> From on76@dial.pipex.com Thu Sep 12 14:07 EDT 1996
>
> >There is a way to check for proper contact adjustment and a way to
> >install a diode to reduce the burning and pitting of the contacts.
> >You'll have to get that wisdom from the other list members as I
> >haven't gotten that far yet.
>
> From my electro-mechanical telecommunications days spark quenching
> diodes were used connected straight across the contacts, to oppose
> the normal current flow. I think the theory is that the collapsing
> magnetic field in the (usually inductive) load induces a voltage
> across the just-opened contacts in the reverse direction to normal.
> The diode thus provides a lower resistance path for this reverse
> voltage than the (at that stage) minute air gap between the contacts
> and stops arcing and material transfer (pitting and spiking). It has
> the side effect of slowing down the release of the armature. But its
> all been a loooong time ago.
The time added by slowing down the fuel pump with a diode shouldn't be
near long enough for the LBC or owner to notice. I believe, when the
pump was designed, semiconductor diodes weren't perfected. I remember
trying to convince some electricians that I could replace their burned
out, bread loaf sized, selenium rectifier with a pea sized silicon
rectifier diode and improve the circuit at the same time.
- -Mark
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