voltage stabilisers buyers guide v1 3

8/13/2019 Voltage Stabilisers Buyers Guide v1 3

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Advice and guidance on how to ensure youselect the most appropriate power protectionsystem at a cost efficient price.

If you are not familiar with choosing theright Power Protection system for yourneeds it can be a daunting and at timesfrustrating task. Over engineer the solutionand it can be very expensive. Select a

system that does not address all youridentified power problems, or considerlocally available resources, and you canso easily waste money.

For those unfamiliar in the selectionprocess it is essential that you:

Know clearly your own r equirements

Know the right q uestions to ask of a

potential supplier

Know the advantages and di sadvantages of

the various design types

Mains Supply VoltageProblems - Symptoms,Causes & Solutions

Sags: are short duration decreases in the mainssupply voltage which generally last for several cy-cles.

Formal Definition Voltage below 80 to 85% ofrated RMS voltage for 2 or more cycles.

Typical symptoms - Sensitive equipment can lock orhang causing data loss and system resets.

Common Causes Heavy equipment turned on,starting large electrical motors, switching of the mainssupply.

Solutions - AC Voltage Stabiliser, AC Power Con-ditioner & Uninterruptible Power Supply.

Voltage Sags

Brownouts: are long term sags in the mains supplyvoltage which can last up to several days.

Formal Definition A steady state of RMS voltageunder nominal by a relatively constant percentage.

Typical Symptoms -Equipment can reset or evenshutdown.

Common Causes Heavy equipment turned on,starting large electrical motors, switching of the mainssupply or just low voltage output from the generatingsource.

Solutions -AC Voltage Stabiliser, AC Power Condi-tioner & Uninterruptible Power Supply.

Brownouts

Over-Voltage & Surges: are short duration in-creases in the mains supply voltage which generally

Formal Definition Voltage above 110% of therated voltage for 1 or more cycles.

Typical Symptoms -When surges occur equipmentcan suffer from premature failure. The high voltagecauses wear and tear and general component degra-

dation. This is often unnoticeable until failure occurs.Unusual heat output can be an early sign of problemsahead.

Common Causes Heavy equipment being turned

Solutions -AC Voltage Stabiliser, AC Power Condi-tioner & Uninterruptible Power Supply.

Over-Voltage & Surges

To assist in ensuring that you are In the Know, and as a result are able to choose the mostappropriate and cost efficient solution to sol ve your power quality problems, we offer adviceand guidance on ten of the most frequently asked questions.

Why is Power Quality important?

For electrical systems to function properly, it is necessary to make sure that thequality of the power feeding them is of a sufficient quality to ensure that perform-ance is not impaired or system life expectancy reduced.

Without the proper power, an electrical device or load may malfunction, fail prema-turely or not operate at all. There are many ways in which electric power can be ofpoor quality and many more causes of such poor quality.

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2.Do you actually know the mains supply problems you are experiencing?

To indentify the most appropriate solution it is always recommended that you firstidentify exactly the problems you are experiencing. You may of course already havea good idea as to the problems being encountered. If not, it will be necessary tomonitor the supply over a period of time to identify the types, duration and magnitudeof power problems experienced.

Power supply problems are caused by various sources, for example distribution net-work faults, system switching, weather and environmental conditions, heavy plantand equipment, or simply faulty hardware.

Regardless of the cause of the problem, the resulting power quality issue will includeone, or more, of the power problemsdetailed on the right and following page.

3.How do you determine the power sizing of the equipment you wish toprotect?

When determining the total power ratingfor the solution you require do not forgetto allow for possible future expansion ofthe load you wish to protect over themedium to long term.

You will need to check the rating of the equipment to be protected. Such ratings arenormally quoted in Amps or kVA, and whether single or three phase. You will alsoneed to determine the nominal voltage line to neutral and line to line if three phase,plus the frequency and power factor.

Such information is usually shown on therating plate attached to the equipment,otherwise you will need to consult themanufacturers of the equipment or takemeasurements. It is always recommendedthat you measure the loads true RMS value.

