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24 

10.2 Procedure to replace batteries 

 

WARNING:  Do not switch the instrument on with the battery cover removed. 

The rear cover 

must not

 be opened if the test leads are connected.  

 

1.

 

Switch off the instrument and disconnect (the instrument) from any electrical circuits. 

2.

 

To avoid the possibility of electric shock, 

do not

 press the test button or touch the fuse when changing 

batteries. 

3.

 

To remove the rear cover, remove the retaining screw from the rear of the battery cover and lift the cover 
off. 

4.

 

Remove the dead batteries and refit new batteries, observing the correct polarity as marked on the battery 
compartment. 

5.

 

Replace the cover and retaining screw. 

6.

 

Switch on instrument and check battery indicator. 

 

WARNING:  -  Incorrect  battery  polarity  may  prevent  instrument  operation  or  can  cause  electrolyte 
leakage or damage the instrument. If the battery condition indicator does not show a full charge, a 
cell may be reversed. 

 
Note: Batteries should not be left in an instrument, which may remain unused for an extended period. 

 
 

10.3 Fuse Blown indication  

 

If the fuse has blown after contact with a live supply, the fuse blown symbol [

] and the ‘UnS’ message will 

be displayed and the instrument will start beeping. These symbols and a periodic beeping will continue until the 
instrument is switched off. This will only happen if a serious internal fault has occurred.  
 
Please contact Megger Limited at the contact address at the end of this guide, or call Technical support on  
+44 (0)1304 502 102 for further assistance. 
 
The fuse must not be replaced until advice has been received from Megger Limited. 

 

11. Auto power down 

To extend battery life the instrument will automatically switch off two minutes after the last operation. It can be 
switched off by selecting ‘OFF’ with the lower range switch, or switched back on again by pressing the [

TEST

button. 
 
To extend the auto switch off time to 20 minutes, refer to section 8, SETUP options. 

 

12. Preventive maintenance 

Clean only with a damp cloth. Do not use any alcohol based cleaning fluids as they may leave a residue. Isopropyl 
alcohol (or similar solvent cleaner) should only be used to clean the 4mm probe sockets on the instrument on a 
regular basis. 

 
 
 
 
 
 
 
 
 
 
 
 
 

Содержание LTW315

Страница 1: ...M LTW300 Series Earth Loop testers User Guide...

Страница 2: ...lace whilst conducting tests Test leads probes and crocodile clips must be in good order clean and with no broken or cracked insulation On test leads fitted with a outlet plug and flying leads never c...

Страница 3: ...oop test 14 High current Phase to Neutral loop test 14 High current Phase to Phase loop test 15 High resolution loop test LTW425 only 15 Prospective fault current display PFC 15 PFC measurement 15 Pos...

Страница 4: ...nings and instructions before attempting to use the instruments This user guide describes the operation and functions of the following LTW300 series of loop impedance testers LTW315 LTW325 LTW335 LTW4...

Страница 5: ...d return it to Megger as soon as possible to help us reduce any delays in supporting you should the need arise Carton contents for the LTW315 LTW325 LTW335 and LTW425 1 x LTW series loop tester 1 x 2...

Страница 6: ...sults Fuse Blown Refer to User manual Battery status Ranges Supply noise warning R1 R2 Function selected Zref function selected required before R1 R2 can be measured Loop test active Temperature warni...

Страница 7: ...n Backlight On Off Test lead connections See section 2 5 Loop test function all except LTW315 Z MaxZ R1 R2 Zref Neck strap slots Range selector NO TRIP High Current HIGH Res LTW425 Volts Frequency Set...

Страница 8: ...ntrols OK Confirms a test result delete request ESC Aborts a result save process UP DOWN arrows Scrolls through circuit and distribution board numbers STORE Stores last test result LAST As next NEXT S...

Страница 9: ...ifting up front panel tab 1 2 Foldaway underneath instrument 2 3 and push into retaining slot 4 Single or 3 Phase connection Earth Neutral or 2nd phase connection Warning Read user guide Maximum 300V...

