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BillAdams

Having Inverter Issues (Long Post, Sorry)

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Bill, By any chance do you have the OEM ATS ? Could you pull off any and all the numbers and the make of the Switch and post the info.

Also, any info regarding the AC and DC power panels might help. Does the AC breaker panel and the 12 volt panel share the same box?

Maybe with enough information I can try to do a little reverse engineering.  The coach was built before any of the EMS system where out. Thinking its got to be wired with out the use of ant real fancy controls. 

Also, regarding the pictures I posted, look like anything in your coach? and did you convert the shore power to 50 amp by adding a second or 50 amp main breaker box prior to the original 30 amp box?  

Rich.

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Todd Engineering was the original ATS but they went out of business years ago.  This coach is a factory original 50 amp coach.  There is no 12V breaker panel or fuses that I am aware of (interesting, I had to think about that).  There might be some resettable 12V fuses in another box but it's never been opened.  The transfer switch consisted of 2 separate relays each of which had an input for shore power leg 1 and leg 2 and neutral leg1 and legs 2, input for inverter leg 1 leg 2 and neutral leg 1 and leg 2  both relays worked simultaneously to transfer both inverter outputs and both.

You can go here http://gpelectric.com/products/50-amp-transfer-switch and click on the link to manual on the right side.  That's what the old transfer switch looked like and how it functioned.  It's on page 6.  Diagram 1, setup on the left and below that, Configuration C.

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Since that is how the old switch operated and looked like, why not replace it by calling the Toll free #?  Then just run a 50A to TS and forget the twin 30A inn!   

 

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Call the toll free number to a company that has been out of business for so, so many years?  Or did you mean call the company that does not make the ATS pictured in the diagram they show?  I bought the Go Power transfer switch and that's not how the "new" version is setup despite everything they showed online. Wait, that can't be right!  If it's on the internet it must be true!

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Bill, Found this video clip, but there is no video of the electrical panels or of the inverter location, shore power interface, chassis batteries or disconnect switches or the generator connection point to the chassis wiring.

https://youtu.be/rgH8qCr0YAk

Does this coach look anything like your's ?

Regarding the 50 amp transfer switch(s) setup -- Two transfer switches connected in parallel, that would switch between the shower power input and the generator output could be placed inside the OEM box.

The other question I have is the connection (generally a 4 in. square J box close to the generator) that connects the generator wiring to the coach wiring in good condition and what is the status of the circuit breakers mounted in the generator. All connections clean and tight ?

Rich.  

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WOW!  No, that's not what my coach looks like or ever looked like.  The original paint job is similar (done by Prevost before being shipped to the converter) and the dash looks similar but that's about it.  The 50 amp transfer switch for shore / generator is a large (not 4" square) box with 3 relays 2 input / 1 output with a built-in delay for the generator.  The power for the Inverter does not have anything to do with this box as it simply sends either shore power or Generator power to the 120V breaker box.  From the breaker box power is supplied to the Inverter when plugged into shore power or running the genset and this power is "passed-through" the inverter to the 2 dedicated lines connected to the inverter.  If no shore/generator power is available the inverter inverts and supplies 120V power to those same 2 dedicated lines from the battery bank.

20121231_091127.jpg

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3 hours ago, BillAdams said:

WOW!  No, that's not what my coach looks like or ever looked like.  The original paint job is similar (done by Prevost before being shipped to the converter) and the dash looks similar but that's about it.  The 50 amp transfer switch for shore / generator is a large (not 4" square) box with 3 relays 2 input / 1 output with a built-in delay for the generator.  The power for the Inverter does not have anything to do with this box as it simply sends either shore power or Generator power to the 120V breaker box.  From the breaker box power is supplied to the Inverter when plugged into shore power or running the genset and this power is "passed-through" the inverter to the 2 dedicated lines connected to the inverter.  If no shore/generator power is available the inverter inverts and supplies 120V power to those same 2 dedicated lines from the battery bank.

20121231_091127.jpg

Thanks! Bill The wiring you described sounds like one would expect to see ! Setup almost exactly lick most coaches. Mine has the H-1 /L-1 at 30 amps going to the inverter input with the output going to 2 - 20 amp circuits being supplied. When on shore power the 120 volts passes through the inverter and when there is no shore power or generator power the inverter internal relay(s) open and only the dedicated circuits powered from the inverter have 120 volts.

