YR Series Wound Rotor Three‑Phase Asynchronous Motor

YR series wound rotor three‑phase asynchronous motors are high‑voltage heavy‑duty drive units built in accordance with IEC and relevant industrial standards. Distinct from conventional squirrel‑cage motors, this series adopts wound‑rotor structure fitted with slip‑ring and carbon‑brush assembly. By connecting external resistance or liquid resistance to rotor circuit, the motor achieves large starting torque while limiting starting current, which greatly reduces impact to power grid. It is highly suitable for sites with insufficient grid capacity, heavy‑load startup, frequent starting and limited‑range speed regulation requirements. Mostly applied in well‑ventilated indoor workshops, these motors deliver stable S1 continuous operation for mining, metallurgy, cement and heavy‑process industries.

Core Technical Parameters

Electromagnetic performance is optimized via finite element simulation. Stator core is stacked with high‑quality low‑loss silicon steel sheets to cut iron loss, stray loss and magnetic leakage under long‑time full‑load running. Both stator and rotor windings use high‑conductivity copper wire and go through VPI vacuum pressure impregnation process. The integrated winding improves dielectric strength, corona‑resistance and thermal aging resistance, coping with thermal stress caused by frequent heavy‑load startup and rotor resistance switching. The wound‑rotor assembly with slip‑ring is the core feature of YR motor. External resistance connected to slip‑rings can adjust rotor circuit resistance, restraining inrush starting current and boosting starting torque. This characteristic makes YR series irreplaceable for weak power supply networks where squirrel‑cage motors cannot start heavy equipment directly. Each rotor undergoes strict high‑precision dynamic balance calibration to keep vibration and noise within standard allowable range during operation.

The motor frame adopts rigid welded steel plate structure with good mechanical stiffness and anti‑shock capacity. Slip‑ring housing is equipped with observation window for daily visual inspection of brush wear and slip‑ring operating condition. Medium‑power models adopt heavy‑duty rolling bearings, while large‑power specifications are equipped with sliding bearings. PT100 temperature sensors can be embedded inside stator windings and bearing chambers as optional configuration, feeding real‑time temperature signals to central control system for over‑temperature early warning. Since YR series mostly applies IC01 open ventilation cooling mode, internal hot air is directly discharged into surrounding atmosphere and fresh ambient air flows in for heat exchange. This brings high cooling efficiency, yet the motor shall be deployed in clean, well‑ventilated indoor environment without heavy dust or corrosive gas.

Regular maintenance focuses on slip‑ring and carbon‑brush components. Operators need to check brush pressure, wear degree and surface condition of slip‑rings periodically to avoid spark and contact failure. Optional brush‑lifting device can reduce carbon‑brush abrasion for long‑term stable running. YR wound rotor motors are widely used to drive ball mills, winches, hoists, crushers, rolling mill auxiliary units, large compressors and blowers in mines, metallurgical plants and cement factories. Customization services cover special voltage, reinforced slip‑ring assembly, tropical anti‑humidity coating and altitude‑adapted modification according to actual working‑site conditions.

Before shipment, every YR motor completes full‑range factory acceptance tests including insulation resistance test, high‑voltage withstand test, no‑load running test, starting‑performance inspection, vibration and noise measurement. Featuring outstanding starting performance, strong overload capacity and flexible startup adjustment, YR series wound‑rotor asynchronous motors provide mature and reliable heavy‑load driving solutions for global heavy‑industrial projects with difficult startup conditions.