AC power transfer switch or not?

[Ck2hans]

Let me start by stating my Trace inverters were replaced with magnum inverters about 2 yrs ago.
While in a park in S Florida running the AC's I had an approximate load of 42-45 amps per leg (other items Fridge, lights, etc on too). Park breaker kept going out every 45 minutes or so. While park breaker was being repaired (Common white wire on park poll was loose/burnt) I shifted to generator. After half hour or so, power to coach dropped out but gen was still running. Breaker on gen was NOT tripped, gen was still providing power. Turned the rotary switch in the lower bay from auto to gen position. Power came back, all ok.
Once electrician repaired park pole I switched back to park power and put rotary switch in lower bay to auto. Power went out again in about half hour with 42-45 amp loads on each line. Breakers were NOT popped. Switched rotary switch in lower bay to Shore and power came back, systems ran at the higher amperage load without any issue.
I know Featherlight ran all AC power through the original Trace inverters. When the new Magnum inverters were installed I believe it was wired the same. I turn OFF the inverter portion of the magnum inverter at the the control panel so if park power would go off I wouldn't be pulling on the battery's. I assumed (and we all know what that means) by turning off the inverter portion of the Magnum's at the control panel I was bypassing the inverters.
What I think happened (Looking for input from folks who know more about electrical systems) is the AC power was still going thru the Magnum's even though I had turned the inverter portion off at the remote. Because I had so much amperage passing thru the Magnum's I think they over heated, although there were no alarms on the Magnum's. Since I have turned the rotary switch in the lower bay to shore (bypassing the Magnum's) I have had no power loss even while pulling a constant 38-42 amp's per leg on the shore.
NOTE: The generator and inverters are in the 3rd bay and I can see the wires coming from the generator to the 3 position rotary switch (gen - auto - shore). From the rotary switch the wires go to the inverters and to the power panel in the coach. I do not see any transfer switch, I think the Magnums do that when in the Auto position.

Any and all thoughts are welcome
Chuck

[Gil_J]

Chuck,

I assume you have Magnum Hybrid 4KW units.

First, a loose neutral is a very bad thing. The easiest way to see this is through a wide fluctuation between L1 and L2 voltage readings. But that doesn't sound like your problem.

Your current draw is HUGE! is that real? Read the inverter remotes assuming they were wired exactly like the Trace units.

Depending on how the inverters are configured you might see the remotes displaying load sharing. In this case they are adding inverted power to the shore supply. I set mine not to do this even though it's a beneficial feature. These inverters can pass 60A through them, just like the Trace units.

It seems like you can always overcome the problem by using the bypass switches. These bypass the loads without removing the charger function from the inverters. The only thing that should accomplish is allowing the inverters run cooler. Have you looked at the alarms through the Tech menu?

If your Vantare load shedding function doesn't work or is reacting too slow, you are looking for problems. The same with the air conditioners. If EasyStarts weren't installed, the inverters will most likely go into an over current condition when the ACs start. When I replaced my Trace units I rewired my AC distribution adding a transfer switch and inverter sub panel to only pass inverter supported loads through the inverter.

If your generator autostart uses the Magnum network module I wonder if it works. Few, including Magnum, doesn't get this right. The Magnum router is a must for everything to work correctly.

[Ck2hans]

Chuck,

I assume you have Magnum Hybrid 4KW units.

First, a loose neutral is a very bad thing. The easiest way to see this is through a wide fluctuation between L1 and L2 voltage readings. But that doesn't sound like your problem.

Your current draw is HUGE! is that real? Read the inverter remotes assuming they were wired exactly like the Trace units.

Depending on how the inverters are configured you might see the remotes displaying load sharing. In this case they are adding inverted power to the shore supply. I set mine not to do this even though it's a beneficial feature. These inverters can pass 60A through them, just like the Trace units.

It seems like you can always overcome the problem by using the bypass switches. These bypass the loads without removing the charger function from the inverters. The only thing that should accomplish is allowing the inverters run cooler. Have you looked at the alarms through the Tech menu?

If your Vantare load shedding function doesn't work or is reacting too slow, you are looking for problems. The same with the air conditioners. If EasyStarts weren't installed, the inverters will most likely go into an over current condition when the ACs start. When I replaced my Trace units I rewired my AC distribution adding a transfer switch and inverter sub panel to only pass inverter supported loads through the inverter.

If your generator autostart uses the Magnum network module I wonder if it works. Few, including Magnum, doesn't get this right. The Magnum router is a must for everything to work correctly.

