Running a business where uptime matters means you quickly learn that “power” is the most fragile link in the chain. That’s why my office UPS isn’t just a battery in a box — it’s an Internet of Things (IoT) device with its own little brain, sensors, and a secure connection back to a monitoring cloud.
A Real Example: My UPS Sent Me a Power-Cut Alert
I was out of the office when my phone buzzed with a notification:
“Power failure detected.”
What actually happened behind the scenes is pretty clever. The UPS constantly monitors input voltage using internal sensors. When the mains supply drops outside its acceptable range, it:
Switches to battery mode with no change in output power
Logs the event locally
Immediately sends an encrypted status update through its network interface to the vendor’s cloud monitoring platform
That platform triggers a push notification to my phone
All of that happens without me doing anything.
A traditional UPS would have silently switched to battery mode, but I would’ve never known until I stumbled onto it later. The IoT connectivity closes the information gap.
Moments Later: The “All Clear” Message
A few minutes later, I received a second alert:
“Power restored.”
The WinPower View App allows you to keep track of the status of all your IoT UPS’, receive alerts and schedule battery tests.
That update comes after the UPS senses that the input voltage is back within nominal range. It switches off battery mode and sends another message through the IoT platform confirming stability. The cloud logs the event, updates runtime predictions, and notifies me.
Having this timestamped history is incredibly useful. I can see exactly how long the outage lasted and how long the UPS was running on battery.
IoT Scheduled Battery Tests: Not Just a Gimmick
Another feature I’ve grown to appreciate is the automated battery diagnostics. On a schedule I configured, the UPS runs a controlled discharge test using its internal sensors. During this test it measures:
Battery voltage under load
Temperature
Estimated capacity
Expected runtime based on current load
Degradation compared to previous tests
It then uploads the results via its IoT connection for trend analysis. I can log into a dashboard and see graphs of battery health over time. I also get alerts if capacity drops below a threshold — giving me months of warning before I’d need a replacement battery.
The IoT Architecture: A Quick Overview
Here’s what enables all of this:
Network Interface (Ethernet/Wi-Fi): Lets the UPS communicate externally
Embedded microcontroller: Runs the logic, monitors sensors, handles communication
Secure encrypted connection: Typically TLS, to protect data in transit
Mobile/desktop apps: Present real-time status, history, and configuration options
It’s essentially a miniature industrial monitoring system wrapped into a box most people think of as a “battery backup.”
Why This Matters for Business
With a smart UPS:
I don’t need to poll equipment or guess about power conditions
I know exactly how long an outage lasted
I can plan battery replacements instead of reacting to failures
I can detect anomalies (e.g., repeated voltage drops) that hint at bigger electrical problems
I get a live view of my most critical infrastructure element: the power supply
IoT gives the UPS a “voice” — and that voice can save you from unexpected downtime.
Final Thoughts
My IoT UPS has now alerted me several times about events I might never have known about. It’s a perfect example of how IoT isn’t just smart light bulbs and fridges — it can enhance genuinely mission-critical hardware.
When technology quietly keeps an eye on things and tells you when something goes wrong, you suddenly realise just how valuable “connected” really is.
The IoT UPS is coming soon to Power Inspired. You can read more about it on it’s dedicated website: Internet of Things UPS, or contact us to keep informed:
Uninterruptible Power Supplies (UPS) are designed to protect critical systems from power failures, surges, and brownouts. But one of the most common installation mistakes we see is connecting a UPS to a supply circuit that’s rated lower than the UPS itself.
At first glance, it may seem harmless — after all, the UPS won’t always be running at full load. However, undersized circuits can lead to tripped breakers, overheating, and unreliable protection. Let’s explore why this happens, and how Power Inspired’s 10kW UPS range can give you a safe and flexible solution.
Understanding Circuit Ratings
Every power circuit is designed to handle a maximum continuous current, typically defined by its breaker rating and cable size.
For example:
A 13A circuit at 230V supplies up to about 3kW.
A 16A circuit can deliver around 3.7kW.
A 32A circuit can support about 7.3kW.
These limits are there for safety — to prevent cables and connections from overheating under sustained load.
Understanding UPS Power Ratings
UPS systems are rated in kVA (kilovolt-amperes), while actual usable power is measured in kW (kilowatts). The difference is due to power factor (PF) — the ratio of real to apparent power.
For example:
A 10kVA UPS at 1.0 PF provides 10kW of usable power.
A 10kVA UPS at 0.8 PF delivers 8kW.
