Generator not connccting to power coach

[imnprsd]

Here are new edit based on what I know at this point. This will allow you to compare the ATS-5070 schematic to the Lyght 50A-ATS, which looks like a copy from a functional point of view. The only difference is how they handle the Rectifier, Circuit Board and Delay Timer... from what I can tell.

[imnprsd]

On the general subject of what choices we have when it comes to replacing your ATS, I found this website link that summarizes several options:

https://www.rvweb.net/best-rv-transf...ches-reviewed/

12 Best RV Transfer Switch Reviews 2021
1. Go Power! TS-30 Automatic Transfer Switch
2. Progressive Dynamics PD52V Transfer Switch
3. Elkhart LPT50BRD Automatic Transfer Switch
4. Xantrex 8080915 Auto Transfer Switch
5. WFCO T30 Transfer Switch
6. Technology Research 41300 Transfer Switch
7. Furrion F50-ATS Automatic Transfer Switch
8. WFCO Electronics T-30 Transfer Switch
9. Surge Guard 40100 Automatic Transfer Switch
10. Arterra Distribution T-57 Transfer Switch
11. Technology Research 40100 Transfer Switch
12. MOES Automatic Transfer Switch
What to Look for When Buying an RV Transfer Switch
Other Important Factors to Consider
Frequently Asked Questions (FAQs)
Conclusion

[imnprsd]

As I continue to search for the best and least expensive 50A-ATS, I came across this one for $130:

https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1

There appears to be several choices now that are far less expensive to using the Parallax 501 or 503, and all seem to be well received. This one for example has a number of favorable owner comments.

However, upon closer look it would appear that some manufactures are resorting to more elaborate circuit design (which I do not care for) to cost-reduce their product. Further, I do not care to see that FAN needed to cool the device.

...See the circuit board picture below that includes transformers and other devices that IMO may be subject to vibration and heat... meaning I'm not sure I would buy this ATS even if it was cheaper than the Esco-Elkhart ATS previously mentioned for $185.

Of course, no one has also come forward to vouch for any one of these or to warn against. So when it comes to replacing your ATS with a new version the question remains... can you find the best 50A-ATS at the lowest possible cost?

That said, I can't say for sure this T-57 model may be that option?

...Additionally, from the research I have done, the idea of using 120V Contactors seems more advantageous since they are designed to handle 120V coil switching, but they are more expensive.

Ultimately, the cheapest solution, proven to last 10+ years is really all that matters. Consequently, why over engineer an ATS when the objective is to build one the longest lasting 50A-ATS at the lowest possible cost?

Note: I'm still not convinced you cannot repair your existing Parallax ATS-5070 for much less than the cost of buying one of these other ATS-50A boxes, but that maybe hopeful at best.

Why? ...I have yet to find an inexpensive source to replace these "heavy duty" 50A relays in my ATS-5070; and so far all the Contactor Relay types I have looked at are proving to be more expensive than just buying one of these 2nd Source Boxes... who are vying for the attention of winning large contracts from Winnebago and other RV manufactures. That said, this explains why we can find a sub-$150 50A-ATS available on Amazon and I have no reason to doubt these are reliable products. I just don't like fans!

[Kinch]

Thanks for all your work on this.
I now own a parallax ATS 501.$188 two year warranty and free tech support for installation.
I have made arrangements with Poma electric to install it in my MH.
They know MH ATS installations.
Will keep you posted. Robert Poma is coming to my home to do the install.

[imnprsd]

Kinch: On your existing (OEM) ATS-5070, can you check the voltage to the relay coils before you pull it out? I'm unclear if these are 120Vac or 120Vdc or something else?

Note: If you don't have shore power you will need to start your generator to check the voltage.

And if it's not too much trouble? Can you take a picture of the AST-5070 relay markings, if any? This will be of great help to many of us!

Thank you!

[imnprsd]

Quick update, plus a correction, and more about using a Contactors to build a 50A ATS box:

This picture above with that fan and transformer does not belong to the ATS being sold on Amazon. The Amazon vender provided it and when I asked them if it was posted in error, they said, "Yes."

So please disregard the picture.

=== WHEN YOU SWITCH HIGH CURRENT, DOESN'T SIZE MATTER? ===

My concern with any of these ATS boxes are most vendors are using sub-quality parts from China (and to a lesser extent Mexico) that do not have the same reliability as the old relays.

So maybe what you are paying for is the BRAND which is supposed to guarantee "qualified" vendor sources. The reality is "Maybe" it does and "Maybe" it doesn't!!! ...After all, why are so many people blowing-up their ATS?

