Full load operating time
UPS continuous operation time from a fully charged battery when connected to a load with a power equal to the UPS output power (maximum or effective, depending on the type of load, see the relevant paragraphs for details). For a UPS designed to work with a home or office PC, a time of about 10-15 minutes is considered sufficient, this is enough to save data and complete work. To power servers, it is worth using devices with an operating time
of 20 minutes or more.
Half load operating time
UPS continuous operation time from a fully charged battery when connected to a load with a power equal to half the output power of the UPS (maximum or effective, depending on the type of load, see below for details). The operating time with such a load is much longer than for a full load, and even in the simplest models it can reach 20-30 minutes.
Input voltage range
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.
Bypass (direct connection)
Bypass(by-pass) means such a mode of operation of the UPS, in which power is supplied to the load directly from an external source — the mains, diesel generator, etc. — practically without processing in the UPS itself. This mode can be activated either automatically or manually.
— The automatic bypass is a kind of safety measure. It turns on when the UPS in normal mode cannot supply power to the load — for example, when the UPS is overloaded due to a sharp increase in the power consumption of the load.
— Manual bypass allows you to enable this mode at the request of the user, regardless of the operating parameters. This may be necessary, for example, to hot-swap a battery (see below for details) or to start equipment that has a starting capacity greater than that of the UPS. Technically, it can also play the role of a security measure, but automatic systems are more reliable in this sense.
Some UPSs provide both options for enabling the bypass.
Output voltage accuracy
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.
Cold start
The ability to turn on the uninterruptible power supply in the "cold start" mode.
A
cold start is a turn-on mode in which there is no external power, and the load connected to the UPS is powered immediately from the uninterruptible battery (which, of course, must be charged). This mode is especially useful in emergency cases — for example, if you urgently need to print a document, but there is no light.
Battery hot swap
The ability to replace the battery directly during the operation of the UPS, without disconnecting it from the network and the load. To do this, the device is switched to bypass mode (see "Bypass (direct connection)") or, if there are more than one battery, it switches to another battery. The
hot-swappable battery is useful, for example, in the event of a battery failure, or to replace dead batteries with fresh ones if there is no time to charge.
Fuse
Fuses are used to protect the UPS from a critical increase in current strength: at the right time, they open the circuit, preventing unpleasant consequences. Today, these types of fuses are used.
— Melting. At a critical current strength, the conductive element in such a fuse melts and opens the circuit. The fusible protection is disposable, after operation such a fuse must be replaced.
— Automatic. Such a fuse has a sensor that monitors the current strength and opens the contacts at the right time. Its main difference from fusible is reusability: after operation, the circuit can be closed again with literally one press of the button on the fuse.
Surge protection
The maximum energy of an electrical impulse in the mains that the UPS is able to compensate. Short pulses with high energy from time to time can occur in almost all networks — for example, due to interference from powerful radiation sources or due to poor-quality operation of lightning protection on power lines; for unprotected devices, such fluctuations can be very harmful. The greater the amount of absorbed energy, the higher, respectively, the level
of impulse protectionprovided by the UPS.
