It is understood that most people only know that explosion-proof motors are mainly used in flammable and explosive places, such as: flammable and explosive chemical plants, flour processing plants, wine making, oilfields and oil depots. But I don't know how to choose an explosion-proof motor. Today I bring knowledge of explosion-proof motors.

product category

According to the principle of explosion protection

It can be divided into flameproof motors, increased safety motors, positive pressure motors, non-sparking motors and dust explosion-proof motors.

According to the matching host

It can be divided into explosion-proof motors for coal mine conveyors, explosion-proof motors for coal mine winches, explosion-proof motors for rock loaders, explosion-proof motors for local fans in coal mines, explosion-proof motors for valves, explosion-proof motors for fans, explosion-proof motors for ships, explosion-proof motors for cranes and metallurgy And the increased safety brushless excitation synchronous motor for supporting the hydrogenation device. In addition, it can also be classified according to technical indicators such as rated voltage and efficiency, such as high-voltage explosion-proof motors, high-efficiency explosion-proof motors, high-slip explosion-proof motors, and high-starting torque explosion-proof motors.

Explosion-proof motors

Product series and its characteristics

1. The flameproof motor uses a flameproof enclosure to separate the electrical parts that may produce sparks, arcs and dangerous temperatures from the surrounding explosive gas mixture. However, this kind of housing is not hermetically sealed, and the surrounding explosive gas mixture can enter the interior of the motor through the gaps between the joint surfaces of each part of the housing. It may explode when it comes into contact with ignition sources such as sparks, arcs, and dangerous high temperatures in the enclosure. At this time, the flameproof enclosure of the motor will not be damaged or deformed, but also when the explosion flame or hot gas is transmitted through the gap between the joints, Nor can it ignite the surrounding explosive gas mixture.

The basic series of low-voltage explosion-proof motor products currently widely used in our country is YB series explosion-proof three-phase asynchronous motor, which is a derivative product of Y series (IP44) three-phase asynchronous motor. Explosion-proof performance meets the requirements of GB3836.1—83 "General Requirements for Explosion-proof Electrical Equipment for Explosive Environments" and GB3836.2-83 "Explosion-proof Electrical Equipment for Explosive Environments Explosion-proof Electrical Equipment "d","; the motor power range is O. 55-200kW, the corresponding frame number range is 80-315nun for the center height of the frame; the explosion-proof signs are dI, dIIAT4, dIIBT4, which are respectively applicable to mine underground fixed equipment or factories IIA, IIB class, and the temperature group is T1 -T4 group of flammable gas or explosive mixture of vapor and air; the protection level of the main body shell is IP44, can also be made into IP%4, the protection level of the junction box is IP54; the rated frequency is 50Hz, and the rated voltage is 380, 1660, 1140, 380/660, 660/140V; The insulation class of the motor is F class, but the temperature rise of the stator winding is assessed according to class B, which has a large temperature rise margin.

The main models of the low-voltage flameproof three-phase asynchronous motor derived series are: YB series (dIIcT4) (the center height of the frame is 80-315mm), the YBSO series (low power, the center height of the frame is 63-90mm), and the YBF series ( For fans, the center height of the frame is 63-160mm), YB-H series (for marine use, the center height of the frame is 80~280mm), YB series (medium-sized, the center height of the frame is 355-450mm), YBK series (for coal mines) , The center height of the base is 100—315mm), YB—W, B—TH, YB—WTH series (the center height of the base is 80—315mm), YBDF—WF series (for outdoor anti-corrosion and explosion-proof electric valves, base The center height is 80-315mm) and YBDC series (flameproof capacitor-started single-phase asynchronous motor, the base center height is 71-100mm) and YBZS series explosion-proof two-speed three-phase asynchronous motor for lifting. In addition, there are YB series high-voltage flameproof three-phase asynchronous motors (the center height of the base is 355-450mm, 560-710mm).

