Surge protector/low voltage also

[hohenwald48]

I guess I misread the OP. I thought you were looking for a surge protector that also protected against low voltage. It now looks like you are looking for something to boost low voltage. Sorry for the misunderstanding.

[Quincy]

Originally Posted by hohenwald48

I guess I misread the OP. I thought you were looking for a surge protector that also protected against low voltage. It now looks like you are looking for something to boost low voltage. Sorry for the misunderstanding.

No not at all. I am looking for one that watches for low voltage since I think that is just as big a problem as some voltage spikes.

Especially with all the electronics we all have. I just recently heard about the units that boost the low voltage but not knowing enough about them I think I would prefer to have one that shuts off when voltage is too low rather than try to boost the volts.

The rest of the thread I was trying to restate the E=IXR formula. I used to teach it as basic electricity years ago but I think it should be considered more advanced because it can be difficult to wade through.

Thanks for all the input.

[LostDutchman]

I'm not an electrician, so I will leave you guys to argue those finer points... Here is what I do know... I have a 50Amp Hughes Autoformer with surge suppression, that has on-board diagnostics for power issues at the pedestal...

It has a series of indicator (idiot) lights that tell me if there are any harmful issues before I plug the rig in. It also boosts voltage by up to 10% as needed. How? Don't know, don't care. It works. I keep a digital voltmeter in a visible wall outlet. Since October, I've been in 2 parks where voltage was lower and the unit compensated. For a lay person like me, that's good enough. I chose not to have mine hardwired in. I keep it out by the pedestal as the sacrificial "goat". I have built-in surge suppression on the coach, but if that takes a hit, it's done for and runs about $1500 to replace. The Autoformer can be rebuilt for a fraction of that cost - even if I choose to buy a brand new one off the shelf, it's still only one third the cost of the built-in unit. And since it's a stand-alone, plugged in at the pedestal, there is no labor/shop fee associated with removal and rewiring... That works for me.

[vsheetz]

Install a hardwired Progressive Industries full EMS. This checks the power condition before it gates it through to the RV. Over/under voltage and frequency as well as pedistal wiring correct. Additionally it provides a delay to help mitigate damage from quick successive power on/off cycles. And if course offers surge protection.

If you often camp where low voltage from the CG pedestal is common, then add a Hughs Autoformer to boost voltage as needed. This is most common to occur at older CG with dated or marginal power capacity and often have 30a only pedestals. I've been in many CG with such conditions and never seen a restriction on the use if a Autoformer.

IMHO. YMMV.

[wa8yxm]

Ok Surge Protectrors some in 2x2x2 flavors
One is "installed (hard wired) v/s Portable
The second is Progressive Industries v/s everyboday else (more later)
And the final one is the biggie
Some have a Alpha-Numeric display that shows VOltage, Amps,. Error codes and the like. These usually are what you want

Others only have a few lights. These do not actually protect against over/under voltage or frequency. only Spikesn (They all do spikes) note on hard wired the display may be on an optional REMOTE.

Progressive v/s others. Progressive INdustries, at least before the recent sale, offered a LIFETIME WARRANTY on their products. Far as I know most companies are about 1 year.

When I get the cash together I'm putting in a Progressive Industries HW-50c

[momdoc]

We are having the Progressive HW-50 installed on our new rig before we even pick it up from the dealer.
Living where we do with a very unreliable electrical source and constant low voltage I know what it can do to our electronics.

[BCam]

Originally Posted by Quincy

Forgive me but IMHO The Resistance to current flow, or Ohms does not change. If you have 15 Amps created by forcing 120 volts through, in this case, 8 Ohms of resistance you get 15 Amps. 8 X 15 = 120. If you drop the voltage to 100 and push it through the 8 Ohms of resistance you get 12.5 Amps and 1250 Watts.

Dropping voltage actually lowers the current.