Страница 10: ...ssist drying 4 General operating instructions 4 1 Backlight operation Pressing the BACKLIGHT button will toggle the backlight on and off The backlight will automatically switch on at the start and end...

Страница 11: ...zardous in a live socket outlet 4 3 Test lead connection The supplied test leads should be connected to the appropriate sockets on the rear of the instrument marked L0 L2 and L1 Standard test probes a...

Страница 12: ...the noise symbol is displayed at the end of a test the test should be repeated or the test mode changed to mode 2 refer to section 8 SETUP procedure Mode 2 AUTO Default setting In Mode 2 the LTW loop...

Страница 13: ...5 IS NOT RATED FOR PHASE TO PHASE MEASUREMENTS ON 240 VOLTS TO EARTH SYSTEMS 5 2 Performing a loop test Note Factory settings for the instrument are AUTO START enabled Mode 2 extended testing enabled...

Страница 14: ...fast loop test WARNING This test is designed for non RCD protected circuits Due to the high currents used the instrument adds a brief pause between tests to prevent overheating This is indicated by th...

Страница 15: ...nt display PFC NOTES The PSCC of a circuit is the largest Prospective Fault Current PFC In a single phase system this would be the larger of the earth loop PFC and the neutral loop PSCC In a multi pha...

Страница 16: ...ortion of reactance in the measurement Worst case operating error calculated for Non Trip measurement mode in accordance with IEC 61557 3 1997 Intrinsic error or influence quantity Reference condition...

Страница 17: ...ted 6 All subsequent loop test measurements will have the Zref resistance subtracted 7 To view the stored value of Zref press the PFC key press the PFC again to return to the R1 R2 value 8 If measured...

Страница 18: ...Record number Each test result is assigned a unique record number from 0 to 999 logged automatically This cannot be changed by the user 7 2 To store a result 1 Make a Z MaxZ Zref or R1 R2 loop measure...

Страница 19: ...nload from the software tool bar 4 Connect the tester to the PC using the USB download lead 5 Set the lower range knob to SEND 6 The instrument will automatically download its contents to the PC A bar...

Страница 20: ...the function 4 Press the key to cycle through the options available for that function Once the desired option is displayed press TEST to store setting The display will show Ok and then return to the...

Страница 21: ...Press the TEST button to store the offset The display will show Ok to confirm setting has been saved 15 The display will show the as a reminder to warn of there is a loop resistance offset selected To...

Страница 22: ...ing test Retest or investigate source of noise Instrument needs calibration Further testing is possible but not recommended Noise symbol displayed at end of test indicates result may have been adverse...

Страница 23: ...possible until batteries have been replaced Note NiMH rechargeable batteries show a lower charge than Alkaline batteries and may not give much warning before becoming exhausted Faulty stuck key or sw...

Страница 24: ...n unused for an extended period 10 3 Fuse Blown indication If the fuse has blown after contact with a live supply the fuse blown symbol and the UnS message will be displayed and the instrument will st...

Страница 25: ...0 03 100 V a c and 300 V a c LTW325 and LTW425 10 0 02 LTW425 15 0 03 50 V a c LTW325 LTW335 and LTW425 Nominal test current No Trip loop test 15 mA at nominal 230 V a c supply High current loop test...

Страница 26: ...rdance with IEC61326 1 Operational uncertainties Refer to www megger com Power supply Battery 8 x 1 5 V cells IEC LR6 type AA alkaline Rechargeable 8 x 1 2V NiMH cells Battery life 2000 consecutive te...

Страница 27: ...ted by a worldwide network of approved repair and calibration companies which offer excellent in service care for your Megger products Returning your product to Megger UK and USA service centres 1 Whe...

Страница 28: ...com Megger Pty Limited Unit 26 9 Hudson Avenue Castle Hill Sydney NSW 2125 Australia T 61 0 2 9659 2005 F 61 0 2 9659 2201 E ausales megger com Megger Limited 110 Milner Avenue Unit 1 Scarborough Ont...

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