I also see newer ATS 50A box designs are starting to us Contactors in lieu of the old style 50A relays, but I don't think this means Contactor relays are better than the old style 8-pin heavy duty relays. Rather, I think it's about competition and price driving the market quality down.

Here's my concern: If our Generator needs a 70A neutral return line, I don't know if these contactors or cheap 8-pin relays can handle that?

For example: A Contactor spec may indicate 63A, but but then you look closer a the spec sheet you see that this same part is 40A with resistive loads and 32A with inductive loads.

So how can they handle 70A on the neutral switch?

==> MAYBE... I'm thinking this is possible if you use a 4-pole Contactor so you run each of the 2 generator neutral wires through the contactor separately, but I'm no expert on this subject. I'm just an RV owner looking for the best value and I don't want to sacrifice quality and reliability when it comes to using any ATS.

==> AND MAYBE this why you would want to buy a 100A rated ATS if you go with a vendor that uses Contactors? ...But where to find one? ...It's not easy.

*** Here's the thing, when I examine some of the very expensive 100A ATS sources, and there are only a few, they use Chinese Contactors too!

And some of these are interlocking Contactors... and get this: Our old Parallax ATS-5070 had automatic switching, but these new ATS boxes with contactors seem to require you to remove the shore power cord in order to switch from generator power to shore power. IS THIS TRUE?

I get that this action, of turning off the generator with shore power plugged in put a lot of wear on the relay contacts, but is this really why a lot of ATS boxes fail?

My my ATS-5070 has lasted 15+ years!!

So is the real problem that it's getting harder to find a vendor who can produce a quality Heavy Duty Relay (8-pins) as the market is moving more and more to Contactor switching devices. And BTW, if it's not apparent, these Contactors use lighter weight relays inside so how can they be more robust than a heavy duty relay?

==> Personally, I still would like to find a couple QUALITY Heavy Duty Relays to repair my old Parallax-5070, for less than $80, but if I can use a 4-pole Contactor like this one below, I would also consider building my own... as opposed to spending $300+ for an a like or inferior ATS brand.

Below are 3 pictures showing:

* Old style 8-pin Heavy Duty Relays

* Parallax New ATS-501/3 50A ATS using small high current relays. But will this new design outlast the old style heavy duty relays? (TBD)

* Newer style Contactors. Will they work better? ...I'm not convinced, but in the absence of being able to find high quality Heavy Duty Relays to replace our old style ATS-5070 relay, maybe we don't have a choice?

In the last picture you will notice the Contactor on the right is Normally Open (NO)... and the Contactor on the left is is Normally Closed (NC). This configuration will allow shore power to pass without energizing the relay coils; and when the generator is started, the both coils will activate and switch to priority generator power... and back again when the generator is turned off.

Note: This wire diagram has not yet been tested in the field, and think you can solve the 70A neutral return line issue/concern by using a 4-Pole Contactor to handle the 2 neutral wire out of the Onan 7500/8000 generator. (TBD) So if anyone has any comments about the wiring diagram below, I would welcome your expertise as I am just learning more about this subject.

In the end, I still can't say which design is the most robust and cheapest. Also, paying $300 for a BRAND may or may not be your best choice. I do think you are supposed to "get what you pay for." ...But not always.

[imnprsd]

SORRY: I asked if Kinch can check the voltage to the relays, but this is impossible to do in the coach. Those relays points are located behind the faceplate and incarcerable. My mistake.

===

I'm learning that only the Onan 7500/8000 generators (that use "inverter technology") require 70A on the neutral wire, because the newer 10,000 and 12,500 Onan generators use Pure Sine Wave (PSW) technology. This basically means the 10K and 12.5K generator puts out more Watts -- at lower current -- compared to inverter technology in the 7.5K Onan. And it also means the newer generators do not stress the ATS box like the the 7.5K Onan does.

For example: The 7500 outputs 62.5A and the 8000 outputs 66.6A. But the 10000 outputs 45A. (More power, less current.)

So all us Onan 7500/8000 owners need to pay more attention to the type of ATS we use or we will be burning up the newer style ATS boxes real fast.

Why? ...The newer ATS boxes on the market are being built with lighter weight Contactor relays that CANNOT handle 70A in most cases. So if you don't see the 70A neutral being advertised on your ATS, buyer beware! ...And even then I think you need to verify this. (I.e., Marketing may still be promoting the old spec while engineering is cost reducing and changing technology, and the box is miss labeled.)

I will start a new thread on this subject soon. But now it's clear to me the type of generator you have has a lot to do with the type of ATS you need.

