Product Overview

TDMK large three-phase AC synchronous motors are purpose-built for mining grinding mills, serving as core drive equipment for mining, cement and related heavy industries. This flagship product line has been independently developed and manufactured by Changli since our founding in 1946. The lineup covers brushed TDMK synchronous motors and brushless TMW variants, favored across mining and cement sectors for their superior starting torque. They are primarily deployed to drive low-speed, high-power machinery such as lattice ball mills, rod mills and coal pulverizers.

Drawing on over 70 years of expertise in medium & large high-voltage AC motor manufacturing, we integrate global advanced technologies tailored to mining operating conditions. Leveraging our proven design and production workflow alongside innovative processes and premium materials, we continuously refine product engineering. The finished motors feature compact footprint, lighter weight, minimal vibration, low noise, outstanding outdoor adaptability, robust reliability and high operational efficiency.

This synchronous motor series complies with GB755 Rotating Electrical Machines – Ratings and Performance and JB/T1473 Technical Specifications for Large Three-Phase Synchronous Motors for Mining Drives. Its power ratings and mounting dimensions align with both internal factory standards and IEC international norms, also matching German industrial standards. It is fully compatible with export machinery and serves as a direct replacement for imported motors.

The TDMK series utilizes a thyristor excitation system equipped with slip rings and carbon brushes.

By contrast, the TMW brushless series adopts a coaxial AC exciter paired with rotary rectifier plates. Eliminating slip rings and brushes entirely, it avoids regular brush replacement and slip ring abrasion issues, delivering stable performance under severe working environments.

Available voltage grades range from 3 kV to 11 kV.

These motors support both full-voltage direct-on-line startup and soft reduced-voltage starting modes.

Motor Structure & Performance Parameters

This motor series comes in two configurations: bored-shaft and non-bored-shaft versions. Bored-shaft units must be paired with a pneumatic clutch for operation. Non-bored-shaft motors deliver superior starting capabilities.

Performance metrics at rated voltage:

• Starting torque: 1.7× rated torque (0.6× rated torque for bored-shaft models)
• Pull-in torque: 1.0× rated torque (0.6× rated torque for bored-shaft models)
• Pull-out torque: 2.0× rated torque
• Starting current: 7.0× rated current
• Weather-resistant variants including outdoor (W), tropical humid (TH), and outdoor tropical humid (THW) motors share identical performance data, mounting layouts and overall dimensions with the standard base model.

Key Advantages

1. Optimized Advanced Design
   Backed by decades of mature technical experience manufacturing medium high-voltage motors, we apply state-of-the-art design tools to fully optimize the TDMK three-phase synchronous motor series.

Magnetic Field Analysis

Performance Analysis

Shaft system calculation

2. Proven, Reliable Manufacturing Technology

2.1 Motor Frame

The frame is fabricated by welding premium Q235B steel plates. All components undergo finite element analysis and physical testing, delivering outstanding rigidity while keeping overall weight low for stable structural performance.

Rotating components are precision-machined to maintain perfect stator and rotor concentricity, cutting vibration levels drastically. Stress relief treatment is applied to the frame to lock in consistent dynamic performance and minimize operational noise.

2.2 Stator Core

The stator core is stacked from 0.5 mm low-loss silicon steel sheets, with radial ventilation ducts arranged between core segments for efficient heat dissipation.

2.3 Stator Winding

Windings are wrapped with mica tape insulation. The full stator undergoes complete Vacuum Pressure Impregnation (VPI) after coil insertion, reaching Class F insulation with ample temperature rise margin. We adopt advanced LDW slot fixing and connection techniques to guarantee long-term stable running.

2.4 Comprehensive Monitoring Sensors

Built-in coil temperature sensors, bearing temperature detectors, vibration probes and cooler water leakage sensors continuously transmit real-time operational data to the control system, enabling full-condition motor monitoring.

2.5 Rotor Pole Assembly

Pole cores are laminated from 1.5 mm steel sheets. Pole coils, damping bars and damping rings use high-grade copper material with Class F pole coil insulation. All pole coil and damping ring joints are secured via hard silver brazing for robust conductivity.

2.6 Premium Bearings

We source trusted domestic and international bearing brands. These bearings feature extended service life, stable operation and straightforward routine maintenance.

2.7 Wide Operating Adaptability

Generous mechanical strength and temperature rise design margins allow a single motor model to suit multiple working scenarios. Anti-condensation space heaters are pre-installed for convenient daily upkeep.

2.8 Brushless Excitation System

The AC exciter and rotary rectifier feature a split independent layout for easy servicing. The compact rotary rectifier disc integrates wiring, structural fasteners and heat dissipation, with isolated segments for enhanced reliability, fewer faults and simple installation.

This brushless excitation unit supports automatic excitation switching, demagnetization resistor automatic cut-off and out-of-step re-synchronization functions to sustain steady motor operation.

The matched excitation cabinet uses full digital circuitry with strong anti-interference capability and highly reliable control & air cooling components for continuous long-run service. All pluggable modules can be swapped without powering down the motor or unloading the drive; no extra calibration is needed after replacement for fast, hassle-free maintenance and disassembly.