Descriptions of functions
10.29 Field reversal
SINAMICS DCM DC Converter
622 Operating Instructions, 12/2018, A5E34763375A
Braking using field reversal
The function "Braking using field reversal" is controlled using the signal source (binector) set
at binector input p50581 and this has a button-type function.
Binector = 1 (for ≥30 ms) in operating state ≤o5 (line contactor closed) causes the drive to
brake to n < n
min
.
After this, the original field direction is selected.
The motor can accelerate in the original direction of rotation after the braking command has
been withdrawn (binector = 0) and acknowledged using "Stop" and "Switch-on".
Control sequence when specifying "Braking using field reversal"
1. Drive rotates with direction of rotation 1 or 2
2. Specify "Braking using field reversal" using log. 1 (for ≥30 ms) selected at binector using
p50581
3. Field reversal is executed.
Preconditions: Line contactor is closed (for operating state ≤o5) and the drive is not
already braking.
Braking is identified by the negative internal actual speed (whereby, this is obtained in the
negative field direction by reversing the real actual speed):
– Wait until armature current I
A
= 0 , then armature pulse inhibit (the drive then remains
in operating state ≥ o1.4)
– Inhibit field firing pulses (r52268 = 0 also initiates this)
– Wait until I
field
(r52265) < I
field min
(p50394)
– Wait time according to p50092[00] (0.0 to 10.0 s, factory setting 3.0 s)
– Open current field contactor (r53195.0 = 0 or r53195.1 = 0)
– Wait time according to p50092[01] (0.0 to 10.0 s, factory setting 0.2 s)
– Control new field contactor (r53195.1 = 1 or r53195.1 = 1)
– Reverse the speed actual value (with the exception, for p50083 = 3 ... EMF as speed
actual value)
– Wait time according to p50092[02] (0.0 to 10.0 s, factory setting 0.1 s)
– Enable field firing pulses
– Wait until I
field
(r52265) > I
field set
(r52268) × p50398
– Wait time according to p50092[03] (0.0 to 10.0 s, factory setting 3.0 s)
– Enable armature firing pulses (operating state o1.4 can be exited)
4. Sequence when braking the drive:
– n
set
= 0 internally entered at the ramp-function generator input, the drive brakes
– Wait until n < n
min
(p50370)
– Wait until armature current I
A
= 0 , then armature pulse inhibit (drive goes into
operating state o7.2)
– Wait until the braking command has been withdrawn by logical 0, on the binector
selected with p50581
(as long as level = 1 is present, the drive is kept in operating state o7.2)
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