280kw to 530kw 6000V 8 Poles Three Phase AC Induction Motor AMI400L8A For Cement Plant Mill

The ABB AMI400L8A is a compact modular high-voltage squirrel-cage induction motor built on the proven ABB AMI platform, with rated power ranging from 280kW to 530kW. This 8-pole motor features a synchronous speed of 750rpm, standard rated voltage of 6000V and 50Hz frequency. Designed and manufactured to IEC and NEMA international standards, the welded steel-plate motor is intended for S1 continuous heavy-duty operation. It is normally configured with IC611 air-to-air closed cooling and IP55 protection grade. Thanks to its modular mechanical concept, cooling units, condition monitoring sensors and auxiliary components can be flexibly adjusted to adapt to harsh cement plant working conditions. It is specially developed for cement plant mills, and also widely used to drive heavy-duty fans, slurry pumps and other medium-speed process equipment in mining, water conservancy and petrochemical industries.

Core Technical Parameters 

Electromagnetic performance is optimised by multi-working-point finite element simulation, tailored for the medium-speed heavy-torque load characteristics of cement mills. It can withstand long-time continuous running and frequent fluctuating loads that are common in grinding processes. The stator core is laminated with premium low-loss silicon steel sheets to cut iron loss, stray loss and magnetic leakage under full-load and partial-load conditions. Stator windings adopt high-grade corona-resistant magnet wire and receive complete VPI vacuum pressure impregnation treatment. The reinforced winding-end structure improves mechanical rigidity, dielectric strength and anti-ageing performance, resisting grid voltage fluctuations and frequent starting impact from mill equipment. The rotor adopts heavy-duty copper-bar squirrel cage design, which has strong mechanical rigidity, low rotor loss and stable starting torque. Each rotor undergoes multi-stage high-precision dynamic balancing to limit vibration and noise within IEC limits, meeting the stable operation demands of grinding equipment.

The welded modular steel-plate housing is a typical feature of the ABB AMI series, supporting flexible selection of cooling systems and auxiliary accessories for dusty cement workshops. The AMI400L8A is equipped with standard IC611 air-to-air closed cooling. Two independent air loops are arranged inside the motor: internal hot air circulates in the sealed frame and transfers heat to outside ambient air through the top air-to-air heat exchanger. The IP55 enclosure effectively blocks cement dust and splashing water, making it suitable for the dusty, humid environment of cement production lines where open-type motors are prone to failure. For sites with poor ventilation, the IC81W air-to-water cooling scheme can be selected to improve heat dissipation capacity.

The bearing system is designed for 8-pole medium-speed heavy-load mill operation. Heavy-duty rolling bearings are standard for this frame, while sliding bearings can be supplied for high-power end or heavy shock-load working conditions. PT100 temperature sensors can be pre-installed in stator windings and bearing housings at factory, feeding real-time temperature data to the plant DCS system for remote monitoring and over-temperature protection. Space heaters are optional to prevent winding condensation during long standby periods of the mill. For variable frequency energy-saving transformation, the IC616 cooling version can be supplied to guarantee sufficient cooling airflow under low-speed variable-frequency operation. Customisation options include ATEX explosion-proof modification, high-altitude adaptation, tropical anti-humidity & anti-corrosion coating, special terminal box layout and double shaft extension to satisfy complex project requirements.

Typical driven equipment covers cement raw mills, clinker mills, large process fans and heavy-duty slurry pumps. The motor supports direct-on-line starting or high-voltage soft starter starting according to the short-circuit capacity of the on-site power grid. Before delivery, every unit passes comprehensive factory acceptance tests, including insulation resistance test, power-frequency withstand voltage test, no-load running test, efficiency verification, vibration and noise measurement. Built on ABB’s mature AMI modular platform, AMI400L8A provides reliable continuous operation, convenient spare parts replacement and low total ownership cost for cement grinding and other heavy industrial applications.