This interactive demonstration allows you to observe the operation paramaters of the 3 basic types of UPS.
There is offline, or standby types, where the UPS kicks in when the mains supply goes out of limits. In between times, what ever comes in, goes through to your load. This type is officially designated “VFD”, standing for “Voltage & Frequency Dependent”. Most offline UPS have square wave inverters, which produce a power waveform that is unlike your normal mains supply but is a low cost way of delivering power. Most computers can handle this type of waveform, but some power supplies incorporating power factor correction, can have a real issue with this type of waveform.
The next type of technology is “line interactive”, in which the incoming power is either boosted or bucked when it becomes too low or too high. This is useful for facilities which are subject to voltage dips or swells, as the UPS will not needlessly drop onto battery power. These are termed “VI”, meaning “Voltage Independent”. Lower cost Line Interactive UPS will have a square wave inverter, identical to offline types, but higher specification products will have a sine wave inverter, making them suitable for practically all applications. The standards differentiate these two types by adding “S” for sine wave and “X” for non-sine wave, resulting in two categories of line interactive units termed “VIS” and “VIX”. The “sine wave line interactive” UPS, or VIS UPS are increasingly becoming less popular due to advances with online technology, which offers superior performance at an increasingly comparable cost, smaller size and lesser weight. However VIX products, provide low cost and relatively good levels of power protection for certain applications.
Online Double Conversion technology is widely considered to provide the best levels of power protection. The incoming power is converted from AC to DC, and then this DC is converted to AC, hence the term “double conversion”. This type of technology is officially referred to as “VFI”, meaning “Voltage & Frequency Independent”. The output voltage level is fixed with online technology and doesn’t vary at all. The input voltage “window” is also a lot wider than can be achieved with line interactive technology. The main drawback with online UPS systems is the excessive amount of audible noise, however the Power Inspired range of AC Power ReGenerators are designed to overcome this drawback providing the benefits of online double conversion UPS technology without the noise.
Adjust the input voltage by moving the Input Slider up & down. Note the amplitude in the display and also the digital read out.
See how the different technologies respond to increasing higher or lower voltages.
Adjust the incoming power quality by moving the “Harmonics” Slider left (best) and right (worst). Observe how each UPS type responds to harmonic distortion.
Load Health is reported as temperature and blood pressure. Supply voltage affects the load temperature, and power quality effects the blood pressure. Voltage (body temperature) may be good, but poor power quality puts the load at risk of heart attack.
Note that there is always a break in power when standby or line interactive units switch from mains power to battery derived power. This duration however is usually short and unnoticed by the load. Online Double Conversion is the only technology to have no break at all.
