ZF Friedrichshafen has developed test benches that can be used for electric motors, e-axles without the motor, and complete electric drive axles. The core component of these modularly constructed test benches is the drive module, which is powered by an oil-cooled synchronous motor capable of delivering power up to 600kW and torque up to 1000Nm. Because of this, and their geometric characteristics, the test benches are able to cope with the high speeds of e-axles (up to 23,000rpm).
The base for the receiving modules can be either fixed, inclinable or swiveling, and is available for single- or multi-machine operation, with or without cross-table. Various optional modules complement the system, such as receiving modules for electric motors or coaxial test objects. An acoustic cabin for the drive module and an air-conditioning cabin for the receiving module for the test object are also available. Thanks to this modular design, conventional transmissions can also be tested.
Another key aspect in the development of the test benches was the machine dynamics. The drive unit and base frame design have been optimized to create a test bench with negligible rotor excitations, high structural resonances, and damping that eliminates all critical vibrations.