Generator not connccting to power coach

[Morich]

Isn't shopping fun???

I did a check of the Paralaxx site here:
https://parallaxpower.com/product-category/transfer-switches/

On that site, I do not see a 501 BP. so is it possible there is a unit made for Winnebago that is only for them but not in general use?
I do find there are some larger companies who do have items with specific model numbers which can only be found at the specific company. One is appliances at Lowe's or Home Depot and I find the model number to be slightly different but the item is the same! Wal-mart sells TV which have a different number than any other seller but the TV is the same.
I might try calling Paralaxx and ask what they think is correct for replacing what you have.
I find no info on the 501BP.
Perhaps the BP only stands for better profit????

Sorry, couldn't help myself!

SORRY! Slow typing!

 

[Kinch-WO]

I talked with them.
Check thread above.
They recommended 501 for ease of installation.
503 is bigger and heavier duty.
Harder to install.

 

[imnprsd]

Kinch: You are confirming the 501 is for 50A applications? And does it have 3 cutouts for the conduits to screw into one side?

OTHER QUESTONS REGARDING YOUR OLD ATS-5070:

* Is there a way to file points in the old relay? ...Do you have access? ...People talk about doing this, but maybe they have different relays than what comes in the ATS-5070?

* Are those relays revitted to a backing plate?

Many of us have not yet faced this problem, but it would be nice to know a file job will work when camping so you can tend to a more permanent fix when you get home.

* Is there any second source to replace the each relay?

The only information I have is this, and I can't find any second sources. I think you would have to take the relay to a power supply store and get it matched up.

Hot Relay Part #: 20005900-44

Neutral Relay Part #: 20005800-44

The schematic does show a bridge rectifier and a timer, but I think these are compatible with high voltage. And I don't think the ATS uses any 12V parts nor does it step down the voltage inside, but maybe I'm incorrect? (See data sheet for bridge rectifier attached to this post.)


Parts List to rebuild ATS-5070, but I have yet to confirm where to buy these parts and I do not know if these are proprietary parts used by Paralax in some cases... as maybe the case with these two relays. I.e., matching like-part-function is one thing, but finding the same "footprint" could be another? ...So you might have drill a few new hole if you find a compatible part with a different foot print. Right now it would be nice to know if you can rebuild an old ATS-5070 and you can't expect any help from Parallax who only wants to sell you a new 501 or 503!

OLD ATS-5070 Part Number List

Hot Relay #20005900-44

Neutral Relay #20005800-44

Time Delay #ICM102

Bridge Rectifier Assembly #081-5070-002-44

Terminal Block #031-0030-001-44

Slave Lockout Micro Switch #???

 

[Kinch-WO]

The manufacturer Parallax and Winnebago both referred me to ATS 501. It was the original replacement for the ATS 5070.
The 503 is a heavy duty version of 501 according to Parallax. It also requires some modifications as it is larger than the 5070 and the 501. Per Parallax.
Haven’t opened up the 5070. Will let you know about filing the points as a rescue.
Parallax does not make parts for 5070 anc I couldn’t find anything searching on line.

Decided to replace 5070 and be done with it. Two year warranty if purchased from Parallax dealer. Boat and RV hsvevssme price as Amazon and are dealers. Free shipping as well. Parallax also has a very good technical group to help with questions and installation
Will get into 5070 once 501 arrives.
Thank you all for uou knowledge and help.

 

[imnprsd]

Kinch: Thanks for keeping us posted after you remove your old ATS-5071 to let us know how it's constructed; and if you can even access those relay points to file flat.

Here's a new subject: I had a funny ATS concern this last summer and my Onan 7500 Quiet Diesel was putting out a Fault Code #46, but my AC functioned normally... but a tad on the low voltage side.

I took it to 2 Onan authorized shops and both said the only way to fix a Fault Code #46, so long as you have good house batteries, and a good ground, is to replace the Onan Inverter board at a tune of $2000 plus labor.

