Megger testing

[jamiebrennan]

Insulation and earth testing

Hi all, just discovered this forum the other day and this is my first post. I’m hoping you’ll be able to offer me some advice regarding carrying out a Megger test. I have ‘borrowed’ a Metrel EasiTest tester (which I assume is suitable) while our electrical technician is away at work in the hope that I might test the motor and element on my washing machine for possible problems. The problem is that I’m not sure how to carry this out.
Can anyone offer any advice and give me an idea about what results I should be expecting?

Any advice would be appreciated.

Yours ,

J

[iadom]

Re: Megger testing

If you have to ask such questions in the first place then I suggest you start at the beginning. 😉

The make and model of your machine plus a brief description of the fault would be a much better option TBH.

[jamiebrennan]

Re: Megger testing

Thanks for the reply. My machine is an Ariston 1636s that developed a fault where it just stopped working. Before I fit a reconditioned board I have been adviced to Megger the heater and motor. I don’t want to fit the board until I’m sure these components are working fine.

J

I think I’m confused as the meter has 3 leads (blue, black and green) of which two are used, which working it out logically are the blue and black ones. However the examples using a Megger tester have a black and red lead. Is it important which way round the leads are connected when testing?

[suedehead1]

Re: Megger testing

jamiebrennan wrote: it just stopped working.

well it certainly is a brief description of the fault.

[jamiebrennan]

Re: Megger testing

Sorry guys, I’ve just realised how lame that message was!

I’ve just found the instructions online for the meter, I should be able to find whether or not I have a faulty component with these. Thanks for your assistance though.

J

[pearce_jj]

Be *very* carefully with the tester – it can and will present 500V (or more) between the wires which very obviously is extremely dangerous. Keep in mind that the entire machine is made of metal – you really don’t want to be touching it!

It will also destroy any connected electronic circuit boards which potentially could include parts of the motor (only the windings should be tested).

And of course, unplug the machine before you start.

[Specialist01269]

Re: Megger testing

O.k as your determined to get into your machine with a Megger, first & foremost: POWER OFF & PLUG OUT before opening the appliance, getting :zap: can seriously ruin your day.

When testing your heater disconnect the power leads from the heater, put the insulation tester on it’s highest continuity range needs to measure at least 50 ohms (Not insulation) place leads across heater terminals & read heater resistance, this value will depend on the element wattage but all you want to know initially is whether the element has continuity, if it has then proceed to the next test: Connect 1 meter lead to 1 terminal of the element & the other lead to the element Earth, set to 500 volt insulation range & test. Keep your hands well away from the leads when testing, you need to note the resistance shown on the meter. This should be in the high Megohms range.

PLEASE BE WARNED THAT USEING A MEGGER OR OTHER INSULATION TESTER INCORRECTLY COULD DAMAGE YOUR MACHINE OR CAUSE YOU INJURY.

Before carrying out any testing though can you explain the problem with your machine any further? i.e are there any lights on (power etc), does anything happen when set a programme & close the door?

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