ABB DCS 500B, Description

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Functional Software description
DCS 500 Software Description 57
Speed
Current
Field
Current
Speed
Current
Field
Current
Field Reversal
with OPTITORQUE-
function
Normal Field Reversal
Figure 42 Optitorque function compared with normal field
reversal
If the type of the process is such that before the field reversal only a
small torque is needed, e.g. changing of the speed direction, it is
possible to reduce the field current before the field reversal is acti-
vated.
This technique enables for a faster field reversal. The permissible
reduction in the field current can be defined by the required torque
reference. For example, if the speed direction is changed rather
slowly, the required torque can also be quite small, close to zero
speed, and so the motor field can also be reduced.
Selection of
OPTI-TORQUE The OPTI-TORQUE can be selected by the parameter:
FIELD MODE (1001)
4 [NO EMF, OPTITORQUE] Field rev. + OPTITORQUE
5 [EMF + OPTITORQUE] Field rev. + OPTI
EMF-control
Field current re-
duction using
torque reference The relationship between torque reference and field current refer-
ence is defined by parameter
OPTI.REF GAIN (1315) (range
0...10000).
OPTI.REF GAIN * Torque reference
F1 CURR REF (11301) =
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