So all us Parallax-ATS-5070 owners should be looking for an current ATS manufacture that uses the old style (8-pin) relays; or IMO, you need to buy a Contactor type ATS rated for 100A, which very rare and very expensive.

Note: The Furrion 50A ATS below uses Contactors, but I don't think it's 70A compliant? Maybe it is? ...But another concern I have is these these Contactor ATS type boxes are no longer "Automatic." Instead, it takes a full second to switch between Generator to Shore Power.

They call his in their marketing material "Break before Make" and they make it sound like it is an advantage, but I think not.

Why? ...Contactors use lighter duty relays and cannot handle the same switching (aching/wear that occurs) compared to older style (8-Pin) heavy duty relays. So by make you wait 1 full second between Generator to Shore Power switching protects the Contactor.

The problem with "Break" as in "cutting the power" for 1 full second... before you "make" a new connection might be this: Your cable box and internet modem may get switched off and will trip the reset function. Then you have to wait 2-5 minutes for your cable box and/or modem to reconnects, which is a "deal breaker" as far as I am concerned.

Anyway, we now know you cannot just go buy a 50A-ATS if you need a 70A Neutral. Fortunately, we can still buy these lower cost ATS boxes, that still use old style (8-pin) heavy duty relays, but only while supplies las, because the entire ATS market is going to be 100% Contactor based at somepoint soon.

Note: The Parallax ATS-503 is advertising 100A Neutral capability and that sounds fantastic. I do not know if the ATS-501 rated at 50A is 70A neutral compliant, but since the OP just bought one he can tell us! But I do trust Parallax, as long as you qualify the stuff they built 1-2 years ago.

Further, if you have an ONAN 7500/8000 generator, I would very leery of buying the newer style ATS boxes that uses contactors -- until you know exactly what Hot and Neutral loads they are rated for?

This is because 50A Contactors are commonly rated 40A for resistive loads (floor heater), and 32A for inductive loads (like air conditioners, vacuums, refrigerators, microwaves, etc.)

This is also why "Load Balancing" is being talked about more and more. I.e, with lighter-duty-ATS-Contactor boxes it is more important to "load balance," because L1 & L2 are summed-up and then the total current passes back on the return Neutral Line. And if your Contactor can't handle the sum of L1 & L2 circuits on 1-wire, then there is a good chance your ATS is going to fry at some point!

Note: The Parallax ATS-503 picture below may be their old style board. IDK. ...But I do like the looks of these relays.

The Parallax 501 now uses very small relays, but maybe this is the top side of the board that uses low power relays to switch the heavy duty relays mounted underneath. I do not know! And I'm not sure it matters, but it is a radical design departure. I would call Parallax to get an explanation, but as I said, I do trust Parallax.

[imnprsd]

I forgot to point out: Parallax maybe one of the leading RV 50A ATS suppliers, IMO, but I'm not suggesting you buy one of their ATS boxes until you do your homework.

For example, we can now know our old style heavy duty (8-pin) relays are "hardwired" are being replaced in the Parallax ATS using circuit boards. And in the ATS-503 picture shown above, you can see very, very wide circuit board traces that have to carry 50 amps. Maybe more.

Personally, I'm not a fan of high current being routed through circuit boards, and especially not 120V-50A current. So maybe the board carries much lower current and voltage and the relay high voltage side is what we see on top of the board? IDK. But I would want to find out since my RV has an Onan 7500 generator it it!

It would appear Parallax did this to design-out the terminal block (look, not more terminal connections; and while that probably makes assembly costs cheaper, and profits higher, what does going to this design technology do for the RV owner that is better than the old style heavy duty relays?

Likewise, if the Parallax 501 does uses those 4 ultra-small relays you see in the picture above, I have to question the tradeoffs between cost and performance in this model they rate at 50A.

Maybe the OP can see me/us straight since he just bought a new Parallax ATS-501? OP, do you have an Onan 7500 generator? And are you sure this Parallax ATS-501 can handle 70A on the neutral line if you do own the Onan 7500 or 8000?

What I have learned is that when an ATS manufacture or ATS distributor says the ATS is rated for 50A, that this does NOT mean the relays can handle 50A on any one leg, because they never did. It implies when you sum the loads on L1 and L2 that the total return current can pass though the neutral relay.

And as discussed… the Onan 7500/8000 have particularly high current output. Therefore, there is no telling how long your new ATS will last with any of these newer style ATS boxes.

