| Nichrome wire bypass [message #350104] |
Wed, 13 November 2019 21:26  |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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Senior Member |
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Ok ok...i know there are tons of posts and pics etc but heres the question:
Should one re-wire the whole circuit as JB suggests? I see pics of how Kelvin did it by splicing in and clipping one end of the nichrome?
To much info sometimes is just as bad as not enough......the mechanic in me says re-wire the whole circuit....the practical side says a bypass can be just as good.
I only want to do this once so i want opinions from those who have personally done this.
Rich Mondor,
Brockville, ON
77 Hughes 2600
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| Re: Nichrome wire bypass [message #350106 is a reply to message #350104] |
Thu, 14 November 2019 00:05  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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You could bypass it but do not use a 100 ohm resistor as Jim B. states. He misread the wiring diagram years ago. The diagram shows a 10.0 ohm resistance wire and he read it as 100 ohm (missing the decimal point).
Gene Fisher came up with a simpler solution by inserting a diode in series with the start lead of alternator. He makes a "plug and Play" device he calls an APC (Alternator Protection Cable). It is $20 or $25 and I think Jim K has them. It is a 5 or 10 minute no tool install.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Nichrome wire bypass [message #350108 is a reply to message #350107] |
Thu, 14 November 2019 05:48 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Since Gene Fisher's APC came into use, I haven't heard of a single Nichrome
wire incident (with the APC installed). So, I'd feel comfortable using it
only. However, Bruce's point about heating is valid -- I replaced the Wire
with a fixed 10Ohm/25W resistor, before the APC appeared, with it mounted
in the HVAC airflow.
Ken H.
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Nichrome wire bypass [message #350115 is a reply to message #350107] |
Thu, 14 November 2019 12:40 |
Richard Denney
Messages: 920
Registered: April 2010
Karma: 9
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Senior Member |
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That’s exactly what I did, when KenH and I were making do with what could
be bought off-the-shelf in Bean Station. It was a temporary measure. It’s
still there. :)
Rick “~15-watt lamp = ~1 amp = ~10 ohms” Denney
On Thu, Nov 14, 2019 at 5:19 AM Bruce Hislop via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Diode will not allow current to flow in the nichrome wire if the voltage
> on Pin 1 (excitation) goes above the chassis battery voltage. It does not
> prevent the flow when the key is turned to ignition but the engine is not
> started... or if the alternator fails (broken belt, no power out etc) and
> you continue to drive (powering off house battery or onan)... in that case
> the GEN light will be ON and current will continue to flow in the nichrome
> wire and dissipate heat.
>
> I'm thinking to replace the nichrome wire with a single filament 12V lamp
> that is rated at about 1 Amp current (such as a single filament tail lamp).
> The lamp will be the correct resistance and will dissipate the heat
> generated. If something happened to the alternator to cause excessive
> voltage at
> Pin 1, the bulb will get very bright and will burn out cutting the current
> flow.
>
> Anytime the GEN light is ON, the nichrome wire has current flowing in it
> and is dissipating heat (about 10-12 watts).
>
> Just a thought.
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
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--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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