However, the UPS also needs to draw slightly more power than it delivers to account for charging and efficiency losses. If you connect a large UPS to a small circuit without adjusting for this, you can easily exceed the circuit’s rating.
In addition, if a user inadvertently adds more load to the circuit, the circuit breaker in the distribution board will trip but the UPS may continue to operate on battery power.
The Problem With Underrated Circuits
If your UPS draws more power than the circuit can handle, several issues can arise:
⚠️ Circuit Breaker Trips – The breaker will trip during heavy load or battery recharge, cutting power to the UPS and connected equipment.
🔥 Cable Overheating – Sustained overcurrent can overheat wiring, degrading insulation and creating a fire hazard.
❌ Loss of Power Protection – If the UPS trips due to supply limits, your connected equipment is left unprotected at the worst possible time.
For most UPS brands, the only safe answer is to install a larger circuit — but that isn’t always possible or cost-effective.
Power Inspired UPS: Built for Flexibility
This is where Power Inspired’s 10kW UPS range stands out.
Our systems can be downrated to match the circuit they are connected to — allowing you to safely install a high-capacity UPS on a lower-rated supply without overloading the circuit.
For example:
We can configure a 10kW UPS to operate within any circuit from 16A to 63A, by limiting its output current.
The UPS automatically adjusts its maximum load ensuring safe operation within the circuit’s capacity.
When a higher-rated circuit becomes available later, we can restore the full 10kW capability without replacing the unit.
This flexibility is ideal for environments where power upgrades aren’t immediately practical — such as offices, laboratories, or data closets using existing wiring. Another useful feature is that the UPS can be connected to CEENORM pluggable connections and the UPS rating adjusted to suit.
Example: Adapting to the Site
A customer recently needed to install a 10kW UPS in a building with only 32A circuits available. Normally, this would require costly electrical upgrades.
Using the Power Inspired output current limit, the UPS was safely set to operate within the existing 32A supply. The system still provided full power conditioning, battery backup, and surge protection — without tripping breakers or overloading the circuit.
When the building later upgraded to a 50A feed, the UPS was reconfigured to its full 10kW capacity — a simple software change, not a hardware replacement.
Key Takeaways
⚡ Always match your UPS input rating to your circuit capacity.
🧠 Use configurable UPS features to safely operate within smaller circuits.
🔋 Power Inspired’s 10kW UPS range can be downrated to suit your site today — and upgraded tomorrow.
Conclusion
Circuit ratings matter when installing a UPS — but with the right technology, they don’t have to limit your options.
Power Inspired UPS systems give you the flexibility to deploy advanced protection wherever you need it, even when power availability is restricted. Whether you’re upgrading an existing site or designing a new power protection plan, our team can help you size and configure your UPS correctly for safe, reliable performance.
Contact Power Inspired today to learn more about our 10kW UPS range and how it can adapt to your power environment.
Following on from how to install the battery trays in the VFI-RT+ UPS I thought it a good idea to then explain some of the settings that you can set to ensure the UPS works how you want it to.
Note that some of the settings can cause mis-operation or even damage so should only be performed by persons knowledgeable about what they are doing. Reading this guide will help!
The UPS settings are accessed via the LCD screen. No software is required. First of all make sure the UPS is in standby mode by pressing the OFF/ENTER / ↲ key for several seconds. The unit will either enter bypass or standby mode (if it wasn’t already). Now we are ready to enter the UPS settings screen. To do this press and hold the SELECT /▼ key. After around 3 seconds the UPS will enter the settings menu.
The Settings screen shows two parameters. Parameter 1 is usually the number of the setting, but maybe some additional information when adjusting the setting value. Parameter 2 shows the settings current value, or the value you want to set it to. To navigate the settings press SELECT ▼ to increment the menu, the ON/MUTE ▲ button to decrement (I know this is counter intuitive with the arrows pointing up and down but think of the arrows more as next and previous). Use the OFF/ENTER ↲ to enter the settings and the ▼ or ▲ to select the desired setting.
Press ↲ at the desired value to exit back to the settings menu.
Note that icons will also appear on the LCD to guide you.
UPS Settings
Setting # 1 is the output voltage when on inverter. Your choices are 200, 208, 220, 230 or 240V. Note that at 200V the output power is derated by 20%. The default is 230V.
