Y2 Series 4-Pole Three-Phase Asynchronous Motor

Y2 Series 4-Pole Motor — The Industry Standard 1500 rpm Drive

The Y2-*-4 four-pole motor series is the most commonly specified configuration in the three-phase induction motor range worldwide. At 50Hz, the synchronous speed is 1500 rpm — slow enough to couple directly to most industrial machinery without excessive speed reduction, yet fast enough to deliver high power density and compact dimensions. The 4-pole design represents the practical midpoint between the high-speed 2-pole and the lower-speed 6-pole and 8-pole configurations.

Korea Ever-Power manufactures 26 standard model ratings in the 4-pole configuration, covering the power range from 0.12 kW (Y2-63M1-4) through 132 kW (Y2-315L-4). Frame sizes span IEC 63M through 315L, with dimensional compliance to GB/T18680-2008 and JB/T8680-1998. All models are dimensionally interchangeable with Y-series, Y2-series, and equivalent IEC-frame motors from global manufacturers.

The 4-pole range is the basis from which our electromagnetic brake motors and VFD inverter duty motors are derived, sharing the same frame and shaft dimensions for complete compatibility with standard housings and driven equipment.

Environmental Limits

• Ambient temperature: −15°C to +40°C
• Relative humidity: ≤ 90% (no condensation)
• Altitude: ≤ 1,000 m above sea level
• Frequency: 50 Hz standard (60 Hz on request)
• Voltage tolerance: ±5% of rated value
• Duty cycle: S1 continuous operation

Standards Compliance

• GB/T18680-2008 — Y2 series technical conditions
• JB/T8680-1998 — Chinese national standard
• IEC 60034-1 — rotating electrical machines
• IEC 60034-5 — IP protection classification
• ISO 1680 — acoustic noise measurement
• ISO 2373 — mechanical vibration grading

Motor Specifications

• IP54 protection — dust and splash proof
• Class F insulation (155°C limit)
• Temperature rise per Class B standard (80K)
• IC0141 TEFC forced cooling
• Vibration ≤ 1.8 mm/s (frames 63–132)
• Vibration ≤ 2.8 mm/s (frames 160 and above)

The 4-pole configuration accounts for the majority of industrial motor installations worldwide. At 1500 rpm (50Hz), this operating speed closely matches the rated input speed of a very wide range of industrial gearboxes, pumps, fans, and blowers. Many NMRV worm gearboxes and helical gear reducers are specifically optimized for 1400–1500 rpm input, making the 4-pole motor the natural pairing for gearmotor assemblies.

From an electrical standpoint, 4-pole motors have a higher power factor than equivalent 6-pole or 8-pole designs at the same frame size, reducing reactive current drawn from the supply. The rotor inertia is lower than an 8-pole rotor of equivalent power, resulting in faster acceleration times — important for frequent start-stop applications such as conveyors, hoists, and packaging lines.

Efficiency performance improves substantially from small frames to large frames. The Y2-63M1-4 at 0.12 kW achieves 57% efficiency — typical for very small motors — while the Y2-315L-4 at 160 kW reaches 94.9%. For installations requiring IE3 or IE4 premium efficiency with identical frame dimensions, Korea Ever-Power offers the YE3 and YE4 equivalent series as direct dimensional replacements.

Mining Conveyor Drives

High-reliability belt conveyor and bucket elevator drives for quarrying, coal, and mineral processing operations

HVAC and Pump Rooms

Powering chilled water pumps, cooling tower fans, and air handling unit blowers in commercial and industrial buildings

Printing and Packaging

Main drive motors for offset printing presses, flexographic printers, laminating lines, and packaging machinery

Chemical Process Plants

Reactor agitators, transfer pumps, and blower drives in chemical, pharmaceutical, and petrochemical facilities

Why does the Y2-63M1-4 run at 1330 rpm when the synchronous speed is 1500 rpm?

All induction motors run at slightly below synchronous speed under load — the difference is called slip. Small-frame motors (63M and 71M) have proportionally higher slip than large-frame motors because their rotor resistance is relatively higher. At full rated load, the Y2-63M1-4 runs at 1330 rpm (11.3% slip) while the Y2-315L-4 runs at 1486 rpm (0.9% slip). At no-load, all motors approach synchronous speed. Slip reduces as power output increases toward the larger frames.

Which NMRV worm gearbox sizes pair with Y2 4-pole motors?

Our NMRV worm gear reducers from size 025 through 150 are all designed for 1400–1500 rpm motor input. For example, an NMRV063 paired with a Y2-80M2-4 (0.75 kW, 1380 rpm) gives output ratios from 5:1 to 100:1 depending on gear ratio selected. The standard IMA flange adapter system means any Y2 motor with the correct frame can mount directly to the NMRV housing without an intermediate coupling.

What is the star-delta (Y-Δ) connection rule for Y2 4-pole motors?

At 380V supply: motors rated 3 kW and below use star (Y) connection; motors rated 4 kW and above use delta (Δ) connection. This results in the same phase voltage across each winding regardless of rating. For star-delta starting (Y-Δ starter), the motor must be delta-connected in normal operation; only motors rated 4 kW and above at 380V are suitable for Y-Δ starting. Motors at 660V supply always use delta connection across the full range.

Can I replace a Y-series motor with a Y2-4-pole motor of the same frame size?

Yes. The Y2 series was designed as a direct dimensional successor to the earlier Y series. IEC mounting dimensions including shaft height, shaft diameter, bolt hole pattern, and flange dimensions are maintained across the transition. In some cases, the Y2 motor at the same frame size offers slightly higher power output than the original Y motor due to improved winding design. Verify the nameplate power rating matches your load requirements before installation.

Is a soft-starter recommended for large Y2 4-pole motors?

For motors above 37 kW (Y2-225S-4 and larger), a soft-starter or star-delta starter is generally recommended to limit inrush current during starting. The Ist/In values in the data table show that these large-frame motors draw 7.2x rated current at locked rotor. A soft-starter reduces voltage during acceleration, limiting starting current to typically 3–4x rated current, reducing mechanical shock to driven equipment and preventing supply voltage dips that may affect other loads on the same network.

What is the maximum ambient temperature for standard Y2 4-pole motors?

Standard Y2 motors are rated for ambient temperatures up to 40°C. Above 40°C, derating is required: at 45°C reduce output power to approximately 95%, at 50°C to 90%, at 60°C to 82%. For permanent installation in high-temperature environments (steel mills, foundries, ovens), we recommend motors with H-class insulation or with external water cooling. Please specify ambient conditions when ordering for custom thermal assessment.

How do I calculate the rated torque of a Y2 4-pole motor from its nameplate data?

Rated torque (N·m) is calculated as: Tn = (P × 9550) / n, where P is rated power in kW and n is rated speed in rpm. For example, the Y2-132S-4 at 5.5 kW, 1450 rpm gives Tn = (5.5 × 9550) / 1450 = 36.2 N·m. Multiply by the Tmax/Tn ratio from the table (2.3) to find maximum transient torque = 83.3 N·m. This is useful for sizing couplings, belt drives, and gearbox input ratings.

Are IE3 premium efficiency 4-pole motors available in the same frame sizes?

Yes. Korea Ever-Power supplies the YE3 series (IE3 Premium Efficiency) and YE4 series (IE4 Super Premium Efficiency) with the same IEC frame dimensions as the Y2 series. The YE3 and YE4 motors are required in many markets under energy efficiency legislation (EU ErP 2021, China GB 18613-2020). They share identical mounting dimensions for direct substitution. Contact our sales team for YE3/YE4 availability and pricing by frame size.