Allen-Bradley SMC-50, User Manual

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20 Rockwell Automation Publication 1560F-UM001A-EN-P - June 2019
Chapter 1 Product Overview
Dual Ramp Start
(2)
This method is useful on applications with varying loads, starting torque, and
start time requirements. Dual Ramp Start gives you the ability to select between
two separate start profiles via any programmable auxiliary input. Each start
profile can use any of the available starting modes.
Figure 7 - Dual Ramp Start Timing Diagram
Emergency Bypass Run (Full Voltage Start)
This starting mode is used to provide ‘Emergency Bypass Run’ when Power
switching devices are faulted (for example, shorted SCRs) and any of the soft
starting modes cannot be utilized. When programmed for ‘Emergency Bypass
Run’, a 'Start' command will first close the bypass contactor, then the line
contactor for an across-the-line (Full voltage) start of the motor. A 'Stop'
command will open the line contactor first and allow the motor to coast,
regardless of the programmed ‘stop mode’.
Figure 8 - Emergency Bypass Start
(2) Kickstart is also available with Current Limit Start and Dual Ramp Start.
%
Vo
lta
ge
Time (seconds)
Current Limit 2
Current Limit 1
100%
Initial
Torque 2
Initial
Torque 1
Ramp Time 2
Ramp Time 1
Start 1 Run 1
Start 2
Run 2
Percent
Voltage
Time (seconds)
100%