UPS Basic Knowledge Summary- UPS common terms

Time of issue:2023-03-21


UPS common terms:

1. VA & W: UPS capacity unit, VA is apparent power, W is active power.


2. Power factor (PF): For a device, there are two different parameters: input power factor and output power factor. The absolute value of power factor is between 0 and 1. It is W (active power) and VA (apparent power) ratio. The higher the input power factor, the higher the utilization efficiency of the UPS for the grid. Considering from the output end, the higher the output power factor, the stronger the load capacity of the UPS. For example: the parameter of a UPS is: 3000VA/2400W, it can be known that the output power factor is 2400W/3000VA=0.8.


3. Crest factor (CF): refers to the ratio of the peak value of the periodic waveform to the effective value. Since the computer load receives a sine wave voltage, it will generate CF (2.4-2.6 times the current), therefore, the UPS design often needs to provide a specification with a CF value of 3 to meet the application of the computer load.


4. Input voltage range: The range within which the UPS allows the city power to vary. The larger the range, the better the adaptability of the UPS.


5. Distortion: Distortion is divided into waveform distortion, voltage distortion, etc. Whether it is volume distortion, it is calculated as a percentage. The size of the distortion is related to harmonics, voltage, current and power factor.


6. Efficiency (EFFICIENCY): It is the ratio of the output wattage to the input wattage. If the number is closer to 1, it shows that the efficiency is better. In terms of online UPS, the general efficiency is about 85%~90%. , that is, the input is 1000W, the output is about 850W~900W, and the UPS itself consumes 100W~150W of power.


7. Reliability (MTBF): A parameter used to describe the average length of time the equipment can work normally. The larger the MTBF, the longer the life of the equipment.


8. High-frequency unit: Utilizing high-frequency switching technology, the UPS that uses high-frequency switching elements to replace the bulky power frequency transformer in the rectifier and inverter is commonly known as a high-frequency unit. The high-frequency unit is small in size and high in efficiency.


9. Power frequency machine: UPS that uses power frequency transformers as rectifier and inverter components is commonly known as power frequency machine. The main features are stable and reliable main power components, strong overload capacity and impact resistance.


10. Reactive power: the unit is VA, it is not absorbed by the load, so it is called reactive power, which constitutes another part of apparent power. Reducing reactive power is conducive to improving the utilization rate of the power grid.


11. Active power: the unit is W, which is the part of the energy that the load really absorbs and converts, and it constitutes a part of the apparent power.