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Topic: 220 volts from 120 generators

Posted By: richard`6`` on 08/08/09 05:41pm

there must be some electrical device that will convert the output from two 120 generators to 220 volts, but i cannot find it. please help. thank you. richard


Posted By: kaydeejay on 08/08/09 06:03pm

It's called a transformer!

Without very special synchronzation techniques it is not possible to add the output from two gens to make 220V.
However, some gens ARE 220V, they just provide dual 110V outlets and don't tell you.
If you have one of these, then a "Y" adapter to pick up the two hots (as 220V and Neutral) would work.
If you have a voltmeter, check it out.

But I'm curious - why do you need 220V?


Keith J.
1999 Sunnybrook 27RKFS Fiver.
2005 GMC Sierra 2500HD CC/SB/DA 2WD, LLY with LBZ air cleaner, 52 gal Titan tank, Bilsteins, Line-X, Westin steps, Prodigy, Retrax cover, 16K Superglide, 5th-Airborne pin-box, Multi-vex mirrors, TST TPMS.



Posted By: Itchey Feet on 08/08/09 06:04pm

I hope you are not trying to get the generaters to produce the 220 for your trailer, even if it is 30 or 50 amp designated cords they are still 110 volt. The 50 amp cords are two legs of 110 volt. They are (not) the same as a regular household system like the dryer or electric range outlets in your house. If it is for some other reason I am sorry I piped up.


My feet are fine as long as they are traveling.


Posted By: kaydeejay on 08/08/09 06:06pm

Itchey Feet wrote:

I hope you are not trying to get the generaters to produce the 220 for your trailer, even if it is 30 or 50 amp designated cords they are still 110 volt. The 50 amp cords are two legs of 110 volt. They are (not) the same as a regular household system like the dryer or electric range outlets in your house. If it is for some other reason I am sorry I piped up.
Whoa there! A 50A RV service is EXACTLY the same as a household stove or (4-wire) dryer service.
There are two 110V hots with 220V across them, plus a ground and a common neutral for the 110V legs.
Matter of fact this is probably how your house service is connected, except you will have a higher current rating.


Posted By: tvman44 on 08/08/09 06:09pm

Nothing that would be feasable as the 2 generators would have to be in phase.


Papa Bob
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1* 2008 Brookside by Sunnybrook 32'
1* 2002 F250 Super Duty 7.3L PSD
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Posted By: jauguston on 08/08/09 06:17pm

No


2005 Coachman Sportscoach Elite 402 40'
350hp Cat C-7 w/MP-8
7500w Onan quiet diesel generator
6-Kyocera 130w solar panels SB3024i MPPT controller
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Posted By: pkunk on 08/09/09 09:25am

ol Bombero-JC wrote:

~

LOTS of info based on . . . .what?

The OP never said what he wanted 220V - "FOR" - or "WHY".

~

Maybe if he returns he can elaborate a bit.

~

If I 'could' wire a plug for 240v from my Onan 5500 I would have a source for running my deep well pump in the event of a power failure.
We await the OP for his 'why'.


1999 Coachman Mirada 34 ft.V10-F53 chassis
12ft.LR slide-2 gp31 AGM 12V @220AH



Posted By: ol Bombero-JC on 08/09/09 02:37am

~

LOTS of info based on . . . .what?

The OP never said what he wanted 220V - "FOR" - or "WHY".

~

Maybe if he returns he can elaborate a bit.

~


Posted By: gregputzer on 08/09/09 08:17am

kaydeejay wrote:

Itchey Feet wrote:

I hope you are not trying to get the generaters to produce the 220 for your trailer, even if it is 30 or 50 amp designated cords they are still 110 volt. The 50 amp cords are two legs of 110 volt. They are (not) the same as a regular household system like the dryer or electric range outlets in your house. If it is for some other reason I am sorry I piped up.
Whoa there! A 50A RV service is EXACTLY the same as a household stove or (4-wire) dryer service.
There are two 110V hots with 220V across them, plus a ground and a common neutral for the 110V legs.
Matter of fact this is probably how your house service is connected, except you will have a higher current rating.


Agreed, it is 240v just like your home service. There is nothing in the RV that actually USES 240v, but the service is still 240v (which is two 120v legs when hooked to neutral).

I can apsitively posolutely guarantee you that if you put a volt meter between the two hot leads of a "properly" wired 50 amp RV service, you will read between 220v and 240v.

I say properly wired because occasionally a park owner will try to do wiring himself instead of hiring a qualified electrician. This is why so many people plug in and get all their appliances fried.


