YLKK Series High Output Motor – Technical Overview

1. Application Scope
   The YLKK series high-output motor is a medium- or high-voltage three-phase asynchronous motor designed to drive various high-torque and heavy-duty mechanical equipment. It is widely used in applications such as metal cutting machines, crushers, ball mills, compressors, sugar mills, winches, and conveyor systems.

2. Structural Features
   This series adopts a robust box-type structure. Due to its vertical installation design, the shaft extension end cover is made of high-rigidity steel plates to ensure mechanical strength. The non-drive end is equipped with a rain cover, making it suitable for outdoor operation. Additionally, an air cooler is mounted on the side of the motor, allowing convenient maintenance and easy disassembly.

3. Insulation and Manufacturing Process
   The stator features a press-fit structure, and the windings use Class F insulation as standard. For high-temperature (above 50°C) and high-humidity environments, Class H insulation can be provided.

The stator windings are securely fixed and reinforced, and undergo multiple inter-turn impulse voltage tests during manufacturing. For vertical motors, an advanced vacuum pressure impregnation (VPI) solvent-free process is applied, using a fixed lower immersion varnish tank. This ensures excellent insulation performance, enhanced mechanical strength, and superior moisture resistance.

4. Starting Methods
   In industrial applications, several starting methods are commonly used for high-voltage, high-power motors. For the YLKK series, international users often prefer full-voltage direct starting where conditions allow.

• Full-Voltage Direct Start
  This method is simple, cost-effective, and requires minimal equipment. However, the starting current can reach 4–7 times the rated current, and starting torque impact is significant. It is mainly suitable where the power supply capacity is sufficient, especially for motors below 1500 kW.

• Reduced Voltage Starting (Resistor/Reactance)
  A resistor or reactor is connected in series with the stator circuit to reduce voltage during startup, thereby limiting current. Once the motor approaches rated speed, the resistor/reactor is bypassed for normal operation.

• Autotransformer Starting
  This method provides relatively stable starting characteristics with reduced current and torque. However, it is not suitable for frequent or continuous starting applications.

• Soft Starting Methods

• Liquid Resistance Soft Start: Offers near-constant current starting, typically below three times rated current, ensuring smooth acceleration.

• High-Voltage Solid-State Soft Start: Uses thyristors to control voltage through phase angle adjustment, achieving controlled startup.

• High-Voltage Variable Frequency Start: Employs inverter technology to provide variable voltage and frequency control, enabling smooth starting and braking.

5. Standards and Compliance
   The YLKK series motors comply with national standard GB755-2000, mechanical industry standard JB/T10315.2, and international IEC60034-1 standards. Customization is also available to meet Russian GOST and American NEMA standards.

Technical Specifications

Production Overview