A good reason to keep your Generator.

I was surprised to find, on Amazon and eBay, transformers with both Up and
Down connections at very reasonable prices (3000W for Chris
> You must have missed my earlier post that a step up transformer could
> easily be wired in to boost the 120 v from the GMC to power a 240 v well
> pump. I had suggested you check Amazon's site as they have many listed
>
> Emery Stora
> 77 Kingsley
> Frederick, CO
>
> > On Dec 5, 2016, at 9:33 AM, Chris Tyler

> >
> > Going back to a previous discussion, it would be relatively easy to put
> an outlet box off of my well pump site with the 50a plug for the GMC. My
> > recollection is that the 240v will only be seen as 120 in the coach.
> > It would be a handy place to plug in the coach.
> >
> > So, a a 'Backup' backup plan, perhaps that could be connected to the
> house to provide 120 for house if the coleman generator fails.
> >
> > That wont solve the well pump problem though.I have considered adding a
> caged water tank as a resiviour with either a 110v or 12v pump for
> > emergencies.
> >
> > Yes, a transfer switch would be the way to go.
> >
> >
> > --
> > 76 Glenbrook
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
 
Ken / Emery,

Two doors down from my "Shed" is a company called Radameta, the owner has been making custom transformers for over thirty years. He
made one for me that stepped down the 230VAC here to 120VAC so I could run my US power tools. He noted the same thing you've noted
below regarding them being hazardous. Those cheap transformers are available here as well and they come out of China.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken Henderson
Sent: Tuesday, December 06, 2016 8:58 AM
To: gmclist
Subject: Re: [GMCnet] A good reason to keep your Generator.

I was surprised to find, on Amazon and eBay, transformers with both Up and
Down connections at very reasonable prices (3000W for
 
Last edited by a moderator:
I’ve been kind of amazed at reading all the creative (and in some cases dangerous) solutions to get 240V out of our Onans when a step-up transformer with a center-tapped secondary is the best and easiest solution to provide perfect split-phase 120-0-120 power that those of us in the US desire.

The important thing to remember is that our Onan is a rotating-ARMATURE/stationary-field design which means that the main output power comes from the rotating component - and therefore you must have beefy slip-rings and brushes to extract that power. The OEM unit has only two slip rings on the armature which means that you can get 120-0 (or 240-0) power ONLY - the latter by changing the field excitation circuit. The only way to get 120-0-120 directly from the unit would be to add a second set of armature windings and an additional slip-ring and brush to get a third conductor from the added windings. The problem is that there is no room on the shaft to add that third slip ring and no room in the bell housing to add the brush that would ride against it.

The majority of small gensets that you come across are rotating-FIELD/stationary-armature and in that case adding or reconfiguring coils to get different outputs would be a whole lot easier.

—Jim
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
 
Handy yes, EXCEPT you well pump will be missing he white wire neutral necessary for 120 volt to work.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
Matt,

I had an extra 50 amp plug that I had picked up at a flea market
and decided to make an external access plug out of it to use in case
of an extended power outage.

I wired it with four 15 amp plugs that are color coded, two on each
leg of the 50 amp plug. I color coded the output cords to balance
the output power if needed.

With several extension cords, I can run refrigerator, sump pump, freezer,
or anything else I need to power.

Haven't needed to use it yet but it's there if I need it.

JWID
larry
 
Also, if the well pump is constructed like mine, the switch is in the
house, not at the pump, and the wiring to the pump is buried.

