmospheres Explosion-proof electrical equipment *d GB3836.3 Explosion-proof electrical equipment for explosive gas atmospheres Increased safety electrical equipment "e" GB755-87 Basic technical requirements for rotating electrical machines GB4942.1-85 Motor housing protection classification GB531-83 Rubber Beer A spring hardness test method GB1410-89 Test method for volume resistivity and surface resistivity of insulation resistance of solid electrical insulating materials GB2423.4-81 Basic environmental test procedures for electrical and electronic products Test Db: Alternating damp heat test method GB12351-90 Environmental technical requirements for tropical type rotating electrical machines GB 11020-89 Test method for determining the combustion performance of solid electrical insulating materials after exposure to an ignition source GB2900.25 B2 Electrical terminology Motor
GB2900.35--83 Electrical terminology Explosion-proof electrical equipment for explosive atmospheres 3 Types and classifications
3.1, Flameproof motor categories, levels and temperature groups 3.1.1 Flameproof motors are divided into Class I and Class I a. [Class: coal mine motors:
b Class I: factory motors:
3.1.2 The level of flameproof motors, Class I flameproof motors are divided into three levels: A, B, and C according to their maximum test safety gap for explosive gas mixtures. bzxZ.net
3.1.3 The temperature group of flameproof motors is grouped according to the maximum allowable surface temperature of the motor. 1. When dust may accumulate on the surface of Class 1 motors, the maximum surface temperature allowed is 150°C; when dust will not accumulate or measures can be taken to prevent dust accumulation, the maximum surface temperature allowed is 450°C. Approved by the State Administration of Technical Supervision on September 6, 1995 and implemented on January 1, 1997
GB15703-1995
b. Class 1 motors are divided into six groups, T1 to T6, according to their maximum surface temperature. The maximum surface temperature allowed for each group is shown in Table 1. Table 1
Temperature category
3.2 Enclosure protection grade (see GB4942.1) Maximum allowable surface temperature, ℃
3.2.1 The protection grade of the motor main body enclosure shall not be less than IP44. The junction box shall not be less than IP54. 3.2.2 For external fan-cooled motors, the protection grade of the ventilation holes shall not be less than IP20 at the air inlet end and not less than IP10 at the air outlet end. 3.2.3 The protection grade of the fan air inlet end shall not be less than IP103.2.4 Vertical motors shall be able to prevent foreign objects from falling vertically into the ventilation holes 4 Environmental conditions
Unless otherwise required by the user, the motor shall be designed according to the following altitude, ambient temperature and relative humidity. 4.1 The altitude shall not exceed 1000m.
4.2 Ambient air temperature, minimum -20℃, maximum shall not exceed 40℃ with seasonal changes, and shall not exceed 35℃ in coal mines. If the motor is specified to be used at an altitude of more than 1000m or when the maximum temperature of the ambient air is higher or lower than 40℃, it shall be used in accordance with the provisions of GB755.
4.3 Relative humidity of ambient air, the average maximum relative humidity of the wettest month is 90%, and the average minimum temperature of the month is not higher than 25℃; the maximum relative humidity of coal mines shall not exceed 95% (when the temperature is 25℃). 4.4 There is an explosive gas mixture.
5 External filling material and strength requirements
5.11 The base of the motor for mining working face must be made of cast steel or steel plate, and the other parts can be made of HT250 gray cast iron. The base and other parts of the motor for non-mining working face can be made of HT250 gray cast iron. 5.2 The shell of the Class I motor can be made of HT200 gray cast iron or a light alloy with a tensile strength of not less than 120MPa and a magnesium content of not more than 6% (weight ratio).
5.3 The housing with a volume not exceeding 2000cm can be made of flame-retardant plastic, but it is not allowed to make fastening threads directly on the plastic housing (except for the outlet). It must be able to withstand the combustion test according to the flame vertical test method (EV method) specified in GB11020. The test result must not be lower than the requirements of FV1 level.