Setting # 2 is CVCF mode or Constant Voltage Constant Frequency. In normal use the VFI RT+ will track the input frequency and auto set to either 50 or 60Hz depending upon input. In CVCF mode you can output either 50 or 60Hz regardless of the input frequency. E.g. you can have 50Hz input and 60Hz output – useful for operating high voltage US equipment in Europe that may not be suitable for 50Hz operation. The converse is also true, e.g. output 50Hz from a 60Hz supply. In addition if powering from a generator whose frequency may be unstable this is a good option to ensure the load is always provided with high quality power. Your options are ENA for enabled or dIS for disabled. CVCF is disabled by default.
Setting #3 is the converter frequency you want to run. If CVCF mode is ENAbled, it will set the frequency to either CF 50 or CF 60. It also sets the initial frequency in battery mode. For example if you cold start the unit the inverter will output either BAT 50 or BAT 60
Setting #4 is ECO or Economy mode. In this mode the UPS will supply the load in bypass with the inverter ready if need be. In this mode the output is variable and there is a slight break in power during transition, but since there are no conversion losses the efficiency is much higher and therefore running costs lower.
Setting # 5 allows you to vary the amount of out of tolerance voltage the unit will allow in ECO mode before reverting back to an online unit in both high voltage and low voltage. Your options are from +7 to +24V (default is +12V) for high line and -7V to -24V (default is -12V) on the low line.
So if you’re concerned about using ECO you can still have a fairly narrow voltage window by setting to within your acceptable parameters.
Setting #6 is Bypass. This is an important setting and should be given consideration depending upon your power quality / power continuity needs. If the UPS goes off for any reason e.g. fault or somebody switches it off, then if the bypass is disabled then power to the load will go off. This may be a desirous situation as you may want to control the output power from the UPS, or you may not wish your load to receive any unconditioned power. However, if power continuity is more important then you should enable bypass. This way if the unit is switched off you will still have power to the load. Note that this sometimes causes people to forget to actually turn the UPS online. As a reminder if the UPS has bypass enabled and power is present it will beep every minute or so to warn you.
Setting #7 is the bypass high and low points. If bypass is enabled the UPS will switch off bypass if the input voltage is outside the parameters set here. You can have between 230 and 264V for overvoltage and from 170 to 220V for undervoltage. The defaults are 170V and 264V.
Setting #8 is a bypass setting again but this time the frequency. Dependent upon which frequency mode is set (Setting #3) the options you have are from 45-49Hz (default 47Hz) to 51-55Hz (default 53) for a 50Hz system and from 55-59Hz (default 57Hz) to 61-65Hz (default 63Hz) for a 60Hz system.
Setting # 9 is the programmable outlet setting. On the rear of the unit there is a bank of outlets that are “programmable”. It is used for load shedding purposes when on battery power. For example you may have some non essential equipment that you need minimal backup for but others you want to maintain for as long as possible. So the equipment that is non-essential (or perhaps will shut down automagically) can be plugged into he programmable outlet to be load shed when this setting is enabled. It is disabled by default.
Setting # 10 is the number of minutes the programmable outlets will remain active for in the event of a power outage. The range is 0-999. If set to 0 they will immediately switch off.
Setting # 11 is autonomy limitation. You can set this to DIS (default – the unit will keep going until the batteries become too low), or from 0 (in fact 10 seconds) to 999 minutes. This is useful particularly if you have a very low load and don’t want the batteries to deplete to a critical point and may only needs a few hours runtime.
Setting#12 is the connected battery Ah of the UPS from 7-999Ah. If you have a single UPS then this value will (depending on model) be the internal battery Ah so either 7 or 9Ah. Remember if you add further batteries to the UPS (e.g. additional battery cabinets) to add the additional Ah here. For example a VFI1500RT+ has an internal 9Ah battery, so this should be set to 9Ah. If we add 5 cabinets to it, each with a capacity of 18Ah, then we should set this value to 99. (5x18Ah for the cabinets plus 9Ah for the internal).
Setting #13 is the battery charger current. One of the great features of the VFI-RT+ is the ability to extend runtime by the addition of external battery cabinets or even large battery strings. However this additional battery capacity needs a more powerful charger to recharge the system. Luckily the VFI-RT+ has an adjustable battery current up to either 8A or 12A dependent on your model. Options are 1/2/4/6/8 or 1,2,4,6,8,10,12. The default is 2A. You should not set the charge current to a high value with no additional battery cabs connected.
Setting #14 is the charger boost voltage. You can adjust this but this is inadvised. To do so may damage batteries.
Setting #15 is the charger float voltage. Again you can adjust this but this is inadvised.
