Opti-Torque - ABB DCS 500B Description

Functional Software description

Opti-Torque

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The field current must change direction during a period of 2 sec,
otherwise signal ACK_FEXC1_ON goes to 0 and RDYRUN and
RDYREF are set to 0.
Following parameters are needed to supervise the function:
F1 CURR GT MIN L (1305) Defines the minimum level for the field
current
REV.REV HYST (1318) The sign of the torque reference defines
the field direction. Actual field direction is based on comparison of
field current reference and actual. The hysteresis is used in actual
current measurement when field reversal acknowledge signal is
produced.
REV.FLUX TD (1320) If real FLUX of the motor does not follow
rapidly the field current, e.g. in very old DC-motors, it can be nec-
essary to make an extra delay for defining the field direction. Nor-
mally this time can be 0.
Following signals are needed for the controllers and for some
measurements:
Bit 5 of TC_STATUS (11204) is the TC_FIELD_CHANGE indication
and during field reversal this signal blocks the armature current
controller, the I-part of the speed controller and updates the speed
ramp output with a measured speed value.
The time that is normally needed for changing the field direction is
quite long because of the big inductance of the field winding. This
time can be reduced in certain cases by using the OPTI-TORQUE-
function.
DCS 500 Software Description