Note: All the caveats listed above pertain to ONAN 7500/8000 use that are rated 65.5A to 66.6A respectively. (See spec sheets below.)
And again, this is why it more import you find a 70A rated neutral ATS, if you do need one... and I highly recommend you confirm that you are buying 70A by looking at the inside guts of your ATS so see if there is a really large terminal block that can accept 4 wires and 1 ground from your generator, because if it cannot then it seems a certainty this is not the right ATS for you. And please don't rely on the box label to confirm the 70A rating since the label does not typically show what is inside.

My research leads me to believe it will take 2-5 years from now for all the field tests to come back positive and negative as ATS manufactures have been changing the guts inside these ATS boxes over the last 2-3 years. So for now it's buyer beware if you own an Onan 7500 or 8000 generator and you need a 70A ATS on the neutral line.

[imnprsd]

Today I talked with a senior manager and engineer at Parallax to review and compare the Parallax ATS-501 with the ATS-503, and this is what we discussed:

* 70A? ...No problem for either the 501 or 503. This is because both circuit boards offer an "Aux-Neutral" lug (and a jumper, just like the old style ATS-5070) that allows a 50A rated relay to handle INDIVIDUAL N1 and N2 wires out from the Onan 7500 generator.

FACT: 50A Service describes the way loads in the RV are split between L1 and L2 circuit breakers inside the Main Circuit Panel. I.e., all the individual circuit breakers on a line circuit (L1 or L2) get combined and the wiring inside the RV, as they do in any panel box, and in then there are two 50A main circuit breakers to protect the line wires.

FACT: Our Onan 7500 calls for a 70A neutral, but the generator really provides two 35A breakers to protect two neutral wires. So each wire will not carry more than 35A or the Onan circuit breaker will trip. That said, the ATS you buy needs to support 2 generator neutral wires (35A each) and you can't do this if you join the wires together on one relay contact (or pole). And as you can see from the diagram below, the Parallax ATS-501 and ATS-503 circuit board offer an "AUX" neutral lug.

FACT: Despite the size difference of the 501 relays compared to the 503 relays, both offer 8-pin relay connectivity and each contact is rated for 50A.

Parallax told me the future ATS designs will be using smaller relays, because they are smaller and less expensive to assemble on a circuit board. However, in terms of being more robust, and more reliable in harsh environments, it's too early to know if the 501 will last as long as the 503.

What is clear is that the average RV owner does not use there generator that often compared to other industries; so maybe the average RV owner can make do with the ATS-501 and like paying the lower price vs the 503?

ATS VENDOR OPTIONS

* I still have not uncovered a good reason why an RV owner would be better off buying a Contactor type ATS? Further, I also am pretty sure these older style (8-pin) heavy duty relays are more durable than the newer relays, even from Parallax.

* Parallax has dominated the RV ATS market for decades, and they know there are tons of ATS-5070 boxes in the field that will need to be replaced someday. So Parallax designed their newer 501 and 503 boxes with all wires on once side to keep their market share. I.e., if you go to another Vendor's ATS design you might find the box is larger and the knockout holes are on multiple sides... making it more difficult to replace an ATS-5070. (TBD) This might really depend on the amount of room you have in your electrical bay, because my in my 2004 Itasca Horizon I have an electrical cord real just below the ATS and there is not much room in that area.

* The Paralax 501 & 503 use electrical switching to prevent both generator and shore power relays from coming on at the same time. And just as important switching only takes milliseconds.

* Other ATS that use mechanical or interlocking Contactors will try to sell you on their "Break Before Make" feature, but translated that means it will take 1-2 seconds to switch power. And for me, I would not prefer that.

* In general, I think we can assume a 50A ATS box is build with heavier duty relays or Contactors inside vs. a 30A box. So if you are wondering if you can buy a 100A ATS to buy more reliability and longevity, the answer is, "May be someday." Right now 100A contactors with 120V coils are practically nonexistent or cost prohibitive, but this maybe possible in the future.

Note: The smaller ATS-501 relays can be wave-soldered directly to the circuit board. However, it is also true Parallax sells the beefier ATS-503 (for more money) and these relays screw on to the circuit board, which frankly I don't like very much either in high vibration environments, but obviously Parallax has tested them to be reliable.

* If you have an Onan 7500 or 8000 then whatever ATS you buy needs an "Aux-Neutral" so you ATS relays can handle separate N1 and N2 current out of the generator. Note: You could tie both neutrals together, but then your ATS may fry under heavy L1 and L2 circuit loads at the same time. Or not, if you don't use much power at the same time.

