Electronic Thermal Relay Function Pre-alarm

What does Electronic thermal relay function pre-alarm mean?

The cumulative value of the electronic thermal O/L (overload) relay has reached 85% or higher of the Pr. 9 Electronic thermal O/L relay setting. This warning signifies that the motor or inverter is approaching an overload condition based on its thermal model. Continued operation without reducing the load could lead to an overload trip.

• Motor experiencing sustained mechanical overload, drawing current close to or above its rated value for extended periods.
• Motor cooling fan is obstructed, faulty, or operating in a high ambient temperature environment, reducing its ability to dissipate heat.
• Pr. 9 (Electronic thermal O/L relay) setting is too low for the motor's actual thermal capacity or application requirements.
• Motor rated current (Pr. 81 Motor rated current) is set incorrectly, leading to an inaccurate thermal model calculation.
• Insufficient motor cooling due to dirty cooling fins or operating in a confined space.

Click steps to track your progress.

1. 1

   Inspect the mechanical load connected to the motor for any signs of obstruction, binding, or excessive wear causing sustained high current draw.

2. 2

   Verify the ambient temperature around the motor and inverter to ensure it's within specifications (e.g., typically below 40°C).

3. 3

   Measure the motor phase currents (U, V, W) using a clamp meter and compare them to the motor's nameplate rated current during operation.

4. 4

   Confirm Pr. 81 (Motor rated current) is accurately set to the motor's nameplate rated current value.

5. 5

   Consider increasing Pr. 9 (Electronic thermal O/L relay) setting slightly, after confirming the motor's actual thermal capacity and operating current.