Biddle WM_6_UG 电路图.pdf

Wee MEGGER Te s t e r WM6 catalog No. 21805-3 User Guide Guide de lutilisateur G e b r a u c h s a n l e i t u n g Gua del usuario MEGGER RadioFans.CN 收音机爱 好者资料库 SAFETY WARNINGS #The circuit must be de-energized and isolated BEFORE connections are made for any test. #Do not touch the circuit during an insulation test. #After insulation tests, capacitive circuits MUST be allowed to discharge BEFORE disconnecting the test leads. #Test leads, including prods and crocodile clips, must be in good order; clean and having no broken or cracked insulation. #Replacement fuses must be of the correct type and rating. Refer also to page 8 for further explanations and other precautions. The warnings and precautions must be read and understood before the instrument is used. They must be observed during use. 2 NOTE This instrument must only be used by suitably trained and competent persons. RadioFans.CN 收音机爱 好者资料库 CONTENTS Safety Warnings2 General Description4 Applications4 Specification5 Accessories7 Operation8 Warning8 Preliminary checks8 Fuse replacement8 Insulation testing9 Continuity testing9 Using the Insulation Tester10 Preventive maintenance10 Insulation Testing concepts11 Mode dEmploi12 Betriebsanleitung14 Instrucciones de Uso16 Setting-up Procedure18 Repair and Warranty19 3 RadioFans.CN 收音机爱 好者资料库 GENERAL DESCRIPTIONAPPLICATIONS The WM6 MEGGERInsulation and Continuity Tester is a completely self contained instrument designed to give rapid and accurate measurement of insulation resistance and continuity resistance. The WM6 uses a low voltage hand-cranked a.c. brushless generator as the power supply. This generator is easy to turn and is connected to a rectifier and d.c. to d.c. converter to provide the test voltage. The WM6 uses a moving coil meter with taut band suspension, white scales on a black scale plate and an orange dayglow pointer. An electronic circuit is employed to produce a four decade calibrated scale for insulation resistance measurement from 0 to 200 M. Two shrouded sockets are provided in the side of the case for the test leads and a slider switch selects either insulation or continuity tests (M or ). The case is robust, made of ABS plastic, and the generator handle folds neatly against it when not in use. The WM6 is intended for the direct measurement of insulation resistance and continuity of domestic and industrial wiring, cables, transformers, motors, generators, electrical machinery and appliances. Because the WM6 is self-powered it is suitable for use during installation and commissioning work as well as for service and maintenance applications. Note: The cover of this instrument has been given an antistatic treatment which should be effective for many months. If in the course of time the cover is found to retain electrostatic charges, it should be re-treated with a suitable antistatic solution. 4 SPECIFICATION WM6 Rangesinsulation0200 M and continuity0100 Terminal Voltageinsulation range<600 V on Open Circuit (d.c.)continuity range800 mV approx. Terminal Voltage atinsulation range500 V + 10% 5% 1 M Load (d.c.) Terminal Currentinsulation range1,3 mA approx. on Short Circuitcontinuity range55 mA approx. Voltage Stabilityinsulation range<1% 160 r.p.m. to 240 r.p.m. Ripple Content at 160 r.p.m.insulation range500 mV pk-pk approx. on Open Circuit Accuracy1,5 mm (0,060 in) from any marked position on the scale when measured against standard resistors. Temperatureoperating10 C to +50 C storage20 C to +70 C Flash Test2,3 kV a.c. r.m.s. Voltage Source (d.c.)Brushless a.c. hand-cranked generator with rectifier and d.c. to d.c. converter. 5 SPECIFICATION Fuse1 A 20 x 5 mm ceramic Dimensions131 x 98 x 61 mm (51/8x 37/8x 23/8in) Weight650 g (1 lb 7 oz) Terminal Voltage Characteristics 6 WM6 SPECIFICATIONACCESSORIES Illustrations of Typical Scales (full size) WM6 SUPPLIED WITH THE INSTRUMENT Test lead set including shrouded crocodile clips User GuidePart No. 6171-685 Test Record Card (5 supplied)Part No. 6172-111 AVAILABLE AS AN OPTIONAL EXTRA A leather test-and-carry case with a special compartment for test leadsPart No. 6420-088 Test Lead set red/blackPart No. 6220-437 Test Record Card (Pack of Twenty)Part No. 6111-216 7 OPERATION W A R N I N G 1 .The circuit under test m u s t be de-energized and isolated before insulation or continuity tests are m a d e . 2 .When capacitive circuits have been tested allow a suitable time to elapse before disconnecting the test leads, for the circuit to discharge. 3 .Instruments used in dusty environments should be stripped and cleaned periodically. 4 .Do not leave the instrument exposed to direct heat from the sun for long periods. 