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Three-Phase AC Induction Motors

General-purpose IEC-frame induction motors across IE3, IE4 and IE5, plus the large-power and variable-frequency variants of the same platform.

YE3 (IE3)

Premium efficiency

IE30.55–375 kWIP55

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YE4 (IE4)

Super premium efficiency

IE40.55–375 kWIP55

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YE5 (IE5)

Ultra premium efficiency

IE50.55–315 kWIP55

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YE3 Large-Power

IE3, 200–1000 kW low voltage

IE3200–1000 kW380 / 660 V

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YE large-power low-voltage three-phase induction motor

YE4 Large-Power

IE4, 200–1000 kW low voltage

IE4200–1000 kW380 / 660 V

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YVP Series

Variable-frequency induction motor

0.55–560 kWIC416 forced coolingEncoder option

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Technical articles on these series

GB 18613, IEC IE and NEMA MG 1: How to Compare

A procurement method for reconciling Chinese efficiency grades, IEC IE classes and NEMA motor-efficiency requirements without false equivalence.

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How to Read an Electric Motor Performance Curve

Learn how to read motor current, efficiency, power factor, speed and torque curves before selecting or replacing an industrial motor.

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IE3 vs IE4 vs IE5: A Project-Lifecycle Selection Framework

A lifecycle framework for selecting IE3, IE4 or IE5 motors using operating hours, load, regulation, replacement constraints and measured losses.

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Motor Efficiency at Partial Load: Beyond the Nameplate Value

Understand how industrial motor efficiency and power factor change at partial load, and when an oversized motor is worth replacing.

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DOL, Star-Delta, Soft Starter or VFD: Which Start Method?

Compare DOL, star-delta, soft-starter and VFD motor starting by current, torque, control, mechanical stress and application fit.

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Motor Total Cost of Ownership: A Worksheet Buyers Can Audit

A practical motor TCO worksheet covering purchase, energy, installation, downtime, maintenance and end-of-life costs without relying on generic savings claims.

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B3, B5, B35 and V1 Motor Mountings Explained

Practical engineering guidance on b3, b5, b35 and v1 motor mountings explained, including the checks, evidence and common mistakes that matter before purchas

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Belt Tension and Motor Bearing Life

Practical engineering guidance on belt tension and motor bearing life, including the checks, evidence and common mistakes that matter before purchase or comm

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How Dust, Oil and Moisture Damage Motor Windings

Practical engineering guidance on how dust, oil and moisture damage motor windings, including the checks, evidence and common mistakes that matter before pur

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Electric Motor RFQ Checklist: What Buyers Should Specify

Practical engineering guidance on electric motor rfq checklist: what buyers should specify, including the checks, evidence and common mistakes that matter be

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Insulation Resistance and Polarization Index

Practical engineering guidance on insulation resistance and polarization index, including the checks, evidence and common mistakes that matter before purchas

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What an Inverter-Duty Efficiency Figure Actually Measures

Converter-fed efficiency is tested against a standardised reference converter — good for comparing designs, not a prediction for your drive.

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Motor Bearing Selection: Ball, Roller and Insulated Types

Practical engineering guidance on motor bearing selection: ball, roller and insulated types, including the checks, evidence and common mistakes that matter b

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Motor Derating for Altitude and Ambient Temperature

Practical engineering guidance on motor derating for altitude and ambient temperature, including the checks, evidence and common mistakes that matter before

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Motor Frame Size vs Power Rating: What the Number Really Means

Why an IEC or NEMA motor frame identifies mechanical dimensions rather than one fixed power rating, and what buyers must verify before replacement.

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Motor Grease and Relubrication Intervals

Practical engineering guidance on motor grease and relubrication intervals, including the checks, evidence and common mistakes that matter before purchase or

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Motor Manufacturing Tolerances: What Can Vary?

