1. VA RATING :

The UPS VA Rating you require will depend on the load current of the equipment you intend plugging into the UPS.

To calculate the VA Rating : multiply the Amps of the equipment (normally indicated on a lable on the rear of the equipment or in the technical manual or ask the supplier) you will use with the mains voltage you require and divide by the Power Factor (PF) of the equipment.

2. SIZING A UPS SYSTEM :

For example :

Computer equipment requires : 2 Amps (current)
Mains voltage used : 230VAC (AC voltage)
Power factor of computer equipment : 0.6 (typical for computer equipment)

2A x 230V = 460W / 0.6 PF = 766 VA

You will require a 800VA but to cater for your future expansions and to not stress the UPS by running on 100% load all the time, you always add 20-25% capacity. Therefore a 1000VA UPS (1KVA) should be used in this case.

When choosing a UPS system it is a good idea to also plan ahead to cater for expansion so that your investment in a UPS does not outgrow your future needs.

Please contact us if you need any assistance. We will gladly calculate the system for you if you provide all the relevant details.

3. BACKUP TIME :

The backup time is proportional to the load that is connected to the UPS. The more the load, the less the backup time. You can have backup time as little as 5 minutes which will enable you to shutdown the equipment connected to the UPS before the power fails; or many hours of backup time so you can keep your equipment running until mains power returns.

Longer backup time and higher protection levels cost more than short backup times and lower protection levels.

A UPS system is often used to provide uninterrupted power after mains fail until a generator starts up.

The level of protection you need will determine which of the following topologies is most suited to your needs.The main UPS topologies are :

A. OFFLINE UPS / SQUAREWAVE UPS / MODIFIED SINEWAVE UPS / STANDBY UPS

B. LINE INTERACTIVE STEPPED SQUAREWAVE / MODIFIED SINEWAVE UPS

C. LINE INTERACTIVE PURE SINEWAVE UPS

D. SINGLE CONVERSION TRIPORT CVT BASED SINEWAVE UPS - sometimes misrepresented as a Double Conversion Online system

E. DOUBLE CONVERSION ONLINE SINEWAVE UPS

In our very developed electronic environment where computers and communiction systems are vital for companies to function, it is very important that some form of power / lightning protection device be installed. We recommend you look at purchasing the best power / lightning protection equipment you can afford if your company is dependent on its computer and communication systems.

Your computer is running at standard mains via a small limited AC Filter under normal circumstances (some systems do not have filters at all). After a power failure this type of UPS system switches, via a small relay, over to a simple inverter to provide power to allow you to save your open files and shutdown your computer.

The backup time is normally short and will depend on the VA rating (see definition above) of the UPS and the amount of power your equipment draws from it. This type of UPS will give you very limited or no protection against power surges, spikes and sags. Typical backup time = 5 - 10 Minutes maximum. The backup time cannot be extended.

This type of UPS System is aimed at the SOHO & small business market and is mainly used when you have repeated, short power failures but a reasonably good mains supply. This type of UPS system is not recommended for critical applications or areas where there is bad or high fluctuating mains supply.

Cost : Very Low

Power Level : from 300VA to 600VA

Protection level : Approximately 0 - 10%

Your computer is running at standard mains via a small AC Filter under normal circumstances. After a power failure this type of UPS system switches, via a small relay, over to a simple inverter to provide power to allow you to save your open files and shutdown your computer. The system also normally includes a limited AVR (Automatic voltage regulator) which controls incoming mains fluctuations to a small degree.

The backup time is normally short and will depend on the VA rating (see definition above) of the UPS and the amount of power your equipment draws from it. This type of UPS will give you very limited protection against power surges, spikes and sags. Typical backup time = 5 - 10 Minutes maximum. The backup time cannot be extended. Our range is intelligent (RS232) but the automatic shutdown software and serial cable are not supplied as this is seldom required.

This type of UPS System is aimed at the SOHO & small business market and is mainly used when you often experience short power failures but a have a reasonably good mains supply. This type of UPS system is not recommended for critical applications.

Cost : Low

Power Level : from 300VA to 1200VA

Protection level : Approximately 0 - 20%

This type of UPS system will provide backup to enable you to save your work and shutdown your computer after a power failure and is also designed to regulate the output voltage and prevent, to a large degree, any spike, sags and blackouts from reaching your sensitive equipment (ranging from computers and telecommunications systems to computerised instruments).

Once again, the backup time will depend on the VA rating of the UPS (see VA rating definition above) and the amount of power your equipment draws from it. Typical backup time = 5 - 10 Minutes. With the relevant model, the backup time can be extended to several hours. Our range is intelligent (RS232) and comes with automatic shutdown software and serial cable.

Recommended for semi-critical applications and small to medium sized businesses. Only recommended for semi-critical applications if the UPS output is pure sinewave (as line interactive UPS systems are also available in stepped squarewave or modified sinewave).

Cost : Medium

Power Level : from 700VA to 3200VA

Protection level : Approximately 20 - 60%

This type of UPS system will provide protection and backup on power failure for some applications. Your computer system is always running via a constant voltage transformer which basically regulates the output voltage and also filters, to a large degree, spikes, sags, etc.

The single conversion and sinewave output provides a reasonable sinewave and in most cases, adequate protection for computers and any some other load. It is sometimes less efficient and older technology.

Typical backup time = 5 - 10 Minutes. This unit can be intelligent (RS232) and sometimes automatic shutdown software is available

This type of UPS System is aimed standard computer equipment where total protection is not necessary.

Cost : Medium high

Power Level : from 1KVA to 10KVA

Protection level : 60-80%

This type of UPS system will provide total protection and backup on power failure for critical applications. Your computer system is always running on electronically produced power and it is not directly connected to the utility supply. The double conversion, double isolation and the pure sinewave form output ensure the cleanest, most compatible AC output for computers and any other critical load.

Typical backup time = 5 - 10 Minutes. Plug-in external battery packs are available to extend the backup time to several hours. This unit is intelligent (RS232) and comes with automatic shutdown software and serial cable.

This type of UPS System is aimed at the professional, medical/industrial and upper business market and is recommended when you have a very dirty, noisy & unreliable mains supply. It is also recommended for all critical Computer and medical applications. This type of system has the highest protection level available.

Cost : High

Power Level : from 700VA to 100KVA (or several MVA with imported systems which can be paralleled)

Protection level : 100%