5 .The instrument circuit contains a static sensitive device. If the instrument casing is opened for any reason (this will automatically invalidate any warranty covering the instrument), care must be exercised in handling the printed circuit board. This should be done in accordance with DEF STAN 59-98 and BS 5783 specifications for handling electrostatic sensitive devices. Printed circuit boards containing such devices are identified either by a yellow warning label or by a yellow legend and a large yellow dot on the p.c.b. (Initially the dot may not be included.) PRELIMINARY CHECKS Inspect the test leads to see that they have good unbroken insulation. Connect the red and black leads, terminated with the clips, to the red (+) and black () terminal sockets respectively in the side of the instrument case. Leave the leads coiled or twisted together, but ensure that their clips are not touching anything. Set the slider switch to the M position. Turn the generator handle at approximately 160 r.p.m. and observe the meter pointer, it should rest over the (infinity) position on the scale. If it does not the test leads may be faulty and should be inspected more closely for damage. Replace them if necessary. Connect the test lead clips together and turn the generator handle again, the meter should read zero. If it indicates infinity or a high resistance value the leads may be open circuit and should be inspected further, replace if necessary. Shorting the leads together and obtaining a zero reading also proves that the instrument is working. To check that the fuse in the continuity circuit is intact, leave the test leads connected together and set the slider switch to the position. Turn the generator handle again, the reading obtained should be zero (or very nearly so). If the reading is beyond full scale on the range the fuse has ruptured and should be r e p l a c e d . 8 FUSE REPLACEMENT The fuse is held in a screw-type holder. To change a fuse, use a screwdriver to release the centre part of the holder containing the fuse. Replace with a 1 A 20 x 5 mm ceramic fuse part no. 25413-286. An alternative fuse should not be used as the fuse resistance will affect the lower continuity readings. INSULATION TESTING After connecting the test leads to the instrument and making the preliminary checks as detailed above, set the slider switch to M. With the circuit to be tested isolated, connect the test leads as follows: ( a ) for insulation tests to earth connect the red lead to earth or frame of the equipment, and the black lead to that part of the circuit to be tested. ( b ) for insulation tests between wires connect a lead to the core of each of the wires. Turn the generator handle at between 160 r.p.m. and 240 r.p.m. The meter pointer will indicate the value of insulation resistance on the M scale. (If a capacitive circuit is tested the pointer will initially deflect towards zero and then gradually rise to its final steady value as the capacitance is charged up to the output voltage of the tester.) If several successive readings of are obtained, connect the two further ends of the test leads together and turn the generator handle. A zero reading should result which double checks that the leads are not disconnected or broken and therefore the insulation resistance readings are correct. Capacitive circuits automatically discharge through the tester when the generator handle stops rotating. The meter pointer will deflect beyond the position on the scale and then return to its normal rest position at when the circuit has discharged. Wait a few moments for this to happen before disconnecting the test leads. The discharge time (to 0 V) is approx. 8 seconds per microfarad. CONTINUITY TESTING With the test leads connected to the instrument, and having checked them and the fuse as described above, set the slider switch to the position. With the circuit under test isolated, connect the test leads across the appropriate points and turn the generator handle at between 160 r.p.m. and 240 r.p.m. The resistance will be indicated on the scale. This resistance includes that of the test leads which should be measured separately, (by performing a test with the clips joined together), and the result deducted from the total. 9 Preventive Maintenance The proverb A stitch in time saves nine inspired the title of an AVO International booklet on insulation testing, as it neatly sums up the benefits of preventative maintenance. The savings come in financial terms from costly repairs, lost production, lost profits and in human terms, from lives saved in the event of dangerous electrical faults. Regular insulation testing of electrical equipment can help to detect deteriorating insulation. The effects which cause insulation to deteriorate include mechanical damage, vibration, excessive heat or cold, dirt, oil, moisture and localized voltage stresses - all of which can arise on most industrial or utility equipment. Insulation tests are sometimes used in isolation as absolute measures of the quality of the insulation. This is most appropriate when equipment is being installed and checked for compliance with a specified Pass level. For operational equipment the key factors are trends in the insulation readings. It is therefore important that records of insulation readings are kept, relating to each piece of equipment or Asset in your testing regime. AVO International supplies test record cards to assist with such record keeping. There are also a number of influences on the insulation readings - temperature, humidity and surface leakage for example and a range of test techniques have been developed to help with the interpretation of your insulation tests. 