Megger MIT410, MIT400 CAT IV Operating Manual

MIT400 Series Insulation and continuity testers

USER GUIDE

USER GUIDE CONTENTS

1. Introduction 3

Safety Warnings 4

3. Symbols used on the instrument 5

4. General Description 6

Unpacking the carton 6 Carton contents (all instruments) 6

5. Preparations for use (all instruments) 7

Batteries 7 Preliminary test lead check 7

6. General operating instructions 8

General functions 8 LCD Display 9 Backlight operation 10

7. Test lead connections 11

Standard test leads 11 SP5 Switched probe (not MIT400, MIT480 and MIT40X) 11

8. AC/DC voltage and frequency measurements 12

9. Insulation resistance testing - general 13

Standard insulation resistance testing 13 Insulation resistance testing – timed modes ‘t’, PI and DAR 14

10. MIT40X testing 17

11. Continuity testing [] and buzzer [

12. Resistance measurements (k Range) 19

13. Capacitance measurements 20

Capacitance measurement procedure 20 Distance measurement by capacitance 20

14. Setup options 21

15. Saving , recalling and downloading test results. 23

Saving test results 23 Test results recall 23 PI and DAR recall. 24

16. Deleting test results 26

Procedure for deleting a single test result (refer to Figure 16) 26 Procedure for deleting all test results (refer to Figure 19) 27 Preparing your MIT430 or MIT485 for “Bluetooth” Communications 29 Preparing your MIT430 or MIT485 to your PC 29 Standard download operation 32

17. Battery and fuse replacement 32

Battery condition and replacement 32 Blown fuse indicator 33

18. Preventive maintenance 33

19. Specification 34

20. Basic and service errors 36

Basic error 36 Service error: 36

21. Accessories 37

22. Repair and Warranty 39

] 18

1. Introduction

Thank you for purchasing the Megger insulation test instrument.

For your own safety and to get the maximum benefit from your instrument, please ensure that you read and understand the following safety warnings and instructions before attempting to use the instruments.

This user guide describes the operation and functions of the MIT400 series of insulation and continuity test instruments:

These instruments are designed and manufactured by:

Megger Ltd Archcliffe Road Dover Kent CT17 9EN England

Megger Limited reserves the right to change the specification of these instruments at any time without prior notice.

2. Safety Warnings

mus t

N OTE

MIT400 series insulation testers

Safety Warnings and Precautions must be read and understood before the instrument is used. They must

The circuit under test must be switched off, de-energised, securely isolated and

proved dead before test connections are made when carrying out insulation and continuity tests.

Circuit connections and exposed-conductive-parts and other metalwork of an

installation or equipment under test must not be touched during testing.

The live circuit warning and automatic discharge are additional safety features,

which may fail, and therefore safe working practices must be observed.

The voltage function will only work if the instrument is functional and switched on.

After insulation tests, capacitive circuits must be allowed to discharge before

disconnecting test leads.

The instrument should not be used if any part of it is damaged.

All test leads, probes and crocodile clips must be in good order, clean and with no

broken or cracked insulation.

Ensure that hands remain behind guards of probes/clips when testing.

National Safety Authorities may recommend the use of fused test leads when

measuring voltage on high-energy systems.

Replacement fuses must be of the correct type and rating. Failure to fit the correctly

rated fuse may result in a safety hazard and may cause damage to the instrument in the event of an overload.

The battery cover m

be observed during use.

be in place whilst conducting tests.

THE INSTRUMENT MUST ONLY BE USED BY SUITABLY TRAINED AND COMPETENT

PERSONS.

Users of this equipment and/or their employers are reminded that National Health and Safety Legislation requires them to carry out valid risk assessments of all electrical work so as to identify potential sources of electrical danger and risk of electrical injury such as inadvertent short circuits. Where the assessments show that the risk is significant then the use of fused test leads may be appropriate.

3. Symbols used on the instrument

F Caution: risk of electric shock

G Caution: refer to accompanying notes

Displayed on the LCD during an insulation test, warns that a hazardous voltage may exist at the test lead probes also observe voltage discharges to a safe level.

On battery cover see section 2.0 notes 10 and 11.

At terminals do not exceed rated input voltage.

Equipment protected throughout by Double Insulation (Class II)

Equipment complies with relevant EU Directives

Equipment complies with ‘C tick’ requirements

Do not dispose of in the normal waste stream

G>600 V Maximum input voltage 600 V rms

4. General Description

4.1 Case contents

There are important documents that you should read and keep for future reference.

Please complete the pre-paid warranty card and return it to Megger Limited as soon as possible to help us reduce any delays in supporting you should the need arise.

4.2 Case contents (all instruments)

1 x MIT400 series instrument

1 x Hard carry case 1 x Red/black test lead set with clips 5 x AA (LR6) batteries fitted 1 x Warranty card 1 x Calibration certificate 1 x Owners CD manual 1 x SP5 remote switched probe (Not MIT400 &MIT480) 1 x Download Manager software CD (MIT430 and MIT485 only)

MIT400 storage with holster MIT400 storage with no holster

5. Preparations for use (all instruments)

5.1 Batteries

The Megger MIT400 series instruments are supplied with batteries fitted. When batteries become exhausted, refer to section17 for battery replacement.

Warning: Do not switch the instrument on or connect test leads with the battery cover removed.

5.2 Preliminary test lead check

Functio nal verification

Before each use of the instrument visually inspect the test leads, prods and crocodile clips to confirm that their condition is good, with no damaged or broken insulation.

Check continuity of the test leads by firmly shorting the leads together and read the

test lead resistance measurement directly from the d isplay, which should be less than

1.0 .