The YB2 series jointly designed by the industry has passed the national appraisal at the end of 2014 and will gradually replace the YB series and become the basic series of flameproof three-phase asynchronous motors in my country. The YB2 series has a total of 15 frame numbers (the center height of the frame is 63, 355nmm), and the power range is from 0.12 to 315kW. Its main features are:

(1) The corresponding relationship of power level, installation size and speed is consistent with DIN42673. At the same time, considering the inheritance of YB series and the interchangeability of Y2 series, necessary adjustments have been made to be more effective and applicable.

(2) The whole series adopt F grade insulation, and the temperature rise is assessed according to B grade.

(3) The noise limit is lower than the YB series, which is close to the class I noise of the YB series, and the vibration limit is equivalent to the YB series.

(4) The enclosure protection level is increased to IP55.

(5) The whole series use low-noise deep groove ball bearings, and the center height of the frame is above 180mm. The motor is equipped with oil injection and drainage devices.

(6) There are two types of motor cooling fins: parallel horizontal distribution and radiation distribution, mainly parallel horizontal distribution.

(7) The main performance indicators have reached the international advanced level in the early 1990s.

2. Increased safety motor is a motor structure that does not produce arcs, sparks or dangerous high temperatures under normal operating conditions. Some mechanical, electrical and thermal protection measures are taken to further avoid normal or approved overload conditions. There is a danger of arc, spark or high temperature, so as to ensure its explosion-proof safety.

The basic series of low-voltage increased-safety type currently used in our country is the YA series increased-safety three-phase asynchronous motor, which is a derivative product of the Y series (IP44) three-phase asynchronous motor. Explosion-proof performance meets the requirements of GB3836.1-83 "General Requirements for Explosion-proof Electrical Equipment for Explosive Environments" and GB3836.3-83 "Safety Increased Electrical Equipment for Explosion-proof Electrical Equipment for Explosive Environments "e"; the power range is 0.55~ 90kW, the corresponding base center height is 80-280mm; the explosion-proof signs are eIITl, eIIT2, and eIIT3, which are respectively applicable to places with explosive mixtures in the temperature group of T1-T3 and slightly corrosive medium in the factory; The protection level is IP54, the protection level of the junction box is IP55; the rated frequency is 50Hz, and the rated voltage is 380V; the motor adopts class F insulation.

The main models of the derived series of low-voltage increased-safety motors are: YASO series low-power increased-safety three-phase asynchronous motors (the center height of the base is 56-90mm), YA-W, YA-WFl series outdoor and indoor anti-corrosion-increased safety type Three-phase asynchronous motor (the center height of the base is 80-280mm).

At present, the industry joint design work of the YA2 series has been completed, and trial production is being organized to replace the YA series. The YA2 series has 15 frame sizes (the center height of the frame is 63-355mm), and the power range is 0.12-400kW, which will enable my country's increased-safety motors to reach the advanced level of similar products in the world in the 1980s.

The series of high-voltage (6kV) increased safety three-phase asynchronous motors are: YA355-450, power 160-450kW; YA560-900, power 500-1800kW; YAm355-630 water-cooled, power 220-2500kw; YAKK355-630 air-to-air cooling, power 185-2000kW. The TAKW4000-20/2600, 4000kW increased safety brushless excitation synchronous motor, which was trial-produced in 1999, is a new type of explosion-proof motor developed to meet the needs of oil refinery deep processing hydrogenation equipment. Its characteristics are:

(1) Meet the requirements of increased-safety explosion-proof motors, adopt a series of reliable measures to prevent sparks, arcs and dangerous high temperatures, and can safely operate in explosion-hazardous areas in Zone 2.

(2) Brushless excitation is adopted, with a rotating rectifier plate and a static excitation cabinet, the excitation control system is reliable; the forward polarity slip excitation is accurate, no impact; the excitation system has reliable out-of-step protection, and the re-stepping ability is strong; the circuit design is reasonable , The discharge resistance does not generate heat during work; the excitation current has a wide adjustment range.

