Biddle MIT520_UG 电路图.pdf

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1、M MIT520 5kV Digital Insulation Tester USER MANUAL RadioFans.CN 收音机爱 好者资料库 GSAFETY WARNINGS Safety Warning must be observed during use. IThe circuit under test must be switched off, de-energised, isolated and checked to be safe before insulation test connections are made. Make sure the circuit is no

2、t re-energised whilst the instrument is connected. ICircuit connections must not be touched during an insulation test. IAfter completing a test, capacitive circuits must be completely discharged before disconnecting the test leads. Capacitive charges can be lethal. ITested items should be firmly sho

3、rted out with a shorting link, after discharge, until required for use. This is to guard against any stored dielectric absorption charge subsequently being released thereby raising the voltage to potentially dangerous levels. IThe voltage indicator and automatic discharge features should be regarded

4、 as additional safety features and not a substitute for normal safe working practice. IIt is rare, but in certain circumstances, breakdown of the circuit under test may cause the instrument to terminate the test in an uncontrolled manner, possibly causing a loss of display while the circuit remains

5、energised. In this event, the unit must be turned off and the circuit discharged manually. ITest leads, including crocodile clips, must be in good order, clean and with no broken or cracked insulation. IThe instrument should not be used if any part of it is damaged. IWater on the surface of the inst

6、rument may lead to erroneous results. It is recommended that the instrument is not used in wet weather conditions. IThis instrument is not intrinsically safe and must not be used in hazardous atmospheres. 2 NOTE THE INSTRUMENT MUST ONLY BE USED BY SUITABLY TRAINED AND COMPETENT PERSONS. RadioFans.CN

7、 收音机爱 好者资料库 Pre-Test / during test key action table14 Test mode summary15 Insulation resistance IR test15 Breakdown mode / burn mode15 Alarm limit mode15 Step voltage SV test16 Polarisation index PI test, and dielectric absorption ratio DAR test16 Dielectric discharge DD test16 Specifications18 Acce

8、ssories19 Repair and warranty20 Symbols used on the instrument are: FCaution: risk of electric shock GCaution: refer to accompanying notes tEquipment protected throughout by Double Insulation (Class II) cEquipment complies with current EU directives. Terms used in this manual The word must is used t

9、o indicate that the instructions following should be followed under all circumstances. Failure to follow these instructions could result in damage to the instrument and / or a hazard to the operator. The word should is used to indicate that the instructions indicate best practice. CONTENTS 3 Safety

10、warnings2 Introduction4 General description4 Features4 Cleaning4 Power lead and battery charging5 Instrument controls and indicators6 Power On/Off button7 Test voltage L and M buttons7 Test start / stop button7 /I button7 Bbutton10 Fn button10 Mode button10 Timer L and M buttons11 Record button11 Re

11、cording to on-board memory11 Downloading results11 Deleting results11 Recording to a PC11 High voltage warning LED12 Line input present LED12 Test terminals12 Guard terminal12 RS232 / USB connections12 Battery bar graph13 Voltage at terminals13 Timer indicator13 Digital display13 Analogue display14

12、Secondary display14 RadioFans.CN 收音机爱 好者资料库 Features IContinuous resistance or current measurement on main display. IOptional resistance, current, or figure of merit measurements on secondary display. IStandard test voltages 250 V , 500 V , 1 kV , 2.5 kV , 5 kV INon-standard test voltages selectable

13、 between 50 V and 1 kV in 10 V steps, and selectable between 1 kV and 5 kV in 25 V steps. ITest modes include insulation resistance, polarisation index, step voltage and dielectric discharge. IThe dielectric absorption ratio is automatically calculated if the corresponding timers are set. IEither bu

14、rn or breakdown selectable in insulation resistance mode. IInsulation Alarm Limit available in insulation resistance mode. IProgrammable timers include a main test duration timer, plus T1 and T2 timers for time resistance method type tests. ILoad capacitance and time constant measurements displayed

15、at end of test. ILCD backlight. IData storage, data retrieval and real time data output. IUSB or RS232 communications. IBattery level / charge level indicator. Cleaning Disconnect the instrument and wipe it with a clean cloth slightly damped with soapy water or Isopropyl alcohol (IPA). INTRODUCTION

16、4 General Description The MIT520 is a microprocessor controlled 5 kV insulation tester offering measurement capability of up to 15 T. The instrument performs automatic tests and has data storage and data retrieval facilities. Polarization index and dielectric discharge tests are performed automatica