* A number of people say their ATS has caught on fire, but it is unclear what all the variables are? It could also be that Parallax stopped making the ATS-5070, because all those 8-pin relays had 8 screws, and are difficult to assemble, and over time those screws can come lose. ...And we all know what happens when a high current connection is lose! So is that why Parallax redesigned the ATS-5070 came out with the 501 & 503 or was it driven by competition and profits?

* Can you repair your old ATS-5070. Well, now I do think it's possible since I have shown you what all your components you need, but is it practical if you can still buy a competitor old syle ATS, with a 70A Neutral rating for less than the cost to overhaul your ATS-5070?

... Just make sure you find one with a large terminal block that has a "AUX" neutral port and one tip I can give you is to look for blue wires and neutral jumpers which are needed to to comply with the Onan 7500 generator, 70A neutral demands.

[imnprsd]

My research on this subject suggests ALL the ATS manufactures are now building their ATS boxes using less expensive components and Contactors vs. the old stand by 8-pin heavy duty relays.

...And now I just learned we may not be able to order/buy an "old style" ATS as you can see in the pictures below.

Specifically, I just ordered an Arterra "WFCO" brand T-57 ATS, but what I received in the mail was a T-57R, and this is NOT the same box inside!

The problem(s) I have are that this new Arterra T-57R does NOT offer a "AUX" connection to accept my Onan generator second neutral return wire. So this mean this T-57R does not support a "70A neutral" even though their marketing material say it does. ...And I did not like the quality of the heavy duty relay they used in this box.

So how can this happen? ...Simple. Arterra engineering redesigned the box, but marketing did not take down the old T-57 ATS picture and replace it with the new T-57R picture.

* To clarify, a 70A neutral means the Onan 7500/8000 uses 2-35A neutral wires that pass 35A through each relay pole. And since your relay is rated at 50A you will be okay. ...However, if you join these 2 generator neutral wires together and connect 2-35A wires to one terminal rated at 50A, then you are asking for trouble when you loads on both L1 & L2 exceed your Contactor's rated current spec, because whatever you put on both L1 & L2 gets returned though the neutral wire and this is why neutral wires are thicker gauge than the "hot" wires.

Speaking of Contactor ratings, many of these parts cannot pass a full 50A thru a pole for very long. And I think if you research this you will find, for example, a 63A rated Contactor is really rated for 40A-resistive loads, and 32A-inductive loads.

And since most of our electricity is "inductive" this situation could occur:

==> Your 50A main circuit breakers will not trip unless you exceed 50A, right! ...But if your ATS-Contactor-Relay will fry above 32A, if you run it that way for very long, then it's your new ATS contactor that is protecting your circuit and not your 50A breaker.

Now I know many of you will say you have never seen your power panel display more than 30A with your basement AC running and you TV on and your residential refrigerator running. ...I get it. ...But that's under "normal" conditions. ...The more important questions is this: Under non-normal conditions, what do you think will happen first? A) Will your circuit breakers trip; or B) Will your ATS fry? ...And all I know is that there are more and more RV owners complaining about their ATS failing and or burning terminal blocks.

==> Therefore, I now consider my ATS part of my 7-year service. And by that I mean, if your ATS is 7-years old or more, then I think you might want to take it out of your RV and inspect it... and tighten all those 8-pin relay screws... to avoid an early ATS-5070 failure.

SO WHAT DO US ONAN 7500 OWNERS DO WHEN IT COMES TO SERVICING OUR ATS-5070?

If you use an ATS-5070, which probably means you need a 70A neutral (2-35A neutral wires) to support your Onan 7500W generator, then I see 2 good options when it comes to fixing an ATS problem:

* Go with Parallax ATS-501 or ATS-503 to replace your ATS-5070.
or
* Service your old ATS-5070.

ATS-5070 SERVICE

Now that I have seen how these ATS boxes are built. It's really quite simple inside. And once you take your ATS-5070 out of your rig and put it on the bench you will see how easy it is to:

A) File the contact points as needed.

B) Replace the bridge rectifier with a RS207L if needed and only $7.

C) Replace the delay timer (ICM102 or TD-69) if needed and only $10. Note: You will need to modify 2 wire connections since the old delay timer has a different footprint compared to the ICM102 or TD-69.

D) Replace the hot & neutral relays. Note: Finding quality built 50A heavy duty 8-pin relays may be a concern.

Note: Those Deltrol Controls 900QR "hot relay" and the Deltrol Controls 900QR-1C "neutral relay" relays look like high quality relays, but they are more expensive can cost ~$110 for the pair. So if anyone finds a cheaper source than going thru an Electrical Distributor that pump-up the cost, please let us know.