Well, there was no way I was going to spend $2,500+ if my AC was working; so I just decided to let time present some additional symptoms.

Then I went about changing the Onan coolant and while doing that service... I realized I was running my generator while still being plugged in to 50A shore power.

Okay... no big deal, the generator gets priority power over shore power anyway, but for some reason I decided to pull the shore power cord while the generator was running... and the Onan died.

Humm, I thought.

I promptly started the generator and completed my coolant service... and then I decided to check for fault codes again. ...And this time no more Fault Code #46!!! ...And after weeks of running the generator, that FC#46 has not reappeared.

* So now I'm wondering if you were operating your RV generator while on shore power?

* And I am wondering if you have any fault codes registering in your Onan system?

Note: I'm just fishing here, but wouldn't be something if you have a stuck Neutral Rely in your ATS-5070 and this is a known bug you can fix by pulling the shore power cord while your generator is running? ...After all, why did Parallax redesign this part after so many years of service?

...Which may mean there is nothing wrong with your ATS "as-is?"

 

[Kinch-WO]

Very interesting.
I try to never operate Generator when plugged to shore power. To me it just creates potential conflicts.

No fault codes on any of my systems as of now.
I can’t guess why Parallax changed ATS’s.
Maybe some young genius convinced them change was good. Lol!
I’ll keep you posted when I tear into the 5070. Should be fun...

 

[imnprsd]

Yes... Very interesting. And what have you got to lose?

I'm suggesting you plug in to shore power (preferably 50A, but I don't know if that matters); and then you start your Generator and check for power inside your coach... If all is normal and you are now running on generator-priority-power...

...Then pull your shore power plug and see if that kills your Onan, like it did mine?

Then plug into shore power with the generator off... normally... and try not running your generator while you are plugged into shore power... and see if all is good and fine with your ATS.

Maybe you don't need a new ATS-501 or 503?

Note: My 2004 Itasca "Horizon" 40AD has a 17 year old ATS-5070 and it's working fine after 110,000 miles. There are thousands of these ATS-5070s still in service. So if there is a way to repair these, inquiring minds would like to know how! So thank you for helping us with this objective even if you decide to buy a new ATS-501.

 

[jerichorick]

The manufacturer Parallax and Winnebago both referred me to ATS 501. It was the original replacement for the ATS 5070.
The 503 is a heavy duty version of 501 according to Parallax. It also requires some modifications as it is larger than the 5070 and the 501. Per Parallax.
Haven’t opened up the 5070. Will let you know about filing the points as a rescue.
Parallax does not make parts for 5070 anc I couldn’t find anything searching on line.

Decided to replace 5070 and be done with it. Two year warranty if purchased from Parallax dealer. Boat and RV hsvevssme price as Amazon and are dealers. Free shipping as well. Parallax also has a very good technical group to help with questions and installation
Will get into 5070 once 501 arrives.
Thank you all for uou knowledge and help.

I don't recall what your coach year is. Do you have surge protection? If not, consider this option: https://smile.amazon.com/Technology...ld=1&keywords=TRC+41260&qid=1612660582&sr=8-2
An all in one may not always be the best way to go but it's a thought to ponder.


I didn't see your testing results. Might have skipped over it. Do you have generator power in the ATS when the generator is running? I ask because it seems like a wast of time to change the ATS if gen power is not getting to it.

 

[imnprsd]

Right. I think the OP needs to be sure before spending big bucks on a new ATS.

Since an ATS-5070 will work for 10+ years and 100+K miles, I would consider it a very stable device until she blows. So if there is an intermittent problem (not caused by a loose wire) then maybe you should make sure those Onan fuses hidden where your Onan radiator cap is located are not rusty or something else is causing your voltage to go in and out?

