A UPS, or uninterruptible power supply, are devices that provide a way for computers to carry on running for a while after the main power source has been lost. UPS devices also offer protection from a power surge.
The UPS devices, provided by companies like Source UPS, have a battery that will “kick in” as soon as the device detects power loss from the main source. When the end-user is currently working on a computer the UPS will notify the user of the loss of power, which provides them with the time they need to save data and what they are currently working on, and to close the computer down before the battery on the UPS runs out.
UPS devices also protect the computer from a power surge. Once the power has run out, data in the Random Access Memory (RAM) on the computer will be erased. When a power surge does occur, the UPS will intercept the surge which will stop it from damaging the computer.
UPS in Data Centres
All UPS devices will convert incoming AC to DC through the rectifier and then convert this back using an inverter. Flywheels, or batteries, store energy that is then used during utility failure. The bypass-circuit routes the power around an inverter and rectifier, running the IT load on generator power or incoming utility.
Generators, unlike UPS devices, fail to keep a device continuously running once the primary device loses power. However, the generators will maintain power for longer periods when compared to a UPS. The UPS systems are unable to provide power for a long time due to the batteries that are used to power them.
The UPS systems are also called standby, line-interactive, and double-conversion designs, the terms are frequently used inconsistently, while manufacturers implement these devices differently. All of these systems does allow for any of the 3 modes. The IEC (Electro-Technical Commission) has adopted terminology that is more technically descriptive in the IEC Std. 62040.
UPS Types and their Core Features
VFI (Voltage and Frequency Independent) UPS systems are typically called double or dual conversion as incoming AC is rectified into DC to make sure the batteries remain charged and to drive an inverter. The inverter in these systems re-creates a steady AC power in order to run IT equipment.
When the power fails, the battery will drive an inverter, that carries on running the IT load. When the power comes back on, either from a generator or the utility, the rectifier will deliver DC (direct current) to an inverter which will recharge the batteries simultaneously. The inverter operates full time. The utility input will be isolated completely from the utility output, while the bypass is used only for the purposes of maintenance safety. The bypass function is also used when there is an internal electronic failure.
Since there are no power breaks delivered to IT equipment, VFI (vacuum fault interrupter) is typically regarded as a type of UPS that is highly robust. Many of the systems will synchronize output frequencies with input frequencies, yet this is not always necessary, which means they still qualify as “frequency independent”.
The Pros and Cons of UPS
- No delays occur when the switch occurs from the main source to a UPS.
- Has the ability to support instruments that are critical in a better way when compared to a generator.
- UPS systems come in different sizes and types, and choosing one will depend on the power needed to supply specific devices.
- UPS systems are silent.
- Maintenance for UPS systems is a lot cheaper when compared to a generator.
- UPS systems cannot be used to operate heavy appliances as they operate off batteries.
- If the batteries used are substandard, the batteries will most likely need to be replaced more frequently.
- UPS systems may require professional installation.