User Manual

Rockwell Automation Publication 193-UM002I-EN-P - December 2011 57
Protective Trip & Warning Functions Chapter 3
Jam Protection (High
Overload)
Motor current greater than the motor’s nameplate rating may indicate a high
overload or stall condition, such as an overloaded conveyor or jammed gear.
These conditions can result in overheating of the motor and equipment damage.
Rapid jam fault detection helps to minimize damage and loss of production.
Jam Trip
The E3 Overload Relay will trip with a jam indication if:
• no trip currently exists,
• Jam Protection is enabled,
• Jam Inhibit Time has expired, and
• the maximum phase current is greater than the Jam Trip Level for a time
period greater than the Jam Trip Delay.
If the E3 Overload Relay trips on a jam, the:
• no trip currently exists,
• Jam Protection is enabled,
• Jam Inhibit Time has expired,
• maximum phase current is greater than the Jam Trip Level for a time period
greater than the Jam Trip Delay.
If the E3 Overload Relay trips on a jam, the:
• TRIP/WARN LED status indicator will flash a red 6-blink pattern,
• bit 5 in Trip Status, Parameter 14, will set to 1,
• bit 0 in Device Status, Parameter 21, will set to 1,
• Trip Relay contact will open, and
• outputs will be placed in their Protection Fault State (if so programmed).
Jam Inhibit Time, Parameter 41, allows the installer to inhibit a jam trip from
occurring during the motor starting sequence. It is adjustable from 0…250
seconds.
Jam Trip Delay, Parameter 42, allows the installer to define the time period a jam
condition must be present before a trip occurs. It is adjustable from 0.1…25.0
seconds.
IMPORTANT
The Protection Fault State of OUT A and OUT B is defined by:
• OUTA Pr FltState, Parameter 65
• OUTA Pr FltValue, Parameter 66
• OUTB Pr FltState, Parameter 71
• OUTB Pr FltValue, Parameter 72