I mention one odd thing I found related a sticking ATS-Neutral-Relay that was cause a grounding (bonded-ground-to-neutral) problem with my Onan Inverter Board... and still think you should simulate this condition just to confirm you too do not have a sticking ATS-5070 relay.

jerichorick brings up the need to double-verify your assumptions it's a bad ATS-5070. ...Or did you say you banged the AST-5070 with a hammer and then your 120V started working again?

IMHO... somehow I think you have to simulate and verify the problem before you go spend some big bucks on an ATS that you need to rework and remount.

For example, if someone wiggles those Onan fuse wires (located by the Onan radiator cap) while another person in in the coach is watching the AC voltmeter plugged into a wall socket... and then you lose your 120V for just a split second... then you know you have a trouble spot.
(And there are other ways to verify a 120V glitch.)

Maybe one of those Onan fuses are rusty?

 

[Morich]

While I do like theory and I do like testing, I think you have gotten to a point where actual looking will tell you more and it will likely be a definite answer!
You know the look of burned points on a car, right? And you can see it!
Most of us know the "look" of dropping a wire fused at 15 amp on something? We can see it!
So if you have a 50 amp circuit arcing, what do you expect?
I'm thinking pulling the cover will tell you a lot about whether the points on the relay are arcing!!!
You may also be able to smell the results!
I've stolen this snip from the video I posted about changing the ATS.
If you find this in your ATS, stop testing!

 

[imnprsd]

If you do have to replace your 50A ATS, here's a$185 ATS designed for 50A RVs that is a lot less expensive than Parallax's ATS-501 and 503.

https://www.amazon.com/Elkhart-LPT5...f5066&pd_rd_wg=X89KU&pd_rd_i=B007HS0ONG&psc=1

==> And all 3 conduit knockout ports are on one side!

==> And the size of the box looks more like the ATS-5070 you have now. (TBD)

==> The specs on the Elkhart 50A ATS (By Todd Engineering) are as follows:

Elkhart 50A Specifications

Contactors General Purpose DPDT 50 amp Relays
Coil 110 VDC 2 watts
70A Neutral
Time Delay Custom time delay, 30 seconds nominal can bypass for instant switching.
Knockouts Assorted

==> And FYI, all the 120V-DPDT-50A Relays I have found are in the $50-$100 range EACH. So I'm guessing there is no cost effective way to rebuild an old ATS-5070; and acquiring these heavy duty electrical components is more difficult.

* I wonder if the Parallax ATS-5070 uses 30A or 50A relays?

...Because technically I don't think there are any loads in the RV that use more than 30A on any one line. (Note: There are 2 lines on a 50A service.)

...And from what I can tell, it's those "blue" wires in the schematic and diagram (shown above) that allow the Parallax ATS-5070 to utilize 70A on the neutral line. Consequently, this maybe why the Neutral-Relay in the ATS-5070 sticks or fails first, becuase it's the neutral return wire that has to support L1 & L2 return power. (Just a guess.) Maybe this is why Parallax discontinued the ATS-5070?
I.e., the went to 50A relays in newer models. (Again... this is just speculation.)

Consequently, this Elkhart ATS look pretty attractive and there are a number of positive ratings from other people who have used this device.

==== $25 Mini 100A/120VAC ATS ===

What is a Mini ATS and is this a viable option? ...It is an option, then why can't you just gut your old ATS-5070, keep the box, and put this Mini-ATS inside for just $25! Seriously? ...Plus there is an optional selector switch and you can switch to "auto".

https://www.amazon.com/Automatic-Tr...0bcd71&pd_rd_wg=Xwl2h&pd_rd_i=B07RQVDJ71&th=1

 

[imnprsd]

Apparently this Elkhart ATS is also sold by Esco and Lyght too, but they all use the same Part# LPT50BRD. I also saw a reference to "Todd Engineering" but I can't say for sure who designed this 50A ATS or where they get there components/relays? The size of this box is: Size 8.5" x 8.5" x 4.5".

