ABB Relion REG670, Technical Manual, Page: 1236 / 1298

22.3 Coupling capacitor unit REX061
22.3.1 Introduction
REX061 isolates the injection circuit from the rotor exciter voltage.
The REX061 coupling capacitor unit grounding point and grounding brush of the
rotor shaft should be properly interconnected.
22.3.2 Design
Measure points are added to the capacitor box that enables the measuring of rotor
voltages without any connection to a hazardous voltage, by the use of protective
impedance. This enables the usage of standard oscilloscope or handheld DVM.
The measure ports cause an additional rotor impedance of 20 MΩ per
terminal to ground. However, the rotor calibration procedure extracts
this impedance.
REX061
Coupling Capacitor unit
Rotor -
Rotor +
Injection
Measuring point +
Ground (measuring)
Measuring point -
Ground (injection)
PE
IEC11000040-3-en.vsd
IEC11000040 V1 EN
Figure 570: REX062 principle design
Section 22
1MRK502052-UEN B
Injection equipment hardware
1230
Technical manual