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Mains Supply VoltageProblems - Symptoms,Causes & Solutions

High Voltage Spikes

Electrical Noise: this is a high frequency noiseeither common or normal mode.

Formal Definition Electrical noise is high-frequency interference on the incoming mains

Typical Symptoms - Processing errors, com-puter lock-up, burned circuit boards, degradation

Common Causes Electric motors, relays,motor control devices, broadcast transmission

Solutions - Isolation Transformer, AC PowerConditioner & Online Uninterruptible Power Sup-

High Voltage Spikes:these are very fast highenergy surges or spikes in voltage lasting only afew milliseconds.

Formal Definition Rapid Voltage peak up to6,000 volts with a duration of 100msec to acycle.

Typical Symptoms - Equipment can lock orhang, crash and even suffer damage which inevi-tably causes data loss and corruption.

Common Causes - Switching of equipment,especially heavy inductive loads, arcing faults oratmospheric electrical disturbance, such as light-ning strikes and static discharges.

Solutions -AC Voltage Stabiliser, AC PowerConditioner, Isolation Transformer, UninterruptiblePower Supply.

Electrical Noise

Blackout and Mains Failures: when the mainssupply fails completely this is known as a total

Formal Definition Loss of incoming mainssupply

Typical Symptoms - Complete disruption ofequipment operation. A break in the mains supplyof only several milliseconds is sufficient enough tocrash, lock or reset many of the components thatmake up a typical data or voice processing IPnetwork, such as PC, terminal, console, server,

Common Causes - Storms, lightning, wind andutility equipment failure. Typically occurs as aresult of loss of power, a mechanical failure, or

Solutions - Uninterruptible Power Supply& Diesel Generator

Blackouts & Mains Failure

4.What is the best solution for you?

If you have a good idea as to the mains problems you are experiencing and the powerrequirements of the equipment you wish to protect you are in a very strong position toidentify clearly the best and most cost efficient solution.

If you are experiencing all of the Power Quality issues identified in Question 2 anonline UPS (Uninterruptible Power Supply) will often be viewed as the obvious choice.But be warned, these are usually expensive to buy and have high ongoing mainte-nance and support costs. In many less developed countries the high technology skillsets required to maintain such systems are not readily and inexpensively available.

For most applications where the loss of mains is not really a critical issue, or can beaccommodated by the use of a standby generator, the deployment of an AutomaticVoltage Stabiliser / Regulator or AC Power Conditioner will be a far more cost efficientsolution both in terms of initial outlay, ongoing maintenance, support costs and therequired local skill sets required to install, maintain and support the solution.

Be Warned- Over engineering a solution due to a lack of understanding on the powerquality issues being experienced is an all too common mistake that can deeply im-pact your wallet!

5.

What exactly is the dif ference between a Voltage Stabilizer and PowerConditioner?

One of the most common questions we get asked is what exactly is the differencebetween a Voltage Stabiliser and an AC Power Conditioner. In essence both protectagainst voltage transients, spikes, sags and brownouts, but an AC Power Conditioneralso offers additional protection against Electrical Noise and higher level defenceagainst transients and spikes.

In most cases an AC Power Conditioner (Power Line Conditioner) is simply a VoltageStabiliser with the inclusion of an isolation transformer.

When a good earth cannot be provided Common Mode Noise (E to L and E to N) canbe a problem. With the inclusion of a shielded isolating transformer in a Power Condi-tioner, this interference will be suppressed to harmless levels. The output of an ACPower Conditioner is commonly referred to as a Clean supply.

As you would expect an AC Power Conditioner is normally more expensive than aVoltage Stabilizer / Regulator.

6.Why is determining the input voltage variation you are experiencingand output voltage accuracy required important?

Choosing a stabiliser with the r ight input variation capability is important because if itsinput voltage range is exceeded, then its output will increase or decrease by the sameamount by which it has gone "out of limit".

