The Fordson Tractor Pages Forum

I have the original dynamo off one of my majors, is there any way of testing it? Will it produce a voltage without being connected to a battery? Ive never really got involved with them before

Take fan belt off and put 12v + on to both terminals. It should start to turn like a motor. If it does it should be ok. Then just connect up properly and test the output with multimeter.

Ideal, will try that later. I have it in bits at the moment, everything looks in very good order suprisingly! I did just check that the insulation was ok between the windings and the outer case, it read 6.3 ohms, this sounds around the right amount to me, hopefully it will work!

Just in case you're not too familiar with checking it out:
Using the voltmeter check your battery voltage first. Then start the engine, obtain a fast idle and check the battery voltage again -- it should be slightly above the your first reading as the dynamo/generator starts to replace the volts used by the starter motor. Increase the revs to about 1000 [turn lights on if you have them] where the volts across the battery should be around 13 plus. If it doesn't obtain this voltage you should also consider checking the voltage regulator output. Battery, dynamo and regulator wire connectors, plus earth points, would also benefit the starting and charging systems after a good clean.

Pavel.

Hi pavel, the dynamo wasnt on the tractor at the time, but yes i am familiar with the voltage thing.

In the end I hooked up a 12v leadlight ive got to the dynamo and shorted the f and d terminals, and spun it with a drill. And it works!

So I put it on the tractor, installed the new wiring loom, and its all working now (it hasnt been working for at least 25 years lol)

Sorry Nick; I thought from your first post some added info might help.
After 25 years usage [?] who still maintains Lucas equipment was junk?

Pavel.

Oh heck... It should last better than 100 years like the DELCO system in my 1915 Buick... If not, It is junk. Dandy Dave!