What are toroidal cores?

Toroidal cores are wound from grain oriented silicon steel, mostly into a circular shape. 

Production scope of toroidal cores:

- Outer diameter of the core d1 = 15 - 1000 mm
- Inner diameter of the core d2 = 10 - 950 mm
- Core height h = 5 - 100 mm

We deliver toroidal cores in various material grades:

- Thickness 0,18, 0,23, 0,27, 0,30, 0,35mm, as M165-35S, M150-30S, M140-27S, M110-27S,
- HIB grades, thickness 0,20, 0,23, 0,27 or 0,30mm, as M085-23P, M090-27P, M095-27P, M100-23P, M103-27P, M105-30P, H111-30P
- Material for higher frequency 400Hz - 20kHz in thickness 0,10mm - label GT100,
- "Special material" for current and voltage transformer with the highest class of precision

Using toroidal cores:

TToroidal cores made of high permeability materials are used where high sensitivity of induced voltage in the secondary winding to changes of magnetising current is required and where minimal distortion of the transmitted signal is required. These cores are also used for chokes with a high inductance. Very low losses during magnetizing by alternating current is often used as well.

Toroidal cores for high frequencies are used where magnetizing current of the core has a medium or high frequency, usually of  ranges of tens up to hundreds of kHz. At higher frequencies the permeability of material is very low, and its losses increase enormously. As an example of such use can serve cores for antijamming chokes for circuits with thyristors and triacs, high frequency and switching powers or telecommunication transformers.

We can produce and deliver them as

- ​Not impregnated
- Lightly impregnated with polyurethan varnish
- Fully impregnated wit epoxypolyurethan enamal, Type FIX
- Cores with cutted edges (bevelled) in angle of 45° or radius

Impregnation of toroidal cores with epoxy

It is used as a protection for toroidal cores, provides strength to the core, secures them against mechanical damage and enables simpler post-processing.

Protection of toroidal cores by comaxitization

Comaxiting is the electrostatic application of EPOXY - POLYESTER powder No. 2310 and subsequent firing at 180°C. For toroidal cores that are used by the electrical manufacturer of the machine, the copper wire is wound directly without bandaging, the 2nd layer is also applied in order to achieve high-quality insulation in the required thickness of 0.3 - 0.4 mm by double comaxing.

We have toroid meters

The following properties are evaluated:

- Intensity of the magnetic field Heff (A/m)
- Magnetic induction Bmax. (T)
- Core losses P (W)
- Amplitude permeability etc.

NANOCRYSTALLINE CORES

Nanocrystalline magnetic cores are made of nanocrystalline steel with crystalline structure where the sizes of individual grains do not exceed 70 nm. The nanocrystallization process of the FeCuNbSiB material is performed in thermal T or thermomagnetic T+H field that provide the possibility of producing cores with different magnetic properties. The nanocrystalline steel tapes are the most modern soft magnetic materials with very low magnetic loss level. The material has also very low magnetostriction level and therefore it is very useful in low noise electrical applications working in devices at high frequencies. The nanocrystalline tapes are used for the construction of the following types of magnetic cores: wound cores, wound cut cores and also stacked and block cores. The cores protection is provided by plastics, resins or pressboard covers.