In situations where there is a good mains supply, a stabiliser offering an input variationswing of 15% (Our S15 models) will usually be more than acceptable, but in moreremote locations, or countries where the national supply infrastructure is less devel-oped, variations of 20% or greater may be needed to be accommodated by the stabi-liser.

As a general rule the greater the input voltage swing the stabiliser / conditioner needsto correct the greater the price.

An output voltage to within 1% / 1.5% of the preset output voltage is the norm whenspecifying a Voltage Stabiliser or Power Conditioner. However if a lower output voltageaccuracy can be accommodated by the load equipment, then the input voltage rangecan be extended proportionally. As the cost of the stabiliser is linked to the input volt-age range it has to handle, accepting a lower output accuracy may prove to be a moreeconomical solution.

7.Is Supply Frequency Important?

With most supplies operating on 50 or 60 Hz, your normal mains supply frequency isunlikely to vary more than +/- 2%, and this is well within the capability of most stabilis-

ers and conditioners. But if the supply is from a local generator it is possible that thefrequency could deviate beyond this range and suitable protection should be consid-ered to protect both the load and the power protection system.

www.AshleyEdison.com

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8.Are there any other factors you should consider when choosing a Volt-age Stabiliser / Power Conditioner?

Input Output Circuit Breaker: We recommend the specifying of an input or outputCircuit breaker which, in addition to giving over current protection, will trip if the out-put / input deviates above or below a preset level. Certain models in our ranges aresupplied as standard with input circuit breakers and on others the facility is availableas an option.

Bypass Facility:You may also wish to consider fitting a bypass switch that will facili-tate the inspection and maintenance by isolating the stabiliser and connecting yourload directly to the mains supply. Certain models in our ranges are supplied as stan-dard with an inbuilt bypass facility and on others we can supply suitable inbuilt or wallmountable external switches to requirements.

9.What are the differences and advantages to the various design technol-ogy used in Voltage Stabilisers and Power Conditioners?

For the lay person, differentiating between the various technologies employed to de-liver voltage stabilisation can often be a daunting task and it is not always clear as towhich technology is best for a particular application.

As a leading manufacturer and supplier of Voltage Stabilizers and Power Conditioners,

we offer a wide cross section of alternative design types.

Load VoltageReductions

Effects

Voltage

Increases

Computers An 8% drop will

often cause

computer errors

and downtime.

A 10% rise will

cause com-

puter damage,

errors and

Lighting A 10% voltage

drop reduces

lumen output by

over 25% (15%

for florescent

tubes). Infra

Red lamp heat

output is re-

duced by over

A 10% volt

rise reduces

life expec-

tancy of incan-

descent lamps

by over 50%.

Radio & TV

Transmission

Volt drop will

reduce quality

of the transmis-

sion and cover-

Over voltage

by 2% will

significantly

reduce tube

Photographic

Processing

A 5% volt drop

will increase

exposure times

by 30% and

reduce quality

of colour print-

Voltage rise

during printing

cycles will

cause inferior

results

X-Ray Equip-

ment

A 1 % change

in the filament

voltage of an X-

Ray tube will

produce an 8%

change in the

anode current.

When used at

its maximum

rating an X-

Ray tube will

be perma-

nently dam-

aged in the

case of a 5%

Magnetic Equip-

ment

A 10% volt drop

can cause

relays / contac-

tors to open

chatter. Sole-

noids become

sluggish and

vibration will

cause malfunc-

tions and over-

Over voltage

will cause

magnetic core

saturation

high current

and overheat-

ing. Wear and

distortion is

increased.

Induction Heat-

ing

Heat output is

reduced by

more than 20%

on a 10% volt

drop.

Heat output

varies ap-

proximately

with the

square of

Welding Equip-

ment

A 10% volt drop

will increase a

welding cycle

by 20% if weld

quality is to be

maintained.

A 10% volt

rise will over-

heat a weld,

reducing

quality and

causing possi-

ble burn

Transformers At 100 kVA a

10% drop will

reduce trans-

former rating to

90%.

