When considering the capacity issue during the selection of UPS power supply for the computer room, relevant factors that determine the capacity size should be listed, and the specific relationship between each factor and capacity should be explained. The main factors to consider when determining the size of UPS capacity are: actual load capacity, type of load, capacity utilization rate, environmental conditions, type and actual load capacity of UPS, potential expansion needs, etc.

A、 In practical applications, the following should be considered:

1. Actual load capacity：

This is the most fundamental factor determining the capacity of UPS power supply. The output capacity of UPS power supply must meet or exceed the load requirements to ensure normal power supply. In practical applications, it is necessary to consider whether UPS power supply adopts centralized power supply or distributed power supply. The total load capacity using centralized power supply should be the cumulative power of all UPS powered loads in the computer room. The use of distributed power supply is determined based on the different loads carried by each UPS.

The load capacity of electrical equipment is usually referred to as apparent power, expressed in S and measured in VA. The apparent power includes active power P (measured in W) and reactive power Q (measured in Var), with the relationship of S2=P2+Q2. Here, we refer to the ratio of active power to apparent power as the power factor. The power factor of a pure resistive load is 1, while the power factor of a capacitive load is generally between 0.6 and 0.7.

2. Type of load：

As mentioned above, the ratio of active power to reactive power varies for different types of loads, but UPS needs to provide sufficient active and reactive power to the load simultaneously, so the actual output capacity is limited by the type of load. For computer loads, UPS can basically output the rated power. If the load is resistive or inductive, the output power of UPS may decrease and the UPS capacity needs to be increased. For example, a 1KVA UPS with a power factor of 0.7 can carry up to 1KVA with a computer load, up to 700VA with a purely resistive load (at which point the active power is 700W), and even lower with an inductive load. Therefore, when calculating load capacity, resistive and inductive loads that represent power in W value should be converted to VA value. The general calculation method is: VA value of resistive load=W value ÷ 0.7; The VA value of inductive load=W value ÷ 0.3.

3. UPS power capacity utilization rate：

Due to the non-linear loads of various switch power supplies and printer loads in computer room equipment, these loads have high impact currents. If the power supply UPS capacity is too small and operates under heavy loads for a long time, waveform distortion is likely to occur, and the output final power device is prone to overcurrent. In addition, the heat generated by heavy loads is significantly detrimental to system reliability. For high-power UPS, it is generally recommended to control the capacity utilization rate between 0.6 and 0.8.

Of course, the UPS capacity should not be too large. Although carrying a small load on UPS is beneficial for reliability, excessive light load operation not only wastes investment, but also leads to low current discharge of the battery during long-term power outages, which can easily cause deep discharge and damage.

4. Environmental conditions：

The working temperature of UPS should generally be controlled within the range of 0-40 ℃. If the temperature is too high and the ventilation conditions are poor, it is not conducive to heat dissipation and should be downgraded for use. In addition, altitude also has an impact. For every 1000m increase in altitude above 1000m, UPS should be downgraded by 5% for use.

5. Types and actual load capacity of UPS：

The carrying capacity of different types of UPS varies. The output capability of power frequency machines is good, while the actual load capacity of high-frequency machines is only 0.9 times that of power frequency machines.

Other manufacturers' products may have actual load capacity lower than the nominal capacity, which is a reliability issue for the product. Users have to consider this factor when applying it. The products produced by CNKHZ company have undergone strict testing and quality control, and users can rest assured.

6. Potential expansion needs of the equipment：

When configuring UPS capacity, consideration should be given to the future expansion needs of the equipment, leaving a certain margin so that if the load increases in the future, UPS will not be purchased again. In addition, it is recommended to choose models with parallel operation capabilities, and if necessary, the output capacity can be doubled through UPS parallel operation. At the same time, when configuring the input/output distribution cabinet of UPS, a certain margin should be left for cables and air switches to facilitate future expansion.