Rockwell Automation 825-P Modular Protection System for Motors User Manual - Manual (Page 79)

Rockwell Automation Publication 825-UM004D-EN-P - November 2012 79
Configuring Protection & Logic Functions Chapter 6
Protection Disable
You can disable Trip and Warning levels of preselected protection elements for a
set time delay during motor Starting. Set the Protection Inhibit Time for a delay
to disable Undercurrent, Short Circuit, Current Imbalance, Ground Fault, and
Undervoltage elements. Set the Overload Inhibit Time for a delay to disable the
Overload (Thermal Model) element. If you are using the time delay settings, keep
them as short as possible.
Start Monitoring
If motor starting has not finished by the set time, the relay produces a trip. The
start monitoring is independent of the overload protection provided by the
thermal model. Figure 30 shows the typical current during motor start and the
Start Motor Time setting.
Table 20 - Protection Disable Settings
Setting Prompt Setting Range Factory Default
PROT INHIBIT TIME Off, 1…240 s Off
OL INHIBIT TIME Off, 1…240 s Off
ATTENTION: The protection can be seriously jeopardized when either of the Inhibit
Time settings is used. For most applications, set the value of PROT INHIBIT TIME and
OL INHIBIT TIME to Off.
NOTE: The 825-P determines the motor state (Starting, Running, or Stopped) primarily based on
the motor current.
Table 21 - Start Monitor Settings
Setting Prompt Setting Range Factory Default
START MOTOR TIME Off, 1…240 s Off
NOTE: With Star-Delta (Wye-Delta) starting, the total starting time (Star and Delta) is monitored.
If immediate tripping is required in the event of stalling, monitoring must be provided by a
Speed Switch Function.