YBX4 Explosion Proof AC Gear Motor | IE4 Three Phase Motor

Product Overview

The YBX4 series represents the current generation of explosion-proof three phase motor technology from our production facility. Designed from the ground up as a fully enclosed, fan-cooled squirrel-cage motor, the YBX4 carries ATEX-equivalent certification for use in Zone 1 and Zone 2 hazardous areas — locations where ignitable concentrations of flammable gas, vapor, or mist may exist during normal operation or under anticipated fault conditions. With frame sizes from H132 through H355 and output ratings spanning 2.2 kW to 315 kW, the series covers the power range demanded by pumps, compressors, fans, and conveyors in petrochemical plants, offshore platforms, grain-handling terminals, and underground mining operations.

Energy efficiency is a defining feature of the YBX4 platform. All models meet the IE4 (super-premium efficiency) classification under IEC 60034-30-1, which translates to measurably lower electricity consumption over the motor lifetime compared to older Ex-rated designs that typically achieved only IE2 or IE3 levels. For facilities in Korea that operate around the clock in continuous S1 duty, the accumulated energy savings can reduce operating costs by a significant margin within the first two years of service. The motor also supports S4, S5, S6, and S9 duty cycles, giving process engineers flexibility to specify the YBX4 for intermittent and cyclic loads without derating concerns.

Safety features go beyond the flameproof enclosure. The casting joints, shaft seal, and terminal box are all machined to explosion-proof gap standards, ensuring that any internal ignition cannot propagate to the surrounding atmosphere. Class F (155 °C) or Class H (180 °C) insulation provides ample thermal headroom, and the IP55 protection rating keeps out dust jets and low-pressure water jets from all directions. For Korean industrial buyers replacing older YB2 or YB3 explosion-proof electric motor units, the YBX4 offers a direct-fit upgrade path with the same IEC mounting dimensions.

Technical Specifications

Main Parameters

YBX4 Series Explosion Proof Three Phase Asynchronous Motor Technical Data:

The following table covers 2-pole (3000 r/min synchronous) and 4-pole (1500 r/min synchronous) variants. 6-pole, 8-pole, and 10-pole data is available upon request. All values are measured at 380 V, 50 Hz.

 

How Explosion-Proof Motors Provide Safety

An explosion-proof AC gear motor does not prevent internal sparking or arcing — rather, it is designed so that if an internal ignition does occur, the resulting flame and hot gases cannot escape from the motor enclosure into the surrounding hazardous atmosphere. This containment principle is called "flameproof" protection (Ex d) under the IEC 60079 standard family.

The critical engineering is in the joints. Every mating surface where two parts of the enclosure meet — the end shields to the stator housing, the terminal box cover to its body, the cable entry gland to the box — is machined with a controlled gap width and path length. When combustion gases expand and travel through these narrow, long gaps, they cool below the auto-ignition temperature of the surrounding gas mixture before reaching the outside atmosphere. The shaft exit point uses a labyrinth seal or a ground-surface gap with similarly tight tolerances to prevent flame propagation along the rotating shaft.

Inside the motor, the construction follows the same squirrel-cage induction principle used in standard industrial motors: a three-phase stator winding produces a rotating magnetic field that induces current in the rotor bars and generates torque. The key differences are the heavier casting walls (which must withstand internal explosion pressure without rupturing), the wider flanges at mating surfaces (which provide the necessary flame path length), and the use of higher-grade insulation materials and impregnation resins that tolerate the elevated temperatures associated with the thicker, less-ventilated enclosure walls.

Application Scenarios for Explosion-Proof AC Motors

Oil Refineries and Petrochemical Plants

Pump drives, compressor duty, and fan applications within classified areas of refineries require motors that carry the appropriate Ex marking. The YBX4 suits both Zone 1 (gas may be present during normal operation) and Zone 2 (gas only under fault conditions) classifications. Its IE4 efficiency rating is especially valuable on large pump installations running 8 000+ hours per year, where even a single percentage point of efficiency gain represents a substantial reduction in electricity cost.

Grain and Flour Processing

Grain dust in suspension is a recognized explosion hazard. Elevator leg drives, conveyor motors, and dust-collection fan motors in grain terminals and flour mills must carry explosion-proof certification. The YBX4 handles the heavy-duty start-stop cycles typical of grain handling while meeting the dust-ignition protection requirements of these facilities.

Chemical Manufacturing

Reactor agitators, transfer pump drives, and ventilation fans operating in areas where volatile organic solvents are handled need flameproof-rated motors. The availability of 2-pole through 10-pole configurations in the YBX4 line means engineers can match the motor speed to the process requirement without adding a gearbox — a 6-pole unit running at 1000 rpm directly drives a slow-speed agitator, eliminating a potential maintenance point and an additional source of heat in the hazardous zone.

Mining and Tunneling

Methane gas is a persistent hazard in coal mines and certain tunnel construction projects. Ventilation fans, conveyor belt drives, and coal-cutting machine motors all require explosion-proof certification. The YBX4 construction, with its reinforced casting walls and conservative temperature rise design (Class H insulation with Class F temperature rise), provides a safety margin that mine operators and safety inspectors appreciate during audits.

