tvman44 wrote: Never could see how a Autoformer could rob other people of power. If you boost the low voltage your A/C and any other electric motor will draw less current than what it would draw with low voltage. Just an old wives tale started by people that know nothing and spread by people that don't know any better either.
"Stealing" may not be the right word. But the use of an autotransformer when the campground voltage is low will indeed result in you getting more power at the expense of your neighbors, whose voltage will drop even lower when you turn on your autotransformer.
(snippin a bunch of stuff)
Hee Hee.......I told ya so in the second reply to your query.....HEE HEEE HEEEEEE
hershey - albuquerque, nm Someday Finally Got Here
My wife does all the driving - I just get to hold the steering wheel.
Expedition - Suzuki Grand Viagra
JoeChiOhki wrote: I've heard this term used a few times, but exactly is an autoformer? From what I've gleamed, it regulates the voltage, but is that all it does? Does anyone make a 20 amp version?
A autoformer is a 12 volt isolated transformer that has an electronic circuit within it to monitor the input voltage and energize a relay when that voltage is below 110 volts, bosting the output voltage by about 12 volts. If the input voltage drops below a target voltage - say 94 volts, it can also shut off power (on some models) output until the voltage goes back up (sometimes with a time delay to prevent damage to the A/C compressor).
Most are rated at 30 amps because they do not tend to overheat and need the reserve capacity in order to start a A/C compressor without the magnetic field in the transformer colapsing due to the starting amperage required. With a 20 amp rated model, I would not try to run a 13,500 Btu air conditioner, who's input amperage while starting can be over 40 amps for the first second or two.
Bushey562 wrote:
tvman44 wrote: Never could see how a Autoformer could rob other people of power. If you boost the low voltage your A/C and any other electric motor will draw less current than what it would draw with low voltage. Just an old wives tale started by people that know nothing and spread by people that don't know any better either.
"Stealing" may not be the right word. But the use of an autotransformer when the campground voltage is low will indeed result in you getting more power at the expense of your neighbors, whose voltage will drop even lower when you turn on your autotransformer.
Consider the following very simplified scenario:
You and one neighbor in a remote part of the RV park share a long power feed from the park's distant main feed. I'll assume that the main feed is always at 120vac, but that the long power wires shared by these two remote sites have a resistance of 0.25 ohms (not unlikely - that's only 200 feet of #8 cable).
Further assume that both of you are using exactly the same appliances which would add up to each of you drawing 25 amps if the voltage remained at 120 volts.
But the voltage won't remain at 120 volts (because of the resistance in the long power feed). Under these conditions, the voltage at each site will be 108.68 volts and each site will be drawing 22.64 amps.
I can not understand how the amperage will drop because the voltage dropped. In a TV set, air conditioner, and battery charger, the amperage will go up under low voltage conditions. Only the refrigerator heating element will go down in amperage, yet it will run more hours per day, thus increasing overall wattage being consumed.
Now, suppose you, but not your neighbor, installs an autotransformer. The Hughes Autoformer product increases voltage by a fixed 10% in a low-voltage situation, so that inside your RV, you now have 118.38v. This raises your current draw inside the RV up to 24.66 amps. (This additional load causes more voltage drop in the shared line, dropping the voltage coming into each RV to 107.62 v. so your inside voltage increased a bit less than the expected 10%).
Your use of the autoformer has reduced your neighbor's voltage from 108.68 v. to 107.62 volts, reduced his current from 22.64 amps to 22.42 amps, and reduced his power usage from 2.46 kilowatts to 2.41 kilowatts. Your voltage inside the RV increased from 108.68 to 118.38, your inside current increased from 22.64 amps to 24.66 amps, and your power from 2.46 kw to 2.92 kw. Your neighbor has a 2% power reduction while you see a 19% increase in your own power usage. This analysis assumes that the loads in your RV are resistive - see footnote.
This seems like a pretty good tradeoff, unless your neighbor has a power management system that shuts off her power when the voltage drops below a certain level. In some situations, your ability to use additional power by using the autotransformer could result in enough additional incoming voltage reduction so that your neighbor loses power completely. If you want to be a nice guy, you can turn off a bit more of your own power usage, returning his voltage and power to where it was before you used your autotransformer while still retaining the advantage of having normal voltage in your own rig.
