EF3 External Fault 3 fault in delta drive

EF3 External Fault 3 fault in delta drive troubleshooting

Description

Like EF and EF2, EF3 is a user-defined trip. It indicates that the digital input assigned to "External Fault 3" (Input MIx) has been triggered. This is often used for tertiary safety devices.

Causes

1. Vibration Switch: Often used for cooling tower vibration sensors.
2. Fire Mode: Sometimes linked to fire alarm relays.
3. Wiring Error: A wire connected to the assigned terminal has come loose (if using NC logic).

Solution

Trace the input:
1. Identify Terminal: Check parameters (Group 02) to see which MI terminal is assigned function code "External Fault 3".
2. Inspect Device: Check the field device connected to that terminal.
3. Check Logic: Verify if the input is configured as Normally Open (NO) or Normally Closed (NC).