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RE: 2 amps, or nor 2 amps? THAT is the question...

To: "rob thomas" <rob@thomasr.greatxscape.net>, "Christopher M West" <chris_west@juno.com>
Subject: RE: 2 amps, or nor 2 amps? THAT is the question...
Date: Sun, 26 Nov 2000 08:47:14 -0500
Cc: "spridgets" <spridgets@autox.team.net>
One failure mode of mechanical relays is for the contacts to weld shut. I've
seen that happen in the launch system at high-power rocketry events, with
spectacular results. If it is a solid-state relay, a likely failure mode is
for it to short out.

Your 40A relay is little protection for your 60A wiring. That 40A rating is
for how much current the contacts can carry without melting.

Tom Zuchowski

> -----Original Message-----
> From: owner-spridgets@autox.team.net
> [mailto:owner-spridgets@autox.team.net]On Behalf Of rob thomas
> Sent: Wednesday, November 22, 2000 5:03 AM
> To: Christopher M West
> Cc: spridgets
> Subject: Re: 2 amps, or nor 2 amps? THAT is the question...
>
> > "60 Mk.1  et al.
> Due to the way the relays are wired, the loom is protected as far down as
> the relay box, about 8-inches from the first headlight.  The
> wiring from the
> switch to the relay carries less than 1 amp to actuate the relay, so is
> unlikely to suffer.  The relay itself would be the first thing to blow as
> the wiring downstream is rated at 60+amps continuous whilst the relay dies
> at 40 amps.  The bulbs draw 22 amps at max.  I totally agree that fused
> lamps are a good idea but I had to decide whether I could trust the relays
> to do their jobs, against the likelihood of the fuses getting wet from the
> front wheels and corroding( as I couldn't find waterproof
> fuseblocks.  If I
> ever find some, I will use them. )
>  Thanks for the suggestion.
> Rob

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