800-1280kW 6000V 50Hz Three-Phase AC Squirrel Cage Motor | IP55 IC611 Cooling | AMI 450L6A Frame

The ABB AMI 450L6A is a medium-frame modular high-voltage squirrel-cage induction motor built on ABB’s proven AMI product platform, covering rated power from 800kW to 1280kW. With a 6-pole design, it achieves a synchronous speed of 1000rpm, paired with a standard rated voltage of 6000V and 50Hz frequency. Designed and manufactured in accordance with IEC and NEMA international standards, this welded steel-plate motor is engineered for S1 continuous heavy-duty operation. It comes standard with IC611 air-to-air closed cooling and IP55 protection grade. Benefiting from the modular mechanical architecture, cooling packages, condition-monitoring sensors and auxiliary assemblies can be flexibly configured to meet diverse and stringent on-site operating requirements. It is widely used in thermal power, cement, mining, water conservancy and petrochemical industries to drive medium-speed heavy-duty equipment such as large centrifugal fans, circulating water pumps and industrial compressors.

Core Technical Parameters  

Electromagnetic performance is optimised through multi-working-point finite element simulation, specially tuned for the medium-speed load characteristics of 6-pole motors, adapting to long-term continuous running and frequent partial-load cycles of fans and pump units. The stator core is stacked with premium low-loss silicon steel laminations to minimise iron loss, stray loss and magnetic leakage under both full-load and partial-load working conditions. The stator winding adopts high-grade corona-resistant magnet wire and undergoes complete VPI vacuum pressure impregnation treatment. The reinforced winding-end structure improves mechanical rigidity, dielectric strength and resistance to electrical ageing, enabling the motor to withstand industrial grid voltage fluctuations and impulse loads generated during repeated startup. The rotor adopts a heavy-duty copper-bar squirrel cage structure, featuring reliable mechanical stability, low rotor losses and consistent starting performance. Each rotor assembly passes multi-stage high-precision dynamic balancing calibration to keep vibration and noise strictly within IEC permissible limits for long-duration medium-speed continuous service.

The welded modular steel-plate frame is a core advantage of the ABB AMI series, allowing flexible matching of cooling systems and auxiliary accessories to suit on-site environmental conditions. The AMI 450L6A is normally equipped with the IC611 air-to-air closed cooling system. Two independent air circuits operate inside the motor: internal hot air circulates within the sealed frame and transfers heat to external ambient air via the top-mounted air-to-air heat exchanger. The IP55 enclosure provides reliable defence against dust ingress and water splash, making it suitable for humid and dusty industrial workshops where open-ventilated motors cannot operate steadily. For sites with poor ambient air quality or insufficient heat dissipation conditions, the IC81W air-to-water cooling option can be selected to enhance heat exchange efficiency.

The bearing system is customised for 6-pole medium-speed heavy-load continuous operating conditions. Heavy-duty rolling bearings are standard for this frame size, while sliding bearings can be supplied for the upper power range or applications with obvious impact and vibration loads. PT100 temperature sensors can be factory-preinstalled in stator windings and bearing housings, transmitting real-time temperature data to the plant DCS system for remote condition monitoring and overtemperature protection. Space heaters are available as an option to prevent winding condensation during motor standby periods. For variable-frequency energy-saving retrofit projects, an IC616 cooling variant can be provided to guarantee sufficient cooling airflow under low-speed variable-frequency operation. Customisation options cover ATEX explosion-proof modification, high-altitude adaptation, tropical anti-humidity and anti-corrosion coating, special terminal box layout and double shaft extension to fulfil complex project specifications.

Typical driven machinery includes large centrifugal fans, circulating water pumps, process compressors and medium-flow centrifugal pumps. The motor supports direct-on-line starting or high-voltage soft starter starting, subject to the short-circuit capacity of the on-site power grid. Before shipment, every motor undergoes 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, AMI 450L6A delivers stable and dependable operation, convenient spare parts interchangeability and low life-cycle cost for critical medium-speed heavy-duty industrial applications.