Knows the capacity, resistance, capacitive reactance and torque of electrical equipment - News - Global IC Trade Starts Here Free

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AVX TPSE226M035R0125 low-impedance tantalum capacitor, 22µF

Probe current and voltage pin, 420x4450, head diameter 5.0, overcurrent and voltage pin

Tantalum capacitor

1. Understand the nature and installed capacity of the plant, and calculate the total variable capacity.

The factory has a variable kilovolt-ampere (kVA) and an estimated kilowatt-hour (kWh). For metallurgical, textile, and cement plants, the kilowatts are approximately equal to kVA. In mechanical manufacturing and processing plants, it's about half of the kilowatts. In light industrial and chemical plants, it's usually around seven thousand kVA.

2. Know the nominal capacity of the shunt capacitor and calculate its capacitance.

For shunt capacitors, the relationship between kVAr and microfarads is calculated by dividing the reactive power by the square of the voltage, multiplied by 3.14 for a three-phase system.

Commonly used shunt capacitors: if the rated voltage is 203 V, then 60 µF per kVAr; if the rated voltage is 400 V, 20 µF per kVAr; if the rated voltage is 6.3 kV, 8 µF per kVAr; and if the rated voltage is 10.5 kV, 3 µF per kVAr.

3. Determine the distribution transformer capacity and calculate the maximum motor capacity that can be directly started.

For a three-phase asynchronous motor, the full-voltage starting power in kW is calculated as: Transformer capacity (kVA) × 0.9.

4. Understand the current transformer capacity and calculate its secondary rated impedance.

For common current transformers: if the secondary rated current is 1 A, the impedance is in VA; if it's 5 A, the impedance is calculated as (VA × 4) / 100.

5. Knowing the 380V single-phase AC welding machine, calculate the transformer capacity, cable cross-section, fuse rating, and load switch capacity.

A 380V welding machine requires a two-core power cable. The aluminum cross-section is 80% of the copper cross-section. The fuse rating is three times the capacity, and the load switch must match the fuse rating.

6. Knowing the incandescent bulb capacity, calculate its thermal resistance.

The thermal resistance of a bulb is calculated by dividing the wattage by the square of the voltage.

For standard bulbs: at 220V, 48W is removed per 1000Ω; at 127V, 1600Ω is removed per 1000W; at 101V, 1200Ω is removed per 1000W; and at 36V, 1300Ω is removed per 1000W.

7. Knowing the capacitor capacity in a power frequency AC circuit, calculate its capacitive reactance.

The capacitive reactance of a power frequency capacitor is calculated by dividing 3183 by the capacitance in microfarads (µF).

8. Knowing the load resistance in a power frequency rectifier circuit, calculate the capacitance of the filter capacitor.

In a power frequency rectifier circuit, the filter capacitor value is calculated as 1000 divided by the load resistance (in ohms).

9. Knowing the motor capacity and number of poles, calculate the rated torque.

The rated torque of a motor is calculated as (10 × number of poles) × (power in kW) / 6. The unit is Newton meters (N·m).