Questions - Zigma Technologies

What does a UPS battery life of 3, 5 or 10 years mean?

3,5 or 10 years when referring to a UPS battery is a general term used for high specification EUROBATT and IEC compliant lead-acid batteries with regard to their in-service life-expectancy when they are designed and built for use in Riello UPS systems. Batteries compliant with these standards guarantee the user peace of mind. Although the UPS backup batteries are generally more costly, they are of a much higher build quality, better performing, and have a longer design life than standard batteries.

How do I size a UPS correctly?

There are many things that affect the sizing of a UPS backup system. These include: · The accumulated overall inverter load to be connected. · The type of loads to be connected to the inverter. · The type of backup, i.e., a short duration of 5 to 30 minutes just to allow time to safely shut down the load when the power goes off, or long battery backup to carry the load through load shedding. · If the load is highly critical, then one may want to consider a parallel redundant UPS plant so that if one UPS should fail, the load will still be protected by the other parallel UPSs. It is very important to choose the right UPS technology for the load you wish to connect. Different technology UPS systems offer different levels of load support and protection – along with higher pricing as the technology gets better.

What is galvanic isolation of a UPS inverter?

Galvanic isolation is the use of a double-wound transformer, generally on the UPS output inverter, to isolate the load from the UPS battery power. Should an inverter short-circuit, there is a chance that the load will be subjected to high DC (battery) power, which will certainly damage any sensitive load connected to the inverter. The isolation transformer prevents the DC from doing this and acts like a one-way valve allowing only AC power through it. Galvanically isolated UPS systems, like the Riello MPT, MHT, and MHE ranges, are widely used when high-demanding power is required by the inverter load, such as mixed building loads, motors, air conditioners, medical imaging loads, and other industrial loads like plasma cutting machines, etc. The inverter output transformer makes the UPS far less susceptible to these harsh loads and is a more reliable solution and lower cost, long term, than a transformer-free UPS inverter.

What is harmonic filtering?

Harmonic filtering is necessary for large 3-phase UPS plants to limit the amount of "electrical noise" that the UPS rectifier generates back into the ESKOM power grid. This noise can be so bad that it will prevent a building's power factor correction equipment from working, which results in huge unnecessary electricity costs. This noise can penetrate other equipment connected to the building's supply and affect its operation; causing overheating of UPS supply cables and UPS supply distribution boards. Its effects cannot be seen with the eye, but they are nasty overall and easily avoided using a UPS with a total harmonic current distortion back into mains of less than 3%. In years gone by, this was achieved by using a 12 pulse UPS rectifier, but this has been replaced with a far more effective component, namely, an IGBT rectifier.

What does battery backup mean in a UPS?

Battery autonomy or battery backup in a Riello UPS system refers to the amount of time the load will continue to run even when the ESKOM supply goes off. The longer the battery backup to the UPS inverter, the higher the cost. Ideally, if one experiences frequent power failures every day or a few times a week, then the UPS should be used in conjunction with a generator so that the battery backup is only for a few short minutes while the generator starts, i.e., the UPS is only there to bridge the gap in power, not supply power for hours.

What is the point of using a UPS or uninterruptible power supply anyway?

An uninterruptible power supply, also known as a UPS system, is primarily aimed for use in protecting the sensitive IT/electronic and other connected inverter loads from the following: · Power failures · Brownouts or short loss in power · High spikes, or transients, caused by lightning and the switching of high voltage switches on the ESKOM grid · General bad power as experienced in areas near to or in heavy industry, such as arc furnaces, etc. The UPS acts as a filter and prevents the connected inverter load from "seeing" the bad power supply while using the battery backup power to carry those situations of power supply loss and ensure the load keeps running unhindered by the battery power being supplied from the UPS inverter. A UPS thus protects its connected inverter loads from bad power or loss of power supply. It prevents software corruption, data loss, injuries in production, loss of production, loss of time, equipment damage, and many other things.

Can I use a UPS for an air conditioner or motor supply?

An air conditioner, or any motor with a start/stop load, is a very harsh load that distorts the mains supply due to its very high current demands on start-up, and often regeneration of power back into the mains supply when it switches off – also called a regen load. These high start-up currents normally exceed the UPS inverter's ability because, although it can cater for peak loads, it can only supply a certain amount of peak inverter load for a very limited time. For this reason, it is not advisable to put an aircon or start/stop motor load into a UPS. One way around this is to put a variable speed drive between the UPS and the motor load which will soft-start on the inverter and protect it. Alternatively, a generator is the preferred supply option for these types of loads.