5.4 The housing of the motor must be able to withstand a test of 1.5 times the reference pressure (see Appendix A), but it must not be less than 0.35MPa. When the main cavity is connected to the junction box, collector ring cavity, etc. through a small hole, the area of the connecting hole should be increased to avoid pressure overlap. 5.5 The parts that constitute the motor external filling must be subjected to a water pressure test after fine processing and maintained at 1nin. The test result is qualified if it is discontinuous dripping (one drop of water every 10s is regarded as discontinuous dripping). When the reference pressure measurement is not carried out, the test pressure is: a. Class A, IB motor 1MPat
b. IC motor 1.5 MPa.
5.6 The following housings or housing parts of the motor must be subjected to impact test: a. Transparent parts; b. Light alloy housing,
c. Cast iron,
GB15703-1995
d. Housings made of other metals, the thickness of which is not greater than the following: Class I: 3mm;
Class I 1mm
e. Fan protection cover and other protection covers, etc. 6 Flameproof joint surface structure Xin number
6.1 Plane, stopper and circular shell flameproof structures
6.1.1 Class I, IA and IB motors
The maximum gap or diameter difference W and the minimum effective length L of the flameproof joint surface of the stationary part (see Figure 1 and Figure 4) and the flameproof joint surface of the flameproof insulating sleeve part. The minimum effective length L from the edge of the bolt through hole to the edge of the flameproof joint surface (see Figure 1 to Figure 3), the maximum diameter difference W and the minimum effective length 1 of the flameproof joint surface between the rotating shaft and the shaft hole (see Figure 5) must comply with the requirements of Table 2 to Table 4. Figure 1 Plane type
Figure 2 Plane type
GB 15703-1995
Figure 3 Stop type
When W0.2,1.0, —a+h: No L = a Figure 4 Stop type
When w≤0.2,f1.0, L=a+6
Figure 5 Cylindrical type
Joint surface type
Plane, stop or cylindrical structure
Cylinder structure with rolling bearing
Cylinder structure with sliding bearing
GB157031995
21 Class flameproof joint surface structural parameters
Note! The cylindrical structure with sliding bearing is only applicable to submersible electric pump motors. L
Table 31 A Flameproof joint surface structural parameters Joint surface type
Flat surface, stop or cylindrical structure
Cylinder structure with rolling bearing
Cylinder structure with sliding bearing
Net volume of housing V
Net volume of housing√
100V2000
V>2000
Joint surface type
Flat surface, stop or cylindrical structure
Cylinder structure with rolling bearing
Cylinder structure with sliding bearing
6. 1.2IC Motor
GB15703—1995
Table 4IB Flameproof joint surface structural parameters
Net volume of housing V
1002000
V>2 00
[5, 40
6.1.2.1IC motors should not use flat flameproof joints where the gap tends to increase during explosion. However, this does not apply to motors that are used in places that do not include acetylene and whose net volume of the housing is not greater than 100cm2.
6.1.2.21C (excluding acetylene) The maximum gap or true diameter difference W between the two explosion joints of the static part of the motor; the minimum effective length L of the flameproof joint, the minimum effective length L from the reverse edge of the bolt through hole to the edge of the flameproof joint, the maximum diameter difference W and the minimum effective length L of the flameproof joint between the rotating shaft and the shaft hole,It shall comply with the provisions of Table 5. Table 5IC (excluding B-type) Flameproof joint surface structure parameters Joint surface type
Plane, stopper or cylindrical structure
Rolling bearing
Net volume of housing V
100 ≤ 2000
Note: 1) For the stopper structure, the length of the plane part shall not be less than 6 mm, and the length of the cylindrical part shall not be less than half of the table. 2) The rotating part shall be inlaid with a brass bushing to consider possible friction. mm
V>2000
6.1.2.3IC motors, when used in a fast environment, under the condition that the safety factor is not less than 1.5, the structural parameters can be determined by tests. 6.1.3 Flameproof joint surface of shaft and hole
6.1.3.1 The flameproof joint surface of the motor shaft and the shaft hole should not produce friction under normal working conditions. Its structure can be one of the following forms: b. Flameproof joint surface of cylindrical flameproof joint surface:
b. Curved flameproof joint surface.
