Autoformer

Are autoformers a good idea to purchase for a new RVer? 

I recommend against autoformers.  They only make the problem they're supposed to solve worse.

We've never had one nor even thought of using one.

I appreciate both of your replies.  The idea sounded like a logical one, but being new to RVing I wanted to check before I plunked down that kind of money.  What would you recommend for monitoring electricity coming in from a campground (surge protector?) or would you not worry with it at all?

A surge protector is a good idea and some would say a necessity. And a powerline monitor can save you if the campground has improper wiring, something that is unfortunately not all that unusual in older campgrounds or smaller ones where amateurs have upgraded or repaired wiring.

Here's a basic surge protector from Zapfree RV

Progressive Industries makes a decent and popular line of power line monitors in both portable and hard wired types. RVUpgrades.com is one good source for this product. They also sell the Hughes Autoformer you inquired about, but I personally don't think the low voltage boost function is worth the price.

Surge Guard is another popular brand of power line monitor.

The thing about autoformers is this.... If you are in a properly wired campground (Very rare) and or a lightly occupied campground (More common) then one expects line voltages to be close to 115-120 Volts RMS AC.  However occasionally, you will find yourself in places where it's only 105 or 100 or even less. In these cases an Autoformer can make a big difference in how well things work. As the voltage goes down Microwaves cook slower, Air conditioners do some really bad things and even televisions and radios malfunction.  Generally all but the Air conditioner survive... Generally, but not always.  RV air conditioners are not cheap.

The autoformer can prevent this from happening... however there is (Always) a trade off.

If the park is full, then if you use an autoformer to boost your voltage to normal your rig will draw a bit more power than if you did not... This leaves less for the rest.  So others will be worse off (You won't be a good neighbor)

That said.  I have one.  The one park where I needed it was perhaps 10% occupied (If that)

Not being very knowledgable in electricity, I have found a Surge guard plus 50 amp hardwired power monitor.  Being that we have a travel trailer with a 30 amp plug, will I be able to use this particular unit?  Would I buy a adapter in order to plug into my camper?  I apologize for my ignorance as my head is spinning with all of the options available.  I am attaching a link to the unit I am looking at. ???

http://www.campingworld.com/browse/skus/index.cfm?skunum=22150&src=SRQB

In my opinion, no. First, we've been on the road since late April and have only had one situation where we had low voltage. We have a 50 amp service coach with a top quality level electric management system; surge, low/high voltage, mis-wiring, etc. We run one or two air conditioners/heat pumps, electric water heater and microwave. We have to do some amperage appliance management when on 30 amp service, but haven't had too many problems with it.

My problem with the Autoformer is that there is the potential of affecting the overall electric service in the park and reducing voltage for other campers. Others may disagree but there is no free lunch. For the price of the Autoformer you can get a top quality/full service surge protector (EMS or Surge Guard are the two of which I am aware) rather than the limited surge protection of the Autoformer.

I not only recommend against Autoformers I STRONGLY recommend against  them.  A surge protector yes Autoformer don't waste you money.

I have found a Surge guard plus 50 amp hardwired power monitor.  Being that we have a travel trailer with a 30 amp plug, will I be able to use this particular unit?

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No. It is designed to be hardwired into a system that has two "hot" wires and your 30A system has only one. It could be jury rigged, but why mess around (unless you got it for free). However, you could use a portable 50A Surge Guard with an 50A/30A adapter for your trailer's power cord. Note that to use this with a 30A outlet on the campground power pole, you would need two adapters - one to mate the 50A Surge Guard plug to the 30A outlet and another to mate your 30A power cord to the 50A outlet on the Surge Guard.

Look for a 30A Surge Guard or similar, either the hard wired or portable one. Since you have no electrical skills, the portable model is probably the best for you.

Ned said:

I recommend against autoformers.  They only make the problem they're supposed to solve worse.

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Here's a good explanation of autoformer  by a teckie with an excellent resume and who addresses the issue of stealing power with added insight regarding inductive loads.     


http://www.damouth.com/RVStuff/Autoform.shtml

Thanks for link Leo.

The article makes sense if you consider only resistive loads. But, as the article goes on to say, that's not the case with ac motors that are being discussed here. In these cases, higher voltage results in lower current (it's in the article). So, in such cases, the use of an autoformer to boost voltage reduces the current drawn from the campground.

