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Onan LT II Transfer Switch JB 7.5


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  #61  
Old 10-10-2017, 08:56:50 PM
Leon N. Leon N. is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

I guess I still do not understand what you are doing? So, do you wait until the power goes out and then pull the fridge and plug it into the ATS circuit or do you set this up prior to the outage? if the later, then "you" are paying for the juice they draw from your 240 volt tap?

As for your last question, keep in mind, the neutral and the earth ground are bonded together at the utility incoming service panel. So I would assume your ATS would respect that fact and carry the neutral and the ground wire along from the service entrance panel via that 240 volt receptacle. Yes, some single phase 240 volt receptacles are just three-wire plugs, but note in those cases, I believe the neutral is connected to the 240 volt appliance frame or chassis.
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  #62  
Old 10-10-2017, 09:17:18 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 Leon N. View Post
I guess I still do not understand what you are doing? So, do you wait until the power goes out and then pull the fridge and plug it into the ATS circuit or do you set this up prior to the outage? if the later, then "you" are paying for the juice they draw from your 240 volt tap?
Prior to a storm. Yes, I will pay for the utility power for a short duration which is no big deal since I am only supplying minimal power, but it sure beats having to go out into a heavy snow storm foot of snow or during a hurricane with pounding rain and wind, dragging the JB through the weather into position and laying out the lines. I rather setup before hand and let nature take its course. If or when the utility goes out I will be inside a nice warm house while the ATS transfers the load from the non-working utility to the JB and the reverse once the utility power is restored. I am getting too old to be running around outside during storms.

As for your last question, keep in mind, the neutral and the earth ground are bonded together at the utility incoming service panel. So I would assume your ATS would respect that fact and carry the neutral and the ground wire along from the service entrance panel via that 240 volt receptacle. I agree.

JohnnyC
New Jersey

Last edited by JohnnyC; 10-10-2017 at 10:56:38 PM.
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  #63  
Old 10-10-2017, 09:25:13 PM
Steve Dawkins Steve Dawkins is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

As long as the input plug for the ATS stays connected to the MIG welder receptacle, do not bond the neutral and ground in the ATS.

If you want to run the gen & ATS together without the "Utility Input" plug connected to the MIG receptacle (don't know why you would do this, other than metering and power distribution), get another receptacle like the MIG outlet, and jumper the neutral and ground terminals together. Then you can plug the ATS plug into this receptacle for your neutral/ground bond. Mount the "bonding" receptacle on the ATS, and you won't have to worry about losing it. It will also make a conversation piece when people ask why the ATS is plugged into itself.
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  #64  
Old 10-10-2017, 10:59:28 PM
JohnnyC JohnnyC is offline
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Default Re: Onan LT II Transfer Switch / JB 7.5

Quote:
Originally Posted by Steve Dawkins View Post
As long as the input plug for the ATS stays connected to the MIG welder receptacle, do not bond the neutral and ground in the ATS.

If you want to run the gen & ATS together without the "Utility Input" plug connected to the MIG receptacle (don't know why you would do this, other than metering and power distribution), get another receptacle like the MIG outlet, and jumper the neutral and ground terminals together. Then you can plug the ATS plug into this receptacle for your neutral/ground bond. Mount the "bonding" receptacle on the ATS, and you won't have to worry about losing it. It will also make a conversation piece when people ask why the ATS is plugged into itself.
Excellent suggestion / solution!!

Thanks!
JohnnyC
New Jersey
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  #65  
Old 10-22-2017, 10:40:48 PM
JohnnyC JohnnyC is offline
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Default Re: Onan LT II Transfer Switch JB 7.5

Late last week I ran a bi-monthly exercise of my JB and the LTII automatic transfer switch. All went well until the utility power was restored. The ATS did not transfer the load from the generator back to the utility and the JB did not shut down. Basically, the JB would have ran forever until it either ran out of fuel . This did not happen last time I exercised the complete setup. I posted about this in the following post from "what Have You Done to Your Onan Today": https://www.smokstak.com/forum/showp...postcount=3397

Today I had several minutes to trouble shoot the problem and as I guessed, it was a relay. Specifically the problem relay is the K4 Time Delay Retransfer relay. The relay's delay is adjustable from 2 to 30 minutes and begins the moment when utility power is restored. After the delay time is achieved, the transfer switch will retransfer the load from the generator to the utility power and activate the K5 Stop Time Delay relay which will shut down the generator.

The way I trouble shot the problem was very simple. It is clear that when the K4 relay is activated when utility power is present, 120vac should be present at the K4 relay socket. This was verified as seen in the second picture below. This tells me that the ATS box's wiring and circuitry for this function is working and something may be wrong with the Time Delay Retransfer switch.

My next step was to remove the Time Delay Retransfer switch from the ATS and test. These relays are simple and activated by a 120 vac coil with a timer circuit that is user adjustable. The third picture is not too clear, but I have a line cord plugged into a 120 vac source and attached to the pins of the relay. The picture did not capture the cord as I was trying to focus on the relay and the meter. The timer is adjusted to trip the relay at 3 minutes. It did not trip. I have my volt meter on PC board where the 2 blue wires are soldered to and lead to the relay coil. If the timer circuit was working correctly I would be seeing 120 vac on my meter after 3 minutes. I see nothing.

In conclusion, something in the Time Delay Retransfer relay's electronic circuitry failed and may cost me several hundred dollars to replace. There is no evidence of burnt components and I hit all solder points on the PC board with my solder iron to eliminate the possibility of a cold solder joint. Looks like I will have to find another relay on ebay.

JohnnyC
New Jersey
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Last edited by JohnnyC; 10-23-2017 at 06:23:48 AM.
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  #66  
Old 10-22-2017, 11:55:47 PM
Vanman Vanman is offline
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Default Re: Onan LT II Transfer Switch JB 7.5

Ugh, electronics. Seems to be the Achilles Heel of everything these days.

One of my "old" (1943) Kohlers has an automatic transfer switch built in. It has a time delay retransfer relay as well, but no electronics there! It's all motors and coils and springs and such.
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  #67  
Old 10-23-2017, 08:32:00 AM
JT240Z JT240Z is offline
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Default Re: Onan LT II Transfer Switch JB 7.5

My LTII is a little simpler it seems. No red relays for delays. I'll post pics of the internal some time today.
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  #68  
Old 10-23-2017, 08:41:44 AM
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 JT240Z View Post
My LTII is a little simpler it seems. No red relays for delays. I'll post pics of the internal some time today.
Well, my LTII will now have one less red relay

JohnnyC
New Jersey
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  #69  
Old 10-23-2017, 10:04:53 AM
squidtrap squidtrap is offline
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Default Re: Onan LT II Transfer Switch JB 7.5

"one less relay" the price of those things is crazy.
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  #70  
Old 10-23-2017, 10:47:05 AM
AngrySailor AngrySailor is offline
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Default Re: Onan LT II Transfer Switch JB 7.5

Can you substitute another timer (read more cheaper) to trigger the relay? Or if current is the issue, use it to trigger a small relay to trigger the big relay?
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