RV Repair: amp draw, volts and amps, vacumming

Question
QUESTION: Hi
My issue is I plugged my Gen in to my the wheel.
started it up . My  wife stared the microwave for some pop corn.
this nearly stopped my Gen (Kipor 3000).
this has never happened before ran it with no problem .
I hooked up to a friends trailer and it ran like a charm with the microwave on .
I took out the micro and ran it at home runs perfect.
I not sure what the problem could be.
I even ran a vacuum 12 amps same as the micro on the gen and they  ran perfect. confused?
Jim

ANSWER: Did you try it again in on your RV, in the same manner as the first time?  Is it possible that something else was on when you ran the micro?  

Watts are found by multiplying Volts and amps.  120V x 12a = 1440 watts.  Your generator is a 3000W, I assume by the name.  That is usually seperated by two different outlets that each have 1500 watt potential.  The 1500 watts is considering a surge amperage.  It probably has a running wattage much lower.  1500W allows motors to start because motors have a large amount of inrush current, then drop down once running.  The vacuum would be such a motor.  It may draw 12amps at first, but need only 5 amps to run while vacumming...with an occasional draw of more, when it labors on a plugged intake hose or something.  The microwave is different.  It draws the whole amount of wattage as it cooks, continuously.  This will cause heat on the wires which adds resistance.  The resistance can add maybe another amp.  You are only 60 watts from maxing out the generator. If you use the formula in reverse, divide the 60 w by 120 v = .5 amps.  That means if your microwave was running on high, and you had even a light on that draws 60watts, you are at capacity.  Combine that with heated wiring and you are overloaded.  Now if the furnace was on, or an electric heater, this is way over the limit.  If you find this is the case, it may be beneficial to wire the microwave on its own circuit, and use the other duplex on the generator.  Then you would have two cords powering up the RV.  One for the micro, the other for the other things.  

Hope this helped.  Follow up if you need more advice.

---------- FOLLOW-UP ----------

QUESTION: I was pluged in to the 30 amp connection on my gen and running every thing through the 5 th wheel converter . would'nt the micro be on it's own circuit to the converter?
could this be a converter problem instead ?
I will bring the trailer home and try running it again and checking if any thing else was turned on.
thanks for your input.
jim

Answer
Hi again,

30A conncetion at 120V is 3600W.  If your generator is 3000W, and I am only going off the name of it, then the 30A plug is actually only able to give a continuous load of 25A.  The fact that is says 30A is actually considering it can handle the need for a surge draw, like to start the furnace motor or the fridge, or the Air Conditioning.  

Regardless of all that, the microwave only draws 12A from the 30A connection, and your buddy didn't have a problem at his camper with the same connections.  If you didn't have anything else on at the time she cooked popcorn, then it would be logical to suspect the converter.  That seems to be the only thing that is different in all your tests.  I hate to say the converter is bad for sure, because I am only able to go off your information.  However, I would definately start looking in that direction.  

The clues are:  microwave works ok at home, friend can hook up to your generator and it doesn't miss a beat, vacuum plugged into generator works great, you had no trouble with this before, and now there is a problem.  The next place to try is the converter.  

Good Luck!  Have a good holiday