（1）Product Classification

Explosion-proof motors

（2）Specifications

• Frame size: 71 - 355

• Power: 0.12 - 315 kW

• Duty cycle: S1

• Insulation class: F

• Explosion-proof mark: Ex tD A21 IP65 T130℃ Db

• Temperature class: T1 - T4

• Energy efficiency class: National standard level 2 energy efficiency (IE4)

• Applicable places: Combustible or explosive dust environments such as grain warehouses, grain processing plants, textile and chemical industries.

（3）Product Information

The YFB4 series high-efficiency dust-explosion-proof three-phase asynchronous motors are fully enclosed self-ventilated squirrel-cage three-phase asynchronous motors. This series of motors features small size, light weight, reliable operation, beautiful appearance, high efficiency, large temperature rise margin, low vibration, low noise, high starting torque, and advanced explosion-proof structure. The power ratings and installation dimensions comply with the standards of the International Electrotechnical Commission (IEC), and their corresponding relationships are basically the same as those of the German DIN42673 standard, which is beneficial for the matching of exported mechanical equipment and the spare parts of imported equipment.

The motor housings of this series are divided into two types, dust-tight and dust-proof, according to their ability to restrict dust from entering the motor housing. The housing protection classes are IP6X and IP5X.

（4）Product Features

1. The housing has high sealing performance to reduce or prevent dust from entering the housing. Even if dust enters, it will not cause an ignition hazard.

2. The maximum allowable surface temperature of the housing is controlled not to exceed the specified temperature class, complying with national standards.

3. While ensuring explosion-proof performance, the motor design is optimized to achieve the level 3 energy efficiency grade in the national energy efficiency standard (GB18613 - 2020).

（5）Product Structure

1. Stator: The stator core is made of high-quality electrical silicon steel sheets treated with oxidation. The electromagnetic wires and insulation materials are polyesterimide enameled wires and high-quality composite insulation materials. The stator core with windings is impregnated with varnish under vacuum and high pressure to form a complete whole, which has excellent electrical, mechanical, moisture-proof and thermal stability. The insulation material is class F insulation, but the temperature rise limit is evaluated according to class B, with a large temperature rise margin and long service life.

2. Rotor: The cast-aluminum rotor is fixed on the shaft by a hot sleeve process and is dynamically balanced. The motor runs smoothly with low vibration and noise.

3. Bearings and bearing chambers: The bearings are specially designed for motors. Small-frame motors use double-sealed bearings. A wave spring is installed in the bearing chamber at the shaft extension end to press against the bearing with moderate elastic force. The non-shaft extension end bearing structure can prevent axial movement, reducing vibration and noise during motor operation. Large-frame motors use open bearings, and the bearing parts are equipped with grease injection and drainage devices, allowing for grease filling without shutting down the motor.

4. Fans and fan covers: The fans of the whole series are keyed to the shaft for reliable operation. The fan covers are made of thin steel plates. They can prevent foreign objects of a certain size from entering while providing the maximum ventilation area, ensuring smooth air flow and a beautiful appearance.

（6）Operating Conditions

1. The ambient air temperature varies with the seasons, but does not exceed 40℃, and the minimum ambient air temperature is -15℃.

2. The altitude does not exceed 1000 m.

3. The average maximum relative humidity in the wettest month is 90%, and the average minimum temperature in this month is not higher than 25℃.

4. The rating is a continuous rating based on continuous operation (S1).

5. The rated frequency of the motor is 50 Hz, and the rated voltage is 380 V.

WN Motor, Industrial Solutions.