Practical engineering guidance on motor manufacturing tolerances: what can vary?, including the checks, evidence and common mistakes that matter before purch

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Motor Nameplate Photos to Request Before Replacement

Practical engineering guidance on motor nameplate photos to request before replacement, including the checks, evidence and common mistakes that matter before

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Motor Noise Limits: How to Specify and Verify Them

Practical engineering guidance on motor noise limits: how to specify and verify them, including the checks, evidence and common mistakes that matter before p

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Motor Phase Current Imbalance

Practical engineering guidance on motor phase current imbalance, including the checks, evidence and common mistakes that matter before purchase or commission

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Motor Shaft Dimensions and Coupling Fit

Practical engineering guidance on motor shaft dimensions and coupling fit, including the checks, evidence and common mistakes that matter before purchase or

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Motor Trips After Two Hours: A Diagnostic Sequence

Practical engineering guidance on motor trips after two hours: a diagnostic sequence, including the checks, evidence and common mistakes that matter before p

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Voltage Unbalance: How a Small Supply Error Overheats a Motor

Learn how to calculate three-phase voltage unbalance, why it creates larger current imbalance, and what to check before a motor overheats.

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Why Motor Bearings Keep Failing After Replacement

Practical engineering guidance on why motor bearings keep failing after replacement, including the checks, evidence and common mistakes that matter before pu

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Rotor Balancing Grades: When Tighter Is Necessary

Practical engineering guidance on rotor balancing grades: when tighter is necessary, including the checks, evidence and common mistakes that matter before pu

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Soft Foot in Motor Installations: Checks Before Alignment

How to identify and document soft foot before motor alignment, with practical checks for shims, base distortion and bolt sequence.

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VFD Reactors and Filters: Work Out Which Side the Problem Is On

Line reactors, dv/dt filters and insulated bearings are not stronger versions of one device. They fix three different problems in three different places.

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What TEFC Actually Means, and What It Does Not Tell You

TEFC describes an enclosure and a fan. It does not say how much dust or water the motor keeps out — that is the IP rating, specified separately.

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Why a Centrifugal Fan Can Overload Its Motor

Practical engineering guidance on why a centrifugal fan can overload its motor, including the checks, evidence and common mistakes that matter before purchas

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GB 18613 and IE Classes: Reading a Chinese Efficiency Grade

The two systems number in opposite directions, and neither is a label — both are tables of values at a rating. Compare the cells, not the words.

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Coupling Selection for Industrial Motor Drives

A practical coupling review for industrial motor drives covering torque, speed, misalignment, shaft fit and driven-equipment constraints.

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Selecting Motors for Mining Crushers and Ball Mills

A motor-selection guide for mining crushers and ball mills, covering breakaway torque, inertia, starting, supply limits, dust and maintenance.

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Motor Bearing Internal Clearance: When C3 Is Not a Default

A clear method for reviewing motor bearing internal clearance using fit, temperature, speed, load and the actual bearing arrangement.

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Pump Affinity Laws and Motor Power

Practical engineering guidance on pump affinity laws and motor power, including the checks, evidence and common mistakes that matter before purchase or commi

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Pump Cavitation vs Motor Failure

Practical engineering guidance on pump cavitation vs motor failure, including the checks, evidence and common mistakes that matter before purchase or commiss

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Resonance, Unbalance or Misalignment? Follow the Evidence

A practical vibration investigation that uses direction, phase, location and speed response instead of diagnosing a motor from one spectrum peak.

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Selecting Motors for a Steel Rolling Mill Line

How to specify rolling-mill motors by stand duty, torque-speed envelope, overload, reversing, regeneration, cooling and mechanical shock.

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Variable-Torque vs Constant-Torque Loads

Practical engineering guidance on variable-torque vs constant-torque loads, including the checks, evidence and common mistakes that matter before purchase or

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Cooling Tower Fan Drives: Direct Drive or Gearbox, and What Decides It

The choice is about a drive train, not a motor. And whether the fan sits in the entering or the leaving airstream decides what the machine lives in.

