Ok, zero watts when running, but not when you have the key on and not running right?
Always design for worst case
________________________________
From: Gmclist on behalf of gene Fisher
Sent: Wednesday, October 3, 2018 8:52 AM
To: gmclist
Subject: Re: [GMCnet] Replacement wire type for nichrome wire
> What is this
>
> Gene should also look on Ebay for anti-feedback for 10, 12, 17 and 27SI.
>
Gene should also look on Ebay for anti-feedback for 10, 12, 17 and 27SI
>
>
>
Over the past few months I have been working on alternative ignition
designs for our Onan generators. During my tenure as a GMC owner I have
suffered the failure of two Pertronix 1181 modules mounted in the blower
housing scroll - one due to a fatigue failure of the module’s aluminum
mounting tab due to wind buffeting - and the other due to a flywheel strike
where the flywheel magnet somehow impacted the module’s face for at least
several revolutions. These two events occurred with super-rigid mounting
arrangements that I made myself - I was NOT using the C-channel mounting
kit commonly found in the GMC community. Photo albums of these two:
http://www.jcmco.com/gallery/Pertronix<
http://www.jcmco.com/gallery/Pertronix> and
http://www.jcmco.com/gallery/PertronixModII<
http://www.jcmco.com/gallery/PertronixModII>
So I decided to experiment with something different…I mounted the module on
the outside of the generator’s bellhousing and have it being triggered by a
magnet embedded in an aluminum tonewheel:
http://www.jcmco.com/gallery/Pertronix-ModIII<
http://www.jcmco.com/gallery/Pertronix-ModIII>
This produced very good results - nearly identical to when the module is
mounted inside the blower scroll and triggered by a flywheel magnet.
However, during testing I made the observation that the ignition coil was
running very hot and was uncomfortable to touch even after very short
amounts of runtime. I determined that the Pertronix 1181 module that people
have recommended for our Onans was keeping the coil energized for about 355
degrees of rotation of the crankshaft - and only dropped its output for a
few milliseconds as the magnet went by the module at which time the spark
plugs fired. This is contrasted with the 140 degrees per revolution which
the OEM breaker points used as a coil dwell time. In other words, the
Pertronix 1181 causes current to flow in the coil primary for almost three
times as long as the original Onan design. No wonder the coil is getting so
hot… once the magnetic field builds up in the core of the coil the
remaining current flow produces nothing but heat. I wrote to Pertronix tech
support for advice and they confirmed that the 1181 is not the right module
for this application. Their words:
"You really should be using what we call a latching Ignitor module. This
module takes two magnets to trigger the unit. One to turn it "ON" then one
to turn it "OFF" to fire. This allows you to control the charge time of the
coil. We use this module on all our applications that have less then 4
cylinders. This is so we don't overheat the coil and don't over heat the
Ignitor module. … The part number I would recommend to modify would be part
number: 1121”
At that point I bought an 1121 and modified my mount and magnet wheel for
it: http://www.jcmco.com/gallery/PertronixModIV <
http://www.jcmco.com/gallery/PertronixModIV>
The 1121 module has been in service on my Onan for 20 hours of runtime so
far and has worked flawlessly. Just as with the 1181 module, the 1121
produces repeatable and precise spark timing but - unlike the 1181 - the
1121 produces no appreciable heating of the ignition coil. Having worked 35
years in an electronics career I know quite
>
>
>
>
>> >
>> > Then I started on the APC. He went to his parts bin and brought out a
>> 2" long pair of 2-wire terminals with a diode in one of the wires -- the
>> > equivalent of the APC.
>> > "Been selling them for YEARS -- cost $3.81." I didn't get a part
>> number, but you may want to reconsider fabricating them, Gene.
>> >
>> > He also reminded me of the fact that when the alternator's producing
>> power,
>> > ALL THREE of its terminals are at output voltage. I guess I forgot
>> that
>> > when I oversized and air stream located my resistor.
>> >
>> > Ken "EE EDUCATED -- NOT experienced" H.
>>
>> Gene should also look on Ebay for anti-feedback for 10, 12, 17 and 27SI.
>>
>> Matt ONP at the casino in Erie PA.
>> --
>> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
>> Electronically Controlled Quiet Engine Cooling Fan
>> OE Rear Drum Brakes with Applied Control Arms
>> SE Michigan - Twixt A2 and Detroit
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://bdub.net/gmcmotorhome.info/
> Alternator Protection Cable
> http://bdub.net/gmcmotorhome.info/APC.html
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Always design for worst case
________________________________
From: Gmclist on behalf of gene Fisher
Sent: Wednesday, October 3, 2018 8:52 AM
To: gmclist
Subject: Re: [GMCnet] Replacement wire type for nichrome wire
> What is this
>
> Gene should also look on Ebay for anti-feedback for 10, 12, 17 and 27SI.