Alternatively: If you can find/buy an old style T-57 or even an old style ESCO/Elkahart #LPT50BRD then these ATS boxes probably support a 70A neutral, but I don't think you can.

Instead most of these ATS suppliers I researched have already cost-reduced their ATS boxes and are no longer using heavy duty relays, but they keep shipping under the old part number(s), and some may claim they support a 70A neutral, when I don't think they do.

TIP TO KNOW IF YOUR ATS SUPPORTS 70A NEUTRAL? ==> If you don't see an "AUX" terminal connections, and if you don't see blue wires and jumpers used inside, then IMO I would not trust their marketing as shown on Amazon or at some RV parts houses.

[imnprsd]

Apparently, all us Onan 7500/8000 owners need a 70A neutral ATS-capable box to switch from shore power to generator power and back again.

The 70A is provided on the generator side and this is accomplished by Stator-Rotor-Circuit that passes 35A on each of the 2 generator neutral wires, which are labeled "AUX" on the terminal strip.

The problem is that he contacts inside the Heavy Duty Relay only handle 50A each, but by splitting the neutral wires between two poles the 35A on each line (N1 & N2) will work with 8-pin relays.

The other problem using Contactors is that these parts can be rated for 50A but, but really only pass 32A when conducting inductor loads and 40A when conducting resistive loads. So this type of relay switch is very borderline under normal RV loads and not a good idea at all if you tie the 2 neutral wires together at the terminal strip. SO WATCHOUT FOR ATS BOXES THAT DO NOT OFFER YOU AN "AUX" PORT.

Note: Old style ATS boxes that do offer an "AUX" port will use blue wires that connect to the heavy duty 8-pin relays. However, in most cases these blue wires do not exist in newer ATS configurations that use lighter duty contactors. So if you need 70A-neutral... I would not buy these type of ATS boxes.

SUMMARY

* The Parallax ATS-501 and ATS-503 will accommodate a 70A neutral. However, Parallax is using low quality relays so there is no telling what the long term reliability may be. These are selling today in the $300 -$450 range.

* Other 50A-ATS manufactures no longer provide an "Aux" terminal connection, and they are using $15 cheap relays inside or lighter duty contactors that is very problematic for us Onan 7500/8000 owners.

These ATS boxes maybe fine for 30A, but not for us 50A users. However, these ATS boxes are much cheaper ($125-$175).

Note: I also found that some of these suppliers still claim they support 70A neutral, but I don't see how that is possible based the guts inside one type of ATS box I ordered and returned... which may also explain why many RV owners are blowing-up their ATS within 1-2 years.

* The last, best, and cheapest way to go, IMO, is to replace the 8-pin Heavy Duty Relays and Bridge Rectifier inside your Parallax ATS-5070. ...And hopefully these Deltrol Controls Heavy Duty (8-pin) Relays are the right part to give you another 15 years of reliable switching life:

RELAY CROSS REFERENCE

* There is a cross to Magnecraft/Schneider Electric which also appears to be a very good quality relay, but these are harder to find in low quantities. ...If you find a source please let us know.

Disclaimer: I have not yet been able to this information, because I don't retrieve my RV from storage for another couple months. So, if anyone decides to order these relays, please let us know how easy or hard it is to overhaul your existing Parallax ATS-5070.

[Kinch]

Thanks gor the info.
Still working on installing the ATS 501
Will let you know how it works.
Here is a photo of ATS 5070 with wires marked to match ATS501.

[imnprsd]

Kinch: Thanks for clearly sharing your Onan terminal connections to your old ATS-5070.

...And us Onan 7500/8000 owners need to pay attention to the two neutral wires coming in from the Onan 7500/8000.

In addition, the size of the terminal connectors (2-6 lug terminals, 12 total) also shows the "Aux" connections and "blue wires" needed for the Onan 7500 two neutral wires which carry 35A each or 70A total.

...And if you look at newer ATS boxes for sale, most no longer offer this long terminal block - meaning there is no "Aux" connections; and I'm saying this would be bad for us Onan 7500/8000 owners, because you don't want to twist those two generator neutral wires together which would put a possible 70A on 1 connection... the relay can't handle... and will burn out when overloaded for too long. ...Also the relay contacts will have bigger arks with more current going through them and that will shorten the relay life... if the terminal block or wires don't burn up first.

===

When you get a chance to take apart your old ATS-5070, can you let us know what type of 8-pin Heavy Duty Relays are installed? This will be very helpful.