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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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Replacing a Fan Motor: Why Matching the Nameplate Power Is Not Enough

Fan power rises with the cube of speed. A replacement motor running 2% faster asks for about 6% more shaft power, and nothing on the nameplate warns you.

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Do High-Voltage Motors Have IE Classes? Only Inside a Narrow Window

High-voltage cage motors do get IE classes — between 200 and 2000 kW, above 1 kV to 11 kV, on two, four or six poles. Outside that, no class exists.

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How to Check If a Motor Nameplate's HP Is Inflated

A clamp meter and a published full-load current table are enough to catch an inflated horsepower rating. Here is the method, with worked numbers.

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Line-Start PM Motors: Permanent Magnet Efficiency Without a Drive

A rotor carrying both a cage and magnets starts like an induction motor and runs synchronously. The catch is what the magnets do during the start.

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Motor IP Ratings: What Each Digit Is Actually Tested For

IP66 and IP67 are not two rungs of one ladder. One digit is about solids and people, the other about water — and above 6 the ladder stops working.

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Same Motor, Different Grid: 50 Hz and 60 Hz

Moving a motor between 50 and 60 Hz changes speed by 20%. What happens next depends on the voltage and on what the motor drives.

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Where Synchronous Machines Are Used, and Why

Exact synchronous speed is the least interesting thing about these machines. What earns them a place is that you can choose the power factor.

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Reading Three-Phase Motor Terminal Markings: U1 V1 W1 and T1 T2 T3

Two marking systems, two rotation conventions, and one of them does not define rotation at all. Which one is on your terminal block changes what you can assume.

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Type Test vs Routine Test: What Each Report Proves

One proves the design, on a sample. The other proves this unit left the factory without a defect. Asking for "the test report" gets you whichever they have.

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Why Buyers Don't Trust Chinese Motor Suppliers

Distrust of Chinese motor suppliers tracks four specific, checkable patterns, not the country of origin itself. Here is what each one is and how to verify it.

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F-Class Insulation, B-Class Rise: What the Margin Buys

F insulation held to B rise limits the average winding temperature 25 K below an F-rise design. Here is what that headroom does and does not mean.

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Fixed and Floating Bearings in Electric Motors

How fixed and floating bearing positions control the rotor axially while allowing thermal growth in an industrial electric motor installation.

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IEC 60034-2-1 vs IEEE 112 Efficiency Tests

Practical engineering guidance on iec 60034-2-1 vs ieee 112 efficiency tests, including the checks, evidence and common mistakes that matter before purchase

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Export Packaging and Storage for Industrial Motors

Practical engineering guidance on export packaging and storage for industrial motors, including the checks, evidence and common mistakes that matter before p

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Motor Code Letters and Locked-Rotor Starting Current

The nameplate code letter is locked-rotor kVA per horsepower, not amps. On a dual-frequency motor it refers to 60 Hz. Both catch people replacing motors.

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Motor Factory Acceptance Test Checklist

Practical engineering guidance on motor factory acceptance test checklist, including the checks, evidence and common mistakes that matter before purchase or

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Motor Foundation and Grouting Inspection Checklist

A commissioning checklist for motor foundations, baseplates and grout, focused on load transfer, level, support and final machine condition.

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Motor Rewind vs Replace: A Decision Framework

In a controlled EASA/AEMT study, best-practice rewinds held efficiency within 0.2 points. Here is how to apply that evidence without overgeneralising it.

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Motor Shaft Alignment: What to Record Before Startup

A field-focused guide to motor shaft alignment records, including machine condition, measurement basis and final evidence before startup.

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Motor Shaft Key and Keyway Fit: Avoiding Fretting

What to verify in a motor shaft key and keyway connection before assembly, including fit, contact, retention and hub installation evidence.

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Motor Starting Voltage Drop: A Review That Includes the Load

How to screen motor starting voltage drop, then test the source, starter, motor torque and driven-load acceleration as one system.

