As fulltimers, we frequently stay at campgrounds that have underpowered 30 Amp service. As a result, the voltage often drops significantly when using ACs, microwave, toaster, and other high-demand appliances.

Finally purchased a Frank's 30 Amp Super Autoformer. Even though we have a 50 amp motorhome, we rarely if ever have problems with low voltage at 50 amp campgrounds. Thus we only needed the device for 30 amp situations.

At any rate, the device works like a dream. Able to run both ACs at a time in places that we could hardly run one. The ACs run better too. Unlike the competition, Frank's cuts out at very low and very high voltages. It also includes decent surge protection capabilities.

I would recommend the product to anyone that often stays at campgrounds that have marginal electrical systems. I paid a little less than $400 including shipping.

Jack

Jack,

How does a 30 amp Autoformer work on a 50 amp service?

All campgrounds that offer 50 amp service also have a 30 amp reveptacle to accomodate 30 amp RVs. In our case, we have rarely seen problems with 50 amp systems because they tend to be newer. Thus, we generally only use the autoformer at campgrounds that only have 30 amp service. In this case, we simply use our 50 to 30 amp adaptor to plug our power cord into the autoformer. Then the aoutoformer is plugged into the 30 site's amp receptacle.

If we're at a 50 amp site that seems to have low voltage problems, we simply plug into the autotransformer and then tap into the site's 30 amp receptacle . We may only have 30 amps to "play with" but the low voltage problem is solved.

Many folks think that if you have a 50 amp RV, you have to purchase a 50 amp autoformer. But in reality, the 30 amp model will do the trick. The only exception would be if you wanted to hard-wire the autoformer into your RV's electrical system. In this case, it would probably make sense to purchase the 50 amp model. In this scenario, you would be using the transformer for both 50 amp and 30 amp sites. Obviously, you would have to use your 50 to 30 amp adaptor (dog bone) to handle 30 amp sites. The one advantage here is that you would have surge protection and voltage boosting at all times. Plus, you wouldn't have to use a lock to secure the autoformer to the pedastal to prevent theft. But I decided to save $300 and go with the compromise. Hope this helps.

Jack

We have used the Franks 50 Amp part time for about 10 months. Only needed it one time and it did the job. I think it was money well spent. Here is my setup

Dieselgem,
The most important option you added to your Hughes is the heavy duty chain that prevents the Hughes from sprouting legs and walking away. LOL
30A service seems much more prone to under voltage problems than 50A service. I have seen problems with 50A service where the L1 and L2 voltages are pretty far apart. I don't know how the Hughes reacts to that.

quote:

Originally posted by Sixpack98:
Dieselgem,
The most important option you added to your Hughes is the heavy duty chain that prevents the Hughes from sprouting legs and walking away. LOL
30A service seems much more prone to under voltage problems than 50A service. I have seen problems with 50A service where the L1 and L2 voltages are pretty far apart. I don't know how the Hughes reacts to that.

Just a note that Dieselgem has Frank's unit, not Hughes Autoformer.

I have the 50 Amp Hughes Autoformer and keep it in the power compartment and plugged in all the time. I can answer your question regarding L1 and L2 voltages being far apart. The Hughes unit is two independant 30a circuits packaged in one box. Either one or both circuits will boost as necessary. As far as I know there's nothing in the 50 amp RV's that would require a balanced voltage. L1/L2 loads in the RV are all independant. Someone correct me if I'm wrong on this.

Thanks for the name correction. In concept 50A service are independant, however in RV's they share common neutral. If there is an open or partially open neutral either at the pedestal or inside the coach all kind of problems can arise. L1 and L2 no longer have a 0v reference and the return is now the other line with a resulting increase of votage across the load. That also means ground and neutral are now different voltages. Often, a bad heater in the refer or water heater can cause a difference between ground and neutral and cause GFCI's to trip

Here's pretty good article on open neutrals in MH and what can happen.

http://www.myrv.us/electric/

So, I'm not sure what impact this has on the Hughes or Franks autoformers. Probably none but I'm not sure.

Interesting article (http://www.myrv.us/electric/). It doesn't sound like an autoformer will protect an RV from an open neutral. There was a recent thread on the forum about an RVer that claimed that his RV suddenly operated at 240 volts. He fried several appliances. It sounds like an open neutral or he inadvertantly plugged into a 240 volt receptacle. The bottom line: It pays to test the pedastal before hooking up.

Jack

quote:

Originally posted by Jackm:
Interesting article (http://www.myrv.us/electric/). It doesn't sound like an autoformer will protect an RV from an open neutral. There was a recent thread on the forum about an RVer that claimed that his RV suddenly operated at 240 volts. He fried several appliances. It sounds like an open neutral or he inadvertantly plugged into a 240 volt receptacle. The bottom line: It pays to test the pedastal before hooking up.

Jack

Jack,
I don't know the answer to that, I don't know how the Hughes or the Franks treat an open neutral. Autoformers are kinda like an isolation transformer and their output windings may develop a neutral for the RV distribution panel. But that is only speculation. In an earlier post I asked how they handled a voltage imbalance between L1 and L2. Do they boost both lines if one leg dips below a certain threshold or do they just boost one leg. What prompted the question was, I was at a campground a couple of weeks ago and one leg was 111v and the other was somewhere around 118v. 7v difference. May be a non-issue but I don't know.

mark

quote:

Originally posted by Sixpack98:

quote:

Originally posted by Jackm:
Interesting article (http://www.myrv.us/electric/). It doesn't sound like an autoformer will protect an RV from an open neutral. There was a recent thread on the forum about an RVer that claimed that his RV suddenly operated at 240 volts. He fried several appliances. It sounds like an open neutral or he inadvertantly plugged into a 240 volt receptacle. The bottom line: It pays to test the pedastal before hooking up.

Jack

Jack,
I don't know the answer to that, I don't know how the Hughes or the Franks treat an open neutral. Autoformers are kinda like an isolation transformer and their output windings may develop a neutral for the RV distribution panel. But that is only speculation. In an earlier post I asked how they handled a voltage imbalance between L1 and L2. Do they boost both lines if one leg dips below a certain threshold or do they just boost one leg. What prompted the question was, I was at a campground a couple of weeks ago and one leg was 111v and the other was somewhere around 118v. 7v difference. May be a non-issue but I don't know.

mark

The Hughs I believe will correct the 111v by boosting it 10% which would be 122v and only a 4v differential.

On an open neutral the Hughs I believe would trigger a fault as the Hughs unit checks for correct polarity and won't engage if it detects a one. The yellow power fault light will come on if this is the case.

I can't speak of the Franks except that their web site claims: "Checks for correct polarity and ground fault". An open neutral should trigger a polarity error so I would believe the Franks would shut you down also.

I have the 30 amp Hughs unit and yes I have seen the power fault light activate on more than one occasion.

I verified mine before using it on my coach by wiring a test socket reversed polarity, no ground and then open neutral. The Hughs would not pass current in any of those situations.

When using it on my test bench I was surprised to see how many times it would activate during the day due to low power events in my home. I hadn't realized how bad the power was where I live and may consider a whole house unit.

I won't travel without one and always plug it in. Just because you don't detect a problem at the time your hooking up, there is no guarantee that there won't be a potentially damaging power incident occurring later on when you arn't looking.

This message has been edited. Last edited by: NeilV,