Posted By: wa8yxm on 08/09/09 08:24am

richard`6`` wrote:

there must be some electrical device that will convert the output from two 120 generators to 220 volts, but i cannot find it. please help. thank you. richard


Yes, a transformer, very common device, also very heavy and very expensive, but Granger should carry them. If you care to look

NOTE: Depending on the generator (Contact it's maker) you may be able to do it by moving two wires in the generator's connections box.

Just which two. I would not tell you (for liability reasons) even if I knew.. You MUST contact the manufacturer or someone who knows your specific generator in order to do it.


Home is where I park it.
Kenwood TS-2000 housed in a 2005 Damon Intruder 377



Posted By: pulsar on 08/08/09 07:39pm

Moved from Forum Technical Support to Tech Issues.


2015 Meridian 36M
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Posted By: Dutch_12078 on 08/08/09 08:07pm

You would have to use two identical generators, such as the Honda EU2000's, with a paralleling harness to synchronize them. That would give you a nominal 4000 watt capacity, but still at 110 volts. Then, you could feed the output of the generators into a 110/220 volt transformer to boost the voltage. The downside would be that doubling the voltage would halve the current, so you would be back to the 2000 watts max the transformer I linked to will handle. It can be done, but a single 110/220 output generator would be more efficient and less costly.


Dutch
2001 GBM Landau 34' Class A
F53 chassis, Triton V10, TST TPMS
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox baseplate



Posted By: Kirk on 08/08/09 08:27pm

Quote:

Nothing that would be feasable as the 2 generators would have to be in phase.
Actually, to get 240V as you do on a typical 50A RV outlet, you would have to get the two gensets synchronized but exactly 180 degrees out of phase. While it is possible, I don't think that anyone builds equipment to do that because there just isn't much call for it.


Good travelin! ........Kirk
Professional Volunteer
Fulltimer for 11 years,
URL: www.adventure.1tree.net



Posted By: AdequateRV on 08/08/09 08:34pm

Dutch_12078 wrote:

You would have to use two identical generators, such as the Honda EU2000's, with a paralleling harness to synchronize them. That would give you a nominal 4000 watt capacity, but still at 110 volts. Then, you could feed the output of the generators into a 110/220 volt transformer to boost the voltage. The downside would be that doubling the voltage would halve the current, so you would be back to the 2000 watts max the transformer I linked to will handle. It can be done, but a single 110/220 output generator would be more efficient and less costly.


Since Power = volts * Amps, if you double the voltage and halve the current, the power stays the same. You will have some losses due to the transformer, say 10%.


Posted By: Generator Jim on 08/10/09 10:43am

The mid size (BG) and larger (NH) ONAN generators have two power coils in them. It is theoretically possible to get 240 vac out of them but the voltage regulator would only be on one of the coils unless you get an ONAN 240 setup from the factory.
ONAN use to make a commercial generator that was identical to the rv units but had 240 volt capability.

Curious minds want to know. What are you going to power with the "220" volts?

JimL


Jim & Jane Latour
08 Chevy 3500HD, crew cab, dually, Duramax/Allison
Crossroads Cruiser CR305SK14, Onan 3.6KY
Retired AF CMS (E9) Power Generation and Onan RV genset Level III tech
Grand Strand Sams
Blog.rv.net


Posted By: Dutch_12078 on 08/09/09 08:36pm

AdequateRV wrote:

Dutch_12078 wrote:

You would have to use two identical generators, such as the Honda EU2000's, with a paralleling harness to synchronize them. That would give you a nominal 4000 watt capacity, but still at 110 volts. Then, you could feed the output of the generators into a 110/220 volt transformer to boost the voltage. The downside would be that doubling the voltage would halve the current, so you would be back to the 2000 watts max the transformer I linked to will handle. It can be done, but a single 110/220 output generator would be more efficient and less costly.


Since Power = volts * Amps, if you double the voltage and halve the current, the power stays the same. You will have some losses due to the transformer, say 10%.

Yep, you're exactly right. Not enough coffee when I wrote that I guess.

Dutch


Posted By: Gdetrailer on 08/09/09 08:53pm

parkmanaa writes "an RV pedestal of 50 amps is actually 240 volt measured across the two hot legs, however except for some of the newer really big rigs, these 240-volts are actually used as two 120 volt circuits running in parallel. One 120-volt circuit runs one a/c unit plus some other items in the rig; the other 120 volt runs the other a/c and the remaining items"

Granted, how ever one must understand that unless both 120V sources are 180 degrees out of phase you will risk overheating the neutral wire which is sized for 50A.

In order to be able to support two 120V sources in phase you would need to have seperate neutrals of the same size in the shore cord or one neutral sized to support 100A. Since this is not the case with standard 50A shore cords I would recommend not trying to use seperate gens or two sources from the same phase.