Note! your coach was set up for 50 amp and ours was set up for 30 amp. Just before they where changed to 50 amp.

That information offers a good base line for how the coach 120 volts is wired. The real trick is to find out where the imbalance or possible feed back loop for the neutral side could be causing you to loose inerters. 

Somethings to ponder for sure - 2 ATS relays / solenoids(They isolate the 2 Hot feeds from things and one delayed relay in the power circuit for the generator to warm up and settle in to 60 cycles at 120 volts. That Relay is most often the source of power for the second roof AC unit. 

That is one good looking coach! Like the paint job and always have liked the style bay doors. 

Rich.

Bill, found this recall for you coach if I have the year of the chassis correct. it is a electrical recall issue!

http://www.safety-recalls.com/content/$so$41/91V111000-PREVOST-BUS-PREVOST-XL-1988.html

Some wiring info for the Prevost bus chassis.

https://prevostcommunity.com/PDF/Prevost Electrical Systems.pdf

 

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BillA.  Thank you for correcting me!  It must be infuriating to you, that you can't solve this problem by yourself.  All we are trying to do, is help you!

Carl

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Bill, was the original inverters, inverters only, or were they inverter/converters? If inverter only what has become of the converter/charger?

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There was a stand along inverter plus 2 - 75 amp stand alone converters.  I changed this all out many years ago (10+) with a Heart MSW inverter and a single 20 amp circuit from the breaker box but the transfer switch remained in place.  Everything worked great for many years and I later upgraded to a PSW inverter which also worked great for many years.  My transfer switch died and I was advised that it was no longer necessary and that I could remove it and use the inverters built-in transfer switch instead.  This is also when I decided to bring in 240V via a 2nd 20 amp circuit from the breaker box so I have 2 changes that took place at the same time.  Everything works (worked) fine for months and then died for no apparent reason and while still plugged into campground power.  The new inverter should arrive Monday and I will either set it up with a single 20 amp (120V) line or a 4 wire line out of the main transfer switch.  I have a new transfer switch but it's not like the old one and I have concerns that I could have similar issues trying to use it.

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This is/was how the original transfer switch was setup except that the power sources were inverter and shore/generator from the main transfer switch.  The panel connections would be the shore/generator (priority) and the generator connection would be inverter (operates only when the other source of power is not available).  Time delay set to zero so you have instant transfer to inverter power any time no other power source is available.20170401_113053.jpg

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Bill, I did find this information, it is a ATS system for the AC input side supplied from the Shore cable, Generator or Inverter.

When you talk about the transfer switches, are you writing about AC input or the transfer relay in the output of the inverter(s) switching between the feed through power and the inverter output AC source?

Rich.

Parallax_ats_503_owner_op_guide_rev_b.pdf

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I don't want/need a three relay  transfer switch as you show.  That's what I already have for the incoming 50 amp service.  This is a 2nd transfer switch used only for the inverter and 2 dedicated inverted only power lines.  When there is power the A/C passes through the inverter to those lines and when there is no 120V incoming power the inverter powers these lines.  In theory, no transfer switch would be required.  That's the part that so puzzling about this whole setup.  The original setup included the transfer switch as I suspect the original inverter (only) did not have a pass through function.  I just let the transfer switch in place for all of these years until the transfer switch failed and there was no replacement immediately available.

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The only thing that I would change at this point is to rewire from the main breaker with a 30 amp, (2 15 amps tied together) 230/240 volt breaker, 10-3 with ground wire. This is based on everything that you have done, and in following the wiring diagram from your manual.

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9 hours ago, kaypsmith said:

The only thing that I would change at this point is to rewire from the main breaker with a 30 amp, (2 15 amps tied together) 230/240 volt breaker, 10-3 with ground wire. This is based on everything that you have done, and in following the wiring diagram from your manual.

I am sorry but I don't understand what you are suggesting here.

