Speed Feedback Loss
Schneider Electric · Altivar Machine ATV320 Variable Speed Drive
What does SPF mean?
A loss of speed feedback has been detected. This means the drive is no longer receiving valid speed information from its encoder or resolver. This is critical for closed-loop speed control and can lead to unstable motor operation or a controlled shutdown. If left unresolved, accurate speed control is impossible.
Complete Troubleshooting Guide
- 1
Check the wiring connections for the speed feedback device (encoder/resolver) to the drive for integrity.
- 2
Inspect the speed feedback device for physical damage or misalignment on the motor shaft.
- 3
Verify the speed feedback parameters in the drive (e.g., encoder type, pulses per revolution).
- 4
Test the encoder/resolver output signals with an oscilloscope if possible.
- 5
Ensure the encoder power supply from the drive is present and stable.