Megger

Thread Starter

Treeman

Joined May 22, 2014
157
Hi,
I have an old Megger that was given to me. I understand that it is used for testing shorts in Hi voltage lines. You wind the handle and it the ohmmeter falls if there is a short in the winding. I read a bit on the net but was not much wiser.
I think I probably have no use for this ever - so what can I do with it that's fun?
It puts out 1.5v with a good wrist action.
 

ericgibbs

Joined Jan 29, 2010
10,005
The early Megger produce a very high voltage, depending how fast you turned the handle and was used to check circuit insulation.
Post a picture or model number.
E
 

Thread Starter

Treeman

Joined May 22, 2014
157
The early Megger produce a very high voltage, depending how fast you turned the handle and was used to check circuit insulation.
Post a picture or model number.
E
Thanks Eric. I got her up to 2 volts that's as fast as I could go. I'm thinking along the lines of using it as a switch maybe. Wind the handle turn on a transistor , some sort of simple circuit after - a timer probably!
 

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Thread Starter

Treeman

Joined May 22, 2014
157
I agree! This may be a case of If it is broke don't fix it!
What could be broken so that it gives 2v instead of 500v?
 

Thread Starter

Treeman

Joined May 22, 2014
157
Well that could be fun; but I'd rather amuse myself by creating something meaningful to me not the rest of society. I need a life too.
 

MaxHeadRoom

Joined Jul 18, 2013
20,649
There were two types of megger of this era, one was high voltage insulation tester, which you have, and the handle is cranked at a certain rate to provide 500vac, at this point an internal clutch kicks in to maintain the 500v.
The second type was a resistance meter, used mainly for ground path measurements, down to fractions of an ohm, and operated on lower voltage.
They are fairly simple instruments so if you don't get anything out you could open it and take a look.
Max.
 
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Thread Starter

Treeman

Joined May 22, 2014
157
With the output leads open, what are you reading on the meter? (of course, while cranking)
The needle seems a bit floaty and sits around 1Meg all the time. In fact it seems to respond to gravity depending on orientation! It does respond to a crank though and if Zeroed by turning on its side and then laying flat carefully (!) it winds up to 1Meg and lives happily.
Maybe this is not correct - seems likely.....
 

MaxHeadRoom

Joined Jul 18, 2013
20,649
Connect it to a AC rated capacitor such as a 1ph motor cap and while cranking it whip the leads off, then short the terminals with a screw driver.o_O
Max.
 

BillB3857

Joined Feb 28, 2009
2,533
My guess is that the cap inside the megger has become leaky. I remember we would "indoctrinate" a fresh trade school grad by showing him how a megger worked. We would hold the leads and have him crank it. Then, we would have him hold the leads, but would start cranking it before he could get his hands on both leads. Those were the good ol' days.
 

ian field

Joined Oct 27, 2012
6,539
Hi,
I have an old Megger that was given to me. I understand that it is used for testing shorts in Hi voltage lines. You wind the handle and it the ohmmeter falls if there is a short in the winding. I read a bit on the net but was not much wiser.
I think I probably have no use for this ever - so what can I do with it that's fun?
It puts out 1.5v with a good wrist action.
The high resistance test generates 500V when you wind the handle, so you can charge up capacitors and leave them for people to find - but you have to pull the test clip off before you stop winding or it discharges through the meter.
 
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