Posted By: gunny357 on 08/09/09 06:25pm

pkunk wrote:

gunny357 wrote:

pkunk wrote:

ol Bombero-JC wrote:

~

LOTS of info based on . . . .what?

The OP never said what he wanted 220V - "FOR" - or "WHY".

~

Maybe if he returns he can elaborate a bit.

~

If I 'could' wire a plug for 240v from my Onan 5500 I would have a source for running my deep well pump in the event of a power failure.
We await the OP for his 'why'.


What is the model/spec/voltage code/serial number of your Onan 5500?

You just might be able to do just that but have to know exacty what you have.

Onan Marquis 5500 generator
BGM-FA/26105H...Ser.#H980782116


Voltage Code on this machine is FA. 120V non-reconnectable.

Sorry.


Posted By: parkmanaa on 08/09/09 02:18pm

I agree with many of the above posts; an RV pedestal of 50 amps is actually 240 volt measured across the two hot legs, however except for some of the newer really big rigs, these 240-volts are actually used as two 120 volt circuits running in parallel. One 120-volt circuit runs one a/c unit plus some other items in the rig; the other 120 volt runs the other a/c and the remaining items.

This is probably one of the most misunderstood aspects of RV power, anyway by
people who know 'a little about electricity.' We own an RV park and quite often we have RVers registering who, when asked if they need 30 or 50 amp service, they come back with something like "well, it's 220 (or 240) volts, I guess it's 50 amp"


Posted By: kaydeejay on 08/09/09 11:44am

LScamper wrote:

I think you could use a small 1:1 isolation transformer to invert the phase of one generator and connect it to the second generator. I'm sure this would cause the second generator to be 180 degrees out of phase with the first one. The common connection would be the neutral connection and the two out of phase connections would be 220V. I don't know what would happen under load but I think it would work. I'm not willing to try this on my generators but you might! This may be a very cheap way to get 220V but still limited to 4KWt peak and 3.2KWt continuous.
And how would you guarantee the 1st generator was "in phase" before you "invert" it.
I say it can't be done with two generators the way the OP described.
A transformer off ONE of them, OK. A transformer off something like a couple of Honda 2000s with a sync package is OK too.
But two totally independent generators - NOT!


Posted By: gunny357 on 08/09/09 12:04pm

LScamper wrote:

I think you could use a small 1:1 isolation transformer to invert the phase of one generator and connect it to the second generator. I'm sure this would cause the second generator to be 180 degrees out of phase with the first one. The common connection would be the neutral connection and the two out of phase connections would be 220V. I don't know what would happen under load but I think it would work. I'm not willing to try this on my generators but you might! This may be a very cheap way to get 220V but still limited to 4KWt peak and 3.2KWt continuous.


I think you will be real disappointed in your results.

Try it with your equipment before suggesting this to others.

What is someone, not knowing any better tried your suggestion and ruined 2 gensets and possibly hurt themselves. You'd be a hero in their eyes for sure.



To answer the OP. Yes it can be done but not the way you are thinking and not without a whole lot more of an expense than what anyone I know cares to spend.

Your best solution, purchase a genset capable of 120/240 single phase output, if your is not capable of it. Not knowing what you have, yours might already be easily reconfigured for that output.

Sample posting that would get you good results:

I need 120/240 single phase. My genset is an Onan 6.5NH 2R/12345F Ser # A93088888. Can I do this?

In this case, the answer would be yes and there are folks on here who would gladly help you with this.


Posted By: Gdetrailer on 08/09/09 12:05pm

While one could speculate all day as to why the OP wishes to combine two non-inverter gens one must understand that to combine two gens it does require having BOTH gens in sync. Both gens must be at the same frequency, voltage. Both gens must react the same at the same time when loads are turned on/off.

This is impossible to do without either proper mechanical or electronic controls.

Combining two gens without these controls can result in destroying one or both gens.

This is best left to professionals using gens properly designed and equipped to do this.

Honda twins can be combined but they will only give 120V, they are designed to sync electronically through the inverters.

My suggestion is if you want 240V buy ONE gen that is already built for that purpose. Some of these like Champion and other Chinese imports are switchable for 120V or 240V.


Posted By: pkunk on 08/09/09 12:38pm

gunny357 wrote:

pkunk wrote:

ol Bombero-JC wrote:

~

LOTS of info based on . . . .what?

The OP never said what he wanted 220V - "FOR" - or "WHY".

~

Maybe if he returns he can elaborate a bit.

~

If I 'could' wire a plug for 240v from my Onan 5500 I would have a source for running my deep well pump in the event of a power failure.
We await the OP for his 'why'.


What is the model/spec/voltage code/serial number of your Onan 5500?

You just might be able to do just that but have to know exacty what you have.