Supply voltage

With the exception of voltage measurement range, this instrument is designed for use on isolated (dead) circuits. Prior to any testing and using an approved method, ensure the circuit to be tested has been fully disconnected and is securely isolated from the supply prior to using the instrument.

6. General operating instructions

Safety note:

If greater than 25 V appears on the circuit under test the instrument will default to a voltage measurement and display the supply voltage.

On supply voltages over 50 V the instrument will be prevented from performing an insulation test, protecting your instrument from damage.

Note: This limit is increased on MIT480, MIT481 and MIT485 to 75 V, but a warning buzzer will indicate voltages above 50 V.

Use extreme care when using or measuring voltages above 30 V, particularly in high energy systems. Fused test leads are available as an optional accessory for local situations where increased protection is required.

Hazardous voltages can exist on the insulation test range all the time the [TEST] button is locked down.

6.1 General functions

Black Test lead connection

LCD screen

Test button and lead null

Insulation lock button

Insulation test ranges

OFF positon

Resistance ranges

Capacitance (μF)

Figure 3 Main features (MIT430 shown)

Red test lead or switched probe

Function buttons

Battery/internal fuse access panel at rear

Voltage range

Result recall and transfer

Insulation, PI test, DAR test or timed test button

Store/last button

TRMS/DC button

Figure 4 Function buttons (MIT430 shown)

Up/down buttons

μA/s/V button

Next button

Buzzer on/off

Backlight button

Test button

6.2 LCD Display

Auxiliary digital display

Multifunction analogue display

Continuity indicator

Lock indicator

Warning – refer to user manual

Fuse blown indicator

Out of range indicator Lead null indicator

Figure 1 LCD display

6.3 Voltage warning

If the voltage is greater than 25 V the meter automatically displays the voltage.

For MIT400, MIT405, MIT410, MIT420, MIT430 and MIT40X instruments, if a voltage greater than 50V exists, testing will be a utomatically inhibited and voltage measurement will be displayed.

For MIT480, MIT482, MIT485 instruments, if a voltage greater than 75 V exists, testing will be automatically inhibited and a voltage measurement will be displayed. Voltages higher than 50 V will be indicated by a warning buzzer.

In continuity mode, if a voltage greater than 25 V exists, testing will be automatically inhibited and voltage measurement will be displayed.

Units of parameters on auxiliary display

Battery condition indicator

Audible alarm indicator

TRMS indicator

Units of parameters on main display

6.4 Backlight operation

All instrument displays are backlit. The backlight function can be selected at any time while

the instrument is switched on by pressing the BACKLIGHT [

The backlight function will switch off automatically after 20 seconds.

] button. Refer to figure 4.

7. Test lead connections

Test lead s co n ne c tions are as indicat e d in f igur e 2 which shows the te st le ad sockets at the top of the instrument, as well as the switched probe socket and test lead.

Black test lead connection

Figure 2 Test lead connections

Red test lead connection

SP5 connection

7.1 Standard test leads

The Red/Black test lead set should be connected to the appropriate sockets on the top of the instrument marked + and –, respectively. (see figure 2 )

Test probes and crocodile clips are supplied for connection to the circuit under test.

Fused test leads are available as an optional accessory.

7.2 SP5 Switched probe (not MIT400, MIT405, MIT480 and MIT40X)

The SP5 switch probe allows the user to start a test by pressing the [TEST] button on the probe, instead of on the instrument. This allows for complete hands-free testing and increases user safety.

Connect the SP5 probe to the instrument using the special 3-pole +ve socket (in place of the RED test lead).

Select a suitable insulation resistance range.

Press and hold down the SP5 probe button. The instrument will start an insulation

resista nce test.

To end the test, release the probe test button.

The SP5 remote switch probe replaces the standard red test lead. The test button on the probe duplicates the test button operation on the instrument when insulation testing.

To operate the switch probe, connect the probe to the circuit to be tested and press and hold down the button on the probe. The insulation test will commence. Releasing the button will terminate the test.

The test lead resistance can be nulled for continuity testing. Refer to section 11.2

8. AC/DC voltage and frequency measurements

Note: Measured voltage must not exceed 600 V phase to earth or Phase to Phase

Frequency measurement is not available on MIT400, MIT405 and MIT480 models.

Procedure for measurement of volta ge and frequency

(Refer to Figure 5)

DC indicated

Screen B:

Analogue a.c. voltage

Screen A (a.c.)

displayed

Step 4:

Measured frequency

Voltage and frequency display d.c. and voltage

display in d.c. mode

Step 5:

Result store button

Step 3:

TRMS/DC

TRMS indication

Measured a.c. voltage (V or mV)

Test button

Step 2:

Connect test lead to circuit under test

Step 1:

Selector switch

Note on TRMS measurement:

IN TRMS mode the MIT400 will measure both AC and DC components of the supply voltage (AC+DC). In DC mode only the DC component is measured.

Rotate selector switch to the ‘V’ position.

Connect test leads to the circuit under test.

‘TRMS’ is the default mode on power-up. Press the [TRMS] button to select DC or return to TRMS if required.

The measured voltage will be displayed on the main digital scale in units of V or mV, as

appropriate In TRMS mode, the measured frequency (Hz) will be simultaneously displayed on the MIT410, MIT420, MIT430, MIT 481, and MIT 40X instruments (as shown on Screen A). See Figure 5 Screen B

For MIT420, 430, 481 and 485, the measured result may be stored if required by pressing the

‘STORE’ button. Refer to section 14 for further information.

Figure 5 Voltage and frequency measurement

for dc mode display.

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