Gil:
You are correct, my magnums are the MSH-RE Hybrid .

My Current draw comes from:
Compressor and fan #1 on basement unit (16 amps line #1) Compressor #2 and secondary fan on basement unit (14 amps line #2).
Rear CruiseAir bedroom unit (14 amps line #1) Front CruiseAir W/2nd evaporator and fin behind the fridge (16 amps line #2)
Galley appliances, lighting and chassis battery charger (10 amps Line #1) Fridge (8 amps), Sat & entertainment,(4 amps), fresh water pump (8 amps) "when running" on line #2

Totals per Line 1 when running 40 Amps Totals per Line 2 when running 50 Amps

I have seen the inverter remotes displaying Load Sharing. That's why I turn off the inverter at the remote display to stop the load sharing.
I have not looked at the alarms through the Tech menu.
Didn't know my Vantare had a load sharing function, thought it all went through the inverters. There are no EasyStarts, on wish list. Have asked Santa but not looking good for this year. I only know enough about electrical things to get myself in trouble. Would be interested in the AC distribution transfer switch you added.

Unfortunately the shop that installed the Magnums did not spend the extra $ for the AutoStart's on the gens, also on Santa's list and also not looking good for this year.

Chuck

[Gil_J]

Chuck,

Set your shore setting to 50A and the load share should not come on. I hope you didn't get sold the basic remotes. They are limiting.

If you use the Magnum AGS you will have to accept shore as your priority power source rather than generator.

Busting up your AC panel may be a bit of a chore. Marathon has a novel approach that looks weird, but works. They run almost everything through the inverters and use a transfer switch at the breakers that controls the main power feed to breakers that should not receive power when on inverter power.

[Ck2hans]

Gil:
You are the guru! I am the student hence the following question to educate myself.
I was told that because I have two inverters each providing 120 volts/50 amps to their designated lines coming from the parks 120 volt/50 amp breaker, that I should have the shore setting no higher than 30 amps on each of the two inverters. Don’t remember what the explanation was but it made sense at the time.
Defiantly trust your input, but can you explain a little further for my education?
Chuck
P.S. Unfortunately I did get the basic ME-RC remote. Would not have cost that much more at the initial installation. Now it’s a bit more to buy the upgraded remote and then I have the still good but useless original remote.

[Gil_J]

Chuck, I don't get why some that do these upgrades aren't smarter. I will cut them a little slack. Some manufacturers aren't the best of conveying information.
Magnum Load Support.jpg

[Ck2hans]

Gil:
Spent the afternoon yesterday re-reading the inverter manual. The one section discussed reducing the setting from 50 amp to 30 amp when on generator so as not to overload the gen. Think that's were I got it in my head to lower the setting.
Chuck

[Hoffman]

Great topic guys.
Gil: You mentioned that a loose neutral can be detected by wide fluctuation between L1 and L2 voltage readings. I check the pedestal every time before I hook up and I see sometimes large differences in voltage readings between L1 and L2, particularly when the weather is warm and lots of AC usage in the park. I attribute that to the park Electrical design not evenly distributing the L1 terminals across both park lines and every pedestal L1 is connected to the same park infrastructure line. Which I assume is a bad idea for leg load balancing. By morning, the Voltages are mostly equal between L1 and L2 as the A/C units are off.
Is my thinking flawed somehow? How does a loose neutral play in this?

[Gil_J]

Gil:
Spent the afternoon yesterday re-reading the inverter manual. The one section discussed reducing the setting from 50 amp to 30 amp when on generator so as not to overload the gen. Think that's were I got it in my head to lower the setting.
Chuck

Chuck, exactly where Magnum didn't think before they wrote. My guess is they assumed the generator would be sized for the same critical loads as those supported by the inverter. But they didn't say that or any other comment about the generator. Sometimes, far too often, you have to understand the function or at the very least assume everything written is just an example. BTW, their reference to the generator isn't relative to the shore cord setting. I'm not sure where you read that. What I do know is you have to be careful reading the manual that's for both the dual input hybrid versions and single input units.

[Gil_J]

Joe,

I should have been more specific. When loading causes a voltage drop, as you describe, then the 240V reading will also drop. In the case of a bad neutral, not only will one leg drop in voltage the other will increase in voltage unless the load on L1 and L2 are identical. Together they will still equal whatever the 240V reading is.

I can tell you running down a poor neutral connection can be a PITA.