$185 on Amazon: https://www.amazon.com/Elkhart-LPT5...f5066&pd_rd_wg=X89KU&pd_rd_i=B007HS0ONG&psc=1

Fortunately, the ESCO-Elkhart folks published a parts list for their 50A ATS and that list appears below. These relays (Hot & Neutral) are mad by Deltrol Controls and both are a 900 Series type. ...And I'm guessing Deltrol Controls has these DPDT relays made in in china, but that's just a guess.

Esco also published an ATS Troubleshooting manual and I have attached it below as well. There is some helpful information in these attached documents if you want to know how an ATS works.

However, if you are more interested in just finding a second source relay to replace the "Hot Relay" and "Neutral Relay" in your Parallax ATS-5070 then maybe these Deltrol Controls Relays (DCR) will work and work safely. (IDK. I'm just proposing possible sources to buy a replacement relay.)

==> Until someone can verify the above DCR will work in an ATS-5070, you need to proceed with caution!

Deltrol Control Relays (DCR) Part Numbers

Hot Relay Elkhart Part# 21080-84 made by Deltrol Controls #900QR

Neutral Relay Elkhart Part# 21082-84 made by Deltrol Controls #900QR-1C

NOTES:

* Are both these DCR 900 series relays are a DPDT type?

* What is the difference between a 900QR and a 900QR-1C? (See schematics and note that current must first pass through the Neutral Relay before the Hot Relay will work.)

See attached data sheets for more DCR information.

Also, I attached some owner/customer feedback by those who used this LPT50BRD to replace their 50A ATS... and all seem to be happy with their decision.

 

[imnprsd]

Below is an updated schematic for a Parallax ATS-5070. (Just double-click on the picture to enlarge.)

Notice the Neutral Relay has a "micro switch" and the Hot Relay does not. ...Other than that, both relays appear to be of the DPDT type.

Can someone explain the purpose of the micro switch?

Also, I saw a note that the MOV protection diode may or may not be present. It is there to protect against power spikes, presumably to protect that bridge rectifier.

===

In my particular situation, I believe my Neutral Relay may have points that are sticking. I think if I can file them that I may be able to extend the life of my Parallax ATS-5070 by a few years, but there is also the chance that when you file the points down the contacts will get hotter and will fail. This bothers me since I have seen pictures of burned-ATS-Boxes and I want to avoid that at all costs!

Fortunately, we are talking about neutral line switching.

Unfortunately, my Onan Quiet Diesel 7500 Generator has an inverter inside it and any power spike to the system may find it's ways back to my Onan Inverter and cause a $2,500 repair. So to avoid this, I'm in favor of replacing the Neutral Relay and the Hot Relay.

I also have no desire to spend $300+ on a new Parallax 501 I have to rewire; or $400+ for the heavier duty Parallax 503 with the proper 3 conduit holes on the side I need for my 50A service, because it's too expensive for the repair we are trying to make by just replacing a simple two DPDT relays that should only cost $30 each in my opinion.

I like that there is a Esco-Elkhart-Lyght ATS available for $185 on Amazon. (Part # LPT50BRD, but I also think there is a cheaper solution out there we can come up with by picking up a few relays from Deltrol Controls Relys and using those. (TBD)

I'm also guessing Deltrol Controls buys these from China and then resells them through their distributors who have to make there "keystone profit margins."

===

The OP will let us know how he handles his ATS repair. I will not be picking up my coach until May-2021 so you can't count on me to get back to your before June/July.

So hopefully more people will let us know how they avoided this very costly upgrade to a newer Parallax ATS-501/503, because I'm sure there is a solution out there.

And again, I would like to keep my Parallax ATS-5070 box and just replace the relays for less than $60-$80 if I can possible find a way.

On the other hand, I may just spend $185 can go that route since the LPT50BRD looks like a direct replacement for my ATS-5070. (TBD)

 

[Morich]

Okay, time for a wild guess as I am pressing hard over into engineer/ design work that is NOT my thing! I kind of see what they are doing and some of it makes sense but then some is not clear at all. So this is what I "think" I see rather than saying it IS TRue!!!

