Home » Public Forums » GMCnet » [GMCnet] New Generator in 23'
| [GMCnet] New Generator in 23' [message #64873] |
Thu, 19 November 2009 08:23  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Well, after buying it 5 months ago and piddling with installation for the
past month, I finally connected the TroyBilt generator wiring into the 23's
transfer switch yesterday and fired it up. It works!
Photos are at
http://www.gmcmhphotos.com/photos/showgallery.php?cat=5330&ppuser=0 You'll
have to sort them on filename because I can't figure out how to make that
arrangement hold -- after all, I've only been using the photo site since day
1. I named them in the proper sort sequence, uploaded them in that
sequence, and I STILL can't make them present properly. :-(
The installation is essentially complete except for replacing the ball
bearing slides with sufficiently sturdy ones (the 100# ones are already
wrecked). Alan's bringing me the ones from my old 4kW Onan next week. If
they're too far gone, I'll try to find some at the surplus place in Orlando
in Jan. I still have to figure out the correct temperatures and locations
for the fan control and engine shutdown thermostats. Haven't yet added the
fans' finger guards nor the tailpipe either. I'll wait to decide what to do
about a remote choke until we get cold weather here (40*F).
But it's operating! It works much better than I ever expected. Starts and
shuts down from the inside panel; even the prime button and the run time
meter operate correctly with no rewiring from the Onan & Generac standard.
It carries loads much better than either the 4kW Onan or the Generac 36G
ever did. I ran it with the 13,500 BTU a/c, a 1500W heater, all the lights,
and the 1200W microwave in order to load it down to 110 vac. Even then
there was no perceptible change in the sound of the engine. Nor is there
any change in sound when any of those loads is turned OFF or ON. Both of
the earlier generators slowed or sped up noticeable with significant load
changes.
There's really not much difference, to my ears, in the noise level from the
earlier generators. Inside the coach the sound level is not really
objectionable. I wouldn't want to sleep with it running but we've never
attempted that and don't expect to.
With only an hour or so of continuous run time, in 65*F ambient temperature,
it's too early to predict what the cooling situation will be. But from what
my IR temperature gun shows so far, the 750 cfm electric fan on the door is
quite capable of cooling the generator adequately.
At a total cost of maybe $850, it's probably a better solution than the
Generac 36G was at $1650+.
--
Ken H.
Americus, GA
'76 X-Birchaven
www.gmcwipersetc.com
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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] New Generator in 23' [message #64892 is a reply to message #64873] |
Thu, 19 November 2009 10:45  |
Rick Denney
Messages: 430
Registered: January 2004
Karma: 0
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Senior Member |
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Ken Henderson writes...
> Photos are at
> http://www.gmcmhphotos.com/photos/showgallery.php?cat=5330&ppuser=0 You'll
> have to sort them on filename because I can't figure out how to make that
> arrangement hold -- after all, I've only been using the photo site since day
> 1. I named them in the proper sort sequence, uploaded them in that
> sequence, and I STILL can't make them present properly. :-(
Ken, here's the process:
Go to www.gmcphotos.com, and log in if necessary.
Click "My Albums".
Next to the album you just created, over on the right, there will be a
button called "Sort Photos". It's next to "Upload Photos", "Delete",
and "Edit".
Click "Sort Photos" and a screen with all your pictures will come up.
Below each picture will be an editable field with a number in it.
That's the default sort order. Change the numbers to reflect you order
you want.
Click "Submit".
That's all there is to it. It is a separate process that has nothing
to do with how you name them or upload them.
> There's really not much difference, to my ears, in the noise level from the
> earlier generators.
Which ear were you using? (You knew somebody would ask that question.)
Let's have HER judgment of the noise level!
Rick "eh?" Denney
'73 230 Ex-Glacier "Jaws"
Northern Virginia
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'73 Glacier 230 "Jaws"
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| Re: [GMCnet] New Generator in 23' [message #64894 is a reply to message #64880] |
Thu, 19 November 2009 11:06 |
Rick Denney
Messages: 430
Registered: January 2004
Karma: 0
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Senior Member |
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Thomas Phipps writes...
> Ken, Excellent work. Rick will be jealous. Tom
I'll wait until my Generac breaks again, and give Ken a little time to
explore the potential problems with this arrangement.
Rick "still a KenHen follower, but at a safe distance" Denney
'73 230 Ex-Glacier "Jaws"
Northern Virginia
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'73 Glacier 230 "Jaws"
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| Re: [GMCnet] New Generator in 23' [message #65053 is a reply to message #65002] |
Fri, 20 November 2009 12:31 |
Rick Denney
Messages: 430
Registered: January 2004
Karma: 0
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Senior Member |
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Ken Henderson writes...
> Some folks just never learn!
Joking aside, some things I would like to learn:
1. Does your generator use an inverter? My job-site generator that I
use for emergency backup at home has a fixed throttle, so I'm assuming
it doesn't and that it uses a conventional generator head. But I
wonder how good the throttle regulation is.
