It uses flameproof enclosures to separate electrical parts of sparks, arcs, and dangerous temperatures from the surrounding explosive gas mixture. However, the housing is not hermetically sealed, and the surrounding explosive gas mixture may enter the interior of the motor through clearance of each part of the housing. When the shell and the spark and arc ignition source temperature, dangerous encounter may explode, then the motor flameproof enclosure not only damaged or deformed, and the explosion flame or hot gas through the gap of joint surface spread, also cannot ignite explosive gas mixture around.
The basic series of low voltage flameproof motor products widely used in our country is YB series flameproof three-phase induction motor, which is the derivative product of Y series (IP44) three-phase asynchronous motor. The explosion-proof performance accords with GB3836.1 - 83 "explosive environment with explosion-proof electrical equipment requirements" and GB3836.2 83 "electrical apparatus for explosive atmospheres - flameproof electrical apparatus" d "," the provisions; motor power is in the range of O.55 - 200kW, corresponding to the frame size range is as high as 80 - seat machine center 315nun; dI, dIIAT4, explosion-proof symbol is dIIBT4, which is suitable for coal mine equipment factory or fixed IIA, IIB level, temperature group T1 - T4 group of combustible gas or vapor and air to form explosive mixture of places; main body shell protective grade is IP44, also can be made into IP%4, junction box the protective class is IP54; the rated frequency 50Hz, rated voltage of 380, 1660, 1140, 380/660, 660/140V; the motor insulation class is F, but as B class of stator winding temperature rise, with large Wen Shengyu Degree. The main types of low voltage flameproof three-phase asynchronous motor derived series: YB series (dIIcT4) (the center height of 80 315mm (YBSO), a series of small power, the center height of 63 - 90mm), YBF series (fan base, center height of 63 160mm, YB) - H series (Marine base, center height is 80~280mm), YB (medium, high base center was 355 - 450mm), YBK series (used in coal mine, the center height of 100 - 315mm), YB - W, B - TH, YB - WTH series (frame center height 80 - 315mm), YBDF WF series (outdoor anticorrosive explosion-proof electric valves, the center height of 80 - 315mm) and YBDC (Series flameproof capacitor start single-phase asynchronous motor, the center height of 71 - 100mm) and YBZS series crane flameproof three-phase asynchronous motor. In addition, there are YB series high voltage flameproof three-phase induction motors (stand center height is 355~450mm, 560 - 710mm). The YB2 series of joint design of the industry has passed the national appraisal at the end of 1 and four. It will gradually replace the YB series and become the basic series of flameproof three-phase induction motors in our country. YB2 series of 15 frame number (chassis center of 63, 355nmm), power range of O.12 - 315kW.