Setting #16 is the Emergency Power Off (EPO) ports control logic. You can set this to AO (Active open) or AC (Active closed).
AO is default, and therefore requires the EPO connector at the rear of the unit to be linked through and present. If you want to remove it or work on a different logic then you can do so by setting the logic here.
Setting # 17 is for when an external isolation transformer is connected to the output of the UPS. If enabled the unit will attempt to compensate for transformer regulation by adjusting the output voltage depending upon the load power being drawn. E.g. the voltage at low power draw will be lower than at high power draw. It is disabled by default.
Setting #18 is a preference for how to display autonomy when the unit is running on battery. Options are either EAT (default) or RAT. EAT will display how much autonomy time the VFI-RT+ thinks you have left based on the connected battery Ah, the current load and battery capacity. RAT will display how much autonomy time has been accumulated already.
Setting #19 defines the acceptable high points and low points before the unit will revert to battery power. The options are from 110/120/130/140/150/160 (default 110) to 280/290/300 (default 300).
The purpose for this is really on the low voltage side, since if you are supplying a fixed KW output then the UPS will draw as much power as required from the input to maintain the output voltage and power. This could potentially mean overloading a circuit if it susceptible to brownouts. (A system at 240V will draw half as much current as a system at 120V for the same power for example)
That’s It!
And finally we are here. Press OFF/ENTER ↲ to accept all the settings. The UPS will then revert back to standby with all the settings enabled and you can now switch it on.
If you made a mistake don’t press the OFF/ENTER ↲ key, just wait a minute or so and the system will time out and come out of the menu. Or you could just switch off the mains power.
The VFI3000RT+ is Power Inspired’s 3KVA Rack/Tower Online UPS System. If you have ordered from our online store the product will no doubt arrive in 2 boxes. This is simply due to the total weight being close to the maximum courier weight limit of 30Kg and also to prevent damage to the unit if the box is manhandled – well dropped to be precise.
What we do is extract the battery tray and send the UPS in one box sans battery and the tray in another. Both boxes will then weigh in at a more manageable 15kg each.
To assemble the system take the UPS and the battery pack out of their boxes.
Remove the front panel from the UPS – it pops away from the left hand side as shown.
Remove the 4 screws indicated from the battery retainer (note the battery won’t be connected as shown here).
Insert the battery tray into the UPS.
Refasten the screws on the retainer and connect the battery
And refit the front panel.
Cold start the UPS to make sure all is well. Then you’re good to go!
Battery Life or “design life” of a battery is based on average use at room temperature (20-25°C) operation. For a modest UPS System, the design life is typically 5 years. Since, UPS applications are standby applications, the batteries are float charged, and the life is also referred to as “float life”.
The moist gel interior of VRLA batteries dries up over time, gradually reducing the effectiveness until the battery capacity is no longer viable for the application. This is why batteries will wear out regardless of how well they are maintained.
Typically, you have around 200 charge/discharge cycles in a 5 year design life battery. This is because the charge and discharge process involves a chemical reaction and this causes corrosion within the battery itself.
As this limit is approached the battery capacity starts to tail off, and can become very low very quickly. You can see that if a battery is used daily for example, the life expectancy is lower than one year.
Note how cycle life can be extended significantly by reducing the battery depth of discharge
Sulphation
If the battery is allowed to stand unused for a prolonged period of time, lead sulphate crystals form- blocking recharge. If this happens the UPS charger is usually incapable of recharging these batteries. It is possible to sometimes recover such batteries using high charging voltages that break down the sulphate but also having a current limited charger. Temperature monitoring is also required and as such, this is beyond the scope of most UPS built in chargers.
Sulphation occurs mainly when batteries are allowed to stand in an uncharged state. This is why it is important to have your UPS charged as soon as possible after an outage.
Heat
The float life of batteries is rapidly reduced with heat, and I mean rapidly.
HIGH TEMPERATURE will reduce battery service life often quite dramatically, and in extreme cases can cause Thermal Runaway, resulting in high oxygen/hydrogen gas production and battery swelling. Batteries are irrecoverable from this condition and should be replaced.
Based on this, if the batteries are locked in a cupboard with little ventilation and temperatures allowed to build, for example to 50°C, then a 5 year float life battery would be expected to last no more than 6 months, regardless of how it has been used.
Thermal runaway results on VRLA battery
Battery Life Conclusions
A battery cannot be expected to last in excess of its design life so schedule a replacement before this.
