Y-Series Large High-Voltage Three-Phase Asynchronous Motor

1 Overview

The Y, YKS, YQF, YKK and YR, YRKS, YRQF, YRKK series of large-scale, high-voltage, three-phase induction motors (frame sizes 710–1120) are the latest products designed and developed by our company. They incorporate advanced motor technologies introduced from abroad during the 1980s and comply with relevant national and industry standards. These series serve as the upgraded replacements for the older Y and YR series.

These motors feature high-quality materials and precision manufacturing, offering advantages such as high efficiency and energy conservation, low noise, minimal vibration, reliable operation, and convenience in installation and maintenance.

The power ratings, electrical performance, mounting dimensions, and tolerances of these motors comply with national standard GB 755 (*Rotating electrical machines – Rating and performance*), International Electrotechnical Commission standard IEC 34-1 (*Rotating electrical machines – Rating and performance*), and national standard GB/T 13957-2008 (*Technical requirements for basic series of large three-phase induction motors*), among others.

The enclosure protection ratings for these motors include five types—IP23, IP44, IP54, IP55, and IP56—in accordance with GB 4942.1 and IEC 34-5 (*Degrees of protection provided by the integral design of rotating electrical machines*). IP23 motors can be manufactured as IP44 (duct-ventilated) or IPW24 (weather-protected) versions upon user request. Other protection ratings can be supplied upon request.

The cooling methods for these motors include three types—IC01, IC611, and IC81W—in accordance with GB/T 1993 and IEC 34-6 (*Methods of cooling for rotating electrical machines*). Other cooling methods can be supplied upon request.

The structural and mounting arrangement for these motors is IMB3 (horizontal with feet), complying with the specifications of GB 997 and IEC 34-7 (*Classification of types of construction and mounting arrangements of rotating electrical machines*). This series of electric motors is categorized into the following eight series based on rotor type, degree of protection, and cooling method:

The tables in this catalog list the technical data and outline/mounting dimensions for the various specifications of 6kV and 10kV motors within the aforementioned series; motors with 3kV, 10.5kV, and 11kV ratings can also be derived from these series.

2 Scope of Application

Motors in this series are suitable for driving various general-purpose machines—such as compressors, fans, water pumps, machine tools, and transport equipment—serving as prime movers in industrial and mining enterprises across sectors like mining, machinery manufacturing, petrochemicals, and power generation. For motors intended to drive machinery with high inertia—such as blowers, coal mills, rolling mills, hoists, crushers, and belt conveyors—relevant technical data must be provided and a technical agreement signed at the time of ordering; this serves as the basis for the motor's special design to ensure reliable operation.

Basic conditions for normal motor operation:

(1) Altitude not exceeding 1,000 m;

(2) Maximum ambient air temperature not exceeding 40°C; minimum ambient air temperature of 5°C;

(3) For YKS and YRKS series motors, the cooling water temperature at the inlet must not exceed 33°C, with a minimum temperature of 5°C;

(4) Monthly average maximum relative humidity of 90% during the most humid month, provided the monthly average minimum temperature does not exceed 25°C;

(5) Power supply frequency of 50 Hz ± 1%;

(6) Operating voltage fluctuation range within ± 5% of the rated voltage;

(7) Motor duty type: Continuous duty (S1).

3 Model Designation

In accordance with the GB4831 standard, the motor model designation consists of two parts arranged sequentially: the product code and the specification code. The product code is represented by the motor series designation, with the following meanings:

Y — Squirrel-cage rotor three-phase asynchronous motor;

YKS — Enclosed squirrel-cage rotor three-phase asynchronous motor with air-to-water cooler;

YQF — Weather-protected squirrel-cage rotor three-phase asynchronous motor.

The specification code consists of the shaft height and the number of poles. Examples are as follows:

4 Structural Description

The "Y" series is the base model, featuring an IP23 protection rating and IC01 cooling method. Derivative models with various protection ratings and cooling methods are available, such as the YKS (air-to-water cooling), YQF (climate-protected), and YKK (air-to-air cooling) series.

The motor utilizes a widely adopted box-type structure; the frame and end shields are fabricated from welded steel plate, offering high rigidity and low weight. Removing the protective cover (or cooler) allows for visual inspection and physical access to the motor interior, facilitating installation and maintenance. The stator employs an external press-fit assembly structure. Stator windings utilize Class F insulation and corona-resistant materials; a special binding process ensures the winding end turns are securely and reliably fixed. The entire stator undergoes Vacuum Pressure Impregnation (VPI) with Class F solvent-free varnish. Consequently, the motor exhibits excellent, reliable insulation performance, as well as superior moisture and impact resistance.

For Y and YKK series motors equipped with copper cage rotors, medium-frequency welding is used to join the rotor bars and end rings. Additionally, the copper bars undergo a slot-tightening process, ensuring high reliability.

The bearings are of the end-shield-mounted spherical sleeve type, offering high load-bearing capacity and ease of maintenance.

The main terminal box features a sealed design with an IP54 protection rating. It is typically mounted on the right side of the motor (viewed from the shaft extension end) but can be mounted on the left side upon request. The cable entry port can be oriented upwards, downwards, to the left, or to the right. A dedicated grounding terminal is provided inside the box. For motors with a power rating of 2000 kW or higher, an auxiliary terminal box is installed on the side opposite the main terminal box to provide access to the neutral point of the three-phase stator windings.

5 Starting of Squirrel-Cage Induction Motors (Y, YKS, YQF, and YKK Series)

Advanced computational techniques are employed to analyze the starting temperature rise and stress of the squirrel-cage rotors, thereby preventing premature motor failure caused by excessive starting loads. Users are advised to verify the following:

(1) The moment of inertia of the driven equipment's rotating parts (referred to the motor speed) must not exceed the value specified for "Load J" in the technical data table;

(2) The user's power grid must ensure that the motor terminal voltage during the starting process remains no lower than 85% of the rated voltage;

(3) The load torque characteristics of the driven machinery correspond to those of water pumps or fans.

Under the conditions above, the motor is permitted to start twice consecutively from a cold state (allowing for the motor to coast to a stop naturally between starts) or once from a hot state. Any subsequent start exceeding these limits must only be attempted after the motor has been stopped for one hour.

If the moment of inertia of the driven machinery's rotating parts exceeds the "Load J" value in the technical data table, or if frequent starting or heavy-load starting is required, please contact our company beforehand to discuss a special design that ensures reliable motor starting.

6 Ordering Information

Please specify the following details when placing an order:

(1) Motor Model: Y710-4

(2) Rated Frequency: 50 Hz

(3) Rated Power: 3150 kW

(4) Rated Voltage: 6 kV

(5) Number of Poles: 4

(6) Degree of Protection: IP23

(7) Cooling Method: IC01

(8) Mounting Arrangement: IMB3

(9) Direction of Rotation: Clockwise (viewed from the shaft extension end)

(10) Terminal Box Position: Right side of the motor (viewed from the shaft extension end)

7 Precautions

(1) Verify the moment of inertia of the driven machinery (referred to the motor speed); please refer to Section 5 above: "Starting of Squirrel-Cage Induction Motors";

(2) If operating conditions change or there are other special requirements, a separate technical agreement must be signed prior to the sales contract;

(3) The technical performance data listed in the tables within this catalog are guaranteed values, intended for reference during design selection and ordering;

(4) Technical data and dimensions in this catalog are subject to change without prior notice due to technological advancements or revisions to relevant domestic and international standards; please request the official outline drawing from our company after placing an order.