You're sort of right, but not in the context of this discussion for whichTechWriter is correct. The full answer is:

"For a purely resistive load the current will decrease in direct proportion to voltage. However, motors and other inductive loads may actually draw MORE current when run under voltage. So, it depends on what is connected to the voltage." (copied from https://answers.yahoo.com/question/i...3182525AAmZCIN)

The power demands of an RV aren't purely resistive but are a mix. Therefore lower voltage will result in higher amps. This is especially true if you're running your A/C.

[wa8yxm]

Originally Posted by TechWriter

I think P (Power in Watts) = I (Current in Amps) x E (Voltage in Volts) is a better fit.

For example, if you have an 1800W AC running at 120V @ 15A, the formula is:

1800 = 15 x 120

However, if the voltage drops, then the current rises in order to maintain the power draw:

1800 = 18 x 100

So boosting low voltage just reduces the current draw (which save motors from overheating).

You are correct. the E=IR only comes into play if it's running at maximum current. if current is being limited by the load (IE: the converter may be drawhign a great whomping 1 amp) then E-IR works for the coverter. but the resistance of the autoformer basically does not matter.

Also all the above formulas assume DC current. AC is a whole different animal.> You can change voltage easily with a transFORMER. Aut-former is made up of two words AUTOmatic and transFORMER.. Not to be confused with a Single winding saturated core transformer (Variac)

[EZRider800]

Originally Posted by WA Larry

It sounds like you want a Hughes Autoformer.

https://youtu.be/E2NdhNa-ZTQ

I have a Hughes Autoformer and LOVE IT! My favorite thing is the little gauge they give you to plug into a wall socket in the coach that reads out the current amp level at all times. One look at the gauge and I know exactly the situation with the electricity coming into the coach.

BTW........... it is a surge protector AND it will BOOST the amps if they are too low. Many older campgrounds have poor wiring and have low amps which will cause your motors to run hot. Protect your investment!

[Quincy]

Yes Mr. WA Larry, I do want a Hughes Autoformer but the budget says no. I opted for a Progressive HW 50 C with the digital readout satellite. About half the price but I sacrifice the "Low Voltage bump" feature. It has a "component" platform so I can replace parts if necessary. Thank you for all the information and if so inclined your opinions as to my choice will be read with interest.

Thanks again all.

[Quincy]

Originally Posted by BCam

You're sort of right, but not in the context of this discussion for whichTechWriter is correct. The full answer is:

"For a purely resistive load the current will decrease in direct proportion to voltage. However, motors and other inductive loads may actually draw MORE current when run under voltage. So, it depends on what is connected to the voltage." (copied from https://answers.yahoo.com/question/i...3182525AAmZCIN)

The power demands of an RV aren't purely resistive but are a mix. Therefore lower voltage will result in higher amps. This is especially true if you're running your A/C.

So you and I and 1 or 2 others can bore the rest of the thread to tears, I post a quote from a little deeper into the link you provide.

The main reason you see a current increase is if there is a motor involved because of IMHO the heat created which will increase the resistance in the windings as they get hotter.

If you think of E as Electromotive Force pushing electrons through the wire and Ohms as Resistance to this force. The Ohms will not change unless something changes the conditions around the wire ie; heat. The result is then Amps which is how you measure those Ohms effect on the Voltage when trying to flow will be the result.

I am not talking about a situation where there is circuit protection that gets tripped but a situation which can be maintained for a period of time.

Also since I have always believed that Basic Electricity was never Basic, but very complicated and your post bears me out.

I also dont claim to be the last word on the subject but do enjoy discussing it. You have already caused me to look at schematics and a page on the subject just to refresh my understanding either pro or con and I appreciate it. I dont want to "win" an argument here but do want to increase my own knowledge and help others if we can.

Please respond in kind.


You didn't indicate what educational level the question was directed at. For high school and younger students, they are taught ohm's law which is stated as:

i=v/r

where i = current, v=voltage and r is resistance

So, for a constant r, a decrease in v will cause a decrease in i

For college level:

For a purely resistive load the current will decrease in direct proportion to voltage. However, motors and other inductive loads may actually draw MORE current when run under voltage.
So, it depends on what is connected to the voltage.