Sveba-Dahlen InFA

What does Sveba-Dahlen InFA mean?

The SD-180's Schneider frequency converter has detected that its internal input power section is not functioning correctly. The input section includes the rectifier stage and associated components that convert incoming mains AC to the DC bus voltage that powers the drive. This fault indicates a significant hardware issue within the converter's power electronics.

Symptoms

• InFA fault code displayed on the SD-180 touchscreen
• Converter fails to build up normal DC bus voltage on power-up
• No drive output to the motor; oven conveyor or deck drive does not operate
• Possible tripping of upstream fuses or circuit breakers if input components have failed short
• Fault present from initial power-up with no run command required to trigger it

Common causes

• Failure of the rectifier bridge or input power components within the converter
• Damage to the converter input section caused by mains voltage spikes or surges
• Incorrect mains supply voltage being applied to the converter input terminals
• Phase loss on the incoming mains supply causing abnormal input section behaviour
• Internal precharge circuit fault preventing normal DC bus energisation
• Physical damage to the converter power board affecting the input stage

Diagnostic steps

1. 01

   Verify incoming mains supply

   Before opening the converter, use a calibrated voltmeter to confirm that the mains supply to the SD-180 is correct in voltage, frequency, and that all phases are present and balanced. Correct any supply issues before proceeding.

2. 02

   Isolate, lock out, and discharge

   Switch off at the main isolator, apply lockout/tagout, and wait at least 5 minutes for the DC bus capacitors inside the converter to fully discharge before opening the enclosure.

3. 03

   Inspect input terminals and wiring

   Check the converter's mains input terminals for loose connections, signs of overheating, or arcing. Tighten any loose terminals to the torque values specified in the SD-180 service manual.

4. 04

   Inspect input power components visually

   Examine the converter power PCB and rectifier components for visible damage such as burn marks, cracked components, or bulged capacitors. Do not attempt component-level repairs in the field.

5. 05

   Document and escalate

   Record all findings including supply measurements, any visible damage, and the conditions under which InFA appeared. Provide this information to the attending drive technician to expedite diagnosis and repair.

When to call a professional

InFA indicates a fault in the converter's internal power electronics that requires specialist drive repair or converter replacement. Do not attempt to continue operating the SD-180 with this fault active. Escalate immediately to an authorised Sveba-Dahlen service engineer or Schneider drive specialist, as further operation risks permanent converter damage or electrical hazards.