Applicable Systems
ATV930
Symptoms
Schneider ATV930 process drive reports fault during normal operation indicating drive system issue requiring diagnostic evaluation.
Possible Causes
- Drive power section IGBT desaturation fault indicating switching device failure
- Encoder feedback signal loss during closed-loop speed control
- DC bus ripple voltage exceeding 5% indicating capacitor degradation
- Safe Torque Off (STO) signal unexpected activation during operation
Troubleshooting Steps
- Step 1: Read fault code on ATV930 HMI graphic display
Fault code and description shown on color display - Step 2: Check encoder wiring and signal quality
Encoder pulses show clean signal on oscilloscope - Step 3: Measure DC bus ripple with oscilloscope
Ripple voltage less than 5% of DC bus nominal voltage - Step 4: Verify STO circuit wiring and safety relay operation
STO circuit shows closed loop in normal operation
How to Reset
Reset by: 1) Correct the fault condition. 2) Reset from HMI or cycle power. 3) Run test. 4) Verify normal operation.
Common Replacement Parts
- ATV930-CTL-01: Schneider ATV930 control board (Verify power rating and voltage class)
Frequently Asked Questions
- Q: What is Safe Torque Off (STO)?
Safe Torque Off is a safety function that removes torque-generating power from the motor without disconnecting the main power. When STO is activated, the drive prevents IGBT switching, ensuring the motor cannot generate torque. This is used for emergency stop and safe maintenance scenarios.
Source: Schneider ATV930 Programming Manual
Category: Electrical