Regular cycling of the battery will diminish its performance. If your application is for regular charge/discharge cycles then the life expectancy reduction needs to be considered.
Avoid heat build up. Ensure the UPS and batteries are well ventilated with adequate air flow though the air intakes. Ensure vents are free from a build up of dust and the UPS is not in direct sunlight.
Always recharge the batteries as soon as possible after an outage to prevent the possibility of sulphation.
Did you know BS7671:2018 Requirements for Electrical Installations, a.k.a. The IET Wiring Regulations 18th Edition states that any socket outlet 32A and under must be protected by a Residual Current Device (RCD)?
Section 4.11.3 is the Requirements for fault protection. Subclause 4.11.3.3 entitled “Additional requirements for socket outlets and for the supply of mobile equipment for use outdoors” states:
In AC systems, additional protection by means of an RCD with a rated residual operating current not exceeding 30mA shall be provided for:
(i) socket-outlets with a rated current not exceeding 32A
BS7671:2018 Section 4.11.3.3
In other words any socket outlet that you plug anything into (basically anything powered from a 13A outlet, or up to 8KVA Systems on Commandos) must have an RCD protecting that circuit. There are exceptions to this, dwellings excepted, but only following a documented risk assessment which clearly states why an RCD would not be necessary.
Purpose of RCDs.
An RCD works differently to a miniature circuit breaker (MCB) or fuse. An MCB renders devices safe in the event of an overload, or short circuit to earth. They are rated in Amps, generally in stages from 1-32A. RCDs work by tripping on an earth leakage fault typically of 30mA. This is a fault current of up to 1000 times smaller than the MCB! RCDs are useful as certain hazards can exist in the event of a fault that will not trip an MCB. Typically this involves applications that are, or may, come into contact with water.
Earth leakage is a small current that stems from phase conductors to earth. This causes an imbalance between live and neutral and it is this imbalance that RCDs detect. If the earth leakage is high enough on an appliance due to a fault or water contact then the equipment chassis can deliver a dangerous “touch current” if a user touches it. The RCD is there to protect against this scenario. If your application has water involved, then it is very difficult for a risk assessment to justify the omission of an RCD from the electrical infrastructure unless other safety measures are taken.
Isolation Transformer
An isolation transformer, by its very nature will stop RCDs from tripping – even in the event of an earth fault. See Isolation Transformers – what you need to know for further reference on this. However this isn’t a problem. In fact, the isolation transformer can make the installation more safe than with the RCD alone. Even a device with a fault can be touched by a user without any hazard occurring. Unless – and I can’t stress this point enough – the isolation transformer has the output Neutral and Earth bonded!
N-E bonds are not there for safety, but rather for noise rejection performance by establishing a zero volt neutral-earth voltage. Isolation transformers in conjunction with UPS Systems provide a very resilient power protection solution. However, in order to ensure the system is safe, then you should not bond the N-E. Our isolated UPS systems leave the system floating, providing true isolation and an inherently safe electrical environment. If you use a N-E bonded system and no risk assessment has been carried out to determine that no RCD is necessary then this contravenes the requirements of BS7671:2018.
Decision Flowchart
Start by asking if there is a documented Risk Assessment as to why there is no need for an RCD on a socket outlet. If there is, then you’re good to go and any UPS is good for this scenario. You can use isolated (floating or N-E bonded) or non-isolated depending upon your requirements.
If there is no risk assessment in place then we check if there is an RCD fitted. If not, or unknown, then in order to provide the safest environment, the solution is a truly floating isolated UPS. Granted, if no RCD is in place, fitting any UPS does not make the situation less safe, it’s just that a floating isolated UPS does make it safe.
If there is an RCD fitted, and no risk assessment has been carried out, then you must not use any NE bonded system NOTE 1. This removes the safety aspect of the RCD.
Conclusion
According to the 2018 Wiring regulations there needs to be an RCD fitted on any sub 32A circuit. This will cause power to be removed if earth leakage of over 30mA is detected. Any standard UPS will not interfere with the operation of the RCD, however an isolated UPS will prevent the RCD from operating.
However, a floating isolated system, where Neutral and Earth are not connected provides a safe electrical environment. In situations where an RCD should be installed, for example there is water required by the application, and the electrical infrastructure is unknown (for example older installations to which RCD was not a mandatory requirement), floating isolated UPS provide the ideal solution.
An isolated UPS that is floating renders RCDs ineffective but provides enhanced safety by removing any touch current hazard.
