SIMO YKK and YXKK Series High-Voltage Three-Phase Induction Motors (Frame Sizes 355–630)

 Product Overview:

This series is an optimized redesign based on the original SIMO YKK high-voltage three-phase induction motors, featuring upgraded power ratings. These motors offer compact structure, light weight, high efficiency, energy savings, low noise, minimal vibration, high reliability, long service life, and convenient installation and maintenance.

The standard mounting configuration is horizontal with feet (IMB3). Under normal operating conditions, the motor duty type is continuous duty (S1); ambient air temperature: −15 °C to +40 °C; altitude: up to 1000 m.

The basic data covered in this catalog are as follows:

— Frame sizes: 355 mm–630 mm;

— Synchronous speeds: 3000 r/min, 1500 r/min, 1000 r/min, 750 r/min, 600 r/min, 500 r/min;

— Rated voltage: 6 kV, 10 kV (motors with other voltages available per customer order);

— Rated frequency: 50 Hz (60 Hz motors available per customer order, except for 2-pole motors);

— Power range: 185 kW–3150 kW.

This series is primarily suitable for general-purpose mechanical equipment—or similar machinery—in industries such as petroleum, chemical, coal, power generation, metallurgy, transportation, textile, pharmaceuticals, and grain processing, including fans, pumps, compressors, crushers, machine tools, and conveyors.

Structural Features

The motor adopts a box-type construction; the frame is fabricated from welded steel plates, offering light weight and high rigidity. An air-to-air cooler is mounted on top of the motor, equipped with inlet and outlet air temperature gauges.

The stator employs an external clamping structure. The stator winding uses Class 155 (F) insulation material. For 10 kV motors, reliable corona protection measures are implemented. Winding ends are securely fixed and bound, and treated via Vacuum Pressure Impregnation (VPI) with solvent-free varnish. Thus, the motor exhibits excellent insulation performance, high mechanical strength, strong moisture resistance, and extended service life.

Squirrel-cage rotors are available in either cast-aluminum or copper-bar configurations, manufactured using advanced and reliable casting or welding processes, and dynamically balanced. Hence, the motor operates smoothly and reliably. For frame sizes 355–500 and for frame sizes 560–630 with 2–8 poles, all squirrel-cage rotors are cast-aluminum. For frame sizes 560–630 with 10 poles and above, all rotors are copper-bar.

Bearings are available in either rolling or sliding types, selected according to motor power and speed. Their protection rating is IP54 or IP55. Rolling bearings are equipped with a non-stop oiling and draining device.

The main terminal box is located on the right side of the motor (viewed from the drive-end), but can be placed on the left side upon customer request. Separate grounding terminals are provided both inside and outside the terminal box. For motors rated ≥2000 kW, a neutral-point terminal box is provided.

Temperature-sensing devices are installed at critical locations—including the stator winding and bearings—to enable remote monitoring and ensure safe, reliable motor operation.

Applicable Standards

GB 755–2008  Rotating Electrical Machines – Ratings and Performance (identical to IEC 60034-1:1993)

GB/T 997–2008  Classification of Types of Construction, Mounting Arrangements and Terminal Box Positions for Rotating Electrical Machines (equivalent to IEC 60034-7:2001)

GB/T 1993–1993  Methods of Cooling for Rotating Electrical Machines (equivalent to IEC 60034-6:1991)

GB/T 4772.2  Rotating Electrical Machines—Dimensions and Output Ratings—Part 2: Frame Sizes 355–1000 and Flange Sizes 1180–2360 (identical to IEC 60072-2:1990)

GB/T 4942.1–2006  Degrees of Protection Provided by the Integral Structure of Rotating Electrical Machines (IP Code) (identical to IEC 60034-5:2000)

GB 10068–2008  Mechanical Vibration of Rotating Electrical Machines with Shaft Heights ≥56 mm—Measurement, Evaluation, and Limits (identical to IEC 60034-14:2007)

GB 10069.3–2008  Methods for Determining Noise of Rotating Electrical Machines and Noise Limits—Part 3: Noise Limits (equivalent to IEC 60034-9)

Rated Voltage and Rated Frequency

The motor’s rated voltages are 6 kV and 10 kV; the supply’s rated frequency is 50 Hz.

