1. Capacity safety factor
AC stabilized power supply is based on the output apparent power (kVA) as the nominal rated capacity, and in general, the load is not purely resistive, that is, the power factor COS¢≠1, the actual active power that the regulator can output kW= Capacity (kVA)×COS¢. Therefore, in the actual selection, the regulated power supply should be reasonably selected according to the specific conditions of the electrical equipment, such as the rated power, power factor and load type, and its output power should be left with a proper margin, especially for the impact load selection. To be larger, see the following table for the specific selection safety factor
Load nature Equipment type Safety factor Select stabilized power supply capacity
Pure resistive load Incandescent lamp, resistance wire, electric furnace and other equipment 1.25~1.5 1.25~1.5 times the total load power
inductive and capacitive load fluorescent lamps, fans, motors, water pumps, air conditioners, computers, refrigerators, etc. 2 ~ 3 ≥2~3 times the total load power
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In the environment of large inductive and capacitive loads (such as motors, computers), the starting current of the load should be considered when selecting the type is particularly large (up to 5-8 times the rated current), so the capacity of the voltage stabilizer should be the load power 2.5~3 times.
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For example, one three-phase motor 2.2kW and one 5.5 kW. When a voltage stabilizer is selected, the capacity is ≥(2.2kW+5.5 kW)×2.5=19.25 kVA, that is, at least three-phase SJW-20 kVA and above products must be selected. Depressor.
2, output capacity curve of uncompensated regulated power supply
Auto-coupling regulator (single-phase 0.5kVA~3kVA, 10k horizontal and below, three-phase 9kVA and below) when the input phase voltage is lower than 198V, the output capacity begins to drop; when the input phase voltage is equal to 160V, it drops to 50% of the rated capacity of the regulator. Therefore, special attention should be paid to reducing the load and derating at the low end of the power supply voltage to avoid overloading the voltage stabilizer and burning;