Comparison Luxeon UPS-500ZD 500 VA vs Logicpower LPY-B-PSW-800VA 800 VA

The time required to transfer the load from mains power to battery power. In standby and interactive UPSs (see Type), a short-term power failure occurs at this moment — accordingly, the shorter the time to switch to the battery, the more uniform the power supply is provided by the source during a power failure. Ideally, the switching time for the traditional 50 Hz AC frequency should be less than 5 ms (a quarter of one cycle of the sine wave). With inverter UPSs, the transfer time is, by definition, zero.

In this case, the input voltage range is implied, in which the UPS is able to supply a stable voltage to the load only due to its own regulators, without switching to the battery. For redundant UPSs (see "Type") this range is quite small, approximately 190 to 260 V; for interactive and especially inverter ones, it is much wider. Some UPS models allow you to manually set the input voltage range.

The maximum current drawn by the UPS. In fact, the current reaches its maximum value only when the UPS is operating from the mains with maximum load power and a completely discharged battery. However, when calculating the load on the power grid, this parameter should be taken into account.

The operating frequency of the alternating current supplied to the input of the UPS — or more precisely, the frequency range of this current in which the device can supply the required power to the load due to its own regulators, without using a battery. When this range is exceeded, the UPS switches to battery mode. The smallest input voltage range is reserved for standby UPSs (see "Type"), the largest for inverter UPSs.

The maximum output power supplied by the UPS, in other words, the highest apparent load power allowed for this model.

This indicator is measured in volt-amperes (the general meaning of this unit is the same as that of the watt, and different names are used to separate different types of power). The total power consumption of the load, implied in this case, is the sum of two powers — active and reactive. Active power is actually effective power (it is indicated in watts in the characteristics of electrical appliances). Reactive power is the power wasted by coils and capacitors in AC devices; with numerous coils and/or capacitors, this power can be a fairly significant part of the total energy consumption. Note that for simple tasks, you can use data on effective power (it is often given for UPS — see below); but for accurate electrical calculations it is worth using the full one.

The simplest selection rule for this indicator is: the maximum output power of the UPS in volt-amperes should be at least 1.7 times higher than the total load power in watts. There are also more detailed calculation formulas that take into account the characteristics of different types of load; they can be found in special sources. As for specific values, the most modest modern UPSs give out 700 – 1000 VA, or even less — this is enough to power a PC of average performance; and in the most "heavyweight" models, th...is figure can be 8 – 10 kVA and higher.

The effective output power of the UPS is, in fact, the maximum active power of the load that can be connected to the device.

Active power is consumed directly for the operation of the device; it is expressed in watts. In addition to it, most AC devices also consume reactive power, which is "wasted" (relatively speaking) is spent by coils and capacitors. Apparent power (denoted in volt-amperes) is precisely the sum of active and reactive power; it is this characteristic that should be used in accurate electrical calculations. See "Maximum output power" for details; here we note that when selecting a UPS for a relatively simple application, it is quite possible to use only effective power. This is at least easier than converting the watts claimed in the characteristics of the connected devices into full power volt-amps.

The most modest modern "uninterruptibles" give out less than 500 watts. 501 – 1000 W can be considered an average value, 1.1 – 2 kW is above average, and in the most powerful models this figure exceeds 2 kW and can reach very impressive values (up to 1000 kW or more in some industrial class UPS).

The ability to change the output voltage of the UPS at the request of the user. Electrical networks in different countries have different voltages: for example, in the post-Soviet space, the standard is 230 V, in European countries — 230 V. Small differences in appearance may not play a significant role, however, voltage mismatch can adversely affect the efficiency and durability of electrical appliances. Voltage regulation allows you to choose the optimal value, thus providing the best conditions for the operation of electronics.

This parameter characterizes the degree of difference between the AC voltage at the output of the UPS and the perfect voltage, the graph of which has the shape of a regular sinusoid. The perfect voltage is so named because it is the most uniform and creates the least unnecessary load on the connected devices. Thus, the distortion of the output voltage is one of the most important parameters that determine the quality of the power received by the load. A distortion level of 0% means that the UPS produces a perfect sine wave, up to 5% — slight sine wave distortion, up to 18% — strong distortion, from 18% to 40% — a trapezoidal signal, more than 40% — a square wave.

The protection functions provided in the design of the UPS.

— Short circuit protection. A short circuit is a sharp drop in load resistance to critically low values, due to which the current strength increases and the UPS experiences significant overloads that can disable the device and even cause a fire. It may be caused by a problem with the connected device, poor insulation, foreign objects, etc. In the event of such a situation, the short circuit protection system turns off the UPS, preventing unpleasant consequences.

— Overload protection. Overload in this case is the excess of the load power consumption over the output power of the UPS. Working in this mode can also lead to unpleasant consequences up to breakage and fire; to avoid this, a protection system is installed that turns off the UPS when an overload occurs.

— Overcharging protection of external battery. The overcharge protection function prevents the accumulation of excess energy in the battery, from which the UPS operates in autonomous mode. Overcharging is highly undesirable for any type of battery. It can lead to various unpleasant consequences - from deterioration in performance to overheating and fire of the battery. The automatic protective equipment on board the uninterruptible power supply turns off the power after the battery is fully charged. This prevents “extra” curre...nt from entering the battery, which could damage it. This system is convenient in that the battery can be left on charge for a long time without fear of overexerting it.

— Noise filtering. A system that suppresses high-frequency interference in an electrical network — these can be either single voltage surges when turning on and off powerful electrical appliances, or long-term interference from constant sources, such as electric motors. These interferences can adversely affect the operation of electronics connected to the network (up to visible failures); the noise filtering system avoids this. Such systems are quite simple, and therefore most modern UPSs are equipped with them.

— Data line protection. High-frequency interference protection system, similar to interference filtering (see above) — only used not in an electrical network, but in a telephone or wired computer (LAN) network. Such networks are also subject to interference from various sources of electromagnetic radiation, which can cause failures of equipment connected to them: PCs, printers, fax machines, etc. UPSs with this feature have at least two LAN standard connectors (input and output), into which appropriate network or telephone (with RJ-11 connectors compatible with LAN) cables are inserted.

— Emergency cut-off. This connector allows you to connect the UPS to an emergency power off system. Thus, in an emergency (for example, in the event of a fire), the entire room, including and with a power reserve, can be completely de-energized by pressing one button. Without this, the UPS would simply switch to battery when the power goes out and leave the equipment energized, which could lead to disastrous consequences.

— Sound alarm. A system that gives an audible signal in various important situations. It is most commonly used to signal a power outage and the UPS is transferring to battery power. Without a sound signal, this could not be noticed at all (the light is not always on in the room, it goes out when the network fails, the contact in the socket itself may disappear, etc.), which is fraught with a sudden shutdown of the equipment, data loss and breakdowns. Also, sound alarm can be used for other events — low battery, end of charge, bypass on / off, etc.