On the other hand, a N-E bonded UPS system not only negates an RCD but does not make safe any scenario to which the RCD was required to protect against. There’s a reason for section 4.11.3.3 of BS7671 and this situation violates it.
An isolated UPS with a Neutral and Earth Bond renders RCDs ineffective and does not protect against hazards for which the RCD is intended.
NOTE 1: Unless a secondary RCD is fitted to the output of the UPS.
Many moons ago we blogged about BS8418:2010 (Installation and remote monitoring of detector-activated CCTV systems, Code of Practice) and the requirements for UPS Systems. That standard stated:
Unless the mains power supply is supplemented with a stand-by generator, an uninterruptible power supply (UPS) must be able to power the CCTV control equipment and communications devices for a minimum of 4 hours after mains power failure. Where the mains power is supplemented by a stand-by generator, the UPS needs to be capable of providing stand-by power for a minimum of 30 minutes after mains power failure (for example if the stand-by generator does not start).
The 2015 revision relaxed this somewhat, allowing for a documented threat assessment and risk analysis to determine whether a UPS is required or not. That said, it is difficult to state how any threats or risks are mitigated against a loss of power without a UPS, so the requirement for UPS Systems is likely still to remain in BS8418:2015 installations.
If a UPS is used as the “alternative power source” then this has been changed from a 4 hour requirement to a 30minute requirement when supporting control equipment and data transmission devices. However the standby power capability for the detectors and semi-wired detectors remains at 4hours.
Find a UPS Solution
Enter in your load power and how long you need the UPS to provide backup power for. The UPS Selector will identify any UPS that meet your requirements.
You can filter the selection based upon required features, by clicking the checkbox. Many models are available to by online from our webstore but contact us using the form below for specific requirements or for other products not available to purchase online.
The definition of transfer time, sometimes also called switchover time, says it is the amount of time a UPS will take to switch from utility to battery supply during a mains failure, or from battery to mains when normal power is restored. What this means is that when the main power supply fails, the UPS will need to switch to a battery mode to provide sufficient power and ensure smooth running of the attached equipment. The transfer time duration differs, depending upon the UPS system attached. It should, however, always be shorter than your equipment’s hold up time. Hold up time is the amount of time your equipment is able to maintain consistent output voltage during a mains power shortage.
Line interactive UPS systems, such as our VIX or VIS series, have transfer time typically between 2-6 milliseconds. For regular computer based systems, where hold up time is approx. 5 milliseconds, line interactive UPS systems are usually sufficient; however some computer systems, as well as other critical sensitive equipment, are more sensitive and require shorter transfer time. Hence in this case you should always choose UPS with zero transfer time like our VFI series.
If your equipment is critical and doesn’t tolerate even slightest power distortion, we recommend choosing online double conversion UPS technology with zero transfer time to ensure your equipment has the highest degree of protection.
Here’s a quick look up of transfer times for Power Inspired UPS systems:
Product
UPS technology
Typical transfer time
VIX3065
Line interactive UPS
Typically 2-6 milliseconds
VIX1000N
Line interactive UPS
Typically 2-6 milliseconds
VIX2150
Line interactive UPS
Typically 2-6 milliseconds
VIX2000N
Line interactive UPS
Typically 2-6 milliseconds
VIS1000B
Line interactive UPS with sinewave inverter
Typically 2-6 milliseconds
VIS2000B
Line interactive UPS with sinewave inverter
Typically 2-6 milliseconds
VFI1500B
Online double conversion UPS
Line to battery
0 milliseconds
Line to bypass
Approx. 4 milliseconds
VFI3000B
Online double conversion UPS
Line to battery
0 milliseconds
Line to bypass
Approx. 4 milliseconds
VFI3000BL
Online double conversion UPS
Line to battery*
0 milliseconds
Line to bypass
Approx. 4 milliseconds
VFI6000BL
Online double conversion UPS
Line to battery*
0 milliseconds
Line to bypass
Approx. 4 milliseconds
VFI10KBL
Online double conversion UPS
Line to battery*
0 milliseconds
Line to bypass
Approx. 4 milliseconds
VFI1000T
Online double conversion UPS
Line to battery
0 milliseconds
Line to bypass
Approx. 4 milliseconds
VFI3000T
Online double conversion UPS
Line to battery
0 milliseconds
Line to bypass
Approx. 4 milliseconds
VFI10KT
Online double conversion UPS
Line to battery
0 milliseconds
Line to bypass
Approx. 4 milliseconds
TX1K
Online double conversion UPS with isolation transformer
Line to battery
0 milliseconds
Inverter to bypass
4 milliseconds
Inverter to ECO
Less than 10 milliseconds
TX3K
Online double conversion UPS with isolation transformer
Line to battery
0 milliseconds
Inverter to bypass
4 milliseconds
Inverter to ECO
Less than 10 milliseconds
TX6K
Online double conversion UPS with isolation transformer
Line to battery
0 milliseconds
Inverter to bypass
4 milliseconds
Inverter to ECO
Less than 10 milliseconds
TX10K
Online double conversion UPS with isolation transformer
Transfer times are dependent on which stage the power interruption occurs in. That’s why the transfer times stated in the above table are approximate.