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Motor Winding Resistance: When a Phase Difference Matters

A field method for comparing motor winding resistance without confusing temperature, test leads or terminal connections with a winding defect.

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Replacement Motor Interchangeability Checklist

Practical engineering guidance on replacement motor interchangeability checklist, including the checks, evidence and common mistakes that matter before purch

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How to Verify a Motor Test Report Matches the Order

Practical engineering guidance on how to verify a motor test report matches the order, including the checks, evidence and common mistakes that matter before

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Axial Thrust in Vertical Motor Applications

A practical review of upward and downward thrust, coupling behaviour and bearing responsibility in vertical motor applications.

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Pipeline Booster Pump Motors: What the Station Decides

It looks like the easiest duty in the field — constant load, steady flow. Then you learn that capacity is changed by switching whole pumps in and out.

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Drilling Rig Motors: Drawworks, Mud Pump and Top Drive

Three loads on one rig floor, and three different motor problems. One of them spends part of its cycle generating rather than consuming.

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Drive System Efficiency: IE for the Motor, IES for the System

Three efficiency classes can appear on one variable speed drive, and they are not the same scale. The motor class tells you least about the bill.

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dV/dt Filter vs Sine-Wave Filter for VFD Motors

Practical engineering guidance on dv/dt filter vs sine-wave filter for vfd motors, including the checks, evidence and common mistakes that matter before purc

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Gas Compressor Motors: Reciprocating versus Centrifugal

Two compressor families, two different motor answers. The centrifugal one fails on a specification most enquiries never mention: how long the start takes.

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IGBT vs Thyristor Motor Drives: What Changed and Why It Matters

A practical explanation of how fully controlled power switches, PWM and faster protection changed modern variable-frequency motor drives.

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Matching a VFD to a Motor: The Checks Buyers Should Not Skip

A practical VFD-to-motor matching guide covering current, overload, speed range, cooling, insulation, cable length, braking and load behaviour.

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Running a Motor at Low Speed Without Cooling Failure

Practical engineering guidance on running a motor at low speed without cooling failure, including the checks, evidence and common mistakes that matter before

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Motor Overspeed on a VFD: Limits to Check

Practical engineering guidance on motor overspeed on a vfd: limits to check, including the checks, evidence and common mistakes that matter before purchase o

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Oilfield Electric Drive vs Gas Engine: A Decision Framework

A practical framework for comparing electric motors and field-gas engines on pumpjacks and other oilfield surface equipment.

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VFD Retrofit: Keep the Induction Motor or Move to PM?

An existing variable-speed drive is five parts, not one. Which of them a motor swap puts back in play is what decides this — not the motor comparison.

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Screw Compressor Motors: High-Speed PM or Conventional Drive?

A practical comparison of high-speed permanent-magnet and conventional motor arrangements for industrial screw-compressor packages.

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Speed Loop vs Current Loop: Why Motor Drives Use Nested Control

A clear explanation of cascaded motor-drive control, including the roles of the current loop, speed loop, limits and commissioning order.

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VFD Bearing Currents: Causes, Warning Signs and Controls

Understand how variable-frequency drives create bearing currents, how electrical fluting develops, and which grounding and insulation measures help.

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VFD Cable Length and Motor Insulation Stress

Practical engineering guidance on vfd cable length and motor insulation stress, including the checks, evidence and common mistakes that matter before purchas

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VFD Carrier Frequency: Effects on Motor and Drive

Practical engineering guidance on vfd carrier frequency: effects on motor and drive, including the checks, evidence and common mistakes that matter before pu

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Why a VFD Needs EMC Design: Common Mode and Differential Mode

A drive shifts the winding neutral away from ground and couples it to the rotor. What common mode is, and why EMC is a property of the installation.

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Comparing across families, or filtering by power, voltage and protection?See the full range with filters. If the duty falls outside what these series publish, tell us the application — custom builds cover ratings the standard series do not.