A 10% rise will

considerably

increase core

losses and

decrease

efficiency

AC Mot ors A 10% volt drop

reduces torque

by approxi-

mately 18%.

Motor life ex-

pectancy is

reduced due to

A 10% volt

rise causes

higher starting

current and

reduces

power factor

by approxi-

Effects of supply vo ltagevariations on differenttypes of equipment

Electronic Servo / Electro - Mechanical Design

For most applications our Servo Electronic -Electro Mechanical Ranges (SES/SESL -Voltage Stabilisers & PCS - AC Power Conditioners) have proved to be a very reliableand cost-efficient voltage stabilisation solution, being able to accommodate an inputvoltage swing of in excess of 40% whilst still delivering an accuracy of 1% on the out-put.

Comprising a transformer having its secondary winding connected between the mainssupply and the load, the primary voltage is automatically controlled through a motordriven variable transformer - ensuring a continuous, smooth and very stable outputvoltage.

High Voltage / Transient Spikes are normally limited by the inclusion of SpikeClippers. Such clippers typically limit transients to twice the peak voltage of thesupply. To reduce the spikes to totally harmless levels it is often necessary toask your supplier to fit additional Spike Attenuation protection. With Ashley Edi-son SES / PCS solutions this feature is supplied as standard.

While Electronic Servo stabilisers do contain some moving parts, experienceover the last 25 years in some of the most demanding power conditions hasproved the design to be a very reliable method of delivering voltage regulationwith only a low-level of ongoing maintenance required being deliverable byuniversally readily available skill sets.

The long-life expectancy, compact size and low cost of ownership makes servo-electro mechanical stabilisers economical solutions for a wide variety of applica-tions in industry, commerce, mining, aerospace, computing and telecommunica-tions and is normally our recommended solution for most clients.


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Design Advantages Design Disadvantages

Size and weight advantages over othermethods of stabilisation

Moving parts requiring limited mainte-nance

Fast speed of response to voltagechanges ideal for most applications

Lower speed of response compared tosolid state designs

Very competitively priced

Negligible output waveform distortion

Not Frequency dependentWill attenuate voltage spikes if required

Unaffected by load or power factorchanges

Low cost of ownership with ease of ser-viceability

Endurable, with long life expectancy

Due to the general popularity of this method of voltage stabilisation and the high de-mand for models between 1kVA and 500kVA it is often possible to purchase moststandard SES S15 models from stock or, like larger models and those with wider inputvoltage swings, on short lead delivery times.

b. Solid State Saturable Reactor Design

With no moving parts, solid state design based systems utilise the latest in IGBT con-trol circuitry delivering a very high speed of response and output accuracy maintainedto 0.5%. Since all components are of electronic design, they are virtually mainte-nance-free

Solid state based systems (PEN Voltage Stabilisers & PCEN AC Power Conditioners)are ideal solutions for equipment that must have output voltage accuracy better than1%.


High speed of response to voltagechanges

Usually less price competitive when com-pared to Servo Electronic design

Output voltage accuracy better than 1 %,typically 0.5%

High weight to kVA ratio compared toelectronic servo designs

No Moving parts virtually MaintenanceFree

High efficiency

Not Frequency dependent

Output voltage does not collapse onoverload or sever input voltage drop

Low output waveform distortion

Unaffected by load or power factorchanges

Will attenuate voltage spikes if required

www.AshleyEdison.com AC Automatic VoltageStabilisers & Regulatorsfrom Ashley Edison

Electronic ServoDesign Type

SES Series

Single & Three Phase

1 to 500 kVA

SESL Series

Three Phase

1 to 500 kVA

OSES Series


6 to 500 kVA

IP54 Outdoor

SES-R Series

Single Phase

3 to 10 kVA

Rack Mount

SES-HL & LH Series

Three Phase

10 to 100 kVA

Step Up / Step Down

PEN Series


2 to 200 kVA

Solid State SaturableReactor Design Type

5.

