User Manual - GNS Associates Pty Ltd
Contents
1. 7 8 ORDERING INFORMATION 7 5912 KILOVOLTMETER USER MANUAL 1 5912 PRECISION KILOVOLTMETER 1 OVERVIEW Type 5912 Kilovoltmeter is a precision instrument intended for the true rms measurement of power freguency ac voltages up to 12 000V rms The instrument is portable and battery powered There are no operator controls reguiring adjustment during operation Readout is given on a bright 4 2 digit LED display Where reguired the display is easily read at several metres distance The embedded microcontroller automatically trims the internal measurement circuits for enhanced precision To conserve battery energy the instrument automatically enters a snooze mode if left inactive for several minutes Return to normal operation is achieved by recycling the power ON switch 2 FUNCTIONAL DESCRIPTION The voltage to be measured is connected to a free standing resistive divider unit The divider has a nominal ratio of 6500 1 and an input resistance of 100MQ Stray capacitance effects are greatly reduced by a trimming capacitor in the base of the unit and the divider performance is effectively independent of frequency over the specified range of operation The output from the divider is buffered and fed to a precision rms dc converter and thence to a 16 bit analog to digital converter ADC The digitised signal is transmitted in serial format to the microcontroller which in turn control2. the factory provided always that no exceptional events have occurred during this period For more information about accuracy limits and recommended re calibration intervals please contact the factory 5 Crest Factor is defined by Upeak Urms 5912 KILOVOLTMETER USER MANUAL 7 6 MAINTENANCE There are no regular maintenance items applicable to this system Periodically clean the divider column and the instrument front panel with a clean damp cloth Do not use abrasives or solvents For information about recommended calibration intervals and procedures please contact the factory 7 ELECTROMAGNETIC COMPATIBILITY Type 5912 is designed for full compliance with the requirements of Australian and New Zealand Standards for electromagnetic compatibility EMC 8 ORDERING INFORMATION 5912SX Precision kilovoltmeter complete with divider unit connecting cable and instruction manual 5912 01 Divider unit 5912 02 Shielded connecting cable 5912 03 Silicone insulated high voltage test cable 5m length unterminated 5912 04 Battery charger for NiMH batteries 5912 05 Test module 5912M User manual The pdf version is available for download from our website 5912 KILOVOLTMETER USER MANUAL NOTES 5912 KILOVOLTMETER USER MANUAL NOTES
3. 5912 True rms Precision Kilovoltmeter LOODU User Manual GNS Associates Pty Lid http www gnsassoc com au 1 Horace Street Malvern Vic 3144 Australia Telephone 61 3 9509 2203 Facsimile 61 3 9576 0635 Email info gnsassoc com au Copyright 2006 GNS Associates Pty Ltd All rights reserved WARNING THE APPARATUS DESCRIBED IN THIS MANUAL IS DESIGNED TO CONNECT TO AND MEASURE DANGEROUS VOLTAGES USERS SHOULD OBSERVE STRICT SAFETY PRECAUTIONS AT ALL TIMES ON NO ACCOUNT SHALL GNS ASSOCIATES PTY LTD BE LIABLE FOR LOSS DAMAGE OR INJURY ARISING FROM UNSAFE PROCEDURES CONTRARY TO THE INSTRUCTIONS CONTAINED HEREIN AND OR BEST INDUSTRY PRACTICE 5912 KILOVOLTMETER USER MANUAL 0 TABLE OF CONTENTS OVP A VE a ti 1 2 FUNCTIONAL DESCRIPTION ci 1 OPERATING INSTRUCTIONGS vaia mana vanavanaema aan am anavaaa emane 2 NO acted A na ala aaa TR ai 2 I EAE o i oe o aaa ni 3 3 3 Over range Indication aaa bana ad 3 34 500028 Mode maana sidan di viva kaia damn aaa a mk aaa aa 3 3 5 Non Sinusoidal Waves ai 4 3 6 Battery REPIACEMNENI ia 4 4 TROUBLESHOGO TING aaa 4 SSPECIFICATION Sisa 6 5 1 Absolute Maximum Ratings 6 5 2 Electrical Characteristics ii kev A Aid 6 5 3 Environmental 6 A SA A 6 6 MAINTENANGEsG o a 7 7 ELECTROMAGNETIC COMPATIBILITY
4. 912 03 or equivalent Ensure that the HV cable is supported well clear of other cables low voltage circuits and grounded metalwork Also keep the HV cable clear of the sides of the divider column since unwanted capacitive coupling may affect the accuracy of high precision measurements 1 We recommend that all Users should draw up properly structured Safety Procedures governing the use of this equipment and associated facilities For further advice on safety aspects contact GNS Associates 2 For optimum results the HV supply should have short term voltage stability at least one half order of magnitude better than the instrument resolution that is stable to within 3 x 10 For further advice on experimental techniques and performance requirements please contact GNS Associates 5912 KILOVOLTMETER USER MANUAL 3 Keep cell phones and other wireless eguipment well away since such apparatus can interfere with the sensitive circuits of the 5972 Do not approach or handle the divider unit when energised 3 2 Operation 1 Turn ON the instrument Note that the automatic self test is executed with indications as follows a Display momentarily reads 18 888 Display momentarily reads 5912 c Display momentarily reads 0 0XX where XX is the room temperature in C d Display reads 0 000 NOTE If the above sequence is corrupted or incomplete or if any segments are missing from the LED display refer to Section 4 Troubleshoo
