Toroidal Core

Application

      Toroidal cores are widely used for power transformers, instrument transformers, current sensors, inductors and variable transformers.

Advantages

      - Closed magnetic path;

      - Low core loss and humming;

      - Low magnetic leakage and remanence;

      - High magnetic flux density;

      - High permeability;

      - Smaller size and lighter weight;

Material

      High quality silicon steels with high permeability, low core loss and remanence.

      Ultra-thin: 0.05mm, 0.08mm, 0.10mm from Japan.

      Normal: 0.18mm, 0.23mm, 0.27mm, 0.30mm, 0.35mm.

      Supplier: Baosteel, Shougang, Nippon-steel, JFE and POSCO.

Capability

Limit dimensions:

      Min. width:5mm;

      Min. ID:7mm;

Main processes:

      Slitting -> Winding -> Annealing->varnishing->testing

Optional finishes:

      - Varnish;

      - Epoxy coating;

      - Black paint;

      - Chamfered or radiused edge;

      - Plastic cased.

      - Cut in half;

      - Gapped to meet your inductance requirements

      - Multiple cuts

Capacity of automatic winding:

      - OD <= 30mm: 20k pcs/day;

      - 30mm < OD <= 50mm: 6k pcs/day;

      - 50mm < OD <= 100mm: 2k pcs/day;

      - 100mm < OD <= 250mm: 1k pcs/day;

      - OD > 250mm: 500 pcs/day.

Technical

      Toroidal core weight calculation formula

      Weight per core = π/4*7.65*Sf*H*(OD+ID)*(OD-ID)*10-6(Kgs)

      In which,

      H = Strip width;

      ID = Inside diameter;

      OD = Outside diameter;

      Sf = stacking factor, 0.05mm material: 0.88 ~ 0.90;

                                       0.08mm material: 0.89 ~ 0.91;

                                       0.10mm material: 0.90 ~ 0.92;

                                       0.18mm material: 0.94 ~ 0.95;

                                       0.23mm material: 0.95 ~ 0.96;

                                       0.27mm material: 0.96 ~ 0.97;

                                       0.30mm material: 0.96 ~ 0.97;

Performance guaranteed

Toroidal core without varnish guarantees following standard performance:

Performance degradation

      The core loss of toroidal core will increase when they are impregnated with varnish or epoxy coated. Here below is the guide information for reference:

      - Normal condition varnish: +10%

      - Vacuum impregnation under pressure: +20%

      - Epoxy coated:                      +35%

Standards

      The cores can be produced according to IEC60635, other country standards and also customized requirements.

Quality control

      - On magnetic and mechanical qualityof silicon steel;

      - On physical dimension control of wound cores;

      - On annealing process;

      - On magnetic and dimensional values of finished cores;

      - On packaging.