Rick "not that I could park a coach close to the well in any case" Denney

> Handy yes, EXCEPT you well pump will be missing he white wire neutral
> necessary for 120 volt to work.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
'73 230 "Jaws"
Northern Virginia
 
>lineman
>main breaker

The Square D 'Homeline' brand has a UL-approved manual interlock kit. You backfeed the bus through a breaker but you can't flip it on until you turn
off the main.

http://www.homedepot.com/p/Square-D-Homeline-Outdoor-Generator-Inter-Lock-Kit-HOMRBGK2C/203030954

I have 2 of the above on the 400a service (200a x 2) outside for the 240v genset (which probably doesn't run) but found it easier keep a 130v breaker
on a 10/3 SO cord whip to backfeed just 120v into one of the household subpanels from a Honda EU3000is that I picked up to maybe try in the Birchaven.
That subpanel had the kitchen appliances and master bedroom on it. A minor re-positioning of breakers to put the circuits I needed on the same leg
gave me a pretty good setup.
--
77 Royale Coachmen Side Dry Bath
76 Birchaven Coachmen Side Wet Bath
76 Eleganza
Elizabeth City, NC
 
> Matt,
>
> I had an extra 50 amp plug that I had picked up at a flea market and decided to make an external access plug out of it to use in case of an
> extended power outage.
>
> I wired it with four 15 amp plugs that are color coded, two on each leg of the 50 amp plug. I color coded the output cords to balance the output
> power if needed.
>
> With several extension cords, I can run refrigerator, sump pump, freezer, or anything else I need to power.
>
> Haven't needed to use it yet but it's there if I need it.
>
> JWID
> larry

Larry,

Nothing wrong with that plan. It is not too different than what I have done.
As I used to do a lot of winter work on boats, I made an adapter to get a 30amp twist lock (marine standard) from the 50 outlet in the service box. I
already had a L6-30 (30amp twist lock) to four outlet (6-15) box. I have used that the same way before I set up an exclusion panel to feed the house
from the barn. This is not so good in the winter because things have to stay open to run cords in and the heating plant is hard wired.

Matt
--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit
 
If you switch the ENTIRE 200 Amp breaker panel between commercial line feed and auxiliary generator input, you only need to carefully use current draw devices within the total capacity of your generator.

My auxiliary generator is 8 kW plus a small amount of surge capacity. I also have a 40 Amp split 240 Volt outlet and 30 Amp 120 Volt outlet on the outside wall of the garage to provide power to a visiting RVer. My auxiliary generator would therefore also be able to feed a visitor's RV (minding total power drain, of course).

My manual disconnect switch is an Eaton Cutler-Hammer probably very similar to the Square-D mentioned by RC below. I found it brand new on eBay for about 1/2 of "new" price.

This way, I don't have to "pick" which circuits I want to be operational on emergency power; I can use ANY circuit(s) as long as total current draw is within capability of my generator set.

I had it all installed by a licensed electrician to ensure it is safe AND meets code.

Your situation and solution may vary!

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ Since 30 November '53 ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ Member GMCMI and Classics ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
|[ ]~~~[][ ][]\
"--OO--[]---O-"

________________________________
From: Gmclist on behalf of RC Jordan
Sent: Tuesday, December 6, 2016 08:31
To: gmclist
Subject: Re: [GMCnet] A good reason to keep your Generator.

The Square D 'Homeline' brand has a UL-approved manual interlock kit. You backfeed the bus through a breaker but you can't flip it on until you turn
off the main.

http://www.homedepot.com/p/Square-D-Homeline-Outdoor-Generator-Inter-Lock-Kit-HOMRBGK2C/203030954

I have 2 of the above on the 400a service (200a x 2) outside for the 240v genset (which probably doesn't run) but found it easier keep a 130v breaker
on a 10/3 SO cord whip to backfeed just 120v into one of the household subpanels from a Honda EU3000is that I picked up to maybe try in the Birchaven.
That subpanel had the kitchen appliances and master bedroom on it. A minor re-positioning of breakers to put the circuits I needed on the same leg
gave me a pretty good setup.
--
77 Royale Coachmen Side Dry Bath
76 Birchaven Coachmen Side Wet Bath
76 Eleganza
Elizabeth City, NC
 
Matt,

There is one downside to hooking up electrical components in this manner,
there is no fuse or breaker in the circuit.

