Programming
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D
Page
D-61
8
9
10
A
B
C
D
E
1
2
3
4
5
6
7
Functional Description
The flycatching function enables the drive to be restarted smoothly into a spinning motor. It applies small search voltages to
the motor whilst ramping the Drive frequency from maximum speed to zero. When the motor load goes from motoring to
regenerating, the speed search has succeeded and is terminated. If the search frequency falls below the minimum search speed,
the speed search has failed and the Drive will ramp to the speed setpoint from zero.
The flycatching sequence can be triggered by different starting conditions:
ALWAYS:
All starts (after controlled or uncontrolled stop, or after a power-up)
TRIP or POWER-UP:
After uncontrolled stop, i.e. trip or coast, or after a power-up
TRIP:
After uncontrolled stop, i.e. trip or coast
The type of speed sequence may be Bi-directional or Unidirectional:
Bi-directional
Initially, the search is performed in the direction of the speed setpoint. If the drive fails to identify the motor speed in this
direction, a second speed search is performed in the reverse direction.
Unidirectional
The search is performed only in the direction of the speed setpoint.