...And can you tell what failed inside this old unit? ...I'm guessing it is the Neutral Relay that burned, but that's just a guess. The neutral relay is the one with the extra micro-switch on the end. Alternatively, I wonder if the diodes in the Full Bridge Rectifier failed and it's the diodes that are the weak link?

...Or maybe the relay contacts in your old ATS-5070 were shot?

Anyway, when you open up you old box, please let us know what part numbers you find in there. Thanks!

These are the part numbers I have so far for those who decide to overhaul their old ATS-5070. However, these need to be verified:

Hot Relay Deltrol Conrols #900QR (or 21080-84)
Neutral Relay Deltrol Controls # 900QR-1C DPDT (or 21082-84)
Bridge Rectifier Rectron #RS207L
Delay Timer ICM #ICM102 (This ICM102 is not the same footprint but should work.)
Terminal Block Brand and part number???

[imnprsd]

Another owner reported he had trouble with his circuit breakers after changing out the ATS.

He said this condition went away when he rearranged the wires in the ATS; and while he was not really clear as to what he meant, I suspect it had to do with the 2 Onan Generator neutral wires.

So I would come up with a left and right side wire number system to make the swap-out error free. See ATS-5070 pictures below.

Note: When you swap to a ATS-501 or ATS-503 there will be a different footprint.

[Kinch]

That’s good info. I bought a white fine point paint pen to mark all wire prior to removing to old ATS and installing the new. Also plan on swapping the Generator side first.
I appreciate your expertise. Will keep you posted.

[imnprsd]

Yeah... Your diagram you come up with is going to be different since you will be installing a ATS-501/503. (Both have the same footprint that is different than the ATS-5070.)

I'm sure you have instructions from Parallax in the 501 box you received, but I wonder how easy it will be to wire up?

When I contacted Parallax they sent me the terminal connections below, but they labeled the terminals with the box oriented different than how you will be installing it in your RV.

So I turned the picture 180-degrees to represent all our RV power wire coming in from Right-To-Left... and that's why the Parallax ATS-501 labels are all upside down.

Note 1: I also think the Parallax team also left out the Onan 7500 second neutral generator wire -- so you will need to verify the "Aux-1" connections and "Aux-2" neutral wire connections for the generator.

==> For those of you who want to edit pictures, this is how I do it: I use MS-Paint to edit these drawings; and a picture capture freeware program called Gadwin. I also like Gadwin's old version (4.6) better than the newer version, because it is simpler to use. And once you learn the basics you can do a lot with these 2 pieces of software.

You can download Gadwin 4.6 here for a PC and I don't think they support Apple: https://gadwin-printscreen.soft32.com/old-version/

...Or you can just print out the picture below and hand draw your Diagram if this helps? I have no idea how good the Parallax instructions are?

Please keep us posted of you final product, and thank you for sharing with me your old ATS-5070 part numbers, because I will be tearing into my 5070 in May/June when I pickup my RV from storage, and I would like to overhaul my box with new relays and possibly a new Full Bridge Rectifier. (TBD)

[imnprsd]

I forgot to mention you also need to verify:

Shore Power L1 = Red ...or Black?
Shore Power L2 = Black... or Red?

Generator Power L1 = Red... or Black?
Generator Power L2 = Black... or Red?

IDK. ...You would think you can confirm this by looking at your main circuit panel, but when I trace mine I get conflicting information. So you need to do some line testing before you start taking things apart.

...And I would take pictures of your OEM circuitry before you start so you can refer to this if you need to later.

Note: The pictures below are from my 2004 Itasca Horizon 40AD, and I hope I have labeled Circuit #1 (Red) and Circuit #2 (Black) correct. So, if anyone knows I made a mistake, please let us all know.

...because my ATS shows L1/C1 is Black and L2/C2 is Red if I follow conventional labels on ATS terminals.

Truth is... it's just a wire and Winnebago can use either for L1 or L2. So I would check your shore power cord and work back to the circuit panel from there.

[imnprsd]

This terminal block is out of an old style T-57 which shows where the blue-neutral wires and bonding points are made. It also clearly shows how a ATS-5070 should be wired to an Onan 7500/8000 generator.

Note: The wires are numbered for easy identification an order which I recommend before you take your ATS box out of the RV so you can reinstall it without making a wiring mistake.

Note: The newer T57R transfer switches use different components. So I wouldn't buy this ATS if you have an Onan 7500/8000 and need a 70A neutral, which is really two 35A neutral wires connected to the "Aux" terminals... and then the blue wires go to the heavy duty 8-pin relays located behind the panel.