I have thought about how to add a breaker or fuse into it
but have not come up with an idea that would be practical.

Maybe someone out here can chime in with an idea that would
work. I suppose a light socket with a screw in fuse could be used.

Any thoughts?

larry
 
Jim,

Keeping in mind that I am electrically challenged I interpret your email below to read that it is possible to get "straight 240VAC"
out of an Onan.

Here in Australia the power is 240VAC 50Hz. I would gladly pay you for your time to put together specific detailed instructions on
how rewire an Onan to produce that power.

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Jim Miller
Sent: Tuesday, December 06, 2016 12:28 PM
To: gmclist
Subject: Re: [GMCnet] A good reason to keep your Generator.

I've been kind of amazed at reading all the creative (and in some cases dangerous) solutions to get 240V out of our Onans when a
step-up transformer with a center-tapped secondary is the best and easiest solution to provide perfect split-phase 120-0-120 power
that those of us in the US desire.

The important thing to remember is that our Onan is a rotating-ARMATURE/stationary-field design which means that the main output
power comes from the rotating component - and therefore you must have beefy slip-rings and brushes to extract that power. The OEM
unit has only two slip rings on the armature which means that you can get 120-0 (or 240-0) power ONLY - the latter by changing the
field excitation circuit. The only way to get 120-0-120 directly from the unit would be to add a second set of armature windings and
an additional slip-ring and brush to get a third conductor from the added windings. The problem is that there is no room on the
shaft to add that third slip ring and no room in the bell housing to add the brush that would ride against it.

The majority of small gensets that you come across are rotating-FIELD/stationary-armature and in that case adding or reconfiguring
coils to get different outputs would be a whole lot easier.

-Jim
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
 
A little off-topic, but another reason to have a good working generator: to run the roof AC in the heat! We found this out the hard way this past
summer on our Florida trip. Our generator had a bad starter that failed just before the trip and we didn't get it fixed (it's a Generac, not the
Onan). It would have been a lot more pleasurable for the riders on board if we could have run the AC on the road, the dash AC as beefy as it is,
could not keep up when it was approaching 93-95 degrees outside. The second use would have been when we overnighted at Walmart, again for the AC.
--
Chris S. -
77 Kingsley, 3.70 FD, mostly OEM -
S.E. Michigan
 
When I was on a trip to the International convention, my alternator failed,
but had no time to replace it.
I turned on the generator and locked the battery boost switch to on and
drove it that way till I reached destination.

> A little off-topic, but another reason to have a good working generator:
> to run the roof AC in the heat! We found this out the hard way this past
> summer on our Florida trip. Our generator had a bad starter that failed
> just before the trip and we didn't get it fixed (it's a Generac, not the
> Onan). It would have been a lot more pleasurable for the riders on board
> if we could have run the AC on the road, the dash AC as beefy as it is,
> could not keep up when it was approaching 93-95 degrees outside. The
> second use would have been when we overnighted at Walmart, again for the AC.
> --
> Chris S. -
> 77 Kingsley, 3.70 FD, mostly OEM -
> S.E. Michigan
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
> Keeping in mind that I am electrically challenged I interpret your email below to read that it is possible to get "straight 240VAC” out of an Onan. Here in Australia the power is 240VAC 50Hz.


Hi Rob,

The Onan’s rotational speed can be decreased to 1500 RPM in order to get 50Hz. This may affect the output torque from the engine in such a way that it may stumble irrecoverably when hit with a high-inrush load like an A/C compressor - or it may not. For that matter the 60Hz machine stumbles a little in the same circumstance but the governor can bring it back into steady state. Perhaps Matt Colie can comment on the amount of torque that might be lost due to a reduction in speed to 1500 RPM.