(3) Synchronous machine, AC exciter and rotating rectifier disc are coaxial. The rectifier disk is located between the main motor and the exciter or outside the bearing housing.

(4) The enclosure protection grade is IP54.

(5) Class F insulation is adopted, and the temperature rise is assessed according to Class B.

(6) Change the traditional lower water cooling to upper water cooling, that is, the water cooler is placed on the upper part of the motor.

(7) An increased safety type moisture-proof heater is fixed in the cover at the bottom of the motor for heating and moisture-proof during shutdown.

(8) Choose high-quality raw materials, and leave a large margin for electrical and mechanical calculations, which can meet the temperature requirements of operational reliability and increased safety motors.

(9) Complete monitoring measures are installed; the main junction box is equipped with an increased-safety self-balancing current transformer for differential protection; the stator winding is embedded and spare platinum thermal resistance, the index number is Pt100; the leakage monitoring is set The instrument monitors the leakage of the water cooler; the sliding bearing at both ends is equipped with an on-site temperature display instrument and a remote signal terminal.

3. Positive pressure motor is a kind of positive pressure electrical equipment.

Its structural characteristics are:

(1) Equipped with a complete ventilation system, there is no structural dead angle inside the motor that may affect ventilation.

(2) The shell and pipe are made of non-combustible materials and have sufficient mechanical strength.

(3) The casing and the main pipe maintain a sufficiently large positive pressure relative to the outside atmosphere.

(4) The motor must have safety protection devices (such as time relays and flow monitors) to ensure sufficient air exchange. It must also have an automatic protection or alarm device for underpressure in the shell.

(5) The quick-opening door or cover on the shell must have an interlocking device with the power supply.

There is currently no unified series of positive pressure motors in my country.

4. Non-sparking motor refers to a motor that does not ignite the surrounding explosive mixture under normal operating conditions, and generally does not cause ignition failure. Compared with the increased safety motor, in addition to the insulation dielectric strength test voltage, winding temperature rise, te (the AC winding that reaches the rated operating final temperature at the highest ambient temperature, the AC winding starts to pass the starting current and rises to the limit Temperature, time) and starting current ratio are not specially regulated like the increased-safety type, and other aspects are the same as the design requirements of the increased-safety type motor.

Non-sparking motors comply with GB3836.1-83 and GB3836.8-87 "Explosion-proof electrical equipment for explosive atmospheres, non-sparking electrical equipment "n"". The design pays attention to the sealing measures of the motor, the protection grade of the main body shell is IP54, IP55, and the junction box is IP55. For motors with a rated voltage above 660V, the space heater or other auxiliary device connections should be placed in a separate junction box.

At present, YW series non-sparking motors have been developed and produced in China (the center height of the base is 80~315mm). The explosion-proof mark is nIIT3, which is applicable to the area 2 places where the factory contains flammable gases in the temperature group T1-T3 or explosive mixtures formed by vapor and air. The rated frequency is 50Hz, the rated voltage is 380, 660, 380/660V, the motor adopts F insulation, but the temperature rise limit of the stator winding is evaluated according to the B grade, which has a larger temperature rise margin and higher safety and reliability. The power is 0.55~200kW.

5. Dust explosion-proof motor means that its shell is designed and manufactured according to the specified conditions, which can prevent dust from entering the motor shell or although it cannot completely prevent the dust from entering, the amount of entry does not hinder the safe operation of the motor, and the accumulation of internal dust is not easy to cause ignition hazard. It will not cause the surrounding explosive dust mixture to explode. Its characteristics are:

(1) The enclosure has a high degree of airtightness to reduce or prevent dust from entering the enclosure. Even if it enters, the amount of entry will not cause an ignition hazard.

(2) Control the allowable temperature of the highest surface of the enclosure not to exceed the specified temperature group.

At present, it has been used in the mechanized equipment of the national grain reserve.

The national standard for dust explosion-proof electrical equipment is GBl2476.1-90 "Explosion-proof Electrical Equipment for Explosive Dust Environments".