IVSI Series Oil Cooled

Three Phase

500 to 2000 kVA

Independent Phase VoltageCompensation

Solid State MagneticInduction Design Type

MVSI Series

Three Phase

15 to 1000 kVA

Independent Phase Voltage

Compensation


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c. Magnetic Induction Solid State Design

The design technology utilises a simple, yet highly reliable, rotor and stator designprinciple to increase or decrease the magnitude of the voltage in a series transformerwinding, which thereby delivers and maintains a constant voltage.

Unlike the Servo-Electro Mechanical design, this technology does not require carbonbrushes and there is no contact wear. As a result Magnetic Induction based stabilisersare highly reliable and can be viewed as virtually maintenance free solutions.


High output voltage accuracy Less price competitive when compared toServo Electronic design

High reliability

Virtually Maintenance Free with no con-tact wear or requirement for carbonbrush replacement

Available for only larger Three Phase applications above 200 kVA, we offer tworanges of Magnetic Induction based voltage stabilisation solutions MVS/MVSI AirCooled and IVS/IVSI Oil Cooled solutions.

As standard Magnetic Induction based stabilisers sense on a single phase and correctfor voltage fluctuations simultaneously across all three phases, being suitable forunbalanced loads up to 30%. MVSI & IVSI models on the other hand offer independ-ent phase sensing / control and are suitable for unbalanced voltages and loads up to100%.

The Oil Cooled models offer more efficient cooling and as a result tend to be smallerin physical size compared to their air-cooled MVS / MVSI counter-parts. Oil cooledstabilisers are ideal for deployment in very humid environments.

d. Ferro-Resonant - Super Isolation Solid State Design

Based around a highly reliable and endurable Constant Voltage Transformer (CVT),super isolation design based systems (PCV Single Phase AC Power Conditioners)are able to tolerate very wide input fluctuations, even when the input voltage drops aslow as 40%, the output voltage will be maintained at nominal voltage 5%..

With no moving parts and no electronic control circuitry there is no need for mainte-nance and is virtually an install and forgets solution. The design can withstand highinstantaneous overloads and is able to suppress lightning induced spikes and surges.

Compact in size and quiet in operation, this design has the inherent ability to withstanda ride-through even when there is a very short power failure, maintaining voltage for3msecs. This feature is exceptionally useful for sensitive electronic equipment whenthere are frequent short breaks or sever voltage dips.

AC Power Conditionersfrom Ashley Edison

Solid State Ferro-Resonant - Super Isola-tion Type

PCV Series

Single Phase

1 to 5 kVA

Electronic ServoDesign Type

PCS Series


1 to 150 kVA

Solid State Saturable

Reactor Design Type

PCEN Series


2 to 200 kVA

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High speed of response to voltagechanges

Not generally competitive in ratings above10 kVA

Output voltage does not collapse onoverload or sever input voltage drop

High weight to kVA ratio compared toother stabilisation methods

Attenuates voltage spikes

Competitively priced AC Power Condi-tioning solution for ratings of 5 kVA orbelow

No Moving parts virtually MaintenanceFree

Highly reliable with extremely high MTBFperformance

Inherent ride-through ability

Endurable, with long life expectancy

Frequency dependent not ideal forwhere severe frequency variations are anissue

e. Electronic Tap Changing Solid State Design

The Electronic Tap Changer design principle operates by automatically selecting oneof a series of taps on an auto transformer.


Most competitive in price for 2 kVA andbelow

Poor output voltage accuracy typicallyno better than 5%

High Efficiency

Negligible output waveform distortion

No Moving parts virtually Maintenance

Generally / Historically deliver a low MTBF

(Mean Time Between Failure)

Ashley-Edison atyour Service

In Telecommunications

Many such facilities are in remote loca-tions, supplied over long lines or evenfrom their own generators. Ashley-Edisonunits are in service worldwide - with com-

munication networks, even national secu-rity, depending on them.

