What is the difference between explosion-proof motors and ordinary motors?

What is the difference between explosion-proof motors and ordinary motors?
1. Explosion proof motors are generally used in flammable and explosive environments.

2. The sealing of the explosion-proof motor junction box is better than that of ordinary motors.

3. The protection level of explosion-proof motors is as low as IP55, while ordinary motors range from IP23, IP44, IP54, IP55, to IP56, so it can be distinguished from their appearance.

Below is a detailed introduction to explosion-proof motors

Explosion proof motor is a type of motor that can be used in flammable and explosive factories without generating electrical sparks during operation.

Explosion proof motors are mainly used in coal mines, oil and gas, petrochemicals, and chemical industries. In addition, it is widely used in sectors such as textiles, metallurgy, urban gas, transportation, grain and oil processing, papermaking, and medicine. Explosion proof motors, as the main power equipment, are usually used to drive pumps, fans, compressors, and other transmission machinery.

 

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

 

Divided by matching host

It can be divided into explosion-proof motors for coal mine transport aircraft, 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 lifting and metallurgy, and increased safety brushless excitation synchronous motors for hydrogen refueling equipment. 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.

 

Product series and their characteristics

 

1. A flameproof motor uses a flameproof casing to separate electrical components that may generate sparks, arcs, and hazardous temperatures from the surrounding explosive gas mixture. However, this type of casing is not sealed, and explosive gas mixtures around it can enter the interior of the motor through the gaps between the joint surfaces of various parts of the casing. When in contact with ignition sources such as sparks, arcs, and dangerous high temperatures inside the casing, an explosion may occur. At this time, the explosion-proof casing of the motor will not be damaged or deformed, and when the explosive flame or hot gas is transmitted through the gap between the joint surfaces, it cannot ignite the surrounding explosive gas mixture.

 

The basic series of low-voltage explosion-proof motor products widely used in China is YB series explosion-proof three-phase asynchronous motor, which is a derivative product of Y series (IP44) three-phase asynchronous motor. The 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 0.55-200kW, corresponding to a machine base size range of 80-315nu at the center height of the machine base; The explosion-proof signs are dI, dIIAT4, and dIIBT4, which are respectively applicable to fixed equipment or factory IIA and IIB levels underground in coal mines, and places where combustible gases or vapors form explosive mixtures with air in temperature groups T1-T4; The protection level of the main body shell is IP44, which can also be made into IP% 4, and 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 motor insulation level is Class F, but the temperature rise of the stator winding is assessed according to Class B, with a large temperature rise margin.

 

The main models of the derived series of low-voltage explosion-proof three-phase asynchronous motors include: YB series (dIICT4) (with a center height of 80-315mm), YBSO series (low power, with a center height of 63-90mm), YBF series (for fans, with a center height of 63-160mm), YB-H series (for ships, with a center height of 80-280mm), YB series (medium, with a center height of 355-450mm), YBK series (for coal mines, with a center height of 100-315mm), YB-W, B-TH, YB-WTH series (with a center height of 80-315mm), YBDF WF series (for outdoor anti-corrosion and explosion-proof electric valves, with a center height of 80-315mm), YBDC series (explosion-proof capacitor starting single-phase asynchronous motor, with a center height of 71-100mm), and YBZS series lifting explosion-proof dual speed three-phase asynchronous motor. In addition, there are YB series high-voltage explosion-proof three-phase asynchronous motors (with a center height of 355-450mm and 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 as the basic series of explosion-proof three-phase asynchronous motors in China. The YB2 series has a total of 15 machine base sizes (with a center height of 63 and 355mm), with a power range of 0.12-315kW. Its main characteristics are:

 

(1) The corresponding relationship between power level, installation size, and speed is consistent with DIN42673, and necessary adjustments have been made to make it more effective and applicable, taking into account the inheritance with YB series and interchangeability with Y2 series.

(2) The entire series adopts F-level insulation, and the temperature rise is assessed according to B-level.

(3) The noise limit is lower than that of the YB series, approaching the I-level noise of the YB series, and the vibration limit is comparable to that of the YB series.

(4) The protection level of the shell has been raised to IP55.

(5) The entire series uses low-noise deep groove ball bearings, and motors with a center height of over 180mm are equipped with oil injection and discharge devices.

(6) There are two types of motor heat sinks: parallel horizontal distribution and radiation distribution, with parallel horizontal distribution being the main one.

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

 

 

2. An increased safety motor is a motor structure that does not generate arcs, sparks, or dangerous high temperatures under normal operating conditions. It is further protected by mechanical, electrical, and thermal measures to avoid the danger of arcs, sparks, or high temperatures under normal or recognized overload conditions, thereby ensuring its explosion-proof safety.

 

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

 

The main models of the derivative series of low-voltage increased safety motors include: YASO series low-power increased safety three-phase asynchronous motors (with a center height of 56-90mm), YA-W and YA-WFl series outdoor and indoor anti-corrosion increased safety three-phase asynchronous motors (with a center height of 80-280mm).

 

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

 

The high-voltage (6kV) increased safety three-phase asynchronous motor series includes: YA355-450, power 160-450kW; YA560-900, power 500-1800kW; YAm355-630 water-cooled, power 220-2500kW; YAKK355-630 air-cooled, 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 petroleum deep processing hydrogenation units in refineries. Its characteristics are:

 

(1) To meet the requirements of increased safety explosion-proof motors, a series of reliable measures are taken to prevent sparks, arcs, and dangerous high temperatures, ensuring safe operation in Zone 2 explosion hazardous areas.

 

(2) Adopting brushless excitation, setting up a rotating rectifier panel and a static excitation cabinet, the excitation control system is reliable; Accurate and no impact on the smooth transition excitation; The excitation system has reliable out of step protection and strong ability to perform further steps; The circuit design is reasonable, and the discharge resistor does not generate heat during operation; The range of excitation current regulation is wide.

 

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

 

(4) The enclosure protection level is IP54.

 

(5) Adopting F-level insulation, the temperature rise is assessed according to B-level.

 

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

 

(7) Install an increased safety moisture-proof heater, fixed inside the cover at the bottom of the motor, for heating and moisture-proof purposes during shutdown.

 

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

 

(9) Establish comprehensive monitoring measures; An increased safety self balancing current transformer for differential protection is installed inside the main junction box; The stator winding embedding work and backup platinum thermistor, with a division number of Pt100; Install a water leakage monitoring device to monitor the leakage of the water cooler; Two end seated sliding bearings are equipped with on-site temperature display instruments and remote signal terminals.