Quality Certifications and Compliance

Explosion-proof motors face stricter certification scrutiny than standard industrial motors. Every YBX4 unit carries the following credentials:

• Ex d IIB T4 / T3 flameproof certification for gas groups IIA and IIB (covers hydrogen-free hydrocarbon gases, ethylene, and many common industrial solvents)
• CE marking for European market conformity
• ISO 9001:2015 quality management system certification for the manufacturing facility
• IE4 super-premium efficiency verified per IEC 60034-30-1
• IP55 ingress protection tested per IEC 60034-5
• CCC (China Compulsory Certification) for domestic regulatory compliance

Korea Ever-Power PTO Shaft Co., Ltd provides complete certification documentation packages with each shipment, including test reports, conformity declarations, and material traceability certificates. For customers requiring additional regional certifications (KCs mark for Korea, KOSHA approval, etc.), our compliance team can arrange the necessary testing and paperwork — contact us early in the quotation process to allow adequate lead time for certification activities.

YBX4 vs. Comparable Imported Ex-Rated Motors

Disclaimer: We mention third-party brand names solely to help customers with cross-referencing and product selection. Korea Ever-Power PTO Shaft Co., Ltd does not sell, distribute, or represent these brands. Our products are independently manufactured and are not affiliated with, endorsed by, or connected to any of the brands referenced below.

The YBX4 achieves a higher efficiency class (IE4 vs. the IE3 commonly found in imported alternatives) while pricing well below European and American brands. For Korean facilities that must maintain certified explosion-proof motor inventories, stocking YBX4 replacements provides both a safety-compliant and budget-friendly approach to spare-parts management.

Related and Complementary Products

Explosion-proof motors frequently pair with speed reducers and transmission components to form a complete drive system. In hazardous areas, selecting the right gearbox is just as important as specifying the motor, because the gearbox surface temperature and spark potential must also be considered during the hazard assessment.

A worm gear reducer provides right-angle output and high reduction ratios in a compact package — suitable for agitators and slow-running conveyors. For higher efficiency requirements or coaxial shaft arrangements, a planetary gearbox delivers superior mechanical efficiency with minimal heat generation. Chain and sprocket drives are commonly used in grain-handling conveyors where the motor and driven shaft are offset. Browse our full 交流齿轮电机 catalog for additional motor options and complementary transmission products.

Frequently Asked Questions

What gas groups does the YBX4 cover?
The standard certification covers IIA and IIB gas groups, which include propane, methane, ethylene, and most common industrial hydrocarbon gases and solvents. IIC (hydrogen) certification is available as a special order — contact our engineering team for lead time and pricing.

Can the YBX4 be used with a variable frequency drive in a hazardous area?
Yes, provided the VFD output waveform meets the dV/dt limits specified for explosion-proof motor insulation systems. We recommend using a VFD with an output sine-wave filter for installations in Zone 1 areas. The Class H insulation option provides additional thermal margin to handle the harmonic heating inherent in PWM-driven operation.

What is the temperature class of the YBX4?
Standard models are rated T4 (maximum surface temperature 135 °C). T3 (200 °C) versions are also available. The temperature class must be equal to or lower than the auto-ignition temperature of the gases present in your facility — consult your plant safety engineer for the correct classification.

How often should the flameproof joints be inspected?
Industry best practice recommends inspecting all flameproof mating surfaces every 12 months or during any maintenance event that requires opening the motor enclosure. Look for corrosion, mechanical damage, or buildup of paint or sealant on the joint faces. Any surface defect deeper than 0.05 mm should be addressed before returning the motor to service.

Does the YBX4 come with an explosion-proof terminal box?
Yes. The terminal box is integral to the explosion-proof design and is certified as part of the motor assembly. Cable entry glands (metric or NPT thread) are ordered separately based on your cable diameter and gland standard preference.

What is the delivery time for non-standard voltages like 690 V or 1140 V?
Standard 380 V and 400 V units ship within 10 to 15 working days. Non-standard voltages (660 V, 690 V, 1140 V) require a custom winding run and typically add 5 to 10 working days to the lead time.

Customer Reviews

Kwon Dae-sung, Plant Safety Manager, Ulsan (early 2025)
"We replaced six YB3 motors on our polymer reactor cooling pumps with YBX4-200L2-2 units. The IE4 rating was the deciding factor — our energy audit team calculated a payback of 14 months. The Ex certification paperwork was complete and our safety inspector accepted it without questions."

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Park Sang-ho, Procurement Engineer, Gyeongsang-do (mid 2024)
"Delivery was 18 days, which is fast for explosion-proof motors. Our usual European supplier quotes 10 to 14 weeks. The bolt pattern matched our existing baseplates. Two motors, installed in one shift."

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Lee Min-ho, Maintenance Supervisor, Incheon (late 2024)
"Grain elevator environment. Dust is a constant problem. The IP55 rating on the YBX4-160M-4 has held up well — no dust ingress after 11 months of continuous operation. The motor runs noticeably quieter than the old YB2 it replaced."

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Choi Jun-young, Technical Director, Busan (early 2025)
"We tested one YBX4-280S-2 on a 75 kW compressor for three months before ordering more. Vibration, temperature, and current readings were all within catalog specs. The flameproof joint machining is clean and consistent. We have since ordered eight more units for our new LNG terminal project."

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Yoon Hye-soo, Equipment Manager, Daejeon (mid 2025)
"Price was about 40 % less than our previous supplier for an equivalent spec. The certification documents satisfied our KOSHA audit. Motor has been running a ventilation fan in a paint booth (Zone 2) for four months without incident. Good value."

Packing and Shipping