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BillAdams

Having Inverter Issues (Long Post, Sorry)

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According to the manufacturer the error we are getting "E05 A/C short protect" is not field repairable.  The only service available is to return for repairs.  Nothing has changed in the coach setup and the company has sent me 2 replacements under warranty.  I won't even ask them to do it again as I am convinced that I caused the problem with my modified wiring setup.

Thanks to you both for the thoughts.

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I just re-read this whole post again and like Herman, my eyes and brain is starting to cross.  So, as to not over think on this, I still believe that the "other" transfer switch, that was not needed per instruction, is in fact needed.  Why did you decide to use 2, 30A and not the 50A to begin with?  I don't see an advantage of 2, 30A coming in !

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I wired it that way as that was the only convenient wiring available.  Previous setups had simply being with 1 20 amp circuit (3 wire) and using the appliances on that circuit while the battery charger was in bulk mode nearly always tripped a breaker.

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I actually misstated what I did.  This really has nothing at all to do with 30amp coach wiring and I should not have used a 30 amp circuit as an example.  My coach is a 50 amp coach and I have 2 hot lines that come into a breaker box with some of the breakers on leg 1 and some of the breakers on leg 2. 

What I did was pick 2 legs coming from the breaker box (each is actually connected to 20 amp breakers) that were on separate legs.  This gave me the 240V across the 2 hots that I would get if I ran a normal 50 amp circuit directly.  So, I have 2 20 amp circuits using standard 12/2 wiring (hot, neutral ground) but the 2 circuits are on separate legs of the incoming 50 amp power. 

What I believe the inverter wants as incoming power is a 4 wire circuit (hot 1, hot 2, 1 neutral and 1 ground). 

What I wired up was 2 circuits into the named connections.  That is 2 - 3 wire runs from the breaker box to the inverter which means I did not have a 4 wire connection but rather a 6 wire connection with the 2 neutrals and the 2 grounds connected to the 1 neutral and 1 ground connection.

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13 hours ago, BillAdams said:

I actually misstated what I did.  This really has nothing at all to do with 30amp coach wiring and I should not have used a 30 amp circuit as an example.  My coach is a 50 amp coach and I have 2 hot lines that come into a breaker box with some of the breakers on leg 1 and some of the breakers on leg 2. 

What I did was pick 2 legs coming from the breaker box (each is actually connected to 20 amp breakers) that were on separate legs.  This gave me the 240V across the 2 hots that I would get if I ran a normal 50 amp circuit directly.  So, I have 2 20 amp circuits using standard 12/2 wiring (hot, neutral ground) but the 2 circuits are on separate legs of the incoming 50 amp power. 

What I believe the inverter wants as incoming power is a 4 wire circuit (hot 1, hot 2, 1 neutral and 1 ground). 

What I wired up was 2 circuits into the named connections.  That is 2 - 3 wire runs from the breaker box to the inverter which means I did not have a 4 wire connection but rather a 6 wire connection with the 2 neutrals and the 2 grounds connected to the 1 neutral and 1 ground connection.

Bill, if I am reading this correctly,  I see no problem with what you did here.  Though you brought in the two neutrals instead of just one, at the main breaker box, the two neutrals should be on the same neutral buss bar.  So, basically the second neutral is redundant. Same for ground-- both should be "joined" on the ground buss bar in the main breaker box.

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They are both on the same bus bar as they come from 2 separate 20amp breakers in the same breaker box located 1 above the other (every other breaker appears to be on opposite legs).

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Bill,

Just to clarify my thinking. When you refer to your breaker box are you speaking of a breaker box where you get your shore power (aka pedestal)? From which you are connected to two 20 amp breakers that are wired to your 50 amp plug for your coach?

Sorry for the confusion but I am just trying to get my mind around a picture of how you are wired.

When I was into my Inverter here is what I found.

    On the Generator input I had 4 wires, Leg 1 Black & Leg 2 Red for power and a White for neutral and Green for ground. The Inverter was clearly  marked for each.

    On the Shore Powers side I had exactly the same as the Gen. coming into the Inverter on the opposite side.  

 

You mentioned before that you have, many times received a tingle from the side of your coach. There must be a hot lead touching a ground somewhere. Since it is just a tingle is doesn't sound as if it is a 110 volt tingle. Do I remember that the Prevost coaches of your year were 24 volt systems? If so that may be where you are getting the tingle. Any way that is not good or safe for you. Please be careful you or Janet don't need the shock of your lives.

 

Herman 

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The only other concern that I have is that the inverter is set for 240, is that sometime possibly you have used a 30 to 50 amp pigtail in order to be plugged into a 30 amp pedestal, in this event the current is only 120 volts because the pigtail breaks out 120 to both L1 and L2. In this event the inverter may have "starved" for voltage. In this event, the inverter should sense the shortage and simply shut out the supply, if it doesn't, then that would be a fault in the design of the unit.