Onan Marquis 5500 generator
BGM-FA/26105H...Ser.#H980782116


Posted By: Wayne Dohnal on 08/09/09 01:05pm

The Honda eu6500i is a good high-end candidate to supply 240 volts if the cost, size and weight are acceptable. And internally it's two separate 120 volt inverter generators, driven by a single engine. The design allows the two inverter outputs to run in series or parallel at the flick of a switch. The best of all worlds. Now if they could only get it down to 50 pounds and $500.


2009 Fleetwood Icon 24A
Honda Fit dinghy with US Gear brake system
LinkPro battery monitor - EU2000i generator


Posted By: MrWizard on 08/09/09 01:05pm

Gdetrailer wrote:

While one could speculate all day as to why the OP wishes to combine two non-inverter gens one must understand that to combine two gens it does require having BOTH gens in sync. Both gens must be at the same frequency, voltage. Both gens must react the same at the same time when loads are turned on/off.

This is impossible to do without either proper mechanical or electronic controls.

Combining two gens without these controls can result in destroying one or both gens.

This is best left to professionals using gens properly designed and equipped to do this.

Honda twins can be combined but they will only give 120V, they are designed to sync electronically through the inverters.

My suggestion is if you want 240V buy ONE gen that is already built for that purpose. Some of these like Champion and other Chinese imports are switchable for 120V or 240V.


this is a very good answer ...

(2) consumer grade portable gensets are not designed to be phased and series the outputs to make 240v, it NOT feasible and will burn out one or both generators


Options, always have options, and the journey goes much smoother
....

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Posted By: gunny357 on 08/09/09 09:29am

pkunk wrote:

ol Bombero-JC wrote:

~

LOTS of info based on . . . .what?

The OP never said what he wanted 220V - "FOR" - or "WHY".

~

Maybe if he returns he can elaborate a bit.

~

If I 'could' wire a plug for 240v from my Onan 5500 I would have a source for running my deep well pump in the event of a power failure.
We await the OP for his 'why'.


What is the model/spec/voltage code/serial number of your Onan 5500?

You just might be able to do just that but have to know exacty what you have.


Posted By: lawnboy1 on 08/09/09 09:31am

he never came back to explain why?


Posted By: vermilye on 08/09/09 10:09am

Quote:

Yes, a transformer, very common device, also very heavy and very expensive, but Granger should carry them. If you care to look
But the transformer won't sync the two generators. Unless they are properly phased, it still won't work.


Jon Vermilye Travel & Photo Web Pages ... My Collection of RV Blogs & Journals
My Travel Journal - Jon's Journeys
Lake McDonald, Glacier National Park, MT



Posted By: Lug_Nut on 08/09/09 10:15am

gregputzer wrote:

kaydeejay wrote:

Itchey Feet wrote:

I hope you are not trying to get the generaters to produce the 220 for your trailer, even if it is 30 or 50 amp designated cords they are still 110 volt. The 50 amp cords are two legs of 110 volt. They are (not) the same as a regular household system like the dryer or electric range outlets in your house. If it is for some other reason I am sorry I piped up.
Whoa there! A 50A RV service is EXACTLY the same as a household stove or (4-wire) dryer service.
There are two 110V hots with 220V across them, plus a ground and a common neutral for the 110V legs.
Matter of fact this is probably how your house service is connected, except you will have a higher current rating.


Agreed, it is 240v just like your home service. There is nothing in the RV that actually USES 240v, but the service is still 240v (which is two 120v legs when hooked to neutral).

I can apsitively posolutely guarantee you that if you put a volt meter between the two hot leads of a "properly" wired 50 amp RV service, you will read between 220v and 240v.

I say properly wired because occasionally a park owner will try to do wiring himself instead of hiring a qualified electrician. This is why so many people plug in and get all their appliances fried.


Actually there are many RV's that do use 220 VAC. My dryer is a 220 VAC as is all the top of line Newmars and other coach makers.


'07 Newmar Essex 45' ISM 500 4 slides



Posted By: LScamper on 08/09/09 10:16am

I think you could use a small 1:1 isolation transformer to invert the phase of one generator and connect it to the second generator. I'm sure this would cause the second generator to be 180 degrees out of phase with the first one. The common connection would be the neutral connection and the two out of phase connections would be 220V. I don't know what would happen under load but I think it would work. I'm not willing to try this on my generators but you might! This may be a very cheap way to get 220V but still limited to 4KWt peak and 3.2KWt continuous.


Lou



Posted By: rolnrolnroln on 08/10/09 11:02am

Just FYI, A company called "Outback" makes 120 to 240 transformers in the 4kw range. They make an open version and an enclosed version. I'm sure there must be others, but the Outback line is easy to find at web pages that handle large inverters.


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