>
Gene should also look on Ebay for anti-feedback for 10, 12, 17 and 27SI
>
>
>
Over the past few months I have been working on alternative ignition
designs for our Onan generators. During my tenure as a GMC owner I have
suffered the failure of two Pertronix 1181 modules mounted in the blower
housing scroll - one due to a fatigue failure of the module’s aluminum
mounting tab due to wind buffeting - and the other due to a flywheel strike
where the flywheel magnet somehow impacted the module’s face for at least
several revolutions. These two events occurred with super-rigid mounting
arrangements that I made myself - I was NOT using the C-channel mounting
kit commonly found in the GMC community. Photo albums of these two:
http://www.jcmco.com/gallery/Pertronix<
http://www.jcmco.com/gallery/Pertronix> and
http://www.jcmco.com/gallery/PertronixModII<
http://www.jcmco.com/gallery/PertronixModII>
So I decided to experiment with something different…I mounted the module on
the outside of the generator’s bellhousing and have it being triggered by a
magnet embedded in an aluminum tonewheel:
http://www.jcmco.com/gallery/Pertronix-ModIII<
http://www.jcmco.com/gallery/Pertronix-ModIII>
This produced very good results - nearly identical to when the module is
mounted inside the blower scroll and triggered by a flywheel magnet.
However, during testing I made the observation that the ignition coil was
running very hot and was uncomfortable to touch even after very short
amounts of runtime. I determined that the Pertronix 1181 module that people
have recommended for our Onans was keeping the coil energized for about 355
degrees of rotation of the crankshaft - and only dropped its output for a
few milliseconds as the magnet went by the module at which time the spark
plugs fired. This is contrasted with the 140 degrees per revolution which
the OEM breaker points used as a coil dwell time. In other words, the
Pertronix 1181 causes current to flow in the coil primary for almost three
times as long as the original Onan design. No wonder the coil is getting so
hot… once the magnetic field builds up in the core of the coil the
remaining current flow produces nothing but heat. I wrote to Pertronix tech
support for advice and they confirmed that the 1181 is not the right module
for this application. Their words:
"You really should be using what we call a latching Ignitor module. This
module takes two magnets to trigger the unit. One to turn it "ON" then one
to turn it "OFF" to fire. This allows you to control the charge time of the
coil. We use this module on all our applications that have less then 4
cylinders. This is so we don't overheat the coil and don't over heat the
Ignitor module. … The part number I would recommend to modify would be part
number: 1121”
At that point I bought an 1121 and modified my mount and magnet wheel for
it: http://www.jcmco.com/gallery/PertronixModIV <
http://www.jcmco.com/gallery/PertronixModIV>
The 1121 module has been in service on my Onan for 20 hours of runtime so
far and has worked flawlessly. Just as with the 1181 module, the 1121
produces repeatable and precise spark timing but - unlike the 1181 - the
1121 produces no appreciable heating of the ignition coil. Having worked 35
years in an electronics career I know quite
>
>
>
>
>> >
>> > Then I started on the APC. He went to his parts bin and brought out a
>> 2" long pair of 2-wire terminals with a diode in one of the wires -- the
>> > equivalent of the APC.
>> > "Been selling them for YEARS -- cost $3.81." I didn't get a part
>> number, but you may want to reconsider fabricating them, Gene.
>> >
>> > He also reminded me of the fact that when the alternator's producing
>> power,
>> > ALL THREE of its terminals are at output voltage. I guess I forgot
>> that
>> > when I oversized and air stream located my resistor.
>> >
>> > Ken "EE EDUCATED -- NOT experienced" H.
>>
>> Gene should also look on Ebay for anti-feedback for 10, 12, 17 and 27SI.
>>
>> Matt ONP at the casino in Erie PA.
>> --
>> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
>> Electronically Controlled Quiet Engine Cooling Fan
>> OE Rear Drum Brakes with Applied Control Arms
>> SE Michigan - Twixt A2 and Detroit
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Gene Fisher -- 74-23,77PB/ore/ca
> “Give a man a fish; you have fed him for today --- give him a URL and
> -------
> http://bdub.net/gmcmotorhome.info/
> Alternator Protection Cable
> http://bdub.net/gmcmotorhome.info/APC.html
>
--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://bdub.net/gmcmotorhome.info/
Alternator Protection Cable
http://bdub.net/gmcmotorhome.info/APC.html
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
