Excitation units for synchronous generators and motors with external power circuits


Our excitation devices are equipped with a thyristor controller for driving external thyristor-based power circuits.

This thyristor controller for external power circuits can be integrated within the device or be connected via a bus, in order to, for example, physically separate the control and power subsystems.

The XD2S family is a system of compact devices for synchronous machine excitation with two basic configurations. The devices can be either integrated with the power circuit or control/drive an external circuit for excitation and monitoring of machines in the range of hundreds of megawatts, and can also be used for smaller units of a megawatt or less.


Voltage: 24 V DC

Synchronization voltage: 3 x 10 … 450 V AC

Control accuracy: ± 0.5 %

Early grid detection: from 10 V AC

Applications: synchronous machines






For easy, comprehensive parameter management and diagnosis, we provide the EM2. Additional options are available for special applications.



Operating modes

Reactive power control

Power factor control

Voltage control

Excitation current control

Reactive power statistics

Stabilization of real power

V/f droop control

Voltage control blocked (motoring)

Power factor control cascaded on excitation current control (motoring)




Limiters and additional functions



Excitation current limiter: 2 stage, time-overcurrent principle

Armature current limiter: 2 stage, time-overcurrent principle

Armature voltage limiter

Under-excitation limiter



Machine monitoring and control



Generator overvoltage with release

Monitoring of rotating diodes (for brushless machines)