Nanocrystalline toroidal core 30×20×12 mm

Applications

• CTs for higher current
• medium-frequency power transformers
• ground-fault sensing
• auxiliary transformers
• higher-current protection/metering CTs
• medium-frequency isolation power transformers
• ground-fault/residual-current sensing cores
• auxiliary bias/control power transformers

When to choose this size

This 30×20×12 mm toroidal core is sized for CTs for higher current and related designs in the nearby size family. Step down to the 25×16×10 mm core when board space, enclosure height, or a tighter footprint matters more than winding room. Within the same 30 mm OD, the 30×20×15 mm core adds stack height and Ae when you need more VA or easier secondary winding without growing the outer diameter. If height is constrained, the 30×20×10 mm core keeps the same OD with a lower profile. Move up to the 40×25×15 mm core when you need a larger outer diameter, winding window, or higher throughput than this part can comfortably support. In short, pick CCNT-030-020-012-MFBL when your design for CTs for higher current fits this window and OD; pick a neighbor when compactness or power handling shifts the trade-off.

Winding notes

Magnetic calculations should use the bare 30×20×12 mm geometry (Ae 0.49 cm², Le 7.9 cm). The winding must fit the finished window: cased ID is 18 mm, not the 20 mm bare ID. Keep the winding distributed around the toroid to limit leakage and local heating. High permeability (μi 80,000) supports useful magnetizing inductance at practical turn counts; stay within 1.25 Tesla saturation and the -40°C to +130°C PBT Class B 130C limit.