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Hi Bill, The part that has me confused is you measure a short between the neutral and ground when the inverter is running and not plugged into the shore riser. From my understanding of the inverter operation / there is no reason for the inverter to cause a connection between the Neutral and ground.

NOTE. only the L1 leg supplies power to the charger portion and the L2 leg is only active when connected to the shore power riser. The L2 leg output is not powered from the inverter.

The only time both L1 and L2 are both hot is when the coaches are equipped with 2 inverters and not connected to a riser.

Inverters can be connected in series or parallel. The 3000W units have inputs for both L1 and L2 

Note- I do not have the wiring or install manuals for your model charger / inverter !

Rich.

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Bill, over looked the fact that the generator circuits run through a the ATS and in many cases a delayed transfer relay for the second 120 volt circuit. That relay is often located in the secondary circuit panel and it could be an issue if the contacts are fused together due to high current draw of the roof AC unit often connected to that relay. A item worth checking ! due to the common neutral and chassis ground, only other point I can think of that might be causing the short between the neutral and chassis ground when disconnected from the shore riser and when the generator is running or when the inverter is running.

Rich.   

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8 hours ago, hermanmullins said:

Bill,

Just to clarify my thinking. When you refer to your breaker box are you speaking of a breaker box where you get your shore power (aka pedestal)? From which you are connected to two 20 amp breakers that are wired to your 50 amp plug for your coach?

Sorry for the confusion but I am just trying to get my mind around a picture of how you are wired.

When I was into my Inverter here is what I found.

    On the Generator input I had 4 wires, Leg 1 Black & Leg 2 Red for power and a White for neutral and Green for ground. The Inverter was clearly  marked for each.

    On the Shore Powers side I had exactly the same as the Gen. coming into the Inverter on the opposite side.  

 

You mentioned before that you have, many times received a tingle from the side of your coach. There must be a hot lead touching a ground somewhere. Since it is just a tingle is doesn't sound as if it is a 110 volt tingle. Do I remember that the Prevost coaches of your year were 24 volt systems? If so that may be where you are getting the tingle. Any way that is not good or safe for you. Please be careful you or Janet don't need the shock of your lives.

 

Herman 

No, the engine start circuit is 24V but the rest of the coach is 12V.

All of the incoming power be it shore or generator goes to a transfer switch and that power is sent to a home style circuit breaker panel.  This is where the power going to the inverter comes from.   This is where all the 120V power in the coach comes from.  The main transfer switch has the same setup for shore or generator.  4 wire red/black hot, white neutral and bare copper ground.  If I power up the generator it will default to generator power after a short delay to ensure the genset is up to power.

The inverter powers 2 dedicated circuits that do not get power from anywhere unless it is going through the inverter either using shore power and the inverter by-pass option or coming from the inverter while no power is available and the inverter is inverting.

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8 hours ago, kaypsmith said:

The only other concern that I have is that the inverter is set for 240, is that sometime possibly you have used a 30 to 50 amp pigtail in order to be plugged into a 30 amp pedestal, in this event the current is only 120 volts because the pigtail breaks out 120 to both L1 and L2. In this event the inverter may have "starved" for voltage. In this event, the inverter should sense the shortage and simply shut out the supply, if it doesn't, then that would be a fault in the design of the unit.

During the last failure the coach was plugged into the same 50amp service for the entire time from the time we replaced it and the time it gave up the ghost.  Even if I was plugged into a 30 amp circuit I believe the inverter would see the same circuit as the inverter never sees 240 but rather 2 120V lines which is what it would still see on a 30 amp circuit.

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Maybe you could look at the owners manual from the links I posted (did I post it here?)  Nothing in my coach ever sees 240V so I don't see how the inverter could.  Yes, there are 2 120V hots that, if measured between the 2 show 240V but no circuit in the coach has access to 240V.  There are simply 2 legs of 120V.  If anything in this coach got hit by 240V it would blow itself to pieces!

http://www.kisaepower.com/products/abso-inverter-chargers/abso-inverter-chargers-low-frequency/model-ic-1230150/

 

 

IC-High-Power-Low-Frequency-Series-REV-B.pdf

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Brett, here is the direct link to Bill's inverter model manual, the manual refers to three different models, his is the 150 at the end of the model #.

http://www.kisaepower.com/wp-content/uploads/2016/07/IC-High-Power-Low-Frequency-Series-REV-B.pdf

Wiring instruction is on page 7. His model can be wired with 240 split phase, or 120 single. If wired with 120, it must be from the same source ie 30 amp single circuit, but using two wires connected to L1 and L2. So far I find nothing to tell the inverter which way it is wired, so for now I am assuming that the unit can sense the difference.

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Bill, Been on the road for a few months and do not have all my information for wiring in a 3000 W inverter, but I attached 2 pictures of the common wiring for a 30 amp system.

