148 Rockwell Automation Publication 193-UM015D-EN-P - February 2015
Chapter 6 Protective Trip and Warning Functions
Stall Protection
A motor stalls when its inrush current lasts for a longer than normal period of
time during its starting sequence. As a result, the motor heats up rapidly and
reaches the temperature limit of its insulation. Rapid stall detection during the
starting sequence can extend the motor’s life, and minimize potential damage and
loss of production. The E300 Electronic Overload Relay can monitor for this
condition with its Stall Trip function and stop the motor before damage and loss
of production can occur.
Stall Trip
The E300 Electronic Overload Relay trips with a Stall Trip indication when:
• No trip currently exists
• Stall protection is enabled
• Current is present
• The maximum phase current is greater than the Stall Trip Level for a time
period greater than the Stall Enabled Time
If the E300 Electronic Overload Relay trips on a stall, the:
• TRIP/WARN LED status indicator flashes a red 4-short blink pattern
• Bit 3 in Current Trip Status Parameter 4) sets to 1
• Bit 0 in Device Status 0 (Parameter 20) sets to 1
• Any relay outputs configured as a Trip Relay open
• Any relay outputs configured as a Control Relay open
• Any relay outputs configured as a Trip Alarm close
• Any relay outputs configured as a Normal Relay are placed in their
Protection Fault state (if so programmed)
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