Morris Minor Owners Club

Even alternators are earthed at ''zero'' potential through the engine, onto which it is mounted. I'm just curious and open minded. I freely admit that I don't have the benefit your considerable expertise in this area. So in this battery disconnected scenario, I think you seem to be implying that th...

I wonder if anyone has ever seen an alternator being function tested by disconnecting a battery terminal whilst the engine is running? Never done this myself but I gather that it may have been a common practice if we go back a few decades. If the engine continues to run with the battery disconnected...

i guess the HT 'earth' must be running back through the 12v feed through the battery and to the car/engine earth otherwise a high voltage at the coil with no earth reference would not create a spark gap. Rob is in good company here as Hillier agrees with him. Or at least he did in 2005 (Ed. 5): &qu...

Thank you for your kind reply, I will endeavor to read further.

For the avoidance of doubt, could you possibly say:
- Is the diagram I posted correct?
- What is the path taken by the HT current? (In particular from the engine block back to the coil).

Both primary and secondary clearly have a common earth - the car structure, back to the earth side of the battery. This is the part that I am interested in - happy to take the other points as read for now. I think that this drawing correctly shows the arrangement of a standard points ignition syste...

yes... I know but just want to solve for myself where the 'earth' for the HT side of the coil gets back to the block 1: coil is turned on 12v one side, earth via dizzy/contacts the other 2a: when a spark is needed points open in dizzy and HT build up in coil 2b: dizzy directs 'output' to correct sp...