You need to look at the OEM wiring of the coach to match up how the OEM inverter was installed. Also there is a possibility of a neutral current problem if you are upgrading from a 2000 W series inverter to the 3000 W unit.

If you have go to 6 AWG for (Dual Input) / 10 AWG (Split phase)  as noted in the 3000 model wiring.  Question is do you have a main circuit panel with 2-50 amp mains or 2-30 amp breakers that feed the sub breaker panel? Then are you powering the same circuits from the inverter or are you adding a circuit or 2 that will be supplied power from the new unit?

The common practice is to use number 10 wire for L 1 and 2 with a # 8 wire on the neutral. I well be on the road tomorrow so I'm not sure we will have WiFi or not when we stop for the night.

Good luck! Rich. 

IMG_5459.JPG

IMG_5460.JPG

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Just as an additional clarification, I used some wrong terms so let me see if I can clarify.  This coach has 50 amp SERVICE.  As you are aware that means I have 2 HOTS coming into the coach plus the neutral and ground.  This wiring goes to a transfer switch (generator and shore) and then to a standard breaker panel where there are 30 amp and 20 amp breakers.  The wires leaving these breakers go to all of the outlets in the coach (the 30 amp circuits are A/C only) so I have 20 amps available on each of the 3 wire lines running to the inverter.  If I exceed 20 amps draw on any line it simply trips the circuit breaker.  As Brett mentions, the neutral and grounds are all connected to their respective bus bar in this breaker box.  The setup works fine for a few months and then for no reason at all the unit shows the A/C short fault and is dead.  The rep. says this is an A/C feedback problem and I am using the same 2 output lines that the manufacturer installed oh so many years ago.  I did change from a 2000W to a 3000 W inverter but it worked fine until my transfer switch went bad and I was advised that a separate transfer switch was not required since the new inverters have their own transfer switch.

So, if it's A/C feedback, does that mean that somehow there is A/C current on the D/C line or that somehow there is A/C being sent to the output side of the inverter (backfeed?) somehow?  This happened while the coach was plugged into shore power, with the inverter set to "on" but not being utilized. The battery charger did it's job, went through the 3 charge modes and was in "float" as it should have been.

As I mentioned, the 2 lines that leave the inverter do not get any power if there is not an inverter in the loop (or directly wired as they are now to the same 2 lines with the inverter removed).

I only mention the feedback thing as I am trying to figure out what a transfer switch might have eliminated that keeps blowing up my new inverter.

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Never mind the Rep.  You need to go back to a transfer switch.  Why?  Don't have a clue, but the system worked until you stopped using it...:blink::rolleyes:

Carl

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On 4/18/2017 at 5:14 PM, manholt said:

Never mind the Rep.  You need to go back to a transfer switch.  Why?  Don't have a clue, but the system worked until you stopped using it...:blink::rolleyes:

Carl

Bill, Did you remove the ATS ? The key is to go with the OEM wiring. Like Carl  mentioned. 

As a side note, If the Rep mentioned removing the ATS, I bet he or she has never seen one installed in a coach or a home installation where the owner has solar and backup generator. The relays that are built into the inverters are to disconnect the power line feed from the breaker panels to isolate the home from the main power source.

Rich. 

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The person who told me to remove the (dead) transfer switch is a very knowledgeable RV person.  He builds generators and it is his generator installed in my coach.  The inverter is no longer made and needed replacement.  It was his suggestion that I simply remove it as it was installed in a time when the inverter was an inverter only and there were separate battery chargers.  I suspect the inverter did not even do a pass-through back in the 80's.

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Yea!  Well, his expert opinion or knowledge has not done you any good.  Just because he builds Generators, does not make him an Electrical engineer or electrician.  I go with Rick and Kay on your issue...

Carl

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But then again, you really don't know his background and you don't seem to be able to explain why the transfer switch would resolve the problem.  I also changed the wiring at the time I removed the transfer switch so it's trying to figure out whether it's simply the wiring choice that I made or the transfer switch.  I cannot find a similar transfer switch anywhere so one additional concern is that even if I install a new transfer switch it will still not give me the same isolation that was available from the previous unit.

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Bill,

I don't know that much about shore power and generator power through the ATS. But my thoughts would be to find how the coach was wired when the conversion was done and go back to that. It worked for years.  Why not now?

Herman 

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2 hours ago, BillAdams said:

But then again, you really don't know his background and you don't seem to be able to explain why the transfer switch would resolve the problem.  I also changed the wiring at the time I removed the transfer switch so it's trying to figure out whether it's simply the wiring choice that I made or the transfer switch.  I cannot find a similar transfer switch anywhere so one additional concern is that even if I install a new transfer switch it will still not give me the same isolation that was available from the previous unit.

At this point My best recommendation would be to take it to your friend (you said he is familiar with it) and say PLEASE fix it. 

Bill

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