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Hazardous Area

YBX4

YBX4 Series High-Efficiency Flameproof Three-Phase Induction Motor

The same flameproof construction as YBX3, one efficiency grade higher — grade 2 of GB 18613—2020, corresponding to IE4.

Ex db IIB T4 GbIE40.18–315 kW
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YBX series flameproof three-phase induction motor

YBX4 is a totally enclosed, high-efficiency flameproof three-phase induction motor meeting grade 2 of GB 18613—2020 — the middle of the three-grade scale, above YBX3 at grade 3 and below YBX5 at grade 1.

Protection is by flameproof enclosure to GB/T 3836.1-2021 and GB/T 3836.2-2021, with the same two ratings as YBX3: Ex db I Mb for underground mining and Ex db IIB T1 Gb to T4 Gb for surface industrial plant.

Core specifications

ParameterValue
Frame sizeH80 – H355 mm
Power range0.18 – 315 kW
Explosion protectionEx db I Mb (mining) · Ex db IIB T1 Gb – T4 Gb (industrial)
Efficiency classIE4 · GB 18613—2020 grade 2
Voltage380 V · 660 V · 1140 V · 380/660 V · 660/1140 V, 50 Hz
Protection degreeIP55
Thermal class155 (F), assessed to class B rise
CoolingIC411
MountingB3 / B5 / B35

Standards and certification

  • GB/T 3836.1-2021
  • GB/T 3836.2-2021 (flameproof enclosure "d")
  • JB/T 14517-2022 (mining rating, frames 63–355)
  • GB 18613—2020 grade 2

Typical applications

  • Continuously running flameproof drives where efficiency accumulates
  • Underground mining (Ex db I Mb) and surface IIB plant
  • Hazardous-area retrofits replacing older flameproof machines

Selection guide

Like YBX3, YBX4 is certified to gas group IIB. It is not rated for hydrogen, acetylene or other group IIC atmospheres.
Identical envelope and identical protection concept; the difference is efficiency grade and price. Where the motor runs continuously, the higher grade returns the premium through energy. Two things to settle before a like-for-like swap: the product standards guarantee a locked-rotor current roughly 15 to 25 per cent higher than YBX3, and a locked-rotor torque about 10 per cent lower. Those are the guaranteed envelopes rather than measured values, and our engineering department reports that the measured difference between the two series is smaller than the envelope suggests — so in practice the swap is usually uneventful. It is still a check worth doing: confirm the starter, the protection settings and whether the load still breaks away, and ask for the measured locked-rotor figures of the specific rating if the margin is tight.
This is where the gap is widest. The eight-pole column of YBX4 is complete and reaches grade 2, while YBX3 follows a product standard written before eight-pole efficiency grades existed at all. At eight poles the two series are not one grade apart — they are on different footings.

FAQ

Certification copies for the explosion-protection marking, and the dimension drawings for your frame size, are issued on request. Tell us the area classification, gas or dust group and temperature class for your site.

Downloads

DatasheetPDF · 822 kBDownload
Installation & maintenance manualInstallation, commissioning and servicingRequest
CertificationCertificates and test reportsRequest

Certificates and test reports are issued against the specific model and rating rather than the series, so we send the ones that apply to your order. Tell us the rating and the market and we will send them.

Related products

YBX3

Flameproof induction motor

YBX5

Flameproof, IE5 efficiency

YFBX4

Dust ignition-proof, IE4 efficiency

YE4 (IE4)

Super premium efficiency

Technical articles on this series

ATEX vs IECEx vs NEC: Which Motor Certification Do You Need

ATEX, IECEx and NEC Class/Division certify the same physics through three different paperwork systems. Here is how they map, and how to pick the right motor.

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Reading a Chinese Motor Model Number: What Each Segment Commits To

YBX4-280S4-W is four segments in a fixed order, and the second character tells you the protection type before you find the Ex plate.

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Equipment Protection Level: What Ga, Gb and Gc Mean

The last segment of an Ex marking says under which fault conditions the protection holds — and it is not the lowercase letter earlier in the string.

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Explosion-Proof Motor Selection: How to Read the Marking

Ex db IIB T4 Gb is five separate decisions written as one string. Each segment answers a different question, and none substitutes for another.

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What a Flameproof Joint Does, and Why It Cannot Be Re-Machined

A flameproof enclosure does not keep gas out. It lets the explosion happen inside and cools what escapes, through a gap that is a certified dimension.

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Hazardous Area Classification: Who Does It and Who Carries the Risk

Classification describes the place, not the motor. The owner or designer decides it before any equipment is specified — and the drawing is what you buy against.

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Motor Temperature Classes T1 to T6: What Sets the Limit

The numbering runs against intuition — T6 is the harder requirement. And the figure that actually decides which class you need is not a property of the motor.

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How to Verify an Explosion-Proof Motor Certificate

A certificate covers a model and rating, not a product family. Five checks — and the one suffix that changes what you may do with the motor.

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From Zone to Motor: What a Zone 1, 2, 21 or 22 Area Actually Requires

The area classification comes first, the nameplate later. Here is the zone-to-protection-level correspondence, from the installation standard.

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Request a quote — YBX4

Tell us the rating, quantity and application and an engineer will come back with a specification, the documents for that model, and a price.

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