First pic is what I see as we are plugged in and Ac is fed pretty much straight through on normally closed transfer contacts. L1 and L2 both in and through to the load.

Second is more complex as it has several things going on at near the same time.

Pic at right is when we have the cord disconnected but the generator started. The generator power comes in straight to the relay but at that time and that point, the relay is open and still connected to the feed from the shore power!
The genset gets time to settle and begin to produce steady AC power but not loaded at this time! Good for starting!

But the lower picture has the more complex deal shown. When AC power shows on L1 and neutral, the circuits for the rectifier are complete as the green arrows. As the bridge rectifier gets powered, it begins to "make" DC from the AC and pass it on along the blue line to the time delay circuit. This DC current goes down through the time delay circuit until it times out and closes the time delay contacts! Once those contacts are closed, the path (blue line)becomes clear for the DC current to flow to the neutral relay which will then operate and close the path to transfer the neutral portion of the genset AC.

But if we have the "lockout micro switch" open, the main L1/L2 lines are not transferred! The red lines and blue lines are connected together full time and when we close the switch, power then will flow to the main transfer relay coil along the red line and the full transfer is completed.

WHY do they have a lockout on the transfer switch?? Unknown to me why we would not want it to transfer if we do already have a time delay for the generator start up!!!???
Why do we build a transfer and put a switch on it to keep it from working???
Sorry, never did understand the why of lots of engineers work!

But this is fully known to be a "best guess" on things I do not understand! Approach with caution!

Whether it is worth filing the contacts will depend on how burned they may be. If looking at the new relay, the contacts are shown fairly well as small like 1/ 16 high by 1/8 inch wide contacts which makes them big enough to be able to get in and file them much like older points on a car ignition. The new relay and contacts wound up as last picture but if you find the relay looks more like the first relay and not only the contacts but the wires and insulation around them is also burned, that's not a good time to try to reclaim them as the coils and lots of little details may also be degraded.

 

[imnprsd]

Morich: Thank you for explaining some principles to me. I took another look at this ATS-5070 schematic and would like you to review and correct my findings as needed. These your findings really, with more color added by me.

50A ATS FUNTTIONS:

* These relay coils require 12v to operate.

* It does not matter which direction you energize a relay low voltage coil. I.e., it is enough to accept what when you power-on a relay coil with low voltage, in either direction, the relay will operate and pass high voltage to the load.

* That Timer is key to the coil switching. I.e., for as long as the timer is "open"... no current can flow to both the Neutral Relay Coil and no current will flow the the Hot Relay Coil. So no relay switching will occur until that Timer "closes" the circuit.

* The "slave" in this design is the generator for as long as the timer is open, but then the generator turns in the "master" when the Timer "closes" the circuit

* The timer is Normally Open (N.O.) and will not close until the bridge rectifier is powered on by the Generator.

* Once you start the generator, and the bridge rectifier passes 12V to the Timer, but there is no load placed on the generator for a short period of time to give the generator time to settle and warm up. During this start-up phase the Timer remains as an "open circuit."

* Once the Timer is "closed" the Generator Circuit is now the "Master" and with the both relay coils energized, both the Neutral Relay and the Hot Relay are switched at the same time. This is the loud "clunk" you hear... and you may hear your generator bog down a bit until the it settles at one RPM. (Check your EMS for amps drawn.)

==> This is why you do NOT want to have your AC thermostat "on" when you start the generator. ...Cuz that AC load is going to draw a lot of current and will bog down your generator... stressing both your generator and your AC system. ...In fact, I recommend you let your generator warm up for a couple minutes and then start your AC compressors by using your thermostat temperature up and down arrows vs. that CHEAP thermostat slider-switch. (But I digress. So getting back to the subject at hand.)

