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Onan LT II Transfer Switch JB 7.5


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  #11  
Old 06-06-2017, 09:08:53 PM
JohnnyC JohnnyC is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

This evening I serviced all the relays. Many were bad. Some of the relay contacts show absolutely NO continuity while others showed high resistance. Very few of the relay contacts had good continuity.

I took each relay apart, sprayed a commercial grade contact cleaner on all contact surfaces and retested. They now all show perfect continuity in both energized and open states. I also tested the functionality of the time delay relay and voltage sensor relays. Most of the problems were caused by oxidation and the effect was similar to point sets that go unused for a long period of time.

I doubt I'll have time after work Wednesday to reinstall the relay PC board and relays since I have a drywall side job to do. I am looking forward to completing the job on Thursday and hopefully I'll get the stupid LT II switch working although I will be playing with the sensor and time delay adjustments afterwards if the basic functionality is fixed.


**** Should I repaint the box?? I can gut the rest of it in a few minutes.

JohnnyC
New Jersey
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  #12  
Old 06-06-2017, 11:46:51 PM
Vanman Vanman is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

So, you fixed those relay contacts just with contact cleaner and no physical cleaning? I've got to get some of that! The equipment I work on WAY predates enclosed relays, at least commonly available ones, and a good contact cleaner would be very useful.

Keith
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  #13  
Old 06-07-2017, 05:48:17 AM
JohnnyC JohnnyC is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

Vanman, I was amazed too. My Fluke meter does not lie. I double and sometimes triple checked my reading before and after the cleaning. Most of the problem seemed to be heavy oxidation. The stuff I used is made by Wurth and called "Contact Cleaner OL". You will see it in my previous picture postings. This stuff is the only contact / electrical cleaner we use at work. It leaves a film that prevents oxidation.

I hope this is the answer to my LT II switch problem, but knowing how things work for me it won't be. I'll find out Thursday after work because I will be too busy today to play in the garage.

JohnnyC
New Jersey
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Old 06-07-2017, 06:38:11 AM
Kevin K Kevin K is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

Johnny, thanks for the tip on contact cleaner. I am presently using GC Electronics Jiffy Bath contact cleaner, part # 19-638-A, which seems to work well.

So I Googled the Wurth "Contact Cleaner OL" and came up with a number of sites.

You can buy it directly from Wurth for $10.99/can, minimum order two cans.
http://www.shopwurthusa.com/wurthsto...L/p/0890101101

I found an eBay link, selling three cans for $69.99! http://www.ebay.com/itm/Wurth-Contac...-/302256477439

Like that's going to happen! I'm starting to see more of this nonsense on eBay, ridiculously high prices on items that can be purchased elsewhere much cheaper. These sellers know many people search eBay first, and they can double or triple their money with little effort.
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Old 06-08-2017, 09:57:04 PM
JohnnyC JohnnyC is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

This evening I slapped the relay PC board back into the LT II switch and retested. It still ain't working. Without doubt, the relays had problems. You all seen the corrosion on the relays in my earlier pictures and the cleaner fixed it good and they tested good afterwards, but there is another problem that I have not pin pointed yet. It is kicking my azzzzzz, but I think it is a short in the exercise clock circuit wiring which is causing the generator to fire up immediately after flipping the switch to auto. I am currently going over the wiring schematics.

JohnnyC
New Jersey
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  #16  
Old 06-09-2017, 05:45:29 PM
JohnnyC JohnnyC is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

JohnnyC is happier than a pig in mud. I figured out the remainder of my transfer switch problem by which the transfer switch would immediately signal the startup the generator when the Generator Selector Switch was set in Auto mode regardless if there was grid power or not. There should be a jumper between 11 and 12 on the TB1 remote start block. It was MISSING. I jumped 11 and 12 and the LT II transfer switch functions 100%. How did I find the problem? Simple ...... I read the schematics. JohnnyC is a happy dude tonight...

JohnnyC
New Jersey
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Old 06-09-2017, 06:41:43 PM
LRomero LRomero is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

Quote:
Originally Posted by JohnnyC View Post
JohnnyC is happier than a pig in mud. I figured out the remainder of my transfer switch problem by which the transfer switch would immediately signal the startup the generator when the Generator Selector Switch was set in Auto mode regardless if there was grid power or not. There should be a jumper between 11 and 12 on the TB1 remote start block. It was MISSING. I jumped 11 and 12 and the LT II transfer switch functions 100%. How did I find the problem? Simple ...... I read the schematics. JohnnyC is a happy dude tonight...

JohnnyC
New Jersey
So if one was to wire up a toggle switch across 11 and 12, the ATS could be controlled manually? If so, bingo to what I've wanted on when I install my ATS. Basically, I don't want to be away and have my generator starting when nobody is home. Also, if the power goes out for just a few minutes, I don't want the generator starting. I want to control when it starts, but have the start and transfer be auto.

On the timer, it's a cool down timer in my eyes. You never want to shut and engine down without cooling it down first.
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Old 06-09-2017, 07:01:40 PM
JohnnyC JohnnyC is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

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Originally Posted by LRomero View Post
So if one was to wire up a toggle switch across 11 and 12, the ATS could be controlled manually? If so, bingo to what I've wanted on when I install my ATS. Basically, I don't want to be away and have my generator starting when nobody is home. Also, if the power goes out for just a few minutes, I don't want the generator starting. I want to control when it starts, but have the start and transfer be auto.

On the timer, it's a cool down timer in my eyes. You never want to shut and engine down without cooling it down first.
From what the schematics list the use for the two terminals is a "remote test switch". With the circuit open between the two terminals (no jumper), you could essentially manual start the generator as well as shutting it down at the generator rather than having the automatic function of the transfer switch doing it. The transfer switch will automatically cut the output over between the grid and generator depending if the generator is running or not.

To make things easier if you have an LT II switch, I think you would want to run the switch set to "Hand Crank" mode (see picture below) for what you want... For me I want to run it fully automatic mode. It is nothing more than a flip of a toggle switch on the ATS.

Below is a quick video that I shot this evening after I installed the missing stupid jumper.

https://www.youtube.com/watch?v=5ink...ature=youtu.be

Thanks for the clarification on the timer.... I guess it could work both ways - for cooling down period and to ensure the power is back on and stable. There is a second adjustable relay that is a voltage sensor too. On the label inside the ATS, the Onan tech noted that it is set for 80%.

I never played with an ATS until recently. I am having a blast and learned a few things, but there is more to learn in order to set everything correctly. Right now, my garage is like a mini learning lab with all this crap hooked up. I think people pay money to take courses in this stuff.

JohnnyC
New Jersey

p.s. - you may notice the exercise clock in the video above is missing. I simply bypassed the clock by using a jumper to eliminate the possibility of a defect clock that may be triggering the starting of the genset no matter how programmed the switch is or not. The clock is nothing more than a DPST switch ran on 120vac.
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Last edited by JohnnyC; 06-09-2017 at 07:30:41 PM.
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  #19  
Old 06-09-2017, 10:59:53 PM
JohnnyC JohnnyC is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

After I finished my yard chores (finish cutting the lawn and trimming) I played some more with the transfer switch after closing it up I simulated power failures by cutting grid power and doing various tests. The ATS seems to work A-1.

Now that it is done, I have absolutely no clue what I will do with the switch, but it was fun to play with the switch.

JohnnyC
New Jersey
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  #20  
Old 06-10-2017, 06:00:47 AM
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Billy J Shafer Billy J Shafer is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

I thought about that. But in all my years with Onan. I have never seen the remote test switch used. Even at places where they were supposed to have one.
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