We lost our shore power

[Ron]

Sorry but I have disagree.  Have never seen an Autoformer that actually did that.  Have ou ever heard of Ohms law?

I stand by my recomendation to avoid the autoformer.

 

[Alaskansnowbirds]

Autoformers do not alter power up stream in the park.

Then where does the additional 1 1/2 amps come from?

As Ron said, Ohms law!

 

[Roland]

OK Gentlemen,

Yes, I have heard of Ohm's Law.  If I am on a 30 AMP service, using an A/C rated at 15 AMP's @ 120 VAC I would be consuming 1800 Watts. At 100 VAC I would be drawing 18 AMP's or 3 AMP's more, to accomplish the same task. By boosting from 100 VAC to 110 VAC (10%) the AMP draw would be reduced from 18 AMP's to 16.4 AMP's or a reduction of 1.6 AMP's. Still think the 1 1/2 AMP's is additional? Ohm's Law cuts both ways.

And even if you didn't gain back some of the available AMP's, if the user of the autoformer is drawing less than the 30 AMP's their power pedestal is rated to deliver, are you being injured? If so, why not tell the individual "Do not turn on your 29" television while you have your A/C on as you will be using an additional 3 AMP's."? Also, a 30 AMP Hughes Autoformer only draws about 1/2 amp, less than the 50 AMP which bucks L-1 and L-2 separately.

Green lights and soft breezes,

Roland

 

[John From Detroit]

Well I am John.. A point of clairfication

The Hughes is a boost/pass, IF voltage is in the "normal" range it will simply pass it, if the voltage drops low it will Boost it by a fixed percentage, if it drops even lower... Well. it won't help. 

The problem, and this is a serious problem if you have fur-kids, is if the voltage drops low and I'm in the rig, I may well notice that the Air Conditioners do not sound right and figure it out.  But if I've left the AC on so the fur kids don't roast, and voltage dropps and the AC either 1: Simply quits or 2: Overheats and burns (Fire type) not good.

The auto-former will boost voltage in an attempt to keep this from happening.

IT also contains surge protectors (Rather good ones)

Now the Franks auto-former is, as the other poster stated a buck/boost/pass device.  In addition to all above it will buck if the voltage goes too high, (Which can also happen) dropping the voltage some 10 or 17 percent (Forget which) if it goes over 125 volts, again offering protecting to senestive electronics inside the rig.

I have been in one CG where I had low voltage.... The amazing thing is the CG was next to empty,  IT was in a windmill area (Where they have big windmill farms that generate electric power) and the breeze that evening was 90MPH sustained with 100+ gusts (So there was lots of wind power)  Got dang good millage on the motor home that portion of the trip,,, being as when I was moving it was a TAIL wind.

 

[Alaskansnowbirds]

Roland,

We're not arguing what it does for YOUR RV.

Have you thought what you are doing to the rest of the RVers in the campground when you use one of these transformers when the campground is already suppling low voltage? That 1 1/2 amps has to come from somewhere. If you are using one and John is using one and Pete is using one and Sam is using one, where is the additional 6 amps coming from? I have been in campgrounds that have signs posted the forbid the use of transformers and they state they will ask you to leave if you're caught using one.

 

[Ron]

One might say there is NO free lunch.  Somebody has to pay when someone else is using one of those darn things.

 

[Roland]

By boosting from 100 VAC to 110 VAC (10%) the AMP draw would be reduced from 18 Amp's to 16.4 Amp's or a reduction of 1.6 Amp's.

Please read the above post where the quote is taken from. I have taken the effort to show that the increase of voltage results in the decrease of Amps consumed. If I was drawing 27 Amps at 105 VAC and through the use of an autoformer the voltage was boosted to 115.5 VAC the AMP draw would be reduced to 24.5 Amps. That is 2.5 Amps less draw! If nothing else changed the Park is now 1 to 1.5 Amps ahead.  When provided a range of consumption please don't just seize on the high end in an attempt to validate a position. So if John, Pete, Sam and I were all consuming 27 Amps each the net result would be a 4 to 6 AMP reduction, on the power load. Just as you have seen signs prohibiting transformer use, I have been in Parks, with known power problems that have no problem with Autoformer use. In one park, the park's electrician said "...I wish everyone had one -- my problems would be a lot less!...".

In the interest of balance, I would agree that, in a Park, where the voltage is so low as to prohibit the sensible use of an A/C (e.g. 100 VAC) the use of an autoformer strictly to enable individual use of an A/C would place that additional load on the system. In that instance or when a prohibition is posted I would respect the circumstances and not use the autoformer. That appears to be a relatively rare occurrence. The overwhelming majority that I have experienced have been below 116 VAC down to the 105 VAC range.

I believe it will be counter productive, on my part, to attempt further replies to euphemisms such as: 

Have ou ever heard of Ohms law? or One might say there is NO free lunch.

