Biddle CM300_400_500_UG 电路图.pdf

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1、MEGGER MEGGERCM300 MKII,CM400 MKII the black lead to Neutral, and the green lead to Earth (ground). 3.Select (M ) L-PE, L-N or N-PE as required. 4.Press either the Ior the TYPE key to display the test voltage. Press again until the required test voltage is displayed. 5.Press and hold the TEST key. 6

2、.Circuit resistance value is displayed. 7.Release the TEST button, but maintain connection to allow the test voltage to discharge. Power plug method The insulation resistance of an installation may be tested by using the plug terminated test lead at a convenient socket outlet. However:- a)The instal

3、lation must be isolated from the supply. b)The insulation test will incorporate the immediate circuit and any other circuit connected on the load side of the distribution board (D.B.). c)If a low reading is obtained, each circuit must be individually tested from the distribution board to locate the

4、fault. Operation (contd.) 14 After performing an insulation test, maintain connection to the circuit under test to allow the circuit to discharge. If voltage remains after a test, the instrument will normally display this as it is discharged. It must be verified that the test voltage has been discha

5、rged before moving onto the next test. When using the 2-wire lead set to measure insulation, always select (M ) L-N. The insulation will be measured between the two leads. 1.Disconnect Phase, Neutral and Earth from the D.B. 2.Insert the power plug into an installation socket on the isolated circuit

6、to be tested. 3.Select (M ) L-PE, L-N or N-PE as required. 4.Press either the Ior the TYPE key to display the test voltage. Press again until the required test voltage is displayed. 5.Press and hold the TEST key. 6.Circuit resistance value is displayed. 7.Release the TEST button, but maintain connec

7、tion to allow the test voltage to discharge. Method of measurement A current limited d.c. source is used, and the resistance is calculated from measurements of the voltage and current. The polarity of this d.c. source is as follows:- Range +ve terminal -ve terminal L-NNeutral (Black)Phase (Red) N-EN

8、eutralEarth L-EPhase (Red)Earth (Black) The voltage is only present when the test button is pressed. A measurement of the terminal voltage is made before the test and if this exceeds about 25 V the test is disabled. If d.c. voltage is detected across any of the terminals a discharge resistor is conn

9、ected across it. The reading is stable with a circuit capacitance less than 5 F. Loop Impedance measurement Loop impedance measurement of 0,01 up to 3.00 k can be made via installation sockets using the plug terminated test lead, or at any other convenient point on the installation using the two wir

10、e lead set. If Setting A is selected when using the plug terminated lead set, the polarity of the mains socket is immaterial. Line and Neutral will be swapped if necessary, and an indication given on the display. Setting b requires Line and Neutral to be fixed. The Installation Testers will measure

11、the loop resistance from the supply end of the standard test leads, allowing for their resistance. 15 Test results may be adversely affected by supply voltage fluctuations or electrical noise during measurement. It is recommended that tests are repeated and the results verified, if measurement resul

12、ts are considered abnormal. V o l t s Resistance- M 1000 V 500 V 250 V Insulation Test Voltage Phase to Neutral or Earth loop impedance measurement - Power plug method 1.Select (Loop) L-PE or L-N as required. 2.Insert the plug into an installation socket. 3.Supply voltage and polarity are displayed.

13、 4.Press the TEST key. 5.Measured loop value is displayed. On completion of this test, prospective fault current can be displayed by pressing the DISPLAY key. If desired the test can be repeated by pressing TEST again. Phase-Earth loop impedance measurement-Two wire method If an installation socket

14、is not available, use the the 2-wire lead set. 1.Select (Loop) L-PE. 2.Connect the red lead to phase and the black lead to earth. No connection to neutral is required. 3.Supply voltage is displayed. Note:- Though displayed, polarity indications are invalid with the two wire lead set and should be ig

15、nored 4.Press the TEST key. 5.Measured loop value is displayed. On completion of this test, prospective fault current can be displayed by pressing the DISPLAY key. If desired the test can be repeated by pressing TEST again. Bonded Metalwork Testing (1) This test is performed using the two wire lead

16、set. 1.Connect the black lead to the bonded metalwork. 2.Connect the red lead to phase. 3.Select (Loop) L-PE 4.Supply voltage is displayed. 5.Press the TEST key. 6.Measured resistance value is displayed. Bonded Metalwork Testing (2) This test can also be performed using the optional earth bond test