GB 15703--1995
6.1.3.2 When a cylindrical flameproof joint surface is used, the minimum single-sided air gap K (see Figure 6) between the shaft and the shaft hole shall not be less than the provisions of Table 6. Figure 6
K—Minimum single-side clearance im—
-Maximum single-side clearance, D—&—Diameter difference
Flameproof category
I, IA, IB
6.1.3.3 For rolling bearing structure, the maximum single-side clearance m between the shaft and the hole (see Figure 6) shall not be greater than two-thirds of the W value specified in Tables 2 to 5.
6.1.3.4 For curved flameproof joint surfaces, if they can withstand 50 flameproof performance tests, their structural parameters may not comply with the provisions of Tables 2 to 5.
6.1.3.5 For sliding bearing structure, one of the flameproof joint surfaces shall be inlaid with spark-free material (such as brass). 1C motors should not use sliding bearings.
6.2 Threaded flameproof structure
6.2. 1 The thread accuracy shall not be less than 6H or 6 g, and the pitch shall not be less than 0.7 mm. 6.2.2 The minimum number of engagements and the minimum screw-in depth of the thread shall comply with the provisions of Table 7. Table?
Net volume of housing V
102000
V>2 000
Minimum penetration depth
Note: 1) 2 times the number of test safety threads, but not less than 6 threads. 6.2.3 The thread structure shall have measures to prevent self-loosening. F, IA, IL
Minimum number of engagement threads
6.3 Other flameproof joint surface structures
GB 15703—1995
Other types of flameproof joint surface structures (see Appendix B) are allowed, but the structural parameters and safety performance shall be determined through tests. 6.4 Maintenance margin and roughness
6.4. 1 For Class I motors, due to the need for repair, when designing flameproof components, the flange thickness of the flameproof joint surface should be increased by 15%, but at least 1.0 mm,
6.4.2 The roughness R. of the flameproof joint surface is 6.3 μm. However, the roughness R. of the shaft is 3.2 gum. 6.5 Anti-rust measures
There are anti-rust measures for the flameproof joint surface, such as electroplating, phosphating, and coating with 204-1 anti-rust oil, but paint is not allowed. 7 Gaskets and viewing windows
7.1 When a gasket is used as a sealing measure on a housing component that needs to be opened during maintenance, the gasket cannot be used as a flameproof component, that is, there should still be a flameproof joint surface that meets the requirements outside the gasket (as shown in Figure 7). 0-type barrier seal
7.2 The transparent part of the observation window is made of glass or other materials that are resistant to mechanical, thermal and chemical effects, and can withstand the specified impact test. 7.3 When the transparent part of the observation window is fixed with a gasket screw, the gasket can be made of a rubber material with heat-resistant aging performance. Its thickness must be not less than 2mm, and the width of the embedded part α (see Figure 8) must not be less than the provisions of Table 8. Figure 8
1—Outer shell; 2—Southern seal 3-Transparent plate 14-Pressure plate Net volume of outer shell
B Fastening of outer shell and fasteners
GB15703—1995
8.1 The bolts and nuts used for fastening must be equipped with anti-loosening devices. At the same time, after the bolts and the blind holes are tightened, a thread margin greater than 2 times the thickness of the anti-loosening gasket must be left.
8.2 The screw holes for fastening shall not penetrate the shell wall. The original diameter around and at the bottom of the screw holes shall not be less than one-third of the bolt diameter and shall not be less than 3.0 mm.
8.3 For process through holes or screw holes that must penetrate the shell in structure, the cylindrical explosion-following structure or threaded explosion-proof structure shall be used. The exposed end shall be permanently fixed or buried in the guard ring. 8.4 If there are special requirements in the structure, special fasteners such as guard ring type or countersunk type shall be used, but they must meet the following requirements: The bolt head or nut is set in the guard ring and can only be opened with special tools. a.
