Welcome to a regular feature on the Powertecnique blog. Every Monday we talk you through an A-Z of the terms you hear associated with critical power supplies. In this latest post we’ve reached the letter U. Rather obviously; U is for UPS (Uninterruptible Power Supply).
Over the past 20 weeks we’ve been taking you through some terms that you hear associated with critical power. Most of these terms can be applied to both generators and UPS, but today we’re asking one of the most basic questions associated with critical power; what is a UPS and why would I want one?
A UPS does almost exactly what it says on the tin. It provides an uninterruptible source of power to ensure that when your main source of power goes down, all electrical systems keep running. This is particularly important in computer rooms and data intensive organisations where a spontaneous loss of power would incur enormous loss of earnings.
Speaking in hugely broad terms, there are basically two ways of storing power in a UPS so as to ensure that it keeps your business running during a power cut. One is batteries and the other is a flywheel.
Battery based UPS are the most flexible of these approaches as you can increase your autonomy time simply by increasing the number of strings of batteries (see ‘A is for Autonomy’). This means that, given enough space and budget, you could have a relatively high autonomy time of anything up to or even over an hour . Flywheel UPS on the other hand tend to be much lower maintenance and have a wider temperature operating window, but offer significantly lower autonomy times; typically less than a minute.
In a typical standby power system, your UPS acts as a bridge to provide short term backup power whilst your diesel generator starts up to prepare to take the load. Diesel generators take time to start-up and get ready to take the full electrical load. This is why organisations that are slightly more risk averse may prefer a tried and tested battery based UPS over a relatively new flywheel system. The longer autonomy time gives the generator more time to get up to speed.
This isn’t to say that flywheel based UPS are without benefits. They have lower maintenance requirements and don’t require the same level of care to be taken as battery based systems in order to prolong their life.
Protecting from power failures though are only part of the job carried out by UPS. They also help to condition the power being delivered to your electrical load so as to ensure that any spikes, surges or sags don’t damage the equipment that you are protecting.
Performing the jobs that they do make UPS a critical piece of equipment for virtually all modern organisations.
Hopefully this has given you a bit more of an idea as to what a UPS does and the differences between battery based and flywheel UPS. If there’s a topic you’d like covered in our A-Z why not get in touch via twitter. Our handle is @powertecnique.