(Z0940) STAC100 Manual (Inglés)

CONTENTS

1 Unpacking

1 General Description

2 Technical Data

3 Health and Safety

4 Electromagnetic Emissions

6 Installation

7 Operation

8 Calculating the test voltage

9 Applications

10 Maintenance

10 Declaration of Conformity

UNPACKING

(a) Remove the ST-AC 100 and the handle from their bags and check them for damage. Ifany part is damaged, notify the carrier and supplier immediately. Keep all packing material forinspection. Do not use the ST-AC 100.

(b) The package contains the following items:

1 Generator unit.1 Probe handle.1 Flexible electrode.1 Operating instructions.

If any of these are missing, contact your supplier immediately.

(c) Keep the packaging in case the unit needs to be sent back for repair in the future, orneeds to be stored. All items should be in plastic bags before being placed in the carton.

GENERAL DESCRIPTION

(a) The ST-AC 100 high frequency tester comprises of a light weight, hand held probeconnected by a cable to a portable generator.

(b) A robust aluminium case houses the generator and its components. On the front panelof the case there is a :-

Mains ON/OFF rocker switch, with an indicator lamp.Variable output control knob .Handle probe connection.

On the back panel of the case there is a :-

Earth return socket, 4mm with plug.Mains voltage selector switch.IEC mains input socket.

Buckleys (UVRAL) Ltd. Range Road, Hythe, Kent. CT21 6HG.Tel:- 01303 260127/8 Fax:- 01303 262115

TECHNICAL DATA

Operating temperature range : 0 to +30°C

Storage temperature range : -10 to +40°c

Supply voltage(see rear panel of generator unit) : 120V ± 10% A.C. or 240V ± 10% A.C.

Supply frequency : 50 to 60 Hz

Power consumption : 48 watts

Output voltage : 5 to 55KV

Output frequency : 100KHz

Net Weight : 3.7kgs

Dimensions (Generator) : 205mm W x 175mm D x 130mm H

Altitude : Up to 2000m

Relative Humidity : Maximum 80% (Non-Condensing)

Installation Category : Category II (over-voltage transients)


HEALTH AND SAFETY

Below is a list of markings that are used on the unit :

CAUTION : Refer to accompanying documents

CAUTION : Risk of Electric Shock

WARNINGS: Denotes hazards to the operator

Read the information in this manual before using the equipment.

The works safety officer should approve the installation of this equipment and that theoperator has been trained in its use.

(a) The ST-AC 100 Spark Tester is intended to generate a powerful high frequencydischarge, therefore the unit should only be used by responsible and authorised personnel thathave read and understood this manual.

(b) The ST-AC 100 spark tester is designed to protect the operator from receiving adangerous electric shock. The case is earthed and the high voltage output is isolated from themains supply.

(c) The probe should NEVER be directed at the body.

(d) The high voltage generated by this unit is at a frequency of 100 KHz, well above themotor frequency of the human central nervous system. A serious shock is unlikely if the probeis accidentally touched during operation, but the greater risk is to those who might have anincipient heart condition, or the reflex action when receiving a high frequency shock, relatingto contact by the operator if working in the vicinity of hot surfaces or rotating machinery.Injury could also occur if the spark reached sensitive parts of the body (e.g. eyes).

(e) In a reasonably ventilated room of a volume greater than 40 metres cubed, theexposure to ozone produced by the high voltage spark should not present a major risk tohealth.

(f) In a 'confined space' situation then it is likely that ozone levels will exceed theexposure limit and present some risk to health. Under these conditions adequate ventilationshould be provided.

(g) When in use always position the unit so that mains ON / OFF switch is easilyaccessible to the operator


ELECTROMAGNETIC EMISSIONS - EUROPEAN UNION DIRECTIVE89/336/EEC:

Before operating this equipment it is essential that the following action be taken.

RISK ASSESSMENT:

As this equipment will produce an electromagnetic emission, when actually arcing downthrough a fault to earth, a risk assessment of the area in which the unit will be used should becarried out. For example, the equipment should not be operated where the electromagneticdisturbance generated may hinder the operation of such apparatus as:-

a) domestic radio and television receivers.b) industrial manufacturing equipment.c) mobile radio equipment.d) mobile radio and commercial radiotelephone equipment.e) medical and scientific apparatus.f) information technology equipment.g) domestic appliances and household electronic equipment.h) aeronautical and marine radio apparatus.i) educational electronic equipment.j) telecommunications networks and apparatus.k) radio and television broadcast transmitters.l) lights and fluorescent lamps.

The Directive also requires the above types of equipment to have an adequate level ofelectromagnetic immunity from such emissions. However, it should be borne in mind, whendoing an assessment, that the directive applies to equipment supplied or taken into serviceafter the 1st January, 1996 and the equipment you are assessing, although legal but because ofage, may not have this immunity.