There are two different ways to get to 240V:

1. The existing 120-0 output voltage of the Onan can be transformed to 240V with a commonly available step-up transformer that will weigh a couple tens of pounds. Using such a transformer with a center-tapped secondary would provide both the 120-0-120 configuration desired by those in the US as well as 240-0 that you desire. In your case you would simply not use the center tap lead.

2. Replace the voltage regulation/excitation circuit in the generator with one designed for 240V. There are many automatic voltage regulators on the market that are designed for other generator models that may be adaptable to our Onan - however their operational parameters (the field resistance range they can accommodate, for instance) are often not published so finding one that will work becomes a matter of experimentation. There’s also the concern of the quality of insulation on the armature after 40 years as doubling the output voltage might possibly cause arc-overs at locations where the insulation is compromised.

Method is something I plan in experimenting with and I will share my results with the net; I just haven’t had time nor motivation to do so since 240V is not of any use in my coaches.

—Jim
1977 Eleganza
1977 Royale
Hamilton, OH
 
Jim,

As I've mentioned here before, I suspect that the reasonably priced units
on eBay are autotransformers rather that isolated winding designs. That
suspicion is based on the prices and on the weight (the one listed below is
quoted as only 25 lbs). What's your opinion? In the application we're
discussing here, I don't see that as a problem though. Do you?

http://www.ebay.com/itm/5000-Watt-Heavy-Duty-Voltage-Regulator-Converter-Transformer-Step-Up-Down-5000W-/130987516279?hash=item1e7f76e177:g:dtcAAOSwDNdV5MNU

Ken H.
BS/MSEE with only one 3 semester hour "power" course in 1971. :-)

> > On Dec 16, 2016, at 10:25 PM, Rob Mueller

>
> > Keeping in mind that I am electrically challenged I interpret your email
> below to read that it is possible to get "straight 240VAC” out of an Onan.
> Here in Australia the power is 240VAC 50Hz.
>
>
> Hi Rob,
> ...
> 1. The existing 120-0 output voltage of the Onan can be transformed to
> 240V with a commonly available step-up transformer that will weigh a couple
> tens of pounds. Using such a transformer with a center-tapped secondary
> would provide both the 120-0-120 configuration desired by those in the US
> as well as 240-0 that you desire. In your case you would simply not use the
> center tap lead.
> ...
 
Hi Ken,
I don’t see an autotransformer’s lack of isolation as a problem in the RV environment - if the referenced item is really an autotransformer at all. Unless one drives a ground rod and bonds the GMC’s chassis and body to it when running the generator then there is no frame of reference to work from anyway; the RV is in its own electrical domain because it sits on top of six pneumatic insulators.

What does concern me about the device you referenced is the “with regulation” mentioned in the description. That tells me that it may be a ferroresonant constant-voltage transformer which introduces more problems - such as audible noise, misbehavior due to the failure of the capacitor in the resonant winding - but most importantly the inherent current limiting nature of this type of transformer. The latter might be a real problem for high inrush loads like the A/C or refrigerator compressors I mentioned in an earlier message.

For the RV application I was thinking more along the lines of a plain old traditional potted-core transformer such as would be used in the industrial environment. A 5-6 kva model wouldn’t be very large nor heavy.

—Jim
BS/Math 1991 with 0 hours of “power” courses

1977 Eleganza
1977 Royale
Hamilton, OH

> As I've mentioned here before, I suspect that the reasonably priced units on eBay are autotransformers rather that isolated winding designs. That suspicion is based on the prices and on the weight (the one listed below is quoted as only 25 lbs). What's your opinion? In the application we’re discussing here, I don't see that as a problem though. Do you?
>
> http://www.ebay.com/itm/5000-Watt-Heavy-Duty-Voltage-Regulator-Converter-Transformer-Step-Up-Down-5000W-/130987516279?hash=item1e7f76e177:g:dtcAAOSwDNdV5MNU

> Ken H.
> BS/MSEE with only one 3 semester hour "power" course in 1971. :-)
 
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