After fastening, the upper plane of the bolt head or nut shall not be left high. b
The diameter d of the bolt through hole, the diameter d of the guard, and the guard height (see Figure 9) shall meet the requirements of Table 9. The guard ring can be provided with an opening, and the opening center angle is not greater than 120°d
It is not suitable to use hexagon socket bolts for this type of motor. Figure 9
Thread specification
Through hole diameter
Guard height
Guard diameter 4 (applicable to hexagonal head)
Guard diameter d (applicable to hexagonal head)
Thread specification
Through hole diameter
GB15703—1995
Continued Table 9
Guard height
Guard diameter α (applicable to hexagonal head)
: The maximum diameter α (applicable to hexagonal head)
8.5 Fasteners should be treated with anti-rust treatment such as electroplating or made of stainless steel. 9 Interlocking and warning signs
Motors that generate sparks or electricity when running must be equipped with interlocking devices to ensure that the shell cover cannot be opened when the power is on, and the power cannot be connected after the shell cover is opened. Shell covers fastened with bolts may be replaced by warning signs, and the warning signs must be marked with the words "Open the cover after power is off". 10 Moisture resistance and light corrosion resistance of the motor
The motor has moisture resistance and light corrosion resistance. After 12 cycles of testing according to the 40℃ alternating damp heat method of GB2423.4, it should meet the following requirements.
The insulation resistance between motor windings and between windings and ground shall not be less than that specified in Table 10. Table 10
Rated voltage.V
Note: U is the rated positive voltage of the motor.
Insulation resistance.MR
3. The motor windings should be able to withstand 1 min 85% of the standard test voltage withstand voltage test without breakdown.
The explosion-proof surface of the motor should not be rusted. 11 Junction box
11.1 Lead-in method
11. 1. 1 Direct lead-in method
When the motor meets the following two conditions a and b, the direct lead-in method is allowed: and, no sparks, arcs or dangerous temperatures are generated during normal operation: b, the rated power of Class I motors is not more than 250W, and the current is not more than 5 A; the rated power of Class I motors is not more than 1kW. 11. 1.2 Indirect introduction method
The cable or wire is electrically connected to the motor through the junction box. 11.2 When indirect introduction is adopted, the connection between the junction box and the main cavity can adopt a flameproof structure (see Figure 10), and a sealed structure can also be adopted for Class 1 motors. When a flameproof structure is adopted, the parameters of the flameproof joint surface must be determined according to the volume of the largest cavity, GB15703—1995
When a threaded flameproof structure is adopted between the junction box cavity and the main cavity, the following provisions must be met: Only metal threads can be used:| |tt||The conductive screw shall not adopt a threaded flameproof structure. b.
Two dry joint surfaces
Terminal box cavity
Main cavity
Two olefin joint surfaces
1Terminal box 2Terminal board (terminal sleeve), 3Terminal box seat Two explosion joint surfaces
11.3 The design of the terminal box structure size shall be convenient for wiring and leave appropriate wire bending radius space. It shall also be considered that after the cable is correctly connected, its electrical clearance and creepage distance shall not be less than the provisions of Table 11 to Table 12. Rated voltage, V
10 000
GB 15703---1995
: The rated voltage of the motor can be higher than 10% of the data listed in the table. Calculated according to the line voltage between the live parts and the grounded parts. Table 12
Minimum electrical spacing, um
Minimum creepage distance, mm
Rated voltage
10 000
600≤CTI
Note: ①) The rated voltage of the motor can be 10% higher than the listed data. Compared with the tracking index classification,CFT
400CTI≤600
② Grading of the tracking index of commonly used insulating materials (see Appendix C). 175≤CTI≤400
When the depth (or height) and width of the grooves and ribs on the insulating surface are not less than 3.0mm, the creepage distance can be calculated according to the length of the outer surface of the insulating part.
11.4 The motor lead-in cable is generally rubber-sheathed (plastic-sheathed) cable, armored cable, steel pipe wiring, and explosion-proof pick-up connection. The lead-in device adopts a sealing ring structure.
11.5 The sealing ring type lead-in device must adopt a pressure plate type (see Figure 11 or Figure 12) or a compression nut type (Figure 13 or Figure 14), and must have measures to prevent loosening and prevent the cable from being pulled out.
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