In Case of Emergency, Don’t Panic!

In most emergency procedures it states, “In case of emergency, don’t panic!” So, what do people do? They panic. It’s an automatic, instinctive response. Threatening things are happening in the midst of the crisis, so what response do people have control of? Panic. It’s a pretty disempowering response though, isn’t it? Time crises force nearly everyone into panic; so do relationship crises — instead of panic over time, there’s a nervousness that results. Crises intuit a panic response. Yet, this is the furthest thing that will help the situation, for it never pays to panic, ever.

Panic not in the midst of crisis… We don’t panic. The crisis is in our heads and our hearts but the World is still as it is… calm, gentle, still… observing, caring for, and watching over us. It is up to us which reality we choose, and it takes a certain amount of courage of faith to go against what you might be seeing. It is a choice to see what does not readily make itself known; the quiet way of God’s steady world, and his eternal power and divine nature.[1] We must fix our eyes not on what is seen, but on what is unseen (but that which is there nonetheless).[2]

In case of emergency:

– Find out the facts and calmly act on them;

– Don’t run and appear panicked — slow down and be responsible;

– Try to communicate to others clearly and effectively;

– Use procedures and checklists to reduce the mental noise; and,

– Ignore the record of your nerves; do not fall into temptation to panic — it never helps.

In crisis, smile. Be still and know that safety is here; it never leaves. For God has said, “I will not in any way fail you nor give you up nor leave you without support. [I will] not, [I will] not, [I will] not in any degree leave you helpless nor forsake nor let [you] down (relax My hold on you)! [Assuredly not!]” -Hebrews 11:5b (Amplified Version).

Know the tranquillity of God now as it exists in you. It is a decision of the will, backed by the strength of the Spirit. It can be yours at any time you choose.

Copyright © 2008, S. J. Wickham. All Rights Reserved Worldwide.

ENDNOTES:

[1] See Romans 1:20 (NIV).

[2] See 2 Corinthians 4:18 (NIV).

Measuring Reliability For Uninterruptible Power Supplies and Power Protection Plans

The criticality for which uninterruptible power supplies (UPS) were created means that their reliability requires some form of measure to give customers a means of comparing different manufacturers and UPS. The purpose being to shield the loads the UPS is protecting from vulnerability, therefore, reliability should not be guessed at.

Mean Time Between Failure

MTBF or Mean Time Between Failure is one such measure – an indicator of the reliability of an uninterruptible power supply. It is the average operational time between powering up and system shutdown due to failure (not power failure in this sense but failure of the UPS system itself). It is represented by a measurement of hours.

Average failure rate is another measure of reliability. This is the total number of failures in a given time period. The failure rate over the lifetime of any UPS system, therefore, is inversely proportionate to its MTBF.

Uninterruptible power supplies are no different to any other electronic equipment in that the rate at which they fail is not constant. There are three distinct periods associated with UPS failure (which are often represented by a bathtub curve diagram showing a) infant mortality failures, b) random failures and c) wear out failures).

Infant Mortality UPS Failures

Infant mortality failures correspond to failures early on the life of the uninterruptible power supply. IT-sized uninterruptible power supplies can suffer what is termed ‘dead-on-arrival’. This could be due to a component manufacturing defect or transportation damage. A sudden shock or jolt in transportation may weaken a soldered joint, for example. Whilst UPS manufacturers strive to reduce these incidents as much as possible through stringent quality checks and testing processes, they do happen. Various processes can be applied to minimise the chances of it happening. UPS from 10kVA, for example, can be run for short burn-in periods (up to 48 hours) at high ambient temperature to reduce the potential for such failures.

Random UPS Failures

Random failures happen less often. During the normal working life of a UPS, the rate of these is low and fairly constant.

Wear Out Failures

Wear out failures at the end of an uninterruptible power supply’s working life are more common (and this is where the curves is steeper). Here, battery problems account for 98 percent of UPS wear out failures. Particularly where uninterruptible power supply has been subjected to high ambient temperatures over long periods, internal cabling insulation becomes brittle and breaks down. There are other consumable items that should be part of a regular monitoring regime, such as fans and capacitors, which will also eventually wear out with use.

Just because a manufacturer shows you some favourable MTBF stats does not necessarily mean that their products are the most reliable. Like most things, these can be massaged into looking more relaxed than they actually are. The important question to ask is: what was the basis for their calculation? There are two primary approaches:

1) A record of the total number of failures for a particular UPS size over a given time period.

Commonly adopted by UPS manufacturers, this is a valuable approach if the field population is large and the time period long enough (more than the typical life expectancy of a UPS, which is five to ten years).

