Generator Versus Shore Power

[steve zannella]

It is my understanding that a 12.5 kw generator only provides 50 amps at 120 volts but is capable of providing 100 amps total on 2 feeds at 240 volts.
My understanding is shore power provides 50 amps on 2 feeds at 120 volts for a combined 100 amps.

Since we do use 240 volts I have half as much amps available on generator as compared to 50 amp shore power.

My question is can the generator provide 2 50 amp 120 volt feeds the same as shore power?

The reasons for my question is when running 3 A/Cs, my Xantrex inverter in CHG mode sometimes shuts down and restarts, usually when one or more A/Cs are cycling on and off. This is not a problem when on 50 amp shore power.

Steve

[David T. Richelderfer]

My understanding is 1) the 12.5kw generator supplies power identical to shore power on the 4-prong 50 amp plug.  Two of the air conditioners are supplied directly by one of the 50 amp legs, the third air conditioner is supplied directly by the other 50 amp leg.  2) None of the three air conditioners are supplied power through the inverter.  3) Therefore, to operate any of the air conditioners either the generator or shore power must be supplying power.  4) Unless excessive power is being used for other equipment, then one air conditioner can usually be operated when plugged into 30 amp shore power.

It could be that when the inverter is supplying charging power at a high rate, like when the batteries are down some, then there isn't enough power on one 50 amp leg for both air conditioning and the Xantrex.  The charging rate on the Xantrex can be limited by programming it to a lower maximum charge rate to prevent excessive demand in this case.

Others here know these systems much better than I do, so someone will correct me also as to my understanding.

[Lee Welbanks]

It is my understanding that a 12.5 kw generator only provides 50 amps at 120 volts but is capable of providing 100 amps total on 2 feeds at 240 volts.
My understanding is shore power provides 50 amps on 2 feeds at 120 volts for a combined 100 amps.

Since we do use 240 volts I have half as much amps available on generator as compared to 50 amp shore power.

My question is can the generator provide 2 50 amp 120 volt feeds the same as shore power?
The reasons for my question is when running 3 A/Cs, my Xantrex inverter in CHG mode sometimes shuts down and restarts, usually when one or more A/Cs are cycling on and off. This is not a problem when on 50 amp shore power.

Steve

Steve, The generator supplies the same voltage and amperage as a normal park shore power, 2 legs 120 V each @ 50 amp per leg total of 100 amps. What in your coach uses 240 volts. Not sure why the inverter reboots could be as David states when the other A/C comes on it might be causing the inverter problem. It is possible that your contactor  in your power switch box has dirty or corroded contacts on that one leg causing low amps. Just a guess.

[Edward Buker]

Steve,

All generators have to respond to load and with two running and then a third kicking on the starting current puts a momentary severe load on that drops the voltage until it can respond and recover. The main power line has ample reserve to supply whatever current is needed until the point that the breaker value is exceeded for a sufficient enough time to kick it. Think of it as a large reserve of power and a limited supply of power. The electronics in modern devices that have protection like the charging system will examine the situation, sampling in real time and decide to alter normal charging as needed. What you can do is make sure that all the screws holding wire feeds in the transfer switch and the main breaker panel as well as the inverter 120V supply lines are all tightly connected so you have the best connections you can. As Lee points out, check the transfer switch contacts also. If all is good then you have done the best you can and the results are normal. There may be some options on the inverter menus or even the air conditioner controls that will alter how they operate to share the available power. Check the manuals on these units and see what is possible.

Later Ed

[steve zannella]

Thanks for your comments,
I was able to tighten 3 AC input screws on my xantrex inverter, that were loose. One connector looks like if was getting toasted .
So far problem seems to be resolved.

Steve