Home » Public Forums » GMCnet » More new genset
| Re: [GMCnet] More new genset [message #287129 is a reply to message #287105] |
Sat, 12 September 2015 10:15   |
Jim Miller
Messages: 501
Registered: March 2008
Karma: 10
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On Sep 11, 2015, at 8:33 PM, Johnny Bridges wrote:
> With the door closed, the top of the bay in back gets up to 180 in places according to my IR gun. Exhaust pipe is ~~400 degrees at the engine, 340 at the muffler input. I may fiddle around with some flashing tin and see if I can get the air stirring in the top rear of the compartment The engine fan blows out the opening fairly well already. 180 isn’t earthshakin, but I believe it can be got a bit lower.
Hi Johnny,
This isn’t directly pertinent to your new Onan but it is pertinent to those with the OEM unit. I have seen a lot of speculation over the years about the temperatures in the Onan compartment - especially above the exhaust manifold so I did an experiment where I instrumented the compartment with a couple thermocouples attached to a logging meter. I attached one thermocouple on the insulation at a point directly above the exhaust manifold and one in a slot that I sliced between the OEM foam and the aluminum compartment skin at a point directly above the exhaust manifold.
Here is the graph of the readings: http://www.jcmco.com/gallery/album29/aae
..the left 1/3 of the graph is with the Onan running at 75% electrical load; outdoor temp was around 88F. The temperature excursion occurs at the moment the Onan was shut down because there was no more cooling air being moved through the compartment by the Onan’s blower. One interesting takeaway is that the compartment temps both at the foam and at the foam-body interface are nearly the same as the outdoor temp while the unit is running. The temperature excursion occurs immediately after shutdown as expected and peaked around 210F.
There are some more pictures at:
http://www.jcmco.com/gallery/album29
I’ll be re-doing this experiment with more thermocouples and a slightly different approach soon. I prefer using thermocouples because IR thermometers tend to lie when aimed at reflective surfaces like reflectix. I also had some problems with noise being induced into the thermocouple leads so I’ll be using shielded thermocouples next time.
--Jim "saving the lives of Onans...one unit at a time" Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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Jim Miller
1977 Eleganza II
1977 Royale
Hamilton, OH
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| Re: More new genset [message #287156 is a reply to message #284805] |
Sat, 12 September 2015 19:02 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Jim, thanks. This one isn't an Onan, but your numbers indicate I can get it a bit cooler in the compartment with a bit of baffling. I think I can direct the engine fan air out the rear bottom across the exhaust with a piece of tin, and close off the bottom front so the forced air blows forward, through the engine, and out. I'll keep playing with it.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
[Updated on: Sun, 13 September 2015 19:12] Report message to a moderator |
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| Re: More new genset [message #287188 is a reply to message #284805] |
Sun, 13 September 2015 19:15 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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My new shore power cable arrived while I was at a show this weekend (74 Australian Terriers in my ring this morning, can you say "Ratdog Overload"?)I will install it shortly. 50' 50 Amp and the setupis complete. Two troubleshootings - The remote start doesn't, and the airflow needs directing. I expect both will be fairly simple fixes. Remote stop works correctly, GEN light on the remote works, Hobbes clock works. Pictures shortly.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: More new genset [message #287333 is a reply to message #284805] |
Tue, 15 September 2015 16:23 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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The new power cable required enlargement of the cable bay, hope to finish the [project tomorrow. Same depth, double the length. After some searching, I found a manual 60Amp transfer switch which will fit in the available space. $62 from Amazon, plus tax. We're Amazon Prime, two day shipping is free. Reliance Controls 60 Amp.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: [GMCnet] More new genset [message #287363 is a reply to message #287333] |
Wed, 16 September 2015 06:59 |
Jim at the Co-op
Messages: 291
Registered: May 2014
Location: Orlando Florida
Karma: 2
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Brother I sure want this to succeed for ya and not being a totally self
contained unit like it is and your stripping away the frame the baby may
work. I'll tell you fitting that smaller 3000 watt portable Dometic was
not a viable issue. Had all the props, remote start, 3K inverter power and
all but heat and fuel issues plagued the process. Many of you remember I
was all proud of it still wet behind the ears, steps after showing it off
made it not work well and my experiment ended on a positive note... that's
not the way. Keep us all abreast, if it works we ne to take an electric
start Using a non inverter type will probably work much better than the
inverter driven one I was trying but I wanted the unit to work on it's own
outside the coach if needbe... probably a bit too ambitious. Taking a unit
like that and modifying it fit would solve several issues but being a pull
start and the noise issue my make it a problem for my customers. Looks
good though. Hey, rig up an electric start on the puppy... would
make "Heathen" much more civil...
Jim Bounds
On Tue, Sep 15, 2015 at 5:23 PM, Johnny Bridges wrote:
> The new power cable required enlargement of the cable bay, hope to finish
> the [project tomorrow. Same depth, double the length. After some
> searching, I found a manual 60Amp transfer switch which will fit in the
> available space. $62 from Amazon, plus tax. We're Amazon Prime, two day
> shipping is free. Reliance Controls 60 Amp.
>
> --johnny
>
> --
> '76 23' transmode Norris upfit
> Braselton, Ga.
>
> "Sometimes I wonder what tomorrow's gonna bring when I think about my
> dirty life and times" --Warren Zevon
>
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| Re: More new genset [message #287366 is a reply to message #284805] |
Wed, 16 September 2015 08:42 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Jim, this one has an electric self-commencer. That's why I went with the 7KW, smallest one which did.. They make a 5KW with a yanker cranker. The engine on it has the cast pad for the starter, but you'd have to machine it. It would be an easier install, though, it's a bit smaller. It will be at Wekiwa 7 - 14 DEC if the creek don't rise too far, and you can see how it was done. If I had your facilities, I might have done it a bit differently. I was shooting for ease of install. Also, if the genset bay in my coach was unmodified I might have taken a bit different approach. I've figured a way to make it slide out, but it would be very involved.... I don't have the facilities to make the curved slide it would need. Things I might do differently in an equipped shop:
1. Machine and thread a hole in the upper case for the pump pulse line.
2. Design and fab a breaker panel that fits the opening in the bay.
3. Work out the air flow in advance, and baffle the bay before the set goes in.
4. Build up a remote start panel if the coach doesn't have one.
5. Remote the air filter.
6. Mount a solenoid on the choke.
7. Fab slides to let the set slide out of the bay when needed.
The noise isn't all that bad in the coach - it ain't Onan level, but it ain't too obtrusive. I suspect if you sat down and figures some with the set running in the original frame, you could quiet it down quite a bit. Much of the noise is intake and mechanical. I suspect removing the manual starter assembly would stop a lot of it... but I like the ability to hand crank it if/when all else fails. Remoting the air filter would make life simpler in several ways, silencing being only one.
There are others you'll think of I'm sure. However, this mod ought to be doable for about $2K retail and show a profit.
--johnny
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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