Commutating reactors
A converter must always be connected to the line supply through a commutation inductance. This must have at least 4 %uK! The commutation inductance can be in the form of a converter transformer or, for the appropriate line supply, in the form of a commutating reactor.
A line supply can be considered to be "stiff" if the power ratioPs/Sk is 0.01. Even for stiff line supplies, the commutation inductance must have auK of at least 4 %!
For high-rating converters, the line reactance, i.e. the finite fault level (short-circuit power) of the line supply must be taken into account; this also results in higheruK values. Recommendation for the ratio of the line supply fault level (short-circuit power) to the apparent drive power > 33:1.
The commutating reactors are dimensioned according to the rated motor current in the armature or field circuit.
Operation with line frequencies of 50 Hz and 60 Hz
The rated currentsILn of the reactors, specified in the table, apply for operation with a line frequencyf = 50 Hz. It is permissible to operate the reactors with a line frequencyf = 60 Hz. In this case, a 10 % larger reactor should be used.
At the same time, the voltage dropV increases by 8 %.
Arrangement of reactors and radio interference suppression filters
(1) The commutating reactor in the field circuit is dimensioned for the rated motor field current.
(2) The commutating reactor in the armature circuit is dimensioned for the rated motor armature current.
The line current is 0.82 times the DC current.
(3) The radio interference suppression filter for the armature circuit is dimensioned for the rated motor armature current.
The line current is 0.82 times the DC current.
(4) The radio interference suppression filter for the field circuit is dimensioned for the rated motor field current.
(5) Radio interference suppression filters are not required for the electronics power supply alone.
Current consumption at 400 V 1 A, at 230 V 2 A.
(6) If the power supply voltages for the armature circuit, field circuit and electronics power supply are the same, then the voltage for the field and electronics power supply can also be taken after the radio interference suppression filter for the armature circuit.