Note that even though you may have a 30-amp power pedestal, you can not increase your internal current all the way up to 30 amps in a low-voltage situation. This is because when the autotransformer increases the inside voltage by 10%, (which is a 20% increase in power), it also must increase the current drawn from the power pedestal by a bit over 20%. So if you turned on 30 amps of loads inside the RV, you would be drawing considerably more than 30 amps from the pedestal, tripping the 30 amp circuit breaker.
Also note that if you and your neighbor both have autotransformers, you both win, since you both have higher voltage and more available power inside your rig. The campground owner loses a bit - a few hundred watts of additional power loss in the campground wiring.
We won't argue about whether the campground wiring in the above example meets code or not - a major reason for buying an autotransformer is that many rural campgrounds have wiring that is not designed to modern codes.
The ethics of increasing your own share of an inadequate power supply at the expense of your neighbors are debatable. Some might say it's unethical to run the heater (or the air conditioner) at all, in situations where there is inadequate power to supply everyone. Others will say "hey - the campground owners are at fault, I paid for 30 amps, and I'm simply using what I paid for".
It seems to me that if both RV's where running a TV set, 75 watts of 12 volt lights, one air conditioner using 1,300 watts, and a 300 watt refrigerator, the only differance is the RV with the autoformer would be using less input amperage on the 30 amp power cord, but would have a slightly higher draw from the power plug to the autoformer.
The real differance would be at 118 volts, the refrigerator heater would draw more amperage than the neighbor's refrigerator at 108 volts, thus the higher voltage refrigerator would run less hours per day than the one with the lower voltage, however both would use about the same wattage each day.
The air conditioner will use about the same wattage with a 118 or 108 volt input, and the TV set will draw the same wattage regardless of voltage input. The battery charger will likewise draw the same wattage (about 8% more than it's output wattage) regardless of the input voltage.
The only thing that will increase it's wattage use while running at the higher votlage is a electric heater. But it's demand will go down, because it will heat the room faster, and thus have more off time than the lower voltage heater. So wattage will basically stay the same.
The transformer might use up 1% or 2% of it's input power in losses to heat, due to in-efficiency.
Now to make some popcorn and enjoy the responces!
I built a boosting transformer with a 12 volt coil, rated at 42 amps, and it does not have the automatic transfer relay like the fancy ones. But my cost was only about $150. I get it out and plug it in when the voltage in my RV is less than 110, and use it until it reaches 125, then go put it away.
Once I was plugged into a power post in the pit area at Bowling Green Raceway, with a 50' #14 gauge extension cord, 15' #12 cord and 30' #10 from my RV through my transformer. I was only running the A/C and some computers on the shore power, and enjoyed getting a full 120 volts to everything. When the A/C compressor sysled off, I would get 120 volts, and with it running, I would get about 107. My guess was I was running about 18 amps through that #14 cord, but I was cool!
* This post was
edited 10/14/08 06:05am by Golden_HVAC *
Money can't buy happiness but somehow it's more comfortable to cry in a Porsche or Country Coach!
ol Bombero-JC wrote: Oh boy . . .a - "I told you so", "told ya so", sheeesh!
Sounds like something from third grade! He he he heeeeeee
Hershey - no can of worms to open.
Never found a campground where I needed one.
Maybe the time will come - but I'll just "manage" power.
~
Sorry to use your post as the "I told ya so" post, but........
I did told ya so.
If you've never been in a campground with low voltage, you probably don't get out much. We fulltime and unfortunately we do find campgrounds that are not providing adequate electrical power and the autoformer isn't just a gadget (toy) that because it says its for RV use we think we have to have, its a necessity just like my surge protector. I wouldn't be without either. My autoformer kicks in only when needed perhaps off and on in 20% of the campgrounds and the surge protector has saved my bacon twice in brownout situations by turning off the electrical even with the autoformer which couldn't overcome the sever low voltage condidtion.
tvman44 wrote: Never could see how a Autoformer could rob other people of power. If you boost the low voltage your A/C and any other electric motor will draw less current than what it would draw with low voltage. Just an old wives tale started by people that know nothing and spread by people that don't know any better either.
"Stealing" may not be the right word. But the use of an autotransformer when the campground voltage is low will indeed result in you getting more power at the expense of your neighbors, whose voltage will drop even lower when you turn on your autotransformer.