OTOH in a low voltage condition, most folks would not run their air conditioner(s), fearing damage. If such a person decides to use an autoformer in that same situation and, because of their higher available voltage, runs their ac, then they will draw higher current from the campground than if they had not run the ac. This additional load (current) will indeed result in additional voltage drop along the campground line and the neighbor without an autorformer will experience even lower voltage. In this scenario, it's not the autoformer that's creating the additional load and lower voltage, it's the fact that the individual turned on their ac.

FWIW the guy in his article incorrectly calls it an autotransformer, which is a different animal (explained in prior posts in this topic). An autotransformer has a single winding with multiple taps, whereas an autoformer (at least the Hughes one) has separate primary and secondary windings (5 in all) which provide isolation between incoming and outgoing voltages. I should go research the other brand of autoformer.

FWIW I have an article in draft dispelling some of the myths I've read here and elsewhere. It's a long way from publication, but will be in our forum library when I'm done. No plagiarizing, all my own work. Hopefully I can back it up with some empirical data, although that might have to wait until I decide to buy an autoformer.

I'm replying here to keep the newer thread more or less on subject.  The end result of using an autoformer is the same regardless of how it works.  The user of an autoformer sees the higher voltage and turns on more loads (hid A/C),  increasing the current draw on the campground electrical system (as you state) which in turn results in lower voltage to the other campers on the system or possibly even tripping a circuit breaker.  You don't get something for nothing.

I can only agree with the use of an autoformer IF you use it only to increase the voltage without adding additional loads, and then what would be the point.  I stand by my dislike of autoformers for the stated reasons.

Where is your article, I'd like to read it.  There are certainly enough real myths to dispel.

Looks like I was distracted by other happenings and the article didn't get beyond a draft. I have too much on my plate right now to resurrect it. As I write, I realize that I missed a possible opportunity to gather some empirical data when we recently had a full-time boater berthed at our house for a month; The boat has an autoformer and 4 a/c units that received lots of use during that hot month.

Note: Just in case someone is wondering where the "newer thread" is, it's here.

My position on autoformers is this

The park, by accepting your site rental, has contracted to provide you with a proper power source

if the park wiring is not up to the task and as a result your autoformer kicks in, causing you to draw more current and causing problems elsewhere in the park the fault lies with the owners of the park for not upgrading the wires.

The only exception to this is if you can somehow figure out how to draw more current than the 30 or 50 amps the breaker next to the outlet you are plugged into is rated at.  (Which would require tampering with the breaker)

The only way an autoformer draws more power is by allowing you to operate appliances that you would otherwise have to shut down to avoid equipment damage. Well, I guess there is a small loss of efficiency in the former too.

Perhaps there is the ethical question of why should the autoformer user be allowed to continue using his a/c when others cannot?

However, I don't have one and don't ever plan to get one, nor do I recommend them to others. It's a lot of cost for a very small convenience, in my opinion. But then, I keep an eye on voltage. Those who do not might consider an autoformer an insurance policy against the possibility of burned out a/c units.

Also frankly speaking I would not feel comfortable using a device that might let me have better power at the expense of other RVers in the campground.  Much better to just move on to a campground that has adequate power.  In all the years we have been RVing we only once experienced a campground that had low voltage once (as low as 95 volts).  In that case we just run the genset for the AC units. When it cooled off the voltage would rise to 110.

Lot of mone for something that would not be required much and when it would be required its use would increase the problem for fellow campers.

Did Tom, the Administrator back when this thread was started, ever write his article on autoformers?

Did Tom ... ever write his article on autoformers?

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I didn't get far beyond a start; It's in our Library here.

When I bought my first MH, on our first trip to Texas Rio Grande Valley, I bought for half price an Autoformer at a fleamarket and I still have it today, 15 years later using it with my second MH and I use it quite often in different campsites here in Quebec, the reason is always the same, these campsites were built in the '60's and the power lines are either small or to long and at some sites you hardly get ? 105 VAC !  Since I'm paying full price to get full service including 115VAC, not 105VAC, I will always use my Autoformer in those situations..
p.s. I have never damaged any equipment on my MH's due to low voltage.