As previously mentioned, transfer times also measure the amount of time it takes for the UPS to switch back to mains. The transfer back to mains power is always controlled with minimal interruption as this transfer is planned. As opposed to an unplanned mains failure which happens suddenly and hence a variation in the actual time taken.
We have conducted a transfer time measurement using an oscilloscope (photograph above). For purpose of this exercise, we have used a standard line interactive UPS system and stimulated a power cut. The oscilloscope managed to capture the transfer time which on this occasion lasted 15 milliseconds, due to the original sine wave being interrupted at the peak of the cycle.
“How does transfer time affect my equipment?”
That’s simple – if your equipments tolerance is below UPS transfer time, the UPS will not provide power in sufficient time in order to keep your equipment running.
Let’s say you have highly sensitive laboratory equipment with hold up time of 2 milliseconds. Line interactive UPS will not be sufficient in this case as it will not switch to battery mode quick enough. You will need to invest in an online double conversion UPS or Isolated online double conversion UPS in order to avoid any downtime. On the other hand if your equipment is a very basic computer workstation with approximate transfer time of 10 milliseconds, you can use the line interactive UPS system with peace of mind that your equipment is protected.
Transfer time is definitely one of the things you need to keep in mind while searching for suitable UPS. More factors affecting your choice of UPS technology are covered in this article.
Electricity is mainly generated by turning a large magnet through coils of wire. This induces a clean sinusoidal waveform that can be transmitted down cables, stepped up and down using transformers, to eventually find it’s way into our homes, offices and factories. Along the way, however, some power virusescan interfere with this clean power and cause your equipment power problems. Some problems are obvious, and others not so. There’s generally accepted to be 9 power problems but there’s another problem which is often overlooked and we make it 10.
1. The Blackout
This is one of the most obvious power problems. A complete loss of power. Caused by a variety of reasons, tripped breakers, fuses blown, faults on the utility line, the list goes on. Some power cuts are brief lasting only a moment, for example lightning striking a power line causing protection equipment to operate and then reset. Some may be for hours or days, for example when a cable is dug up by accident. Others last until the breaker is reset. Whatever the cause a sudden loss of power is clearly undesirable for electrical equipment.
Oops!
Only a UPS System can protect against black outs. Your choice of UPS will depend upon the load you are protecting and the amount of time you need support for.
2. The Power Sag
Also known as a power dip, this is where the power momentarily drops. It’s usually caused by the start up of heavy electrical equipment. Other causes include overloads on the network, or utility switching. Note that the plant that is causing the power sag may not be in your building but sharing the same substation. The severity of the dip will impact equipment in different ways. Some equipment will have a natural ability to cope for momentary dips where others will shut down or reset.
You will need a UPS System to protect against a power sag.
3. The Voltage Surge
Some call it a spike, but in any event it’s a short term high voltage on the power line. Usually caused by lightning, which doesn’t have to be a direct hit on the power lines but nearby causing the spike to be induced onto them. The surges are generally destructive in nature as most equipment is not designed to protect against them.
This is where the voltage drops below 10% of the nominal voltage for an extended period of time. This is caused by high demand on the network. The effect is more pronounced the further you are away from the electrical substation. In fact, in rural areas this can be a problem when switching on everyday appliances such as ovens or electric showers. Brown outs affect different equipment in different ways. Computer systems tend to be able to cope well with brown outs as the switch mode power supplies have a wider input voltage. Other equipment that relies on a stable AC source such as lighting, motors or heating will not fare so well. Equipment with linear power supplies such as in high end AV applications may fail entirely.
In order to protect against a brown out you will need some form of voltage regulation. A line interactive UPS System incorporates a boost function to raise the voltage higher by a fixed percentage to bring it into the nominal range. It does this without needing to revert to battery operation.