I also believe that further replies to this thread, on my part, would not be in the best interest of the harmony that I have noted, in other threads, on this forum.

Green lights and soft breezes,

Roland

 

[John From Detroit]

There has been quite a lot of chatter.  IT does appear that use of autoformers does indeed result in a overall lower voltage to others in the park and a slight increase in total amps drawn off the park power system.

However. if it comes to a question of protecting my rig from damage.  I will do it, one way or another.

 

[Ron]

However. if it comes to a question of protecting my rig from damage.  I will do it, one way or another.

Hopefully you will be considerate and use the Genset rather than compounding an already existing problem for others.

 

[Alaskansnowbirds]

If I was drawing 27 Amps at 105 VAC and through the use of an autoformer the voltage was boosted to 115.5 VAC the AMP draw would be reduced to 24.5 Amps. That is 2.5 Amps less draw!

Roland,

Yes, that is true on the RV side of the autoformer. On the campground side of the autoformer that is a 2.5+- amps more draw. In order for the autoformer to increase your voltage in the RV it has to get that power from somewhere. Autoformers do not generate electricity.

Been nice talkin' to you.

 

[Tom]

Hughes, in their How does it work, claims that their autoformer draws an incremental max of 1A from the supply (aka campground).

Ohm's law doesn't really apply since this is AC, not DC, although there will be some DC component in the calculation (see this simple model - scroll to the bottom of the page). Methinks it's time to look at transformer theory, although it's really too far back in my school days to be able to explain it. If you're heavy into math, try Maxwell's equations. A simpler treatise can be found at Irregular webcominc.

Hughes' web site says that their autoformer has a total of 5 windings, 2 on the primary (input side) and 3 on the secondary (output side). Although they don't specifically say so, my feeling is that they essentially change the turns ratio in order to achieve the higher (or lower) output voltage. So, if the input voltage decreases and the turns ratio is automatically changed to increase the secondary (output) voltage (see this simple relationship), the higher voltage is achieved without any increase in primary (input) current.

Let the electrical theorists come on down.

 

[Ron]

Are you trying to tell us that a Autoformer is magical and can give increased voltage for free.  That would be pure magic.

I still stand by my reommendation against Autoformers.

 

[Tom]

Ron, nothing is for free, but check out the calculations and let me know if Maxwell, Tesla and others got it wrong. Heck, maybe Einstein was wrong also.

 

[Ron]

No need for me to check out those since I am pretty familure on electricl theory and I am quite sure when it comes to the bottom line they and I will very much agree.

 

[Karl]

Most of these work on the principle of a saturable reactor (magnetic amplifier), where a small control voltage can be used to boost or reduce the transformer output. The problem with these things is that they are a purely inductive load, and inductive loads cause a shift in the phase relationship between voltage and current. When the voltage peak and the current peak no longer occur at the same time, you get less work done, and it takes more power to keep things running properly. Adding a bunch of them to a park system can bring it to its' knees.

 

[Tom]

Most of these work on the principle of a saturable reactor...

I wondered that Karl, but didn't see any hint of it in their description, but it was rather sparse on details.

 

[John From Detroit]

Hopefully you will be considerate and use the Genset rather than compounding an already existing problem for others.

That I do Ron, when I'm am aware of the problem... However there MAY have been a problem in this park yesterday.  I don't know  I had no indication of boost operation from the autoformer but on a DIFFERENT circuit they were reporting strange AC operation... I metered them a bit later at 117.x volts (Good meter, one of mine) but at that time it was working perfect.

117.x volts is well withing the 110-120 normal spec.

 

[Roland]

Tom,

Ron has been vehement in publishing his opinion of Autoformers. It has been done without support offered for others to consider. The impression given is one of a person who has painted himself into a corner and will now defend that position, without reason, to the death. In hope that he will consider modifying his views, I am providing the following link:  http://www.phrannie.org/surge.html    "Electric Surge and High and Low Voltage."  This is one of several documents written by phred Tinseth, a prolific and well respected writer of  articles covering many of the technical aspects of the RV lifestyle. Contained in the article are several paragraphs specific to the Hugh's Autoformer.

Green lights and soft breezes,

 

[Tom]

Thanks for the link Roland. Unfortunately, there's nothing in that article that explains how the Hughes autoformer works or what the resulting current drain on the campground power source will be.

I'm thinking of contacting Hughes' technical folks and asking for a better explanation of how their system works.

BTW I'd forgotten about "Phred's poop sheets" until I followed your link.

 

[Alaskansnowbirds]

Roland,

You're not getting the point we're trying to make. No one is saying that the Hughes autoformer doesn't work. What we're saying is it is bad for the campground power system and all the other RVs in the campground.

Phred's article confirms what you are saying that the Hughes autoformer does work. It says nothing about what it does to the campground electrical system.