Explanation of power terms related to UPS power supply (2)

Explanation of power terms related to UPS power supply (2)

Current Crest Factor (CF): The current crest factor refers to the ratio of the peak value to the rms value of the current cycle waveform. Since the energy absorbed by the computer load when it receives a sine wave voltage is not necessarily a sine wave, it will generate a higher peak current (between 2.4-2.6 times the current), so the design of the UPS should provide a CF value greater than 3. Current Meet computerized load applications.

Battery series/parallel: Multiple batteries with the same performance and capacity are connected in series according to a certain polarity to form a battery pack; multiple batteries or battery packs with the same voltage are connected at the ends of the same polarity to form a parallel output. for parallel connection.

Battery management system: used to protect UPS battery, prolong battery life and achieve high-quality charging effect. The battery management system includes software and hardware, including battery characteristic judgment, automatic charging mode selection, automatic alarm, special battery charging, etc.

Short circuit: refers to the direct connection of the DC positive and negative poles of the circuit or the AC live wire to the neutral wire and the ground wire. A short circuit can cause severe overload and generate a large short-circuit current that may burn the equipment or even cause a fire.

Ground wire, neutral wire and live wire: The ground is a good conductor, and the ground wire is short-circuited to the ground through the deeply buried electrode. The transmission of mains power is three-phase, with a neutral wire. When the three-phase balance is in place, the current of the neutral wire is zero, commonly known as "neutral wire". Another characteristic of the neutral wire is that it is in the system with the ground wire. The electrical input is shorted and the voltage difference is close to zero. The voltage of the three-phase wire and the neutral wire of the three-phase electricity is 220, which can cause electric shock, commonly known as "fire wire". There are strict standards for the installation and layout of circuits. In practice, proper assembly of ground, neutral, and live wires according to standards is very important for safety.

Electromagnetic Compatibility (EMC): A general term for equipment radiated and conducted waves.

Rated safety low voltage (SafetyExtraLowVoltageSELV): IEC regulations specify the limits of rated safety voltage for electrical equipment. In this regulation, it is stipulated that the high voltage or AC power part must be carefully isolated, otherwise it should be difficult for personnel to access to ensure personnel safety.

Crest Factor (CF): The so-called CF refers to the ratio of the peak value to the effective value of the periodic waveform. Since the sine wave voltage received by the computer load will generate CF (the current is between 2.4 and 2.6 times), the UPS design often needs to be able to provide a specification with a CF value of 3 to meet the application of the computer load.

Discharge tube: It is a high-voltage protection element used at the input end of the equipment. If the voltage at both ends is higher than the protection specification value, a short circuit will occur internally to absorb the input overvoltage.

Radiated Wave (EMR): This is a space electromagnetic wave that is present in communications equipment or computer-operated equipment. Some wave sources are radiated into space through the device's wiring or *electronic antennas. In some cases, it may be due to excessive amplitude waves, resulting in interruption of electrical transmission or malfunction of computer-operated equipment.

Float and Equalization: Both float and equalization are battery charging modes.

  1. The working principle of float charging: when the battery is fully charged, the charger will not stop charging, and will still provide a constant float voltage and a small float current to power the battery, because once the charger stops charging, the battery will will stop charging. The power will be released naturally, so the floating charge method is used to balance this natural discharge, and the small UPS generally adopts the floating charge method.

  2. The working principle of equalizing charge: the battery is charged with constant current and timing, and the charging speed is faster. A charging mode often used by professional maintenance personnel when maintaining batteries, this mode also helps activate the battery's chemistry.

Note: The smart charger has the function of automatically switching between floating charge and equalization according to the working state of the battery, which can give full play to the advantages of floating charge and equalization, realize fast charging and prolong battery life.

Load Regulation: The output voltage regulation accuracy when the load changes.

Overload: T