The more common areas of risk are computers, critical safety equipment on lathes (fail/safeelectronics), supply cables, control cables, signalling and telephone cables above, below andadjacent to the area where the tests are being carried out. The wearers of pacemakers andhearing aids should also be considered. Measuring and calibration equipment may also besusceptible.

To make a comparison. Arc Welders, when in use, would create interference far greater thanthis type of tester. It would, therefore, be reasonable to assume that if an arc welder had beenused in the area, without problems, then an AC Pinhole Detector would be safe. However, itwould be unwise to use both of these equipment’s on the same site at the same time as theymay interfere with each other.


The test area itself should also be considered. For example, the layout of the area would affectthe distances which the emissions would travel. Buildings and metal structures would shieldagainst, or reduce, emissions. If the tester was being used inside a metal tank, for instance, thetank would act as a very good shield.

This would not, however, have the same effect if you were testing a plastic tank. If you weretesting the circumference of a metal pipe then the pipe would act as an aerial and transmit theemissions further than expected.

Please bear in mind that electromagnetic emissions travel in all directions and can even bebent or deflected. This includes upwards and downwards so proximity to other floors ofbuildings and even airports must be considered. Neighbouring works or sites should also betaken into account as there may well be equipment in use that could be affected by yourtester's emissions..

Most of the time this type of tester will be used on outdoor sites and be remote fromsusceptible equipment, but the SITE SAFETY OFFICER should always be consulted beforeany testing is carried out. This is particularly necessary where electronically controlledequipment is being used.

Timing of the testing should also be considered as a means to avoiding interference problems.Consider testing when all susceptible equipment in the test area is switched off.

OTHER HINTSIf your tester is only used in one area, then simple tests will ascertain where the testerinterferes with other equipment and these can be resolved by scheduling the proper testingaccordingly. Again, you should remember neighbouring works. You may have switched offyour computer but next door may not have and would therefore be susceptible.

We have designed this unit with EMC in mind and therefore all leads are of optimum length.If longer leads are used then they could transmit in a similar way to aerials and causeinterference.

Always ensure that the tester and test piece is securely earthed because this will reduce anyinterference generated by the spark. This also prevents static build-up in the operator andthereby avoiding electric shock.

WHEREVER YOU ARE INTENDING TO USE EQUIPMENT OF THIS TYPE, ON YOURSITE OR ON A CUSTOMER'S, ALWAYS OBTAIN CLEARANCE FROM THECOMPANY SAFETY OFFICER.


INSTALLATION

WARNING:This equipment should not be installed or used in any

combustible atmosphere as the high voltage will cause aspark, and an explosion could result.

WARNING:This equipment should not be installed or used in a situation

where it would be exposed to damp or wet conditions, orwhere the amount of conductive dust is greater than would

occur in a normal situation.

(a) Check that the operating voltage is in accordance with the available supply voltage byreference to the voltage selector switch on the back of the generator unit.

(b) Connect a suitable plug (preferably fused at 3 Amps) to the mains supply cable asfollows:-

BROWN-LIVE, BLUE-NEUTRAL, GREEN/YELLOW EARTH.

WARNING:This equipment MUST be Earthed


OPERATION

WARNING:THE EQUIPMENT SHOULD NOT BE OPERATED IF

ANY PART IS IN A DAMAGED CONDITION.

(a) Screw the flexible probe electrode into the red end of the handle.

WARNING:DO NOT CONNECT OR DISCONNECT THE PROBE

LEAD PLUG OR THE FLEXIBLE PROBE ELECTRODEWITH THE GENERATOR CONNECTED TO THE

MAINS SUPPLY.

(b) Set the output control knob fully anti-clockwise (minimum output) and check that themains ON/OFF switch is in the OFF position. Connect the plug to the mains supply socketand switch on. Holding the probe handle in one hand so that the probe tip is at least 20cmfrom any object. Switch ON the generator.

WARNING:UNDER NO CIRCUMSTANCES SHOULD THE HANDLE

BE PUT DOWN WITH THE UNIT SWITCHED ON.

(c) Select the output for the required size of spark by holding the probe tip close to the4mm earth terminal on the back panel of the generator and turn the control knob to set therequired spark length.

ANTICLOCKWISE - MINIMUM OUTPUT,CLOCKWISE - MAXIMUM OUTPUT.

(d) The high voltage spark should only be taken from the end of the flexible probe and notfrom the side i.e.. through the probes plastic covering, as the heat of the spark may melt theplastic and could cause a fire hazard.

(e) The probe should always be kept moving when testing as the high frequency outputcan cause heating in the article under test and could burn a hole in it. Also the output controlshould be adjusted for the lowest output at which an effective test can be carried out.

(f) When the testing has finished, switch OFF the generator before putting down thehandle and then remove the plug from the mains supply.


