In the fields of lifting machinery, construction tower cranes, port machinery, and metallurgical production lines, where extremely high requirements are placed on starting torque and overload capacity, the YZR series motor of the Luan brand has long been regarded as a true “armored power source” in the industry.

As a wound rotor three-phase asynchronous motor specially designed for intermittent periodic duty, the YZR series not only carries decades of manufacturing experience from Luan Motor, but also continues to evolve through material upgrades, becoming a reliable power core for harsh working conditions.

1. Core Definition: What Is the YZR Series?

The name of the YZR series motor reflects its technical characteristics:

Y: Asynchronous motor.

Z: Specially designed for lifting and metallurgy applications, with high overload capability and high mechanical strength.

R: Wound rotor, which is its key difference from a standard squirrel-cage motor and allows starting performance to be adjusted through external resistance.

2. Key Technical Advantages: Why Is It Essential in the Lifting Industry?

2.1 Excellent Starting Performance and Torque Adjustment

Because it adopts a wound rotor structure, the YZR series can connect external starting resistors through slip rings.

Heavy-load starting: At the moment of startup, by adjusting the resistance, the motor can obtain very high starting torque with relatively low starting current, usually reaching more than twice the rated torque.

Smooth speed control: During lifting operations, changing the resistance value allows a certain range of smooth speed regulation, ensuring soft starting and soft stopping when lifting or lowering loads.

2.2 Remarkable Overload Capacity

Lifting conditions are highly variable and often face sudden heavy-load impacts. In designing the YZR series, Luan brand has significantly strengthened both the magnetic circuit and structural strength.

Maximum torque ratio: The ratio of maximum torque to rated torque is usually between 2.2 and 3.3, far higher than that of ordinary motors, ensuring the motor will not stall under short-term overload.

2.3 Adaptation to Severe Duty Cycles

The YZR series motor is specially designed for S3 intermittent periodic duty. Its rated power is usually defined by duty cycle ratios such as 25%, 40%, 60%, and 100%.

Frequent starting and stopping: The motor can withstand thermal shock caused by frequent starting, braking, and reversing.

High-temperature insulation: The whole series adopts F-class or H-class insulation, with special optimization for high-temperature radiation in metallurgical environments.

3. Craftsmanship Features of the Luan Brand: The Secret of Durability

When producing the YZR series motor, the Luan brand has applied multiple structural reinforcements to address the pain points of the lifting industry:

Reinforced slip rings and brush system: The slip rings are made of high-strength, wear-resistant alloy materials, matched with high-performance carbon brushes, ensuring that frequent sliding contact does not produce severe sparking and extending maintenance intervals.

Special vibration-resistant structure: Considering the strong vibration experienced by tower cranes and port machinery at high altitude, the motor base is made with reinforced welded ribs or high-strength cast iron, and all fasteners are treated with anti-loosening measures.

Precision rotor winding binding: Wound rotors generate enormous centrifugal and electromagnetic forces during high-speed rotation and frequent commutation. Luan’s manufacturing process uses special binding tape and vacuum pressure impregnation (VPI) to ensure the winding remains stable and secure.

4. Key Technical Parameters (Reference Table)

• Rated voltage: 380V / 660V
  Suitable for standard industrial and mining power grids.

• Duty type: S3 intermittent periodic duty
  Matches the intermittent operating characteristics of cranes.

• Protection degree: IP44 (standard) / IP54 / IP55
  Resistant to outdoor rain, dust, and construction-site debris.

• Insulation class: Class F (155°C) or Class H (180°C)
  Suitable for high temperatures caused by metallurgical splashing or long-term overload.

• Frame size range: 112mm - 400mm
  Covers the full range from small and medium hoists to large gantry cranes.

5. Application Scenarios: Where Is the YZR Most Needed?

Construction tower cranes: In luffing and hoisting mechanisms, the YZR motor provides stable heavy-load output, ensuring the safety of hook lifting and lowering.

Steel and metallurgy: In high-temperature, high-dust environments such as continuous casting machines and charging cranes, its H-class insulation enables long-term operation.

Port terminals: In the slewing and traveling mechanisms of portal cranes, the wound rotor’s speed-regulating characteristics help achieve smooth transition for large inertia loads.

6. Maintenance Recommendations: Keeping the “Old Combat Partner” in Fighting Condition

Although the Luan YZR series is known for its toughness, its carbon brush structure means maintenance should not be neglected:

Check carbon brush wear: Clean carbon dust regularly and ensure the brushes slide smoothly in the brush holder with uniform pressure.

Clean the slip rings: Keep the slip ring surface smooth and polished. Any burn marks should be ground off in time.

Test insulation resistance: Since the working environment is often outdoors or humid, the winding-to-ground insulation resistance must be tested before restarting after long-term shutdown.

With its unique wound rotor design and reinforced structure for extreme operating conditions, the Luan YZR series lifting and metallurgical special motor remains an irreplaceable power backbone in the lifting industry. It not only bears the heavy demands of industrial production, but also represents Luan manufacturing’s commitment to high reliability.