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-   -   Evershed and Vignoles megger. (https://www.vintage-radio.net/forum/showthread.php?t=151380)

sparkymike 14th Nov 2018 9:08 am

Evershed and Vignoles megger.
 
Some years ago I dismantled an Evershed and Vignoles Megger and left myself a note telling me that the magnet was US. However on returning to this project, I found that the horseshoe magnet was good !! I have now started to put it back to one piece, but need advice on one point. I have inserted the needle rollers into the capped end of the generator, but not sure how I should replace needles into the end with the gear. If I insert them into the casing with grease, will the horseshoe magnet pull them out again before I get a chance to insert the armature.? Hopefully some easy trick to do this operation. I guess this may be directed to Ed Dining. !!
Mike.

sparkymike 14th Nov 2018 12:00 pm

Re: Evershed and Vignoles megger.
 
To save needless replies, I threw all caution out of the window, (on hindsight perhaps it should have been the meter !!) and with the aid of grease, held the needle rollers in place on the armature spindle and replaced the other bakelite end housing. I had to play around with the assembly until free movement of the armature was obtained. All was ok, or so I thought, but on fitting it to the case base, it was rocking on the pedestals, so I slackened off the end bolts on the generator just half a turn and this was enough to allow it to settle into the correct alignment. However after soldering meter connections back in place, the meter still refuses to work and so more investigation is needed. The needle on the movement is free, but does not settle in one place or zero. Any suggestions here ? Now that generator is in the case I should be able to check the output for a start.
Mike.

John M0GLN 14th Nov 2018 1:27 pm

Re: Evershed and Vignoles megger.
 
When you say it refuses to work does that mean when you wind the handle with the meter shorted out it doesn't go to zero and when open circuit it doesn't go to infinity? The needle never settles in one place or zero after use.

John

sparkymike 14th Nov 2018 3:11 pm

Re: Evershed and Vignoles megger.
 
Hi John,
yes, shorted out the needle stays at whatever position it is on dial, but on winding the handle at some speed, the needle climbs towards infinity and gets to around 3 meg point.
In open circuit mode, needle stays put .
Mike.


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