CALCULATING THE TEST VOLTAGE

The test voltage needs to be high enough to find the fault but not too high as to makeone. With reference to B.S. 358 (Measurement of voltage with Sphere-Gaps) it can be seenthat 32,000 volts will jump a gap of 1cm between spheres of 5cm diameter. The same voltagewill jump a gap of nearly 3cm between needles. This is because the shape of the electrodeeffects the point at which corona discharge starts i.e. the sharper the points on the electrodethe lower the voltage necessary for corona discharge to start.

Sparkover, or complete temporary breakdown of the air between the electrodes, willoccur when the voltage is increased to cause localised breakdown. This soon spreadsthroughout the whole of the inter-electrode space and gives the required number of ions tocarry the current (this can be tens of amperes). With this sudden increase in current there is acorresponding fall in the voltage across the electrode to a very low level.

For the thicker types of material in the range 1mm to 30 mm the formula used in theNACE Standard RP-02-74 has been found to work well in most cases.

Test Voltage Tcoating= ×1250where Tcoating is the coating thickness

in mils (0.001").

Alternatively

Test Voltage Tcoating= ×250where Tcoating is the coating thickness

in microns (0.001mm).

After the test voltage has been worked out it is necessary to check that the voltage isnot so high as to damage the material. The Dielectric Strength is the voltage at which thematerial starts to break down, this is expressed in volts per mm, normally with D.C.. To takean example, a 2mm thick sheet of P.V.C. would require a voltage of 11,180 volts using theabove formula, referring to the manufacturers technical data, the Dielectric strength is 8,400volts per mm. 2 x 8,400 = 16,800, so the test voltage should not damage the material.

If the Dielectric strength was found to be only 5,000 volts per mm, then the testvoltage would be too high. In this case a high voltage test may still be used if tests are carriedout to ensure that the test is valid. Make a small hole in a test piece, then with the electrodeover the hole, increase the voltage until a spark jumps the gap. Make a note of that voltage(approximately 5,000 volts) and then use a voltage half way between the two (7,500 volts).Now make some more holes in the test piece, this time at an angle, and using a 7,500 volt testvoltage , make sure that all the faults are detected.

The output voltage of the ST-AC 100 can be roughly set by dividing the test voltage by1700, the answer is in mm. e.g. 20,000 /1700 = 11.75mm. Hold the test probe at the calculatedgap from a piece of earthed metal and increase the output voltage until the spark jumps thegap.


APPLICATIONS

Insulation Testing

(a) The insulation to be tested should have a conductive backing, e.g. if a joint in a plasticor rubber sheet is to be tested it should be laid on a metal sheet, if this is not practical a stripof aluminium foil or copper wire can be placed behind the joint. If possible it should beconnected to earth, although this is not necessary as long as the area of the metal backing islarger than area of the probe, e.g. greater that 1000 : 1.

(b) Adjust the output voltage of the ST-AC 100 for the item under test (see Calculatingthe test voltage).

(c) Slowly sweep the area to be tested, looking at the probe at all times. When a fault ispassed over the high voltage brush discharge will change to a single spark, remove the probefrom the surface and mark the point where the fault was detected.

NOTE:The size of the electrode has an effect on the output voltage, the larger the area of the

electrode the lower the output voltage, for this reason we recommend a maximum size of152mm.

Gas Discharge Lamp Testing

(a) The ST-AC 100 can be used to excite gas discharge lamps, to confirm that the vacuumhas not been lost. e.g. fluorescent tubes.

(b) The lamp or tube should not be fitted as the high voltage may accidentally makecontact with the fitting and be passed into the wiring and could damage other equipmentconnected to that wiring.

(c) Hold the probe against the glass of the lamp and increase the output voltage fromminimum, if the lamps vacuum is all right the lamp will glow where the probe touches theglass.

Ozone Production

(a) Small quantities of ozone can be produced from the high voltage spark, useful forchemistry lecture demonstrations etc.


MAINTENANCE

(a) The ST-AC 100 has been designed so that no maintenance is required by the user.

(b) The ST-AC 100 should be inspected from time to time to check that the case, probehandle, probe connecting cable or mains cable have not been damaged. If damage is found theunit must not be used, and it must be returned to the manufacturer for repair.

EC Declaration of Conformity

We: Buckleys (UVRAL) LtdBeta WorksRange RoadHytheKent CT21 6HGEngland

as manufacturer of the apparatus listed, declare that the product:

ST-AC 100 High Frequency Spark Tester

Serial No: ________________________

has been manufactured in conformity with the following standards and specifications:

Safety: IEC 1010-1: 1990and amendments 1: 1993 and 2: 1995(ERA report 97-0187)

EMC: EN 55011: 1991 for emissionsEN 50082-2: 1995 for immunityTechnical Construction FileERA TCF Report No. 4473/1K1/1

and therefore conforms with the requirements of Council Directive 73/23/EEC relating tosafety requirements and Council Directive 89/336/EEC relating to electromagneticcompatibility.

Issued on: 26 November 2002

Authorised by : Cliff MooreQuality Manager


(Z0940) STAC100 Manual (Inglés)

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