How to Fix Siemens V20 Fault F11 Motor Overtemperature Guide

How to Fix Siemens V20 Fault F11: Motor Overtemperature

If your Siemens SINAMICS V20 drive has suddenly tripped with Fault F11, your production has likely come to a stop. While the manual simply lists this as "Motor Overtemperature," there is usually a very specific reason why the drive thinks your motor is burning up.

 

In this guide, we’ll walk through the common causes of the F11 fault and the exact parameters you need to check to get your V20 back into "Run" mode.

What is Fault F11 Exactly?

The Siemens V20 doesn't always have a physical temperature sensor inside the motor. Instead, it uses a thermal model (I2t). It looks at the motor current, the frequency (speed), and the time. If it sees high current at low speeds for too long, it calculates that the motor's internal cooling fan isn't spinning fast enough to keep it cool, and it trips F11 to save the motor from burning out.

Common Causes of the F11 Fault

• Actual Overload: The motor is physically working too hard (mechanical blockage or high friction).
• Low Speed Running: Running a standard motor at very low Hz (below 15–20Hz) for a long time prevents the internal fan from cooling the motor.
• Incorrect Motor Data: The motor nameplate Amps or Power was entered incorrectly during commissioning.
• Duty Cycle: The motor is starting and stopping too frequently.

Step-by-Step Troubleshooting for F11

1. The Physical "Hand Test"

First, safely check the motor. Is it actually hot to the touch?

• If it's scorching hot: Check for mechanical jams, bad bearings, or a blocked cooling fan on the back of the motor.
• If it's cool: Then the drive's "thermal model" is likely misconfigured, and it's tripping prematurely.

2. Verify Parameter Group P03xx (Motor Data)

The V20’s calculation is only as good as the data you give it. Check these parameters:

• P0304: Motor Rated Voltage
• P0305: Motor Rated Current (Make sure this matches the nameplate exactly!)
• P0307: Motor Rated Power (kW or HP)

3. Check the Thermal Model Parameters

If your motor is safe but still tripping, look at these specific V20 settings:

• P0611: Motor thermal time constant. If this value is too low, the drive trips F11 too quickly.
• P0614: Motor I2t overload warning level. This is set to 100% by default. Increasing this slightly can prevent nuisance trips, but be careful—setting this too high can allow the motor to burn.

4. Use an External Fan? (P0335)

Are you running the motor at low speeds (under 25Hz) most of the time? Standard motors cannot cool themselves at low speeds.

• If you have an external constant-speed cooling fan installed, you must tell the drive by setting P0335 = 1 (Force cooling).

How to Reset the F11 Fault

1. Wait! The drive usually won't let you reset F11 immediately. You must wait for the "calculated" motor temperature to drop.
2. Once the motor has "cooled down" in the drive's memory, press the Fn button (Function) on the V20 keypad to acknowledge and reset.
3. If the fault immediately returns, it means the thermal memory hasn't reached a safe level yet. Wait 5-10 minutes and try again.

Pro Tip for V20 Maintenance

If you get F11 faults frequently, check the V20 drive’s own cooling fan as well. If the drive itself gets too hot, it can sometimes influence the temperature calculations for the connected motor.