electric question

By the way there are 3 or 4 different brands, One both bucks over voltage and boosts low voltage but frankly I forget the brand.. ONE sells 3 differnet models, a true 30 amp, an anemic 50 amp (i think it is 40) and a true 50.. Beware the anemic one.

ONE thing you do need to know: 30 amps can become 25(or less) right fast when using an Autoformer.. here is how Transformers Watts out = Watts in - overhead and loss.. There is some small overhead in the unit. and all transformers have some loss.

So if it's boosting say 15% well since volts times current = amps, 30 times 125 = 3750 watts. That is output. But if the input is say 100, that same 3750 watts is now 37.5 amps and the 30 amp breaker won't hold.

On the site I was on last week I kept tripping the 30 amp breaker (Brand new) even with just the A/C (13.5 amp) COnverter (not known but likely in the 1-3 amp range) and Fridge (3.5 amp) no water heater, Oh, 2 lights (totalying less than 0.25 amp) and the TV's and electroincs (4 amps, down from Six back when the main TV was a CRT) That is perhaps 22-23 amps tops at 120 volt.. but it kept tripping the breaker. See math above. Hughes was boosting.

There is also another issue on that site I need to talk to them about once I confirm it. But this would not trip the breaker.

Thanks for all the responses. I guess I will have to break down and spend the money on one

gbopp wrote:
Hughes Autoformer

Backed into a site my wife did not like once (only open site in park what choice did we have) she is crabbing "The woman over there says you won't like it her voltmeter is in the red.

Plugged in, Nice Green arc on volt meter.. YES, I have the product linked to in the quoted text,, Worked perfectly.

Something else, if you have TWO Air conditioenrs.. you can "Break out" one of them (You might want a 2nd autoformer) I do.

Basically I disconnected from breaker box, ran to junction box.. Ran 12ga wire to the outside where I have a plug and a socket.. Plug goes into socket on 50 amp sites, Plug goes to 12ga Extension cord to park 20 amp outlet on 30 amp sites.. But do watch the voltage if you do that or .. As I said, autoformer (you would need a 20 amp unit, since I know of none, that means a 30, for the 2nd A/C).

yes cleaned filter, sensor correct location, all vents open, fan high, what now?
new 5 wheel in 2004

Hi,

Clean the filter and increase the fan speed. Make sure the temperature sensor is in the right place.

fikkellin wrote:
When we were in florida this winter we had the AC would work great for a few days and then freeze up, it would great for a few more then freeze up....the AC seem too check....could voltage be an issue

Hi fla-gypsy,

I shut down my air conditioner at 108 volts. Or I move over to using the inverter.

When we were in florida this winter we had the AC would work great for a few days and then freeze up, it would great for a few more then freeze up....the AC seem too check....could voltage be an issue

Golden_HVAC wrote:

fla-gypsy wrote:
My understanding is sensitive appliances should not be operated at outside of +/- 10% of 120 volts. That would put the lower limit at 108 volts. When I have encountered this I switch everything else off or to LP and let the AC have all available power and monitor my voltage meter.

Yes you can run the A/C at 105 volts. And yes when below about 110 volts, switching the refrigerator over to gas will increase the voltage so slightly, and also have 3 less amps being used by the RV. The compressor motor will draw much more amperage at 105 volts than the normal 120 volts. And in reality, the "Nominal" voltage is 115 volts, so +10% is 126.5 volts and - 10% is 103.5 volts. Anything between 103 and 130 volts it will work. But it will work much better over 108 volts with less amp draw, thus less heat in the compressor winding, and the compressor will be happier, it will turn faster and you will have more cooling capacity at 122 volts than at 108 volt.

I built my own 120 to 132 volt transformer with a isolated 12 volt transformer rated at 40 amps (500 watts). Basically you wire the 120 volts to the transformer, then the 12 volt output to the black input wire and the 120 + 12 to the output black wire, carry the neutral through from input to output. With 120 volt input, you get 132 volt output. With 110 input, you get about 121 output. With 100 input, you get a acceptable 110 volt output.

I was in the pits at Bowling Green Raceway, with my brother's 1967 Dragster! It was exciting, but the humidity was around 100% with a slight rain in the air, and 85F out during Father's day weekend. I was plugged into a 20 amp receptacle without any fuses (well I guess the 00 wire on the pole was fused someplace). Many other motorhomes where plugged into the same receptacles. I had to double up, and set my transformer to +24 volts, as the input at the end of 100' of extension cords was less than 100 volts, and I wanted at least 115 for the A/C.

The Hughes Autoformer is the answer that you can use. It will boost the voltage by 3 volts all the time, and when it detects less than 112 volts it will automatically switch to the +13 volt coil, and boost the voltage to an acceptable level. Inside the RV you will enjoy the A/C and not know if it switched or not. The only problem is cost. $300 - $500 depending on the model. Normally because 50 amp parks do not suffer from low voltage, I would only buy a 30 amp model, as that is the likely time you will need it.

I built mine for about $200, the transformers are not cheap. Mine is manually adjusted, not automatic like Hughes.

Fred.

Thanks for the technical data Fred. I guess I was overly concerned at 108 volts but it makes me nervous to see it struggle like that.

tenbear wrote:
Sometimes the 50A service is better than the 30A. I carry a 50A to 30A adapter for those occasions.

This has been my solution as well.

Sometimes the 50A service is better than the 30A. I carry a 50A to 30A adapter for those occasions.