MAAG™ CEM Drive System

The MAAG CEM Drive is an integrated mill drive system with motor and 2-stage planetary gear unit in one common casing

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Maximum availability and power for your mill

With the novel, integrated and modular MAAGTM CEM (central electrical motor) Drive concept, FLSmidth MAAG Gear combines the benefits of the proven MAAG technology with an innovative motor design. The result is a state-of the-art energy-saving drive system for vertical mills combined in one casing.

The modular design of the MAAG CEM Drive system permits a power range from 4,000 to 14,000 kW drive power, with the best possible availability levels. With the variable frequency converter energising the motor, this drive system allows optimised material grinding. The flexibility of the drive enables the production process to be optimised and actively controlled.

The CEM gear stage is the proven PV stage (double planetary stage with torque split) of the well-known MAAG WPV gearbox. The motor and the planetary stage are in the same axis and directly coupled, thus eliminating the bevel gear stage used in conventional gearboxes. The planetary stage is fitted with smooth-running, maintenance-free sleeve bearings. This results in identical external dimensions compared to conventional gearboxes. The CEM Drive is therefore an ideal solution for replacement and upgrading projects.


The heart of the MAAG CEM Drive is a permanent magnet synchronous motor with a loss-optimised singletooth coil. The use of permanent magnets minimises resistive losses, in turn resulting in reduced energy costs. In combination with the frequency converter, the motor delivers constant torque over a wide range of speeds, with consistently high efficiency.

The integrated motor design brings the mill operator a host of cost benefits:
1. No additional base needed, since there is no external motor
2. The absence of an external main motor saves time-consuming alignment after commissioning, inspection or repair
3. No auxiliary drive required for maintenance work

Variable Frequency Converter (VFC)
The VFC allows the mill speed to be continuously adjusted and therefore ideally matched to the specific grinding requirements of production. The smooth start up allows rotation at intermediate speeds to empty the mill table in a controlled way, in order to prevent overloading of the reject system, as well as slow turning and positioning of the mill for maintenance work. The state-of-the-art drive control allows fine-tuning of speed and torque to reduce the overall vibration level and optimise the running behavior of the mill for different operational conditions. The perfectly matched components minimise system perturbations.

Oil Supply Unit
The oil supply unit is based on well known and proven technology. Just one common oil supply unit handles both motor cooling and gearbox lubrication, which greatly simplifies the storage and provision of consumables and spare parts.

Monitoring / Drive Control / Interlocks
An extensive network of sensors enables the critical indicators to be monitored. The use of intelligent sensor systems provides all the relevant drive measurements to adjust the motor. The direct connection to the process control system allows process parameters to be adjusted quickly. The system enables online monitoring of the state of the drive, so that the risk of unscheduled downtime is kept to a minimum.

Comprehensive customer care, taking into account local conditions such as power supply data, is part of MAAG Gear’s service. This is the only way to ensure that the system is set up and adapted to individual requirements

New drive system - Ingenious and integrated

  • Less vibration due to optimised drive control means an uninterrupted and smooth operation
  • Adaptable to the composition of varying material grades
  • The ability to accommodate different materials in the same mill
  • Optimum balance between smooth operation and energy efficiency
  • Easy handling and easy maintenance (only one cooling system and wearfree motor)
  • Soft start-up of the mill
  • Infinitely variable speed allows slow turning and exact positioning for maintenance
Download "Driving simplicity" and learn what makes CEM Drive ingenious
Download CEM Drive brochure