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Re: (ET) charger failure question

I am an EE, I agree, very unlikely that DC dumped into the secondary would do anything to the primary. It could cook the secondary pretty well. It's low DCR, and 36V with lots of amps available. Diodes can go either way, usually fail shorted first, if nothing else blows, then the diode would blow.
IF the AC power was on when the big DC current hit the secondary, the AC could overheat the primary quickly, because the iron would be saturated, and that is bad. When the iron in a transformer is saturated, the current into the primary rises rapidly. It's one of the design factors / trade offs when designing transformers. 

Dave


On 6/13/2017 12:46 PM, David Roden wrote:

I'm not a EE, but I don't see how a DC hit on the transformer secondary
would have much effect on the primary.  It would induce a pulse, but it'd 
be
of pretty short duration, and wouldn't have time to build up heat in the
primary.

Damage to the secondary is possible, I guess.  I'd expect the diodes to 
give
way (open up) first.  I could be wrong about that, though.

Anybody have an open GE charger handy and can measure the DC resistance of
the transformer secondary, so Michael can check his against yours?  I have 
a
charger here, but it's buried in the tractor.


David Roden - Akron, Ohio, USA

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