2) A system value calculated from the known MTBF values of components and assemblies.

Obviously, this approach is more complex and relies on following standardised calculation formats.

Mean Time to Repair

Mean Time to Repair (Mean Time to Restore) is the time taken to return an uninterruptible power supply to normal operation from shutdown.

Online UPS are designed to fail safely to mains; therefore, the MTBF calculation of the mains power supply is also an important consideration along with mean time to repair (or average repair time).

As it is highly unlikely for a service engineer to be onsite at the very moment a UPS fails, MTTR needs also to include a travel time element. This also assumes the service engineer is carrying the required parts needed to fix the problem in a single visit, which is sometimes not the case. Uninterruptible power supply manufacturers may only provide a figure based on the actual repair time. Although this may be a satisfactory comparison tool, it is not a true representation of reliability. A degree of scepticism is sometimes necessary when comparing marketing data from some manufacturers.

Categorizing UPS Loads and Load Types

Hardly anyone will argue that the need for uninterruptible power supplies (UPS) is on the rise as ancient power supply infrastructures creek under the weight of increasing demand for energy worldwide. But why do power protection load types need to be categorised?

Firstly, business managers must assess what UPS loads are in terms of their criticality to the continuity of operations in the event of a power cut. Usually, uninterruptible power supply loads are categorised as critical, essential and non-essential.

Another crucial assessment at the design stage of a UPS system is how these loads are synergised, i.e., which loads affect other loads?

Computer loads, in terms of a retail business for example, may affect other systems that are part of facilities management. This may include security cameras, door entry systems, lifts, escalators, PoS terminals, kiosks, cash machines and so forth. In a warehousing business, computer loads may also have a significant bearing on the ability of the business to handle both in-bound and out-bound goods. All of this needs to be taken into account when assessing the criticality of UPS loads.

UPS loads also need to be categorised in terms of their electrical draw and the effect it has on electrical systems; whether they are capacitive, inductive or resistive. This will have a bearing on the size and type of UPS system to be installed.

Load Categories. Critical loads directly affect the ability of an organisation to operate and must either be kept running when the mains power supply fails or be powered down in an orderly manner to prevent systems crashes, data loss or corruption, and life-shortening hardware damage. Their routine operation can also be interrupted when the mains power supply is polluted.

Essential loads provide secondary support services and may be required for health and safety reasons or to maintain ambient temperature. Whilst requiring a form of back-up in case of mains power supply failure, they do not require uninterruptible power and can be allowed to fail or ride through the time it takes for a generator (or alterative back-up system) to start up. Examples include air-conditioning, heating and emergency lighting.

Non-essential loads are those that an organisation can afford to lose when the mains power supply fails. For example, general lighting and non-essential printing services.

Some critical loads, especially sensitive medical and scientific equipment, require tight voltage and frequency regulation and this is only possible from the continuously running inverter of an on-line UPS. Essential loads do not need the quality of supply provided by a UPS and can be powered directly from a generator. This will allow the overall size of UPS to be reduced. Non-essential loads do not require any power protection at all.

The Effect on the Electrical System of Critical UPS Loads. In terms of type, UPS loads are referred to as either linear or non-linear, depending on how they draw their current from the mains power supply waveform. They will be inductive, capacitive or resistive.

An inductive load is one the waveform of which lags the voltage waveform and has a potentially high in-rush current at start-up. Examples of this type of load are SMPS (the most common form of power supply unit in use today and the type of computer loads most often found behind today’s power-hungry data centres), transformer or motor. This may be tempered by a soft-start facility.

Capacitive loads are those that lead the voltage waveform with potentially high in-rush current at start-up. An example of this is the latest high-end server technology such as Blade of Edge Servers.

A resistive load is one that has no inductance or capacitance, an example being a resistive load test bank heater element where the device typically has no initial switch-on surge and the current drawn rises immediately to a steady running state.

Whether a load is inductive, capacitive or resistive will determine its power factor and this in itself greatly influences the overall size of the UPS and generator (or alternative source of back-up power) to be installed. By convention, an inductive load is defined as a positive reactive power and a capacitive load is defined as a negative reactive power. However, power factor is never shown as positive or negative; rather it is displayed as either lagging or leading.

Assessing load types, how they are synergised, and their effect on electrical current is critical to correctly sizing and designing UPS solutions to get maximum power protection and value for money. Expertise from specialists like Riello UPS, whose business is to fully comprehend UPS loads and load types, cannot be overlooked. More detail can be found in a fantastic book on UPS – The Power Protection Guide.