17、lead, allowing connection to an installation socket. 1.Connect the black flying test lead to the bonded metalwork. 2.Insert the power plug test lead into a socket (receptacle). 3.Select (Loop) L-PE. 4.Supply voltage is displayed. 5.Press the TEST key. 6.Measured resistance value is displayed. Operat

18、ion (contd.) 16 Automatic testing To aid rapid testing, the instruments can be set to start a test automatically when connected to the supply. This may be of use, for example, when using a clip and a probe. Select the range required and press the test key without the supply present. The instrument w

19、ill display 150 V and 300 V Nominal Voltage 110 V 230 V 400 V 3.Supply voltage is displayed. Note:- Though displayed, polarity indications are invalid with the 2- wire lead set and should be ignored 4.Press the TEST key. Test progress is displayed. 5.Measured loop value is displayed. If desired the

20、test can be repeated by pressing TEST again. Method of measurement The phase-earth, phase-neutral or phase-phase loop resistance can be measured. The instrument takes a current from the supply and measures the difference between the unloaded and loaded supply voltages. From this difference it is pos

21、sible to measure the loop resistance. The test current will vary from 15 mAto 40 A, depending on supply voltage and the loop resistance value. The test duration will depend on the loop resistance value. Possible sources of error The reading depends on a measurement of the supply voltage and therefor

22、e noise or transients caused by other equipment during the test could cause an error in the reading. One way to check for these is to do two tests and look for any difference in value. The instrument will detect some sources of noise and warn the user, where other instruments may give an incorrect r

23、eading. Any leakage current as a consequence of other appliances connected to the supply under test may affect the reading. If the Phase - Earth loop is being measured, this leakage may be due to filter capacitors etc. Operation (contd.) 18 RCD Testing The Installation Testers can test the operation

24、 of a variety of types of Residual Current Devices (RCD), measure the phase to earth loop resistance, and the contact voltage of the installation. Using an earth test spike, the earth resistance and fault voltage may be measured. If Setting A is selected when using the plug terminated lead set, the

25、polarity of the mains socket is immaterial. Line and Neutral will be swapped if necessary, and an indication given on the display. Setting b requires Line and Neutral to be fixed. Pre-Test Configuration Before performing an RCD test it is necessary to ensure that the instrument is correctly configur

26、ed for the rated c u r r e n t and the specific type of RCD to be tested, and for the type of test to be performed. RCD Current Rating From information given on the RCD to be tested, select the RCD current rating on the rotary switch. RCD VAR switch position (CM500 only) This position enables any RC

27、D with a non standard rated current between 10 mAand 1000 mAto be tested. The test is performed at the selected current, taking the 5I multiplier into consideration 1.Select (RCD) VAR. 2.Toggle the DISPLAY key to display the test current. 3.Press the RCL ( ) keys until the required test current is d

28、isplayed. Hold a key down to auto-repeat. 4.Press the DISPLAY key. The Supply Voltage, Test Type and RCD type are shown. These may be set up as given in the following sections. Setting precision:- 10 - 50 mA1 mA steps 50 - 500 mA5 mA steps 500 mA - 1000 mA10 mA steps RCD Type Pressing the TYPE key d

29、isplays the RCD type symbols. From information given on the RCD to be tested, select and set the type of RCD. D.C. Sensitive relays Some RCDs are electromechanical devices which can be saturated by the presence of d.c. Therefore if a d.c. fault occurs, or an a.c. fault occurs in the presence of quit

30、e a small direct current, the RCD may not trip. In this way the RCD is disabled and this becomes a potential hazard. Because of this, d.c. sensitive RCDs are available. 19 SymbolTest General Selective (delayed) D.C. Sensitive Ramp and Auto sequence tests are only available if the test current is set

31、 to 10 mA. The maximum possible test current (including 5Imultiplier) is 1000 mA(300 mA for d.c. sensitive RCDs). These limits are halved if the supply voltage is less than 200 V. Selective or Time delayed RCDs In some cases it may be necessary to have an RCD protecting an individual circuit or grou

32、p of circuits. If a fault occurs, the RCD nearest to the fault should trip to clear it, maintaining supplies to the other circuits. Selective RCDs (normal symbol )are used to discriminate faults occurring on separate circuits, and these have a minimum as well as a maximum trip time. Type of test Pre

33、ssing the Ikey displays the Type of Test symbols individually in sequence. Select the type of the test to be performed. No Trip Tests When an 1 2I (or No Trip) test is performed, the loop or earth resistance is measured, and in Setting b a two second No Trip test follows. Loop or Earth resistance me

