The Hidden Isolation Hero: Split-Bobbin PCB Mount Transformers

The Silent Killer: Inter-Winding Arcing

When primary-secondary insulation fails:

• Ground faults trigger system shutdowns

• Measurement drift corrupts data in test equipment

• Patient/operator risk in medical devices

Real-World Performance Gains

Testing reveals dramatic differences:

Case study: An infusion pump’s PCB mount transformer survived 8kV ESD surges (IEC 61000-4-2) solely due to split-bobbin isolation.

Where This Matters Most

1. Medical Isolation

   • Meets EN 60601 leakage current requirements (<10μA)

   • Blocks defibrillator pulses in patient monitors

2. Industrial Sensors

   • Immune to VFD noise in motor control systems

   • Survives 100G shock in aerospace PCBs

3. Test Equipment

   • Maintains 0.1% accuracy despite humidity swings

Critical Validation Tests

Never assume compliance—verify:

1. Barrier Thickness: ≥1.5mm (per EN 61558-2-6)

2. Material CTI: >600 (e.g., VO-rated epoxy)

3. Partial Discharge: <5pC @ 150% operating voltage

4. Thermal Cycling: -40°C to 130°C (500 cycles)

Red flag: Suppliers who can’t provide cross-section photos of bobbin barriers.

Beyond Isolation: Hidden Benefits

• Fault Containment
  Short circuits won’t propagate across partitions

• EMI Reduction
  Inter-winding capacitance drops by 40-60%

• Thermal Management
  Heat localizes instead of migrating to secondary

The Cost of Ignoring This

A solar inverter manufacturer saved $0.12/unit using standard bobbins—then paid $480k in field replacements when humidity caused arc-through failures.Specify transformers that refuse to fail. Request split-bobbin validation reports: sales@ferrtx.com