ZTELEC Insulation Materials

FR-4 sheet is a double-sided copper-clad PCB sheet made of epoxy resin + glass cloth + copper foil. If you highlight the performance of CCL products, there are three important indicators: dielectric constant, dielectric loss, TG value.
The commonly used FR4 copper clad laminate has a dielectric constant of 4.2-4.7 relative to air. This dielectric constant varies with temperature and can vary up to 20% over a temperature range of 0-70 degrees. A change in the dielectric constant results in a 10% change in line delay. The higher the temperature, the greater the delay. The dielectric constant also varies with the signal frequency. The higher the frequency, the smaller the dielectric constant. The typical dielectric constant of the design is 4.4. read more

The distribution transformer is used as an electrical device and its current value is also an important parameter. So today ZTELEC teaches you how to calculate the high voltage and low voltage side current of the transformer.
1. Fast estimation method
Oil-immersed distribution transformer capacity / 100, take an integral multiple, then * 5.5 = high-side current value, if it is * 144, is the low-side current value
For example, a transformer with a capacity of 1000KVA, /100 takes an integral multiple of 10, then the high-side current value is 10*5.5=55A, and the low-voltage side current value is 10*144=1440A.
2, linear coefficient method
Remember the high and low voltage side current values ​​of a dry distribution transformer with a common capacity. Other capacity can be linearly derived.
For example, a transformer with a capacity of 1000KVA, the calculated value of the high-side current is 57.73A, and the calculated value of the low-side current is 1443.42A;
Then remember this data, other capacity can be derived from this
For example, a 1600KVA distribution transformer, the high-side current is (1600/1000) * 57.73 = 92.368A, the low-voltage side current is (1600 / 1000) * 14443.42 = 2309.427A.
3. Rough estimation method
High side current = transformer capacity / 20, low side current = transformer capacity * 2
For example, 1000KVA transformer, high-voltage side current = 1000/20 = 50A, low-voltage side current = 1000 * 2 = 2000A, this method is too rough, generally used by the design institute for switching element type selection, cable selection and calibration Common methods used in the test
4, formula calculation method
Formula: I=S/1.732/U
I–current, unit A; S–transformer capacity, unit kVA; U–voltage, unit kV read more