5. Over Voltage
Also known as a voltage swell this power problem is caused when the demand on the network is lower than normal. This causes the output voltage from the substation to rise. This is a problem when the voltage is over 10% of the nominal. The effects of over voltage can range from overheating, diminished equipment life to complete equipment failure. It’s the inverse of the brown out in that the closer you are to the substation the more pronounced the effect will be.
Similar to the brown out you will need some form of voltage regulation. A line interactive UPS System incorporates a buck function to lower the voltage by a fixed percentage to bring it back into the nominal range.
6. Electrical Noise
This is generally noise between the live and neutral conductors and is called normal mode noise. Its caused by radio frequency interference (RFI) or electro-magnetic interference (EMI). This is usually from electronic devices with high switching speeds. Since the noise carries little energy it generally does not cause damage but rather disruption in the function of other electronic systems. Some filters may remove this, but this is not always effective. The best way to eliminate noise is to recreate the output waveform and this can only be done with an online double conversion UPS System.
7. Frequency Variation
Frequency variation can’t occur on the utility as this would require all the power stations in the country to suddenly change frequency. In fact, the frequency on the national grade is very tightly maintained at 50Hz. However, when you’re not connected to the utility and instead relying on a portable (or even large scale) generator then this can be an issue. As the load increases on the generator and in particular sudden large power draws from them causes the motor to slow down and hence change the output frequency. Some equipment won’t be affected by this at all but it can cause damage to other systems, particularly those with motors or other inductive devices.
More severe than electrical noise, switching transients are very fast high voltage spikes induced onto the power conductors. Caused by the switching off of inductive loads and variable speed drive systems. Such power problems may not be immediately damaging but they can cause degradation of devices subjected to them, particularly if the transient is of high enough voltage.
A surge suppressor can help if the magnitude of the transient is high enough, but these only work at levels above the nominal voltage. This means you could still have a transient of many hundreds of volts entering your equipment. Like with electrical noise a filter will help, but can only reduce a transient not eliminate it. The only way to be sure to eliminate the transient is with the online double conversion UPS System.
9. Harmonic Distortion
Harmonic distortion is where the supply voltage varies from a pure sine wave. The amount of variation is a measurement called the Total Harmonic Distortion or THD. Since we’re talking about voltage we call it THDv, not to be confused with THDi which is a measure of the distortion of input current which is a different thing entirely.
It is generally caused by non-linear loads. These are types of loads that don’t take current in a smooth sinusoidal fashion but instead take it in large chunks. Depending on supply characteristics these chunks of current cause a greater or lesser degree of distortion on the supply voltage. This causes problems for motors and transformers with hum and overheating. In three phase supplies harmonic distortion can actually cause the burning out of neutral conductors and surprise tripping of circuit breakers. Again the only way to eliminate harmonic distortion from your load is to use the online double conversion UPS System.
Summary
That’s the main generally accepted 9 power problems that can cause issues for electrical and electronic equipment. But wait, didn’t I say there was a tenth?
10. Common Mode Noise
This power problem is often overlooked and can cause equipment malfunction. It’s defined as electrical noise between the earth conductor and the live/neutral conductors. Even an online UPS System may not eliminate common mode noise. This is because it is normal practice to have the neutral conductor connected through the UPS from input to output. So although any noise between the live conductor and ground would be taken care of, any noise between neutral and ground is passed straight through to the load.
In a modern electrical infrastructure this generally may not be a problem since the neutral and earth are tied together at the distribution board. This shorts them together and in theory eliminates any voltage or noise between them. However, particularly on long circuits with a lot of equipment on them, voltages can start to be created and common mode noise becomes an issue. Hospital laboratories are a prime example of this.
The way to solve common mode power problems is to isolate the load from the supply. This is exactly what the TX Series does. The in-built isolation transformer creates a new live and neutral, and the online double conversion technology then ensures a high quality stable output. An an added advantage the isolation transformer can provide a safety shield against electric shock which is particularly important in applications where water and electricity may mix. Again, hospital laboratories are a prime candidate. Thus the TX Series can also be defined as Laboratory UPS System. Click for further information on the isolation transformer.
The new summary is this. If you need to provide the highest degrees of power protection against power problems and viruses then the UPS Technology choice should be online double conversion, and the load should be isolated. Choose the TX Series Isolated UPS System.
For the highest degrees of power protection the TX Series of Isolated UPS from 1-10KVA
