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Onan LT II Transfer Switch JB 7.5

JohnnyC

Subscriber
Last Subscription Date
03/18/2020
Johnny,

What do you plan on doing with the original relay? If you're not going to be using it, I would like to have it and see if it can be repaired. I have a fairly extensive electronics background and may be able to repair or duplicate the circuitry.
I'm going to keep the defective relay since I may take a stab at repairing it. The components on the pc board are easy to replace, but not sure if the IC chip is still available.

JohnnyC
New Jersey
 

ATSman

Registered
Great stuff here. Since we are on the subject of LT series Onan transfer switches, I am looking for the schematic/ wiring diagram for the following
ATS:
Model LTDU1200-4/11280D
SN 1073716121, 1200A, 480V
3-phase, 4-wire
It uses 2 ITE molded case circuit breakers with ITE Telemand motor
operators controlled by relay logic.

Can someone help me?
Thanks in advance.
 

JohnnyC

Subscriber
Last Subscription Date
03/18/2020
Great stuff here. Since we are on the subject of LT series Onan transfer switches, I am looking for the schematic/ wiring diagram for the following
ATS:
Model LTDU1200-4/11280D
SN 1073716121, 1200A, 480V
3-phase, 4-wire
It uses 2 ITE molded case circuit breakers with ITE Telemand motor
operators controlled by relay logic.

Can someone help me?
Thanks in advance.
I wish I could help, but I only have factory manuals and wiring diagrams for the LT II.

JohnnyC
New Jersey
 

JohnnyC

Subscriber
Last Subscription Date
03/18/2020
Update: This evening I installed the ebay time delay relay and adjusted it for the time delay I desired. If you look at the first picture below, the ebay relay is the larger red cased thingy. I installed it to function in the Transfer Delay circuit and will allow the generator to stabilize on startup before the load is applied. The factory setting is 2 seconds which is insane especially if the genny is stone cold and a large load is transferred to it upon startup. I set the time delay for 1 minute 30 seconds. This will allow the set to warm up a little and full circulation of oil.

The smaller cased red relay in the first picture is the Stop Time Delay relay and will allow the generator to run unloaded for a period of time after the utility power is restored. After the set period of time is met (end of delay), the ATS will shut down the generator. I set the time delay for 1 minute. Without the time delay relay, the shut down of the generator would occur immediately once utility power is restored and would not allow proper cooling before shut down.

The second and third pictures show the JB and the ATS working together during the testing and adjusting of the time delay relays.

I hope I don't burn up any more time delay relays. They are expensive.

That's it for tonight!

JohnnyC
New Jersey
 

Attachments

ATSman

Registered
Nice clean setup, JohnnyC
More than enough to power my house, but we don't get
many extended outages in the SF Bay Area.
Would you have any PDF files on the LT II ATS dwgs you could post?
 
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