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I am suggesting that you go to setup different than the two individual circuits, 120 volt on #12 wire with separate breakers. To do this, my suggestion is run a true 230/240 volt circuit from the main breaker panel directly to the inverter, based on your manual, please refer to page 9 of your manual, and if you are you are using the exact same Kiase inverter, on split phase, the manual suggest that a single 230 volt circuit, 30amps. To achieve this one would need to go directly to the main breaker panel and install a 30 amp 230 volt  breaker, I did misstate in the previous post, this will need 3 wire with ground #10 wire would be to code. # 10 is actually necessary for a 230 volt 30 amp circuit. Anyway the 230 volt 30 amp circuit has two 30's that are locked together assuring that if one side trips, the other side will be turned off at the same time. Split phase means that the L1 and L2 measured across actually measures 230/240 volts and insures that the two are out of phase with each other and the neutral is used to balance the load one against the other. My theory is that if only one side trips and the other side remains on at the same time, your inverter, since it automatically shunts common/neutral to ground when in the inverter stage may have been the culprit that was causing an issue in the past. The transfer switch if properly wired in the past would have prevented this condition. This is the only reasonable observation why there was no problem before the transfer switch was removed, then suddenly became one. A 3000 watt inverter only produces  a total of 25 amps at 120 volts, meaning that there would be a maximum 12.5 to 15 available on L1 and the same on L2, therefore.  

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OK, that sounds interesting.  Can I replace the 2 20 amp breakers in the breaker box (this are side by side) with 1 230 V 20 amp. breaker (double pole) 20 amp (the wiring is for a 20 amp circuit) as I am OK with only 20 and can't run new wiring 30+ feet from the breaker to the inverter.  I will have to look at the wiring from a 230 V breaker as I will have 6 wires available from the 2 existing circuits but I assume would only use 4 of them at the inverter (2 hot, 1 neutral, 1 ground).  Let me know if I sound like I have a clue what I am talking about or if I should just go back to 1 20amp input and just return to managing the charging circuit (the reason for a 2nd hot) when we are running the convection oven.

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Bill,

Kay and I had a conversation regarding your electrical system and changing out the converters (that where used to charge the batteries) and the inverter that made 120 volts only did not require 30 amp wiring to the inverter / chargers  that charge the batteries and supply the 120 volts to the 2-120 volt circuits that are powered from an inverter. This change requires the 30 amp breakers and larger wires to supply the needed current at the inputs. That is covered in the installation portion of the owners manual.

Like you mentioned, it is not easy to replace the wiring, the main circuit breaker panel and the sub breaker panel and make sure that there is a time delay relay in the generator output wiring, that allows the generator to warm up before switching over to handle the AC loads and the output of the inverter(s) is isolated from the Main Breaker panel input, so there is no power loop created. Kind of like a microphone placed in front of a speaker. The squeal is hard on the ears and the electrical equivalent is hard on electrical equipment. 

The thing is once it is completed, the coach wiring is completely up to date. 

The second option is to replace the converters with new ones, install a new sine wave inverter and transfer relay(s) and leave all the wiring as is. 

I call it the domino effect. Changing one thing leads to a cascade of changes. 

Good luck and please remember there are no dumb questions. We are all part of a big family on this forum and want everyone to be safe and have fun.

Rich.

Not knowing how the shore power wiring is run on the coach, is there a possibility to run some conduit between the current shore connection and where the new inverter is mounted an room for a new Main Breaker Panel. So most of the current 120 volt wiring could be used?

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imageproxy.php?img=&key=f3c99bdc57031e3aI have not had converters or a stand-alone inverter for about 15 years.  I removed all of that and installed a Heart 458 MSW inverter/charger and it worked great for about 12-13 years.  I then decided to upgrade to a TSW inverter a few years back and it worked fine as well for awhile.  When the transfer switch (secondary to the main transfer switch with no delay set as it only switches between the inverter or power coming from the primary transfer switch which has the generator delay). 

This is the information on the new transfer switch.  It assumes input from 2 hots 1 neutral and 1 ground but the wiring would only be 1 hot, 1 neutral and 1 ground from either the shore power or from the inverter.  I would put the shore power on the generator circuit so it would be primary and the inverter on the shore power circuit.  I was able to eliminate any delay by adding a jumper on the circuit board per directions from the manufacturer.  I have not installed any of this yet.  It still seems to me that a transfer switch should not be necessary and I don't see how/why the transfer switch installation would eliminate an A/C feedback issue that would exist if the transfer switch was not used.  It is an A/C feedback issue that the inverter manufacturer says caused the inverter to fail.

Transfer_1_.jpg

Transfer2.jpg

Transfer_1_.jpg

 

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