(snippin a bunch of stuff)
Hee Hee.......I told ya so in the second reply to your query.....HEE HEEE HEEEEEE
I'm not "snippin" about anything, just quoted what I found on the internet. My Hughes autotransformer works great and if my neighbor doesnt get the volts he needs he can complain to the CG or go buy an autotransformer.
tvman44 wrote: Never could see how a Autoformer could rob other people of power. If you boost the low voltage your A/C and any other electric motor will draw less current than what it would draw with low voltage. Just an old wives tale started by people that know nothing and spread by people that don't know any better either.
"Stealing" may not be the right word. But the use of an autotransformer when the campground voltage is low will indeed result in you getting more power at the expense of your neighbors, whose voltage will drop even lower when you turn on your autotransformer.
(snippin a bunch of stuff)
Hee Hee.......I told ya so in the second reply to your query.....HEE HEEE HEEEEEE
I'm not "snippin" about anything, just quoted what I found on the internet. My Hughes autotransformer works great and if my neighbor doesnt get the volts he needs he can complain to the CG or go buy an autotransformer.
(snippin a bunch of stuff) was my indicating that I didn't include the entire thread, I snipped a lot of the thread out to make it shorter. snip is a common term used to indicate that on emails that generate a lot of response, it wasn't used as a slam on your views or post.
hershey
The Hughes Autoformer is a far cry from Frank's Voltage Booster. They are NOT the same thing... not even close. I've done research on this and based on that research we bought Frank's Electronics Voltage Booster because it is a far superior product. The Hughes product does not provide surge protection, as well as other features, so separate equipment has to be purchase to provide all of the coverage the Frank's product provides. I found it's cheaper to get everything in one product.
I've been to many campgrounds where the voltage dropped below 100 volts. Without proper voltage boost, the equipment in my RV would suffer or burn out. Most people don't notice low voltage because most people don't have a voltage indicator readily visible in their RV... so they think that since everything is working, the power must be okay. Not a good practice.
Someone earlier mentioned the Ohm's Law... Amps=Watts/Volts... That means the lower the voltage, the higher the Amperage... It is the amps that your equipment draws that makes all of the difference. Your 1500 Watt A/C unit will draw 12.5 Amps at 120 Volts. When that voltage drops to 100 Volts, that same 1500 Watt A/C unit is now drawing 15 Amps which will make it run harder and hotter... damaging the equipment.
If I'm "stealing" power, as someone put it, from my neighbor... not my intention... but my equipment is my responsibility and their equipment is theirs. I paid a lot of money for my RV and I'm protecting it. I suggest you do the same. I disagree however that I am actually "stealing" power. I suggest some research on both of the units.
* This post was
edited 10/14/08 08:37am by wantsalife *
tvman44 wrote: Never could see how a Autoformer could rob other people of power. If you boost the low voltage your A/C and any other electric motor will draw less current than what it would draw with low voltage. Just an old wives tale started by people that know nothing and spread by people that don't know any better either.
Well, I understand the concept and technology however in a totally different way I fully agree with you.
It can not "Rob". What is happening is the campground has contracted (By virtue of accepting your rental fee) to provide you with power, either 30 amps at 120 volts or 50 amps at 240 volts divided.
Many times however the campground has not enough capacity to provide that, so they reduce the voltage. This can cause damage to some hardware.
The autoformer by increasing the voltage protects your equipment, but the formula is volt-amps = volt-amps.
Let's say your 50 amp rig is really only using 1/2 that power, that's 50*120 or 6,000 watts.. If the park drops the voltage to 100 volts (Via power loss in the cables) the autoformer kicks in and you are still drawing 6,0000 watts.. that is now 60 amps, (Since it is split between the two legs you won't trip the 50 amp breaker)
That leaves less for your next site neighbor.. So the anti-autoformer folks say you are "Robbing him of power"
In truth, The park is robbing you, (and him) for that matter. Because they promised you not 6,000 watts but 12000 and they are unable to deliver.
Nothin adds excitment like something that is none of your business John is Near Kenwood TS-2000 housed in a 2005 Damon Intruder 377
Not sure I understand your analogy. Your statement about 60 amps - why would this be? Wouldnt the AT up the voltage to 120V therefore maintain the 50 amps? If the AT didnt work, I could understand this.
It only makes sense this power has to come from somewhere - like your neighbor. Power consuming devices (lites, inductors, resistors, capacitors) do work at a designed voltage. Based on that voltage they will draw x amount of current. If the voltage goes down the device attempts to do the same work at a reduced voltage therefore raising the current draw.
* This post was
edited 10/14/08 09:35am by wittmeba *
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