Rockwell Automation 294D ArmorStart LT Distributed Motor Controller DeviceNet Version - User Manual - Manual (Page 29)

Rockwell Automation Publication 290D-UM001A-EN-P - June 2012 29
Product Overview Chapter 1
Figure 6 - Full-Voltage Start
Mode of Operation
Bulletin 294D Sensorless Vector Performance
Using a distributed AC drive to operate mechanical equipment at optimum
speed helps reduce energy costs and eliminates mechanical wear and tear that can
occur in the mechanical parts. The advance monitoring found in ArmorStart LT
protects critical equipment against unplanned downtime with advanced
diagnostics and notification of irregular operating parameters. ArmorStart LT
provides open-loop speed regulation (V/Hz) with slip compensation. This
provides excellent speed regulation and high levels of torque across the entire
speed range of the drive, and improved speed regulation as loading increases.
Open Loop Speed Regulation with Slip Compensation allows the VFD to
automatically adjust the output frequency to compensate for speed changes due
to motor loading. This feature utilizes an open loop, current feedback, slip
compensation circuit. Slip Compensation works as an open loop speed regulator
that increases the output frequency of the drive as the load is increased, or
decreases the frequency as the load drops. This feature is used where the motor
must run at a relatively constant speed regardless of torque output.
100%
Percent Voltage
Time (seconds)
% of speed
% of load
With Slip
Compensation
Without Slip
Compensation
100
99
98
97
96
95
0 10 20 30 40 50 60 70 80 90 100