17、lly, and test duration and voltages can be adjusted according to user preference for these tests. A step voltage test can be performed automatically, with a default voltage of 1 kV , and test duration of 5 minutes. It is possible for the user to set different voltages and test durations for the step

18、 voltage test. The MIT520 can be powered from the mains supply or by its own internal rechargeable battery, which provides for at least 6 hours of continuous testing. A battery level indicator on the LCD display indicates battery capacity. Connecting power to the mains supply connector will automati

19、cally charge the battery whether the instrument is switched on or off. A high level of internal isolation allows the instrument to be used while the unit is supplied from the mains. An internal battery management system switches the instrument off after ten minutes of inactivity. If the battery appr

20、oaches a very low state of charge the instrument turns itself off, and mains power must be applied before the instrument can be used again. Recorded test results and settings will not be lost when the instrument is switched off. A comprehensive LCD display shows resistance, current, capacitance, tim

21、e constant, voltage, timer measurements, and figure of merit measurements such as polarisation index. POWER LEAD AND BATTERY CHARGING 5 If the power lead supplied is not suitable for your mains connection, do not use an adaptor. Always use a power lead fitted with the correct plug. The instrument is

22、 fitted with a two-pin IEC60320 power inlet. Most power leads are made with three-core cable, so the ground connection will not be used. Power lead connection table ConnectionUK/InternationalUSA Earth/Ground Yellow/Green Green Neutral Blue White Live (Line) Brown Black If using a fused plug, ensure

23、that it is fitted with a 3 Amp fuse. The instrument can be powered from 85 - 265 Vrms a.c. at 50/60 Hz. The battery will charge as long as the mains supply is connected, except when a test is in progress. The power On/Off button has a green LED, which illuminates when mains power is present. For opt

24、imum battery life, charge the battery after each use. A completely exhausted battery will take 14 hours to recharge. INSTRUMENT CONTROLS AND INDICATORS 6 Measurement terminals -veguard+ve RS232USBLine input Time L and M selectors Time L and M selectors Line input Present indicator Power on/off /I se

25、lector Burn indicatorAlarmData recordingTest modes Voltage at terminals Battery level Breakdown indicator High voltage warning indicator High voltage warning indicator Analogue display Timers Main, T1, T2 Dielectric absorption ratio/T1 timer Digital display Polarisation index/timer T2 Time constant

26、Capacitance display Data record High voltage warning indicator Test start/stopModeFunction Backlight on/off 7 When the test has stopped, the display continues to show the voltage present on the test leads. Pressing either test voltage L or M button will then display the test voltage immediately befo

27、re the end of the test. Test start / stop button A test will only start if this button is pressed, held and then released as soon as the red high voltage warning indicator LED lights. The LCD and red LED high voltage warning indicators flash when the test starts. A test will not start if the button

28、is released before the red LED shows, or pressed continuously for longer than 5 seconds. This is a safety feature to prevent a test being started inadvertently. The presence of a voltage greater than 50 V on the test leads is indicated with flashing high voltage warning indicators. Testing is disabl

29、ed if the external voltage exceeds 50 V . Testing will stop if the test start / stop button is pressed again, the preset test time is reached, or, if the unit is not in burn mode, insulation breakdown is detected. When a test has finished, the instrument will discharge the load, which may take some

30、time. The operator must always check the load has been discharged before touching the test leads. /I button Pressing this button toggles the digital and secondary displays. The details available when scrolling the secondary display will depend upon the test mode selected, whether timers T1 and T2 ha

31、ve been set, and the duration of the test. The digital display toggles between insulation resistance and current. Power On/Off button The instrument will only turn on if this button is pressed, held and then released when the display responds. The instrument will not turn on if the button is release

32、d before the display responds, or if the button is held down for too long. This is a safety feature to prevent the instrument being inadvertently turned on. The instrument is turned off either by timing out after 10 minutes of inactivity, or by pressing the button again. Upon switching the instrumen

33、t on the display will first show Ini while it undergoes a self-checking routine. When Ini disappears, the instrument is ready for use. Test voltage L and M buttons Using these buttons one of five test voltages can be selected: 250 V , 500 V , 1 kV , 2.5 kV , and 5 kV . The selected voltage is shown