Labels: You can make your own with masking tape numbered 1-10 or for $6 you can order these on Amazon:

https://www.amazon.com/gp/product/B0...PWAZR0IB&psc=1

Alternatively, if you can find an old Elkhart LPT50BRD Automatic Transfer Switch that uses the old style 8-Pin Heavy Duty Relays by Deltrol Controls on Magnecraft, for less than $180, I would buy one of those.

So if you don't see blue wires being used, and you don't see a 12-terminal connector, I wouldn't buy it if you have an Onan 7500 or 8000. And don't believe the picture on the box. You need to verify the guts inside before you rely on a part number match in order to get the heavy duty relays inside.

[SmilingSimon]

a couple of things, where would 120vdc come from? that is scary thought - dc kills humans very easily, and btw generally ALL electronics are DC powered internally but low voltages - ~12v-15v is typically all that is ever needed !!?


and sure 120vac is all around - but never heard of an 'ac' voltage to turn off/on a relay - 'rectified 120v, reduced to 12vdc, sure' NOT 120vac unless something very funky.


by nature a relay is either Operated (on) or NOT (off), and it could be either NC normally closed contacts OR NO normally open contacts - which your need depends upon your elec design/purposes.


a 'latching' relay makes most sense in a auto-switch instance, you 'operate' the relay it changes from NO to NC or connection is made, then de-energizes and relay is latched but 'off' - ie is NOT using any voltage in relay and will not heat up/burn out - much mo reliable.


btw, my old mh had large latching relays for both house and chassis battery disconnect used when in storage, could hear a big thunk when switched on or off - a large bar of steel ~3" wide would either contact or be disconnected - the thunk was an up/down movement - otherwise no energy to that switch was used - powered directly from chassis battery - only when 'operated'.



so unless some surprising design, most/all 'normal' relays would open and close constantly if fed by 120vac, as well as 120volts of either dc or ac seems WAY too high to just energize a small electro-magnetic 'switch' as is used in relays in AS - ie the armature of a relay. (of course pure semi-conductor 'relays' exist too - just relays are cheap and reliable)



the whole concept/use of a relay is to use a small voltage (usually 12vdc or less) to switch a larger volt/amp voltage/current via robust strong contacts resistant to arching which can happen for larger voltages - arching destroys contacts - it is essentially welding, but not good kind.


so a typ AS would OPEN the shore voltage-zero volts, wait a second, then close the GEN voltage-120/240vac, then connect to the house circuit wiring-provide voltage for normal use. generally generators have to stabilize first before using their power.



all above using 3 relays or more, thus most will have some timing between opening and closing of the diff circuits, thus need for a small amt of electronics - delays - all for safety.


but of course ALL this could be COMPLETELY manual, a break-make 2/3 (on/off/on) position switch with output going to house wiring - OR just a 30/50amp PLUG & socket, socket for house PLUG for gen or shore elec source !!!!


ps: everything does not have to be AUTO, auto things make/keep you stupid, push button, done except when it does NOT DO ! now what ?

Originally Posted by imnprsd

Kinch: On your existing (OEM) ATS-5070, can you check the voltage to the relay coils before you pull it out? I'm unclear if these are 120Vac or 120Vdc or something else?

Note: If you don't have shore power you will need to start your generator to check the voltage.

And if it's not too much trouble? Can you take a picture of the AST-5070 relay markings, if any? This will be of great help to many of us!

Thank you!

[imnprsd]

SmilingSimon: 120V contactors have 120Vac coils. However, in RV ATS there is a bridge rectifier used to change 120Vac into 120Vdc. I understand this reduces "chatter" and extends the life of the relay contact points.

As for a latching BDS this is not the subject of this thread. The subject has to doe with ATS problems and rebuild.

But since you brought it up, the BDS and Boost solenoid calls for 12V to the coil. However, when you are driving, what voltage you get has a lot to do with how much voltage your alternator is putting out to the engine battery and if your alternator is joined to your house batteries, via a battery isolator or VSR, then the voltage you can see at the coil on these solenoids can be 14.2V.

So one forum member (Cbeierl) explains, on the Boost Solenoid only, he added two 1-ohm resistors in series to drop the voltage by -2V; and apparently this extends the life of the Boost Solenoid. Consequently, I'm thinking about doing that myself this summer.

I also plan to add a reverse bias 1N4007 Diode to the BDS and Boost to protect the switch on the dash.

Note: The solenoid with the reverse biased diode is just an example, and is used for boost or BDS in my RV, but it does show you how to connect a diode.