Biddle MJ Series - BiddleMegger.com

1 Major MEGGER Insulation TestersMJ159 (212159), MJ160 (212160), MJ359 (212359), MJ459 (212459), MJ559 (212559)User GuideMEGGER Contents2 Safety Warnings3 General Description4 OperationTesting precautions5 Preliminary checks5 Battery condition check (MJ459andMJ559)5 Battery replacement (MJ459)5 Battery Charging (MJ559)5 Performance checks6 Voltage measurement6 Resistance Measurement6 Insulation testing7 Using the Guard terminal7 Fuse Checking and Replacement8 Specification9 Accessories12 Application NotesPreventive maintenance13 Insulation Testing Concepts14 Repair and Warranty15 Safety Warnings Safety Warningsand Testing Precautionsmust be read and understood before the instrument is used. They must be observed during use.

2 The circuit under testmust be switched off, de-energised and isolated before any test connections are made. Test leads, probes and crocodile clips mustbe in good order, clean and with no broken or cracked insulation. Circuit connections must notbe touched during a test. Circuits must be discharged beforedisconnecting the test leads. Replacement fuses mustbe of the correct type and rating. When making a voltage measurement, the Test button must notbe pressed. The instrument should notbe used if any part of it is damaged. Safety Authorities recommend the use of fused test leads when measuring voltageon high energy systems. Refer to Testing Precautions for further explanations and precautions. NOTETHE INSTRUMENTS MUST ONLY BE USED BY SUITABLY TRAINED AND COMPETENT Description4 Major MeggerMJ159, MJ160, MJ359, MJ459, andMJ559testers are compact instruments designed to giverapid, accurate and direct measurement of continuity andinsulation resistance of domestic and industrial wiring, cables,transformers, motors, generators electrical machinery andappliances.

3 Being self-powered, the instruments are suitable for useduring installation and commissioning work as well as forservice and maintenance applications. Insulation measuring range is 0,1 to 2000 M (MJ1600,1 to 1000 M ). Automatic discharge for capacitive circuitsunder test is provided. A guard terminal can be used to minimise the effects ofsurface leakage when carrying out insulation resistance addition each instrument has a 5000 Resistance rangemaking them ideal for testing electrical test voltages are 100 V, 250 V, 500 V and 1000 voltsselectable. (MJ160: 50 V, 100 V, 250 V and 500 volts).All instruments have a mains (line) voltage measuring rangeof 0 to 600 V. Although calibrated for voltage, this featurewill give decaying voltage indication following the testing ofequipment possessing instruments use a moving coil meter with taut bandsuspension; white scales on a black scale plate and anorange dayglow needle indicates the resistance value MJ160are powered by a low voltage, handcranked, brushless generator which is connected, after rectification, to a to converter.

4 The generator isdesigned to be easy to turn even under full load. Dual powered units are mains (line) powered with either aninternal hand cranked generator, or battery cells that are re-chargeable by the instrument s internal charger. TheMJ359is dual mains (line) orhand cranked generatorpowered. TheMJ559 is dual mains (line) orrechargeable batterypowered. Power for the MJ459is derived from six 1,5 V (IEC LR6)cells. The cells are connected to a to converter toprovide the test and MJ559are fitted with a button switch to enablethe battery charge to be case is robust, yet light-weight, made from a strongpolycarbonate plastic. Mounted on top of the case is a 5position, rotary, range selection switch and a Test shrouded 4 mm terminal sockets marked - , G and + are provided on the side of the case for test lead connection.

5 Test lead resistance is included in the instrument this reason, only the test leads supplied or replacementones should be the test leads have been connected to the instrumentterminals, the carrying handle folds down neatly over the carrying handle accidentally become detachedfrom the case it may easily be sprung back into PRECAUTIONS1. The instruments must only be used by suitably trainedand competent persons. 2. The instruments can give an electric shock. Highly capacitive circuits ( long lengths of cable) charged toseveral kV can create a potentially lethal charge. Circuitconnections must notbe touched when Care must be taken to prevent capacitive circuits becoming disconnected during a test, leaving the circuit in a charged The voltmeter and automatic discharge feature of the instruments should be regarded as additional safety features and nota substitute for normal safe replacements must be of the correct type and rating.

6 See Specification .6. If any part of the instrument is damaged, it should not beused, but returned to the manufacturer or an approvedorganization for Should the plug on the power cord (MJ359and MJ559) not be the type for your receptacles (socketoutlets) do not use an adaptor. Use a suitable alternative power cord, or if necessary change the plug by cutting the cord and fitting a suitable colour code of the cord is InternationalGround)GreenYellow/GreenNeu tral WhiteBlueLineBlackBrown If using a fused plug, a 13 Amp fuse to BS1362 should CHECKSB attery Condition Check (MJ459 &MJ559)Before initial use ofMJ559, charge the battery. To carry outa battery condition check, press the black battery conditionbutton (marked ) and confirm that the needle settles withinthe portion of the scale marked with the battery symbol.

7 If theneedle settles at less than half scale, the cells must bereplaced (MJ459), or re-charged (MJ559) beforeproceeding with any checks or Replacement (MJ459 only)The cells are housed in a battery compartment in the base ofthe instrument. To change the cells, use a screwdriver toremove the battery cover securing screw and lift off thebattery compartment cover. Install 6 IEC LR6 cells ensuringthat the polarity is as marked on the base of the batterycompartment. Replace and secure the battery Charging (MJ559)Using the power cord supplied, connect the tester to astandard power supply (120 V 50/60 Hz). The redCHARGE indicator will light to indicate that charging is inprogress.

8 A full charge takes approximately 16 hours. TheMJ559may be used for testing at the same time as thebattery is being circuit under test must be completely de-energized and isolated beforetest connections are ChecksThe instrument will operate in any position, but the specifiedaccuracies assume that the instrument is face up, on a firmlevel surface. This is particularly true for hand cranked unitsto obtain a smooth constant crank speed. 1) Without the test leads being connected to the instrument,but with the rotary selector switch set to the 1 kV range(MJ160to 500 V range) press and hold down the Test button, whilst turning the generator handle,(MJ159, MJ160andMJ359) at >180 meter pointer shouldremain over the (infinity) position on the scale.

9 Thisestablishes that there is no leakage through the ) Check that the test leads, probes and crocodile clips arein good order, clean and with no broken or cracked two of the test leads to the + and - terminals on theside of the instrument case and ensure that their clips are nottouching anything. 3) Press the Test button again and keep it pressed whilstturning the generator handle (Hand cranked models) at >180rev/min and observe the meter needle. The needle shouldrest over the (infinity) position on the scale. If it does not,the test leads may be faulty and should be inspected moreclosely for damage. Replace them if necessary withcalibrated leadsavailable as optional accessories 4) Connect the test lead clips together, press the Test button and turn the generator handle (hand cranked models)again.

10 The meter should read zero. If it indicates infinity or ahigh resistance value the leads may be open circuit andshould be inspected further. Replace them if necessary. (Shorting the leads together and obtaining a zero reading also shows that the instrument is working).Note: To avoid creating leakage paths when insulationtesting, it is advisable not to allow the leads to twist togethernor trail across metalwork etc. more than is really measurementWhen not testing ( in standby mode) the instruments act asa voltmeter (0 to 600 Volts ) Therefore, as soon as the testleads are connected to the item under test, any voltagepresent will be immediately shown. Thus indication is giventhat the item has not been completely instrument also monitors circuit discharge when the Test button is released following an insulation test on acapacitive item, a long cable.