* If shore power is present still be connected, an energized Hot Relay will not allow the shore power to pass since that circuit is now "open."

* If there is no shore power present, then there is no power to connect to the Load.

* When you start the generator we know the timer circuit is waiting to close, and when it does the Neutral Relay and the Hot Relay are activated as explained above, and the generator is now providing L1 & L2 50A power (Single Phase) to the Main Circuit Panel (Load Panel).

OTHER TROUBLESHOOTING TIPS FROM MIKE B. (Thanks Mike!)

We all know that points wear. I'm guessing the 120V side of the points fail first, but this is just a guess.

If however, you DO see 120V working when you are plugged into shore power, but you DO NOT get 120 working on generator power, then it seems likely your Timer or the bridge rectifier may be suspect, because if either of these parts fail then the 12V circuit will remain "open" and no current will be present to energize the relay coils. I.e., you need 12V present at all time for both relays to switch in order for generator power to be connected to the Load.

Mike B. explained how he repaired his ATS-5070 by replacing these parts as follows:

1) RE: "Delay On Make Timer": Mike replaced the Delay on Make Timer" (Part #ICM102) with Part #E174797. However, Mike warns this E174797 is NOT a drop-in replacement. (What Mike means by that I do not know.)

So does anyone have a cross to the OEM Delay Make Timer #ICM102? ...Or know how to wire the E174797? ...Or maybe this will be obvious to a TV repair tech? (Note: Last summer a TV repair tech repaired my Dimensions Inverter so don't forget these guys are like shoe cobblers! ...I.e., not a lost art yet!)

2) RE: "Bridge Rectifier Relay": Mike said he used a Radio Shak #RS207L (4A-400V) and it worked fine. But is there a cross to another part number? ...Further, Radio Shack is not in business any more, so does anyone know a good part number to cross to the RS207L?

RELAY REPLACEMENTS

* We are still waiting for conformation on what relays can be used to repair an old style Parallax ATS-5070. So check back for more information on this later.

* Right now it looks promising you can use the Deltrol Controls 50A relays, but we know you have to go through a distributor to buy these, which is why they are in the $50-$60 each. So hopefully someone will find a $30ea source and will let us know where to buy two DPDT relays of this type and in this price range. (Stay tuned.)

* Deltrol Controls 900 Series relays can be used with 12V coils, but I'm not sure how to intrepret their data sheet. I think we need a 12V coil, but I don't know how many amps I can run on the AC high voltage side of the relay. (See attached Data Sheet.)

I also attached the ATS trouble shooting manual I talked about earlier. Note: This is for the $185 newer ATS by Esco, Elkhart or Lyght.

 

[imnprsd]

More about repairing the old style ATS-5070.

....Continued: I don't know if I can order a 120V coil type relay and do away with the bridge rectifier all together? That sounds like a better solution, but then we still need to make sure the Timmer is used... and from what I can see the Elkhart ATS #LPT50BRD has the timer function built into their circuit board. So unless we can both upgrade to a 120V coil and include a Delay Timer in our re-worked ATS-5070, we might be stumped!

So... while it's fun to think about this stuff... that $185 ATS #LPT50BRD from any supplier (Esco, Elkhart or Lyght) is looking better all the time!

...Unless we can find a 12V coil relay that can handle 50A of 120V AC on the high power side of the relay... and keep our Bridge Rectifier and keep our Delay Timmer?

Morich: What do you think? Can we find a replacement relay to replace a bad Parallax ATS-5070 relay based on what we know now?

Does the Deltrol Controls Data Sheet provide you with enough information to find a second source relay?

 

[Morich]

Let me break it into smaller sections down to this line?
OTHER TROUBLESHOOTING TIPS FROM MIKE B. (Thanks Mike!)
Down to this point I think it all correct except a couple things to be aware of.
One is the polarity "may" matter on a DC relay if there are other parts like an LED indicator or other diode which IS polarity sensitive. Most cases, no, but not something I've worked too much as I normally did have the correct relay and never worked the issue of compatible too far.

