On 20 Sep 2004 01:58:46 -0700, "klog"
wrote:

ChrisGibboGibson wrote:

snip
The damage has already been done.
snip

May I stick my nose in? (it's a low-impedance nose, so should not
disrupt the thread much...).

What exactly is the typical nature of the alternator damage
experienced? Fried regulator or winding insulation breakdown or zapped
diodes ?

You suggested that (whatever the failure mode) it was too fast for an
SCR to catch (I'm thinking of a conventional crowbar circuit - and even
*they* are too easy to get wrong). How about a combo; the grunt of the
work being done by a ballasted SCR, plus some transient suppressor to
handle things whilst this kicks in?
The cheapest protection must be a battery...

Beat me to it klog :^) anyone have know how this could be done?

cheers,
Pete.

Comment below.

Doug
s/v Callista

"Pete C" wrote in message
...
On 20 Sep 2004 01:58:46 -0700, "klog"
wrote:

ChrisGibboGibson wrote:

snip
The damage has already been done.
snip

May I stick my nose in? (it's a low-impedance nose, so should not
disrupt the thread much...).

Actually a high impedance nose would be less intrusive.

What exactly is the typical nature of the alternator damage
experienced? Fried regulator or winding insulation breakdown or zapped
diodes ?

Zapped diodes is what I see the most.

You suggested that (whatever the failure mode) it was too fast for an
SCR to catch (I'm thinking of a conventional crowbar circuit - and even
*they* are too easy to get wrong). How about a combo; the grunt of the
work being done by a ballasted SCR, plus some transient suppressor to
handle things whilst this kicks in?
The cheapest protection must be a battery...

Snubbers seems to work well.

Beat me to it klog :^) anyone have know how this could be done?

cheers,
Pete.

On Mon, 20 Sep 2004 18:33:27 -0400, "Doug Dotson"
wrote:

Comment below.

Doug
s/v Callista

"Pete C" wrote in message
ChrisGibboGibson wrote:
You suggested that (whatever the failure mode) it was too fast for an
SCR to catch (I'm thinking of a conventional crowbar circuit - and even
*they* are too easy to get wrong). How about a combo; the grunt of the
work being done by a ballasted SCR, plus some transient suppressor to
handle things whilst this kicks in?
The cheapest protection must be a battery...

Snubbers seems to work well.

Hi,

We were discussing ways of protecting alternators from load
disconnection, when a high current continues to flow until the
regulator kicks in.

Apart from an SCR a power mosfet might do it, some like a VNP49N04
have an autoclamping feature that would help.

cheers,
Pete.