Drive Control Adjustments - MCi iControl User Manual

Drive Control Adjustments

In AC Flux Vector drive applications, when Run Enable (RE) is active, the control system picks
the main power contactor (PM Contactor) and enables the drive unit. The drive applies voltage
to the AC motor to build up magnetic flux. The amount of time it takes to build up flux in the AC
motor (from 200 to 500 ms) depends upon motor characteristics and temperature. AC drive
logic detects the build up of flux in the motor and generates the Drive ON output. At this time,
the motor may have developed enough torque to hold the load.
The motor no load current value is not high enough to hold the car at zero speed when the drive
is enabled. The normal setting for no load current is 30% to 40% of full load current. Pick delay
(Configuration > Brake > Control tab) is used to coordinate the picking of the brake with the
build up of flux. If the delay is not sufficient, the flux will not build up fully and a DRO fault will
occur. Speed pick delay 1 is used to delay the application of the pattern signal to the drive to pre-
vent the car from moving under the brake.
• Pick delay must be adjusted to achieve a smooth start, prevent rollback, and prevent DRO
faults.
• Speed pick delay 1 must be adjusted to prevent movement of the car under the brake.
Controlling Initial Start of Car Motion
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