Always better to start the generator with minimum load from things like the Air cond. but I don't adjust the thermostat but we use the off setting on it. That saves resetting the preferred temp. Big complaint, huh? With the digital, at least we can see where it is set rather than the "guessimate" of the analog.

On these relays, note that in the picture, the moving contact points are on the "arm" coming from the right, with the fixed contacts above and below? You can see that the contacts are made with the upper as pictured while the relay is not powered. This is due to springs which pull it to this "non-operated" position when no current is there.
So shore power connected to the left side connections in this picture will be the normal, non operated situation as the spring pulled the contacts closed at top and open at the bottom where we might connect the generator to the connections close to us. If we connect generator power to the green, shore power to the red from left and the output line to blue at right, the "normally closed (NC) will keep the red and blue contacts closed, until the power from generator creates the DC power to pull these contacts open and close the green to blue path but that path will still be open at the small switch if we do not have it closed.

Overnight thinking, I see there might be use for that switch on other uses for the transfer. If we had a different situation than most RV, we might have a big cranky old genset that we needed more time than the time delay for it to get stable or we might have machine processes like a lathe which have tools engaged which we need to back off or rest before adding power back on.
Weird situations are normal, it seems and it might be that they design an automatic transfer switch which can be done manually after the downstream equipment is reset and ready?? Some what like us wanting to have the transfer done but we turn off the AC before then completing the transfer with the micro switch. Not critical for us but other uses might really need it?

For choosing a replacement relay, the big points would be the coil voltage spec as we assume it to be 12 volts here but that is not verified, maybe?
But we need the replacement to match the voltage.

The contacts will be rated for how much current and we need to have that as high or higher than the old one. Rated higher makes them bigger and might last better but at the expense of bigger and not fit as well?

The type does need to remain DPDT but what contacts are closed in operated or not, could be worked around by changing the locations where we connect the shore or generator power. Less mind strain if the same but something that "could " be worked around.

 

[Morich]

Got some things done and time to take a second look at this question. I think I see a bit more info on a replacement relay here:

Quote:
* Deltrol Controls 900 Series relays can be used with 12V coils, but I'm not sure how to intrepret their data sheet. I think we need a 12V coil, but I don't know how many amps I can run on the AC high voltage side of the relay. (See attached Data Sheet.)

What I think I see is that the 900E and 900 R are the same relay but with different methods to connect wires, so either might do fine with the ratings at 277 volts and we expect to use 110 as that is somewhat less likely to damage the points at lower voltage. Higher voltage gives more arcing as it "jumps" further (low tech thinking!)

And then there is some question how we are talking about resistive load which is the normal incandescent light and electric heating coils in some basement units versus inductive loading which is the motors on that heater or the bigger load from the air conditioner compressor. So which do we design for more? Always better to just not abuse the relay contacts as much by keeping both those off when we are doing the transfer switching but not always practical.

I would consider E or R to be okay as we are not actually using the full 50 amp in most cases so a rating of 40 for when we might have inductive would suit me good enough.

The second picture on the right says we need to have a rectifier big enough to output 2 watt or more to power this relay coil. Larger output watts from the rectifier is okay but minimum of 2 watt. Larger output usually means larger physical size to work around.

 

[imnprsd]

What Is The Relay Coil Voltage In Our Old Parallax ATS-5070?

When I take a closer look at the ATS-5070 bridge rectifier circuit diagram, it looks like it just converts AC to DC without a transformer to step-down-voltage, but then again, these diagrams are not that detailed to know for sure.

==> So is the voltage to the Relay Coil 120Vdc or is it more like +12Vdc as I drew in the schematic? ...I'm starting to think it's 120V, but I'm not sure?

