09.02 Connection
Siemens AG 6SE7087-6AK85-1AA0
3-53
Rectifier/Regenerating Unit Operating instructions
Recommended power section configurations:
Note: It is of no consequence whether the "12-pulse master" or "12-pulse slave" is supplied by the delta winding
of the 12-pulse transformer. It is only important that a phase offset of 30 degrees is present between the two
galvanically isolated supplies. In contrast to the following configuration examples, the "12-pulse master" and
"12-pulse slave" can also be exchanged with respect to their connection to the "12-pulse transformer".
a) Power section supply with autotransformers
With a small u
k
value for the 12-pulse transformer and/or the autotransformer ("high-power supply"), the
decoupling (commutating) reactors should be installed between the 12-pulse transformer outputs and the
autotransformer inputs. With a large u
k
value for the 12-pulse transformer ("low-power supply") they should
be installed directly in the path of the rectifier bridge to ensure that the total u
k
value in the regenerating
direction is not too large (see note in Section 3.1).
X117
X117
X117
X117
DC link
Arrangement for high-power system
Arrangement for low-power system
Mains
DC link
Mains
Autotransformer
Reactor
12-pulse slave
Rectification
Regeneration
12-pulse master
Rectification
Regeneration
"12-pulse transformer"
"12-pulse transformer"
Reactor
Reactor
Reactor
Autotransformer
Autotransformer
Autotransformer
12-pulse slave
Rectification
Regeneration
12-pulse master
Rectification
Regeneration
Figure 3.39 Power section supply with autotransformers
b) Power section supply without autotransformers, reduced DC link voltage
If an autotransformer for raising the regenerating voltage is not used, "Ud reduction" must be selected. By
selecting a transformation ratio of, for example, ü = 1.25 at the 12-pulse transformer and by using
rectifier/regenerating units of a higher voltage class (500 V unit instead of 400 V unit, 690 V unit instead of
500 V unit. Note: this is not possible for the 690 V unit) it is possible to obtain high DC link voltage with
respect to the primary supply voltage of the 12-pulse transformer despite Ud reduction.
Disadvantage: Worse mains power factor λ due to the phases.
X117
X117
DC link
Mains
"12-pulse transformer"
Reactor
Reactor
12-pulse slave
Rectification
Regeneration
12-pulse master
Rectification
Regeneration
Figure 3.40 Power section supply with autotransformers, reduced DC link voltage
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