Re: Testing Coils (technical data?)

Posted by hendred on Jun 19, 2020; 8:00am
URL: http://silk-motorcycles.221.s1.nabble.com/Testing-Coils-technical-data-tp5001954p5001955.html

Data from original Lucas Motorcycle Service Sheets for 17 M 6 coils:

Primary (LT) resistance 1.7 - 1.9 ohms.  No resistance given for secondary (HT).  Tested on a spark machine.

PVL 6v coil made in Germany to original Lucas 17 M 6 Spec:

Primary resistance 1.7 - 1.9 ohms.  Secondary resistance 6K ohms.

My original Lucas coils were measured for another thread on this topic on this site and were about 1.9 ohms.  Secondary not measured.  Looks like your old Lucas coils are within spec.  Unfortunately testing with an AVO won't necessarily show up a defective  coil which breaks down when generating high voltage.

The resistance of the secondary is determined by the number of turns and the resistance of the wire.  A thin wire has a higher resistance than a thick wire.  Whether the higher secondary resistance coils have a higher energy spark will depend on the overall design of the coil.