==> The only way to tell is if I were to measure the voltage to the relay coil on my old ATS-5070 since I am having a hard time finding out what type of relay they used. (Maybe someone who has access to their ATS-5070 will probe the ATS-5070 coil voltage and tell us? I do not have access to my RV because it is storage.)

==> If our Parallax ATS-5070 does use relays with 120V coils then I think we can replace the "Hot Relay" and the "Neutral Relay" with the same relays used by the Esco, Elkhart, Lyght, Todd Engineering being sold for $185 on Amazon under part number LPT50BRD...

* Hot Relay, by Deltrol Controls #900QR

* Neutral Relay, by Deltrol Controls #900QR-1C (With Micro Switch)

* I just don't like the price of these Deltrol Control parts (~$120 for both) since I still think it's a good idea to replace both relays at the same time. And now that we know we can buy that 50A-ATS (Part #LPT50BDR) on Amazon for $185, and it's a complete package, and newer design, then I think I would be done with it as the OP said he plans to do. ...But at least we know how to repair one of these older Parallax ATS-5070s if we want to or need to.


OTHER OBSERVATIONS

* The Delay on Make Timer" (Part #ICM102) Mike B. used to fix his ATS-5070 is rated for AC voltage, but may work with DC too. (IDK?)

Note: As Mike B. explained, the foot print of the ICM102 is different than the OEM delay timer used, but the ICM102 will work and will fit inside the junction box. This delay timer is used to keep the generator trigger from activating the relay for a while, which gives the generator time to warm up.

And we know if your generator is not getting power to the main circuit panel, but your short power does work normally, then maybe it's a possibility your Delay Timer is not closing the circuit and needs to be replaced?

* And while a low voltage coil may allow the contact points to last longer, it's not like this ATS gets switched on-and-off constantly. So why would someone design this ATS with a transformer if you just use a Relay with a 120V coil, for less cost?

* Mike B. also said he use a bridge rectifier he bought at Radio Shake called a RS207L. Note: The data sheet does not specify voltage type, because diodes pass current in one direction; and therefore a common diode is not AC and DC specific. Note: I circled the location of this bridge rectifier in my Parallax ATS-507.

NOTE: Mike said he repaired his ATS-5070 using a RS207L, but that does not mean Parallax used this device in their ATS-5070. (TBD.)

For more information about this tiny bridge rectifier component , you can refer to the attached RS207L data sheet (.pdf).

 

[imnprsd]

I'm still a bit puzzled by the fact my Parallax ATS-5070 uses a bridge rectifier, which turns 110Vac in to 110Vdc. ...Why do that?

Well... I thought the the coil voltage was 110Vac, but it's not. It's 110Vdc as clearly printed on the Deltrol Controls relay. (See picture.)

Can someone help me correlate the advantages of converting AC to DC in regards to relay switching?

My guess is that with DC the resistance is very high so the current flowing through the circuits and the relay coils are very low. ...But would that help extend the life of the relay coils, Delay Timer, switching contacts (points)?

I'm guessing here, because my bench experience is not that great; and I may be misinterpreting that data sheet. So feel free to make any corrections to what I just said if you like.

The relay pictures below are for the new version ATS by Lyght: #LPT50BRD that use 110V coils. Note: The 900QR-1C has a SPDT coil on the end which is used by the Neutral Relay as a "lockout switch" which is Normally Open. I.e., until the Generator Starts, no current flows though this circuit, which is what we want.

==> After the generator starts, and the Delay Timer closes, then the Relay Coil activates and so does the Hot Relay coil. And now with the coils energized the relays give priority to the Generator... until it turns off... and then the relay coils disengage, and those relay springs pull the contacts back to shore power.

==> It my believe these Deltrol Controls relays can be used to repair our older ATS-5070, but at $120 for two of these, like I said, I would prefer to buy the LPT50BRD for $185 and get all new guts inside.

Now if someone can find us some heavy duty, 50A, compatible relays for $30 each then I may change my mind.