External Thermal Relay Operation

What does E.OHT mean?

This fault occurs when the external thermal relay connected to the CS-SD terminals has tripped, indicating an overload condition detected by an external device. The FR-A800 inverter output is shut off to protect the motor and system. This fault is triggered when parameter T708 (Pr.186) (CS terminal function selection) is set to '7' (external thermal relay input) and the CS-SD terminal circuit becomes open.

• Activation of an external thermal relay due to motor overload or excessive temperature.
• Incorrect setting of parameter T708 (Pr.186) for external thermal relay input while the CS-SD terminals are open.
• A break or open circuit in the wiring between the CS-SD terminals and the external thermal relay.

Click steps to track your progress.

1. 1

   Verify the motor and driven equipment for signs of overload, mechanical binding, or excessive temperature.

2. 2

   Inspect the external thermal relay for proper operation, correct setpoint, and ensure its contacts are closed under normal conditions.

3. 3

   Check the wiring between the FR-A800 inverter's CS-SD terminals and the external thermal relay for continuity and secure connections.

4. 4

   Confirm parameter T708 (Pr.186) (CS terminal function selection) is set to '7' if an external relay is used, or reset to '6' (automatic restart after instantaneous power failure selection) if not used.