What does transformer-based UPS inverter mean?

Since UPS systems were first designed and built, they were always made with an inverter output transformer. This had two functions: 1) The transformer was used to step up the inverter output voltage to 220/400 volts supply for what we use here in South Africa. 2) The transformer galvanically isolated the load from the UPS battery, thereby protecting it. Nowadays, transformer-based UPS like the Riello MPT, MHT, and MHE have a third positive effect in that they create a new neutral for the critical connected inverter load, bringing the neutral much closer to the load. This drastically reduces the effect bad neutrals can have on the functionality of critical data center, IT and software loads.

What does transformerless or transformer-free UPS inverter mean?

In more recent years, transformerless or transformer-free UPS systems have been developed, with most manufacturers moving away from transformer-based UPS systems. This newer technology is far cheaper to produce and thus more competitive. This technology is also more efficient and requires a smaller footprint. However, in most cases, the smaller footprint doesn't necessarily mean less room space use, as almost all UPS systems with transformerless technology require front, side and back access, plus rear clearance for fans exhausting hot air. Essentially, they take up less floor square meterage but need more room area around them. They are very efficient, which is very important in the green energy UPS world we live in. Still, they can easily and more effectively be replaced in high power ranges with more reliable and robust transformer-based Riello MHE flagship products, which give the user peace of mind, offering both high reliability with ultra-high efficiencies – the best of both technologies in one.

Calculating the power draw of the critical UPS loads

The total power draw of the selected critical loads is obtained by making a list of the power rating of each piece of equipment. This detail can be obtained from the rating plate, normally at the rear or under the device, or off the power supply feeding it. Once you have the list, add it all together, and that will be the total power draw to select on the UPS. If you have a problem with sizing, you can email Shaun and request a UPS sizing calculator to assist you in your sizing.

How to select the right UPS size?

Once you have the total power draw added in watts, you can select the UPS size accordingly. It is important to allow 30% on top of the calculated power draw to accommodate when loads startup, resulting in higher than normal inrush currents on the UPS inverter. If the total power draw is in watts, you need to divide this by 0,7 to get to the VA size, which is what UPS units are generally rated in. A UPS up to 3 kVA is a plug-and-play device and doesn’t require installation. Units of 4 kVA and upwards require an electrician to hard-wire the UPS into your building.

What does an automatic-voltage-regulator do for me?

An automatic-voltage-regulator (AVR) device, also known as an automatic voltage stabilizer (AVS), is used to keep the grid supply power feeding your loads within acceptable voltage limits of +/1 10% of the 220 VAC nominal for your connected loads, even if the grid supply varies by as much 220 VAC plus 20% over rated voltage and 220 VAC minus 40% under voltage. Most decent AVRs also include filtering circuits for noise on the grid supply side to prevent it from affecting your load. It is very important to remember that an AVR or AVS is not a UPS. They will not keep your load running when the power fails and have no inverter or backup battery.

What is the warranty time on an elite battery?

A 12-month full replacement warranty covers all ELITE UPS batteries, provided they are installed and operated under a UPS float application environment. Cyclic applications void any warranty unless the battery is sized correctly at the time of purchase for such an application. Some ELITE UPS batteries are available with up to 3-years individual block warranty replacement.

What are the advantages of using a separate external wrap-around maintenance bypass with your UPS plant?

1. It allows for 1005 electrical isolation of the UPS plant from the AC power supply and inverter connected load. 2. It doesn’t require downtime. 3. Risk-free switching and isolation without any back-feed power into the inverter. 4. Simple and easy to manufacture. 5. For single-phase systems, it is available as a standard unit in-rack or tower mount 16 amps 220 VAC.

How do I monitor my UPS remotely?

A Riello or Pureline UPS can be easily monitored remotely via simple and cost-effective remote alarm panels, remote UPS front panel or one of the many network interfaces available such as SNMP, Modbus, and JBus etc. An IP address is allocated to your UPS to interface it into your network and allow the user to set shutdown and monitoring functions to occur automatically when the power fails.

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