Manual MRR1 SEG Electronics GmbH
DOK-TD-MRR1, Rev. B 11
Diode failure protection:
The diode failure protection is based on the measurement of the ripple component of the excitation
current related to the mean value of the excitation current as per following formula:
Typical values for Ir:
All diodes all right: Ir ≈ 15...20%
One diode open: Ir ≈ 110%
One diode short: Ir ≈ 200%
The setting of Ir> should be chosen at about 40% to 50%. The tripping time tIr should be instanta-
neous or with only a small delay, e.g. 200 ms. In case of a diode short the rotor system is extreme-
ly endangered!
Hint!
The required settings depend on various factors like:
- Required power factor of the generator
- Required minimum short circuit duration etc.
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