In Computers

Computers and other electronic businesssystems are highly sensitive to powerfluctuations. Even a brief voltage dropbelow design limits will upset logic circuits,bringing chaos to stored data, calculationsetc. So the fast response Ashley EdisonAutomatic Voltage Regulators (AVRs) areplaying a major role in computer applica-tions around the world.

TV, radio and telephone transmitters andrelay stations, radar installations, naviga-tional beacons etc, all need dependablepower for reliable operation.

In Industry

Many processes and production lines slowdown and even stop as a result of power

problems. With just a simple voltage dropwelding equipment produces faulty welds,ovens and furnaces take far longer to heatup, electroplating processes lose theirefficiency and today's microprocessorcontrolled machine tools develop faults. Allreasons why industrial plants worldwidelook to Ashley-Edison for the solution totheir power problems.

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With our strong and wide manu-facturing base, Ashley Edison isable to meet the requirements ofmost Clients from our own in-house professional resources.

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The sheer span of capability

available from Ashley-Edisontells its own story. Every powerprotection solution we offer isbacked by the unrivalled experi-ence we have gained in worldmarkets over the last 25 years orso. In that time, our unique de-sign innovations have set newperformance levels and thebreadth of our offering hasbroadened to accommodate theneeds and ever demanding re-quirements of our growing Clientbase.

Our success is based entirely on our ability to meet the requirements of our Cus-

tomers dependably and cost-effectively. Today, where performance is everything ,whatever your AC mains supplyproblem Ashley-Edison have theability to offer a solution from ourextensive range of standard andcustom built products.

The Ashley-Edison ranges of ACVoltage Stabilisers / Regulators &Power Conditioners combine excep-tional performance and ISO9001certified build quality to deliverunmatched reliability and versatility,all at truly unbeatable prices.

Any further quest ions?

Dont hesitate to ask.

UK Head Off ice & EMEAInternational Sales:

Asi an / Pacif ic RimRegional Sales Office:

Ashley-Ed ison Asia Pte Limi ted 89 Short Street #02-08Golden Wall CentreSingapore 188216

Ashley-Ed ison International L im itedAbacus House,93 High Street,Huntingdon, Cambridgeshire,PE29 3DP, United Kingdom

Phone: + 44 (0)870 240 6162Fax: + 44 (0)870 486 0956

Email:Sales: [email protected]: [email protected]

Support: [email protected] Site: http://www.ashleyedison.com

Postal Address:Ashley-Edison International Limited, PO Box 1220, Bedford, MK43 9WX, United KingdomOther International Telephone Contact Points:

USA - Washington DC +1 202 657 5380

Aust ral ia - Sydney +61 (0)2 8003 7430

UK - London +44 (0)208 816 8460

Hong Kong - SAR, China +852 8198 0670

Why select a Voltage Stabiliser or AC Power Conditionerfrom Ashley-Edison?

Phone: + 65-6339 9433Fax: + 65-6339 7379

Email:Sales: [email protected]

Ashley-Edison atyour Service

In Refrigeration

When air-conditioning and refrigerationsystems experience any form of powerdisturbance, even just a minor voltagefluctuation, impaired performance or oftensystem shutdown is the end result.

With such problems being of commonconcern, Ashley-Edison units are regularly

relied upon to guarantee the availability ofa clean and regulated power source.

In Research

Electronic instruments play a major role inlaboratory work and their measuring accu-racy depends totally on the quality ofpower they receive. An abrupt voltagedrop from a factory process starting upnearby perhaps can invalidate the resultsfrom a costly research programme.

Today many world research establish-ments depend on Ashley Edison for ensur-ing the quality of their power supplywhether it be for a single instrument or an

entire laboratory.

Want to Learn more about the PowerProtection Solutions available fromAsh ley-Edison?

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Power ProtectioneCatalogue at

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Copyright 2009 Ashley-Edison reserve the right to change any or all

AEID1002 issue 1.3 - January 2009

voltage stabilisers buyers guide v1 3

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