May 19, 2024

Today’s industry demands constantly improved performance for their production tools with a view to reducing running costs and in this context, the client needed to improve the efficiency of its compressed air systems. The next step to delivering machines with improved cost-effectiveness was to adapt the electric motor and the powertrain of GA oil-injected screw compressors.


The project we have been working on is in the field of high-efficiency synchronous motors. The goal of the project was to improve the efficiency of the driveline of the GA+ compressor range. These compressors currently use an induction motor because they are connected directly to the electricity grid. The rotor cage of the induction motor allows the motor to start without the use of (power) electronics and the related losses.

To improve the efficiency of the GA+ compressor range, the client wanted to investigate the possibility of installing a more efficient, directly on-line, electric motor.


The following options were investigated:

  • Direct-online synchronous reluctance motor
  • Line-start permanent magnet motor
  • Hybrid (copper rotor) induction motor

We performed tests on the motors described above, to select the motor best applied in the GA+ compressor range. Data tests are performed on a motor test bench to compare the efficiency of the motors and compressor tests are performed to make sure the compressor behaviour is at least the same if not improved. Other improvements on the driveline, such as an alternative drivetrain set-up, alternative cooling and so on were also investigated.