2. What is the clearance between the door and the fan intake on the
engine?
3. What is the air flow? That has been a key issue, I think, with my
Generac installation (and maybe with yours, too). I disovered that it
is not enough to provide sufficient intake of cooling air, which both
you and I thought about quite a lot. We also have to provide
sufficient exhaust. That's where my installation has been a problem,
and I had to build some shields to route exhaust air appropriately.
The diagonal frame rail is definitely in the way of that exhaust air
on the Generac installation.
4. Why do you suppose the waveform output is so dirty? If it's a
conventional head, one would think the geometry of the coils and
permanent magnets would do what it takes to create a smooth waveform.
That makes me wonder if it really is an inverted output after all.
Guy Peeters installed a job-site generator (to much amusement from the
Peanut Gallery) in his 260, though without a lot of the care you have
taken to provide safe remote control. His had a Robin engine rather
than the B&S, and it was a Harbor Freight special. But it was rated
similarly to yours (and to my emergency generator at the house). He
also was able to rewire the output for combined 120. (A.D.D. moment:
It occurs to me that my coach, with its 50-amp wiring, could easily be
wired using the 240VAC output of the generator, with each leg feeding
each set of circuits, just as with being fed from a 50-amp shore-power
source.) He needed that to start his roof air, which would not start
with just one leg. I suspect his coach was wired for 30 amps, though,
as is yours. But I distinctly remember from his demonstration that he
manually adjusted the throttle, apparently with the notion that if you
had a high load, manually cranke it up.
We used that generator to power tools for cutting the back off the
motorhome I used to replace the back end of mine, so while the Peanut
Gallery was snickering, he was generating electricity.
Based on present experience, I'm expecting my Generac to blow up again
at any time, and this seems the only other option for 23' coaches.
That's why I'm following you further down that same garden path.
Rick "who also wouldn't mind 6000 real watts" Denney
'73 230 Ex-Glacier "Jaws"
Northern Virginia
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| Re: [GMCnet] New Generator in 23' [message #65058 is a reply to message #65053] |
Fri, 20 November 2009 13:21 |
GMCWiperMan
Messages: 1248
Registered: December 2007
Karma: 1
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Senior Member |
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Rick,
You realize, but everyone else must: I just got this thing wired in and
operating the coach yesterday so these answers are not based on much
experience.
1. No, this is a straightforward alternator: Two fixed 120 vac 20+A stator
windings plus a winding and a FW bridge for DC excitation of the rotating
field. It came wired for 120/240 but when I connected it into the coach
wiring I wired the two stator windings in parallel, in phase, to give 120
vac only. That was preferable to changing the Coachmen-style electrical
system. If the windings had not been independently terminated so that I
could parallel them, I'd have just put the A/C on one leg and everything
else on the other.
The throttle regulation is pretty good, but not perfect -- not up to Onan
standards. At no load it hunts from 61.3 to 61.5 Hz at about 127 vac. At
about 3000 W load, it's pretty steady on 60 Hz. and 120 vac. With
approximately 5000 W load the voltage has dropped to 115 vac and about 58
Hz. I won't be running any synchronous clocks on it.
I'll be watching all that anxiously as the time accumulates -- I may have a
continual engine tune-up project. :-(
2. With the 1-1/2" or so clearance I enforced across the back of the
compartment, there's about 2-1/2" clearance between the engine fan inlet
(with the pull starter removed) and the door.
3. I think the air flow's going to be excellent: I got a 12", 750 cfm,
radiator fan through eBay for $25. With it mounted over the compartment
door vents, its guard is about 3/8" from the engine inlet housing. About
1/4-1/3 of it blows directly into the engine fan inlet; the rest flows over
the engine with good flow through the exhaust heat shield. The flow out the
back of the compartment beneath the coach is almost as strong, though more
dispersed, as that out the bottom of the 4kW Onan's blower. It definitely
makes a big difference whether the electric fan is running -- more later. I
have not yet done any blocking of unwanted exhaust routes. There is a big
gap between the door and the generator mounting tray which I'm hoping I can
keep to allow some cooling air around the muffler. Nor have I made any
effort to force air through the alternator, which has surprisingly little
ventilation in the original design. If it proves necessary, I can easily
direct a lot more air around the exhaust, but so far I don't think it will
be needed.
While there's about 20" of the 1-1/2" SS flex exhaust inside the
compartment, that's 1/2" larger in diameter than the engine's exhaust port
so there's little restriction and the relatively large Onan-type muffler
doesn't add much. The IR gun (with a 8-dot aiming circle so I know what I'm
measuring) shows the back of the compartment always at <120*F so far.
Having the muffler outside the frame rail so the engine can come out on
slides is nice -- and it stays cool -- I've only seen about 140*F at the hot
end.