Thermal Class and Temperature Rise Limits

The motor’s insulation class is 155 (F); when evaluated per class 130 (B), the temperature rise limit is 80 K.

Bearing Configuration and Temperature Limits

Bearings are available in two configurations: rolling bearings and sliding bearings. The specific configuration used is detailed in the outline and mounting dimensions table. Sliding-bearing configurations for standard products employ forced lubrication but may also be supplied as self-lubricated upon request. For forced-lubricated sliding bearings, the alarm temperature is 80 °C and the shutdown temperature is 85 °C. For both rolling bearings and self-lubricated sliding bearings, the alarm temperature is 90 °C and the shutdown temperature is 95 °C.

Protection Rating

The motor’s protection rating can be IP54 or IP55.

Cooling Method

The motor’s cooling method is IC611.

Climatic Protection Types and Operating Environmental Conditions

Humid-heat type, climatically protected location (TH); humid-heat type, non-climatically protected location (THW);

Dry-heat type, climatically protected location (TA); dry-heat type, non-climatically protected location (TAW);

Tropical type, climatically protected location (T); tropical type, non-climatically protected location (TW);

Outdoor, light-corrosion-resistant type (W);

Outdoor, medium-corrosion-resistant type (WF1);

Outdoor, heavy-corrosion-resistant type (WF2);

Indoor, medium-corrosion-resistant type (F1);

Indoor, heavy-corrosion-resistant type (F2);

The above protection types are indicated at the end of the motor model number; e.g., YKK560-4WF1.

Connection Method

Star (Y) connection.

Cable Entry Device

The motor is normally supplied with a rubber-sheathed cable entry device; steel conduit or armored cable entry devices may be provided upon user request.

Duty Type

All motors operate under S1 continuous duty.

Performance Tolerance Specifications

Efficiency η: –10 % × (1 – η);

Power factor cosφ: –(1 – cosφ)/6 ;

Minimum absolute value: 0.02;

Maximum absolute value: 0.07;

Locked-rotor current: +20 % of guaranteed current value;

Locked-rotor torque: –15 % of guaranteed torque value;

Minimum torque: –15 % of guaranteed torque value;

Maximum torque: –10 % of guaranteed torque value.

Field Operating Conditions

1   Altitude not exceeding 1000 m.

2  Maximum ambient air temperature not exceeding 40 °C.

3  Minimum ambient air temperature not lower than –15 °C; for motors equipped with sliding bearings or air-to-water cooling, the minimum ambient temperature shall not be lower than 0 °C.

4  Voltage and frequency tolerances:

The motor may operate continuously within ±5 % of rated voltage and ±2 % of rated frequency while fulfilling its basic functions; however, performance may differ from that at rated voltage and frequency, and temperature rise may be higher than at rated voltage and frequency.

The motor can operate within a voltage range of ±10% of the rated value and a frequency range of +3% to –5% of the rated value, maintaining its basic functionality; however, its performance may differ from that at rated voltage and frequency, and temperature rise may be higher than at rated voltage and frequency.

All other electrical operating conditions of the motor comply with GB755.

Starting requirements

When driving pumps, fans, or similar equipment, the user’s power grid must ensure that the motor terminal voltage during starting is not lower than 85% of the rated voltage.

Under the above conditions, the motor is permitted to start twice consecutively from a cold state, or once from a hot state; between two starts, the motor must come to a natural stop, and any additional start must occur no sooner than 1 hour after shutdown.

Load coupling

   The motor is typically coupled to the driven load via an elastic coupling.