34、on the display. A non standard voltage between 50 V and 5 kV can be selected by holding down the Fn function button whilst operating the buttons. The selectable voltage is adjustable in 10 V steps between 50 V and 1 kV , and adjustable in 25 V steps between 1 kV and 5 kV . An auto repeat facility is

35、 enabled when the button is held down, allowing faster travel through the range. If there is an external voltage greater than 50 V on the test leads, the high voltage warning indicators are flashed, and the display shows this voltage instead. The instrument will not perform a test if this voltage is

36、 greater than 50 V . During a test the display shows the actual voltage on the test leads. If the test voltage is changed during a test, the new test voltage will be displayed briefly. 8 Figure 1 - The result of an insulation resistance test (IR) Test settings: T1 and T2 times set in order to measur

37、e the DAR Test conditions: test runs for longer than 10 minutes as this is required for a PI reading. In the IR, PI, and DD modes the secondary display initially shows the PI (polarity index), DAR (dielectric absorption ratio), and, on completion of the test, the TC (time constant) and capacitance m

38、easurements. Toggling the display shows insulation resistances and currents. In the SV (step voltage) mode, the secondary display toggles between insulation resistances and currents. Figures 1 to 4 illustrate the display status for sequential /I key presses in the different modes. Press /I Press /I

39、Press /I Figure 3 - The result of a dielectric discharge test (DD) Test settings: T1 and T2 times set in order to measure the DAR Test condition: test runs for longer than 10 minutes as this is required for a PI reading. Figure 2 - The result of a polarity index test (PI) Test settings: T1 and T2 ti

40、mes set in order to measure the DAR Test conditions: timer defaults to 10 minutes, as this is required for a PI reading 9 Press /I Press /I Press /I Press /I Press /I Press /I 10 test voltage buttons. TL and TM represent the timer buttons. Button PressFunctionComment Fn + VLIncrement in 10 V stepsVo

41、ltage range between 50 and 1000 V Fn + VMDecrement in 10 V stepsVoltage range between 50 and 1000 V Fn + VLIncrement in 25 V stepsVoltage range between 1000 and 5000 V Fn + VMDecrement in 25 V stepsVoltage range between 1000 and 5000 V Fn + TL or TMCycle through timersSelect main timer, T1 or T2 Fn

42、+ ModeCycle through IR modesSelect breakdown, burn or alarm limit for IR test Fn + Download mode See Downloading results Fn + Clear stored dataThe record button is pressed twice Mode button Press down on the MODE button to cycle through and select the test mode. Modes of test to be chosen from inclu

43、de an insulation resistance IR test, a polarization index PI test, a step voltage SV test, and a dielectric discharge DD test. The insulation resistance IR test operates in either burn or breakdown mode, with an option of setting a resistance threshold alarm limit. These modes can be cycled through

44、and selected by holding down the Fn button Figure 4 - The result of a step voltage (SV) test Test condition: timer defaults to 5 minutes and test voltage defaults to 1000 V . Bbutton Pressing this button toggles the display backlight on and off. Fn button The function button when pressed allows othe

45、r keys to perform another function. This is summarized in the table below. VL and VM represent the Press /I Press /I 11 30, 45 and 60 seconds. After 60 seconds, at minute intervals up to 10 minutes. After 10 minutes, results are recorded at 5 minute intervals until the test terminates. At each inter

46、val the recorded data will contain selected voltage, test time elapsed, voltage applied, leakage current, and insulation resistance. Downloading results Connect the instrument to the RS232 / USB port of a PC running Download Manager. Refer to section RS232 / USB connection for set up details. Start

47、Download Manager on your PC, select the MIT520 / MIT1020 driver and right click the icon. Select Download. Switch the instrument on and wait until initialisation is complete. Press the function key along with the record key. The instrument now displays dld to indicate download mode. Press and hold d

48、own test button until download begins, shown by analogue display lighting clockwise. Results will not be erased during this operation and so may be downloaded repeatedly. Deleting test results Switch the instrument on and wait until initialisation is complete. Hold down the function key and press th

49、e record key twice. The instrument now displays clr to indicate clear mode. Press and hold down test button until clear process begins, shown by analogue display lighting anti clockwise. Press the MODE button to exit without deleting the results. Recording to a PC While carrying out a test, the instrument will output the test voltage, test current and resistance every second. Refer to section RS232 / USB connection for setup details. Connect the instrument to the RS232 / USB and pressing the Mode button. Timer L and M buttons The main timer can be set up