The hottest spot I've been able to find on the engine is the crankcase just
below the cylinder. If I run the generator for a while without the electric
fan, that area reaches 195*F pretty quickly and seems to stabilize (but I
haven't tried it for long). When I run the fan, that temperature drops
almost immediately to 160*F. I think the fan control thermo switches will
have to be mounted in that area -- I can't find any compartment temperature
which tracks with the engine at all -- much too cool everywhere else.
4. The dirty waveform has me baffled. It's not very high frequency noise,
and the amplitude is not very great, so it won't be a problem; it's just
curious. Right now my best guess is that the slip rings brushes have not
bedded in well so the rotating field is not getting clean DC. If that's the
case, it should improve quickly. I'll stick the 'scope back on it after
I've run it a few hours.
Right now I'm very happy -- but then I was even more happy when I'd just
installed the Generac. I hope you don't have to follow me down the primrose
path very soon.
Ken
On Fri, Nov 20, 2009 at 1:31 PM, Rick Denney <rick@rickdenney.com> wrote:
> Ken Henderson writes...
>
> > Some folks just never learn!
>
> Joking aside, some things I would like to learn:
>
> 1. Does your generator use an inverter? My job-site generator that I
> use for emergency backup at home has a fixed throttle, so I'm assuming
> it doesn't and that it uses a conventional generator head. But I
> wonder how good the throttle regulation is.
>
> 2. What is the clearance between the door and the fan intake on the
> engine?
>
> 3. What is the air flow? That has been a key issue, I think, with my
> Generac installation (and maybe with yours, too). I disovered that it
> is not enough to provide sufficient intake of cooling air, which both
> you and I thought about quite a lot. We also have to provide
> sufficient exhaust. That's where my installation has been a problem,
> and I had to build some shields to route exhaust air appropriately.
> The diagonal frame rail is definitely in the way of that exhaust air
> on the Generac installation.
>
> 4. Why do you suppose the waveform output is so dirty? If it's a
> conventional head, one would think the geometry of the coils and
> permanent magnets would do what it takes to create a smooth waveform.
> That makes me wonder if it really is an inverted output after all.
>
> Guy Peeters installed a job-site generator (to much amusement from the
> Peanut Gallery) in his 260, though without a lot of the care you have
> taken to provide safe remote control. His had a Robin engine rather
> than the B&S, and it was a Harbor Freight special. But it was rated
> similarly to yours (and to my emergency generator at the house). He
> also was able to rewire the output for combined 120. (A.D.D. moment:
> It occurs to me that my coach, with its 50-amp wiring, could easily be
> wired using the 240VAC output of the generator, with each leg feeding
> each set of circuits, just as with being fed from a 50-amp shore-power
> source.) He needed that to start his roof air, which would not start
> with just one leg. I suspect his coach was wired for 30 amps, though,
> as is yours. But I distinctly remember from his demonstration that he
> manually adjusted the throttle, apparently with the notion that if you
> had a high load, manually cranke it up.
>
> We used that generator to power tools for cutting the back off the
> motorhome I used to replace the back end of mine, so while the Peanut
> Gallery was snickering, he was generating electricity.
>
> Based on present experience, I'm expecting my Generac to blow up again
> at any time, and this seems the only other option for 23' coaches.
> That's why I'm following you further down that same garden path.
>
> Rick "who also wouldn't mind 6000 real watts" Denney
>
> '73 230 Ex-Glacier "Jaws"
> Northern Virginia
>
> _
>
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| Re: [GMCnet] New Generator in 23' [message #65063 is a reply to message #64873] |
Fri, 20 November 2009 13:40 |
Chr$
Messages: 2690
Registered: January 2004
Location: Scottsdale, AZ
Karma: 1
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Senior Member |
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How Loud is it?
-Chr$: Perpetual SmartAss
Scottsdale, AZ
77 Ex-Kingsley 455 SOLD!
2010 Nomad 24 Ft TT 390W PV W/MPPT, EV4010 and custom cargo door.
Photosite: Chrisc GMC:"It has Begun" TT: "The Other Woman"
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| Re: [GMCnet] New Generator in 23' [message #65067 is a reply to message #65063] |
Fri, 20 November 2009 13:56 |
GMCWiperMan
Messages: 1248
Registered: December 2007
Karma: 1
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Senior Member |
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I don't think it's any louder than the Generac which was no quieter than the
Onan 4kW. But notice I said "I don't think..". Rick suggested that SHE
needs to evaluate it (instead of Ken Burton, Roger Black, or me; no one of
whom would be disturbed by the recently discussed train horns).
Seriously, even with the GMC parked under the RV shelter with a wall only 6
feet away from the exhaust, it's really not obnoxious. Inside the coach
(with 2" of fiberglass around the compartment), it won't interfere with a
quiet conversation.
Ken H.
On Fri, Nov 20, 2009 at 2:40 PM, Chris Choffat <cchoffataz@yahoo.com> wrote:
>
>
> How Loud is it?
>
--
Ken H.
Americus, GA
'76 X-Birchaven
www.gmcwipersetc.com
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