34、asurement The loop resistance is measured at half the rated RCD current selected. Contact voltage is displayed which is the loop resistance multiplied by the rated RCD current. A high loop resistance will cause the instrument to display 90 V, and safely abort the test. The earth resistance is measur

35、ed if a lead is connected into socket S on the top of the instrument. Refer to E a r t h Resistance Measurement for correct positioning of the earth test spike. The earth test gives the resistance of the local spike, whereas the loop test will give the entire Line-Earth loop resistance value. 2 seco

36、nd No Trip test (Setting b only) This tests that the RCD does not trip when half the rated operating current of the RCD is drawn for 2 seconds. Tripping of the RCD will indicate that it is over sensitive, or that excessive earth leakage current is being drawn in the system. The load put onto the cir

37、cuit is resistive and therefore the test current is sinusoidal if the supply is sinusoidal. No Trip testing The test is the same for all RCD types. Select the Rated Current, the RCD Type and 12I. Connect to the installation and press the TEST key. If the settings are correct, and the RCD is in order

38、, the RCD trip should not operate and the Contact or Fault voltage will be displayed. If the RCD trip does operate during the Operation (contd.) 20 Display 1 2I 0 180 5I Type of Test No Trip Trip Test Trip test Ramp test Trip Test Description Performs a no-trip test at half the rated current of the

39、selected RCD. The test measures the earth loop resistance and contact voltage, or with a test spike, the earth resistance and fault voltage. Trip test at the rated current of the selected RCD. A 12I test is carried out before this, and the resistance and voltage are available after the test. The tes

40、t is always started on a zero crossing when the instantaneous voltage is on the rise. As above, but the test is always started on a zero crossing when the voltage is on the fall. Test current increases from half the rated current of the RCD. The result is the current at which the trip opens. Trip te

41、st at 5 X the rated current of the selected RCD. The choice of 0 or 180 gives greater accuracy of measurement.A 1 2I test is carried out before this, and the resistance and voltage are available after the test. 21 test, the message is displayed. This could be due to incorrect current rating selectio

42、n, excessive leakage current in the circuit, or a faulty RCD. If the problem is excessive leakage current, the source of the problem must be located and rectified before a trip test is performed, otherwise the result of the trip test will be invalid. Earth or loop resistance can be shown by pressing

43、 the DISPLAY key. Trip Tests The instrument will measure the trip time or trip current of common, selective (time delayed) and d.c. sensitive RCDs. The trip time is measured by timing the period from the application of a resistive load to when the supply fails. Some RCDs are sensitive to the polarit

44、y of the supply, i.e. whether the test current is applied with the instantaneous rising or falling. Tests should therefore be performed with the polarity 0 and 180 and the maximum time taken. D.C. sensitive RCDs are tested with a pulsed waveform. The rms current is 2 x the rated operating current of

45、 the RCD. As with the normal RCDs, these should be tested with 0 and 180 polarity. As the No Trip test can affect the trip time of some selective RCDs, there is a 30 second delay before activation of the trip test. It is possible to override this delay by pressing the TEST button when the instrument

46、 is counting (1.2.3.). Note:- Significant operating errors can occur if loads, particularly rotating machinery and capacitive loads are left connected during tests. For supply voltages above 200 V only. Trip Testing (measuring the trip time) 1.Select the RCD rated current on the rotary switch. 2.Con

47、nect to the supply as detailed below. 3.Select the required test using the Ikey - 0 or 180 for the normal trip tests, or 5Itogether with 0 or 180 for a 5I test. 4.Select the RCD type using the TYPE key. 5.Press the TEST button. If the RCD trips, the first display depends upon the Setting selected. S

48、etting A: The contact or fault voltage is displayed with the Loop or earth resistance and trip time available by pressing the DISPLAY key. Setting b: The trip time is displayed with the contact/fault voltage and Loop/earth resistance available by pressing the DISPLAY key. RCD rating D.C. sensitive R

49、MS currents 10mA14,1 mA 30mA42,4 mA 100mA141 mA 300mA424 mA 500mANot available 1000mANot available 150 mA 40 ms test When an RCD is fitted for personal protection, a test current of 150 mA must cause the RCD to trip in less than 40 ms. 1.Select 150 mA 40 ms on the rotary switch. 2.Connect to the supply as detailed below. 3.Select and set the Trip Test to 0 or 180 using theIkey. 4.Press the TEST key. If the RCD trips within 40 ms, the trip time is displayed. Ramp Test (measuring the trip current) The trip current is measured by applying a test current of