Community Forums

jspande · 10-28-2010, 05:03 PM

One thing not yet mentioned (unless I missed it) is that some ACs, specifically the dual compresser basement units automatically detect 50 amp service by the 230 volt measurement across the two (out of phase) circuits. If it doesn't see that 230 v, only one compressor will run and you'll only have 1/2 normal AC capacity.

azloafer · 10-29-2010, 03:41 AM

I am amazed that I keep seeing these ads for something that doesn't work. Here is an example:
Amazon.com: Camco 55025 RV Power Grip Maximizer 45 Amp Adapter: Automotive

birdman71 · 12-04-2010, 05:56 AM

Got a question do these work for keeping steady amps?Hughes Autoformers 30 Amp Hughes RV Autoformer

palehorse89 · 12-04-2010, 06:26 AM

I have a 50 amp. Plug (50 amp. Per leg =100 amps) when i have to plug into a 30 amp. Hookup i check with a meter to see what is what as far as the 15 or 20 amp. Being seperate from the 30 amp. And if they are i hookup my "cheater box" one side into the 30 amp. And the other into the 20 amp. Now instead of just having 15 total amps on each side of my breaker panel i have a total of 30 usable amps on one side and 20 amps. On the other. It works a little bit better than just being plugged into a 30 amp. Service with a big coach but you still have to be careful what you start and run.
Here is the place to study up a bit on your question--- http://www.autoformers.com/

NJ Hillbilly · 12-04-2010, 07:03 AM

Quote:

Originally Posted by azloafer

I am amazed that I keep seeing these ads for something that doesn't work. Here is an example:
Amazon.com: Camco 55025 RV Power Grip Maximizer 45 Amp Adapter: Automotive

Well at least they are advertising it correctly. It is an adapter and they are only stating 45 amps which is correct if it will work without tripping a GFCI. You get 30 amps on one leg of the cord and 15 on the other.

Still no 50amps on each side, maybe a small portable nuclear reactor would do the trick. Then you could boondock.

Midniteoyl · 12-04-2010, 09:52 AM

Simply amazing...

palehorse89 · 12-04-2010, 10:30 AM

what amazed you?

vermilye · 12-04-2010, 10:35 AM

Just to add a little more confusion to the thread - the voltages in each leg are not 180° out of phase with each other. If you don't believe me, put a scope on them. They are in phase. The current in the neutral is 180° out of phase - that is why it carries the difference, not the sum of each leg.

The sum of the voltage of two equal AC sources 180° out of phase is 0. You can do the math or simply plot the two, or ask what the result is when an audio technician miswires a cable & ends up with a microphone that, when placed next to a correctly wired one reduces rather than increases the gain.

This is why is is much better to describe a 120v/240v single phase service as a "split phase". You are starting with one phase at 240v and using a center tap to split it.

Midniteoyl · 12-04-2010, 10:41 AM

Quote:

Originally Posted by palehorse89

what amazed you?

You have to ask?

Jon is correct...

Single phase power systems are defined by having an AC source with only one voltage waveform.
A split-phase power system is one with multiple (in-phase) AC voltage sources connected in series, delivering power to loads at more than one voltage, with more than two wires. They are used primarily to achieve balance between system efficiency (low conductor currents) and safety (low load voltages).
Split-phase AC sources can be easily created by center-tapping the coil windings of transformers or alternators.

http://www.allaboutcircuits.com/vol_2/chpt_10/1.html

palehorse89 · 12-04-2010, 11:00 AM

when one uses a cheater box do they not have 30 usable amps on one leg and 15 amps. or 20 amps. (what ever the breaker is) on the other leg in a 50 amp. power plug?
assuming the breakers are seperate circiuts.

Wizard · 12-04-2010, 07:32 PM

Yes it can make 50 amps total available if the two recepticals are on separate breakers. However most real 50 amp services make 100 amp avalable for use.

vermilye · 12-04-2010, 08:06 PM

As long as the campground is OK with you using one of these "cheaters" they are useful. A couple of things you should consider:

1. As many have mentioned, if the 15/20 amp receptacle is protected by a GFCI, the tying of the two neutrals will cause a trip.

2. If the campground only ran a single 30 amp 120v feed to the pedestal, then added a local 30 amp breaker for the 30 amp receptacle & a 20 amp breaker for the 20 amp breaker you are going to trip the breaker at the source rather than those at the pedestal if you go over 30 amps. You may need to contact the campground owner or staff to reset it - something to think about.

3. Another interesting, and I admit unlikely but possible problem: If the 30 amp receptacle doesn't work because the neutral is open & you use one of these combiner adapters and plug both the 30 amp & 20 amp sides, you may think you fixed the 30 amp source. Of course, you haven't - if both receptacles are on the same leg, the #12 neutral (remember, it is not fused or breakered) for the 20 amp receptacle will try to carry both loads; as much as 50 amps (at least until it melts).

Again, this device is a good solution if it is used with understanding of what it is doing & how it works. If you don't have a good understanding of how wiring works, it can get you in trouble.