Custom 10uH Ferrite Sendust Toroidal Core Common Mode Choke For Inverter And VFD

The KS068125 4.0mH toroidal inductor is a wound power inductor built on a KS series Sendust (Fe-Si-Al) toroidal core, size 068 with a permeability of 125. It is designed for switching power supplies and filter circuits that need stable inductance under DC bias, low core loss and good thermal behaviour in a compact round package.

The distributed air gap of the Sendust core allows the inductor to carry substantial DC current with a soft, predictable saturation curve instead of the sharp roll-off seen with gapped ferrite, which makes the current loop easier to control at high load. The 4.0mH value is achieved with a full copper enamelled winding applied under controlled tension, and the finished part can be supplied with radial leads, flying leads, a base or a bracket to match your PCB.

Inductance, current rating, wire gauge, termination and marking are all engineered to the customer's drawing rather than sold as a fixed catalogue item, and every unit is 100% tested for inductance and DCR before shipment. Production takes place in our own factory in Dongguan under an ISO 9001 quality system.

• Sendust core with a distributed air gap provides a soft saturation curve, so inductance falls gradually as DC bias rises instead of collapsing suddenly.
• Higher saturation flux density than ferrite of the same size, allowing more current or a smaller part for the same current rating.
• Low core loss at switching frequencies, which keeps self-heating down and improves overall power supply efficiency.
• Very low magnetostriction compared with powdered iron, so the inductor stays quiet and does not produce audible whine in the audio band.
• Excellent temperature stability: the core material has a Curie temperature above 500 C and shows only a small inductance shift across the operating range.
• Closed toroidal magnetic path keeps flux inside the core, giving a low stray field and less interference with nearby components.
• Full copper winding with controlled tension delivers a consistent DCR and repeatable inductance from batch to batch.
• Epoxy powder coated core protects the winding from edge damage and provides reliable insulation between core and wire.
• Compact round shape with a low profile, easy to mount flat on the PCB or to secure with a base, bracket or cable tie.
• Long service life with no measurable ageing effect, unlike some powdered iron materials that drift after long thermal exposure.

• Power factor correction (PFC) boost inductors in AC-DC power supplies.
• Output filter and energy storage inductors in buck, boost and buck-boost converters.
• Differential mode line filters and EMI suppression chokes in switching power supplies.
• Solar inverters, energy storage converters and battery charging equipment.
• Industrial control equipment: PLC power modules, drives, welding machines and automation cabinets.
• UPS systems, voltage stabilisers and power conditioning units.
• LED lighting drivers and constant-current power modules.
• Telecom and server power supplies, and general purpose DC-DC power modules.
• Motor drive filters and snubber circuits requiring stable inductance under load.

• Established in 2000, with 26 years focused on magnetic components for industrial control and power electronics; we are a manufacturer, not a trading company.
• Self-owned 10,000 square metre factory in Dongguan with 8 complete production lines, which keeps lead times and quality consistent on repeat orders.
• A 20-person R&D team supports you from schematic review and sample building through to mass production, and a 20-person QC team controls the process.
• Complete certification framework: ISO 9001 and ISO 14001 system certification, with CE, CB, UL, cUL and RoHS product certification available.
• Annual export value of USD 42 million, shipping to North America (50%), Northern Europe (18%), South America (15%) and Southeast Asia (15%), including OEM customers such as Midea and Federal Signal.
• Flexible cooperation: MOQ from 1,000 pcs, DDP and DDU terms supported, direct factory delivery from China.

• Engineered to your circuit, not sold as a fixed part: inductance, bias current, DCR target and termination are all set by your design requirement.
• Sendust core gives a better cost-to-performance balance than amorphous or nanocrystalline cores while still outperforming powdered iron on loss and stability.
• Predictable soft saturation makes control loop design easier and gives your power supply more headroom during load transients.
• Consistent winding process keeps inductance and DCR within tolerance across large production runs, reducing rework at your line.
• Low audible noise and low stray field help your finished equipment pass EMC testing and stay quiet in the field.
• Free engineering support before the design is frozen: we review your target inductance, ripple current and temperature rise and recommend the most suitable core size and permeability.