5. ity varies modulates Check replace battery Contact factory 4 TROUBLESHOOTING cont d PROBLEM SYMPTOM Display gives unsteady reading Display fails to respond when external voltage 2 50V applied 5912 KILOVOLTMETER USER MANUAL 5 ACTION REGUIRED Check HV supply see Section 3 1 Contact factory Check all connecting cables Connect optional test module 5912 05 and follow instructions supplied with this unit Contact factory 5912 KILOVOLTMETER USER MANUAL 6 5 SPECIFICATIONS Parameter Value Units 5 1 Absolute Maximum Ratings Maximum instantaneous input voltage 25 kV Maximum sustained input voltage gt 1s all waveforms 16 kV rms 20 kV peak 5 2 Electrical Characteristics Voltage measurement range 0 05 12 000 kV rms Nominal Accuracy 0 3 reading 0 002 kV sinusoidal waveform only Display resolution 0 001 kV Frequency range 45 65 Hz Crest factor range all waveforms 1 0 2 0 Input resistance to Divider Unit 100 MA 5 3 Environmental Operating temperature range 15 30 C Storage temperature range 0 45 C Humidity 10 85 non condensing 5 4 Power source Four 4 x NiMH rechargeable cells AA size Endurance in continuous operation active mode 20 typ h 3 All specifications relate to a sinusoidal voltage waveform and an ambient temperature of 25 C except where otherwise noted 4 Guaranteed for six 6 months from the date of initial despatch from
6. s the output display and all peripheral functions The power supply provides all requisite internal voltage sources including the very low noise clean power required by the ADC and associated circuits HV input DIVIDER UNIT Fig1 Simplified Block Diagram 5912 KILOVOLTMETER USER MANUAL 2 3 OPERATING INSTRUCTIONS CAUTION BEFORE USING THIS INSTRUMENT ALWAYS CHECK THAT e ALL RELEVANT SAFETY PRECAUTIONS ARE IN PLACE AND OR READY FOR CORRECT IMPLEMENTATION THE INTENDED MEASUREMENTS LIE WHOLLY WITHIN THE SPECIFIED RATINGS AND CAPABILITIES OF THE INSTRUMENT SEE SECTION 5 SPECIFICATIONS 3 1 Setup Ensure that the HV supply has the necessary electrical characteristics consistent with the desired level of measurement precision and repeatability Any jitter or instability in the power supply will have the same effect as background noise and will detract from the very high resolution of this instrument It follows that unstabilised mains powered apparatus for example a simple step up transformer is unlikely to give satisfactory results Place the divider unit in a safe and convenient position and connect the ground lead Connect shielded cable 5912 02 between the divider and the instrument Attach a safety chassis ground to the terminal at the rear of the instrument HV input Fig 2 Typical Test Setup Ensure that the high voltage HV supply is not energised and attach the active cable 5
7. ting 2 Ensure that all personnel are clear and energise the HV supply Note the indicated potential in kilovolts 3 Smoothly adjust the HV supply level and make voltage measurements as required NOTE For high precision measurements allow not less than three 3 seconds settling time for each reading 4 When measurements are no longer required de energise the HV supply and render all HV circuits safe 5 Turn OFF the instrument power switch 6 If the instrument is to be stored for an extended period 1 month or more remove the battery cells see Section 3 5 below 3 3 Over range Indication If at any time the applied voltage exceeds the specified maximum 15 999 kV the over range indication 7 will appear on the display Immediately reduce the voltage when this indication appears 3 4 Snooze Mode When left switched ON for more than ten 10 minutes with an applied potential of less than 0 1kV the instrument will automatically enter a SNOOZE mode to conserve battery energy In this mode the display is turned off and certain internal circuits are reduced to micropower levels A flashing blue LED on the front panel which itself takes very little power indicates that the instrument is merely asleep and not faulty To return to normal operation simply turn the power switch OFF and then ON again 5912 KILOVOLTMETER USER MANUAL 4 3 5 Non Sinusoidal Waveforms Type 5912 will correctly indicate the true rms val
8. ue of distorted non sinusoidal voltage waveforms within the specified range of Crest Factors see Section 5 Specifications 3 6 Battery Replacement A LOW BATTERY condition is indicated by the red LED on the front panel To replace the battery perform the following steps 1 De energise and disconnect the HV supply and switch OFF the instrument 2 Unscrew the thumbscrew on the rear panel and remove the battery cover 3 Carefully withdraw the battery assembly and replace each of the four 4 cells in turn with new or recently recharged NiMH cells of the correct size and capacity see Section 5 Specifications CAUTION OBSERVE CORRECT POLARITY FOR ALL CELLS 4 Re insert the battery assembly and replace the cover Do not over tighten the thumbscrew PLEASE NOTE The instrument will perform satisfactorily for some hours with the LO BATT indicator alight However the full rated accuracy is not guaranteed under these conditions Also persisting in this mode of operation carries some risk of damage to the battery 4 TROUBLESHOOTING WARNING THERE ARE NO USER ADJUSTABLE OR USER REPAIRABLE ITEMS IN THIS EQUIPMENT ANY ATTEMPT TO OPEN THE CASE OR OTHERWISE TAMPER WITH THE INSTRUMENT OR ITS PERIPHERALS WILL IMMEDIATELY VOID ALL WARRANTIES PROBLEM SYMPTOM ACTION REQUIRED Power ON self test corrupted or incomplete Contact factory No display Recycle power ON switch Check replace battery Contact factory Display intens
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