My bike has a broken ammeter, electrics are fine but the needle sits dead over on the peg. Can this be fixed/rebuilt, or am I better off searching out another? I believe its 1.5 inches -+ Thanks, Bob

email (option): bobdukw@aol.com

Hi Bob,

Inside the ammeter, there is a very fine winding on the needle base,
And a short,tick winding around it, running between - and +.

The thick winding is producing a magnetic field, N or S, depending on the current direction,
(Charge or discharge) affecting the needle.
The good thing about it, is that the thick, short winding would never burn,
(Well, unless you have a super strong generator and a short current)
So you will have charge in the system even if the fine winding is gone.

The only thing to do, is to see if the needle moves freely.
If it does, and still the ammeter does not work, I do not believe it's fixable.

http://www.voc.uk.com/net/docs/tl/lucasammeter.pdf

http://astarmathsandphysics.com/a-level-physics-notes/electricity/a-level-physics-notes-moving-coil-ammeters.html

http://bsass80.blogspot.co.il/2012/05/ammeter.html

Noam.

email (option): noam10@gmail.com

A cheap repro ammeter can be bought for £15-£20. But the correct type is a Lucas CZ27. Like this one.

This is an early type with a dome glass. Ron

email (option): ronpier@talk21.com

AND illumination Ron, on account of the aperture...........

You can photocopy an original face and insert into one of the decent repros (I've done this myself), or even a later Lucas type, but may not get an entirely accurate reading...........also, some original Lucas ammeters are not too easy to disassemble...........but everything's possible with a bit of time and effort.............

Years ago now I went to a "radio rally" and a seller there had box fulls of NOS WD Lucas ammeters at £2.50 each...he must have had at least a 100.............I kick myself now that I only bought enough for the bikes I then had.............