10 Test Record Example Insulation Testing Concepts Insulation resistance can be considered by applying Ohms Law. The measured resistance is determined from the applied voltage divided by the resultant current, V R = I There are two further important factors to be considered. These are: ( i )the nature of the current through and/or over the insulation, and : ( i i ) the length of time for which the test voltage is applied. These two factors are linked. The total current that flows is made up of three separate c u r r e n t s : - 1 .Capacitance charging current. This current is initially high and drops as the insulation becomes charged up to the applied voltage. 2 .Absorption current. This current is also initially high but drops at a much slower rate than the charging c u r r e n t . 3 .Conduction or Leakage current. This is a small steady current that can be sub-divided into two:- (a) A current flowing along conduction paths through the insulation material. (b) A current flowing along conduction paths over the surface of the insulation material. As the total current depends upon the time for which the voltage is applied, Ohms Law theoretically applies at infinite time. The charging current falls relatively rapidly as the equipment under test becomes charged up. The actual length of time depends upon the size and capacitance of the item under test. Larger items with more capacitance will take longer e.g. long supply cables. The absorption current decreases relatively slowly compared with the charging current. In essence it depends upon the nature of the insulation material. The conduction or Leakage current builds up quickly to a steady value and then remains constant for a particular applied voltage under stable conditions. It is this current that is affected by moisture, dirt etc. and the degree to which it flows bears a direct relation to the quality of the insulation, and consequently to the value of the insulation resistance measured. An increase in the leakage current is a pointer to possible future problems. 11 MODE DEMPLOI A V E R T I S S E M E N T S 1 ) Le circuit essayer doit tre mis hors tension et isol, pralablement toute mesure. 2 ) Aprs lessai de circuits capacitifs, attendre le temps ncessaire la dcharge avant de retirer les cordons de mesure. 3 ) Les appareils utiliss dans les environnements poussireux doivent tre dmonts et nettoys p r i o d i q u e m e n t . 4 ) Ne pas laisser lappareil trop longtemps expos au s o l e i l . VERIFICATIONS PRELIMINAIRES Vrifier si lisolement des cordons de mesure est correct. Pour ce, brancher les cordons rouge et noir, munis de leur pince crocodile, dans les bornes rouge (+) et noire () de lappareil. Torsader ensemble les deux cordons et sassurer que leurs extrmits ne sont pas en contact. Placer le commutateur de gamme sur “M”. Tourner la manivelle du gnrateur environ 160 tours par minute et controler que laiguille de lindicateur se place sur la position “” de lchelle. Si ce nest pas le cas, il faut vrifier minutieusement ltat des cordons et les remplace si ncessaire. Court-circuiter les pinces crocodiles et actionner nouveau la manivelle. Laiguille de lindicateur doit se placer sur le zro de lchelle. En cas dindication de rsistance de valeur leve (ou position ) les cordons sont peut-tre coups. Vrifier leur tat et les remplacer si ncessaire. Le fait dobtenir une lecture zero apres avoir court circuite les cordons dessai est aussi une preuve de bon funcionement de linstrument. Pour vrifier ltat du fusible du circuit de continuit, laisser les cordons en court-circuit et placer le commutateur de gamme sur la position . Tourner la manivelle du gnrateur. On doit obtenir une lecture trs proche de zro. En cas de lecture ohmique leve, le fusible est coup et doit tre remplac. REMPLACEMENT DU FUSIBLE Le fusible est plac dans un logement fix entre les bvornes de sortie de lappareil. Pour remplacer un fusible, dvisser laide dun tournevis la partie centrale du logement porte-fusible. Utiliser des fusibles ceramique 1 A (20 x 5 mm). MESURE DISOLEMENT Aprs avoir branch les cordons sur lappareil et avoir ralis les essais prliminaires indiques ci-dessus, placer le commutateur de gamme sur M. Une fois le circuit tester isol, brancher les cordons comme suit: 12 ( a ) Pour les essais disolement par rapport la terre Relier le cordon rouge la terre ou au bti de la structure en essai, et le cordon noir la partie du circuit mesurer. ( b ) Pour les essais entre fils Relier un cordon chacun des deux fils. Tourner le manivelle une vitesse comprise entre 160 et 240 t.p.m.