My German's a bit rusty, but I know about electronics!
This certainly sounds like a phase-angle control (from your previous question, a motor speed control, I think?)
But I think it may be the other way round --- it sounds to me as if the phase-angle controller is being bridged with a 'dummy load' equal to the effective impedance (do remember that Widerstand is very often (especially in AC contexts) impedance rather than the more usually given resistance. There might be some validity in replacing the motor load with a dummy load under some kind of fault conditions, so the technique is perfectly feasible.
Hope this helps you unravel it a bit!
| Tony M|
Local time: 03:54
Native speaker of: English
PRO pts in pair: 12