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Onan OT 150 transfer switch

jurick

Registered
Hi, this is my first post to this forum. I have a little bit of a problem. I have a Onan automatic transfer switch specs are as follows,
Model no. OT 150
Serial no. E940543337
Spec. 4911J
Current rating: 150 Amps
Voltage: 480 VAC
Frequency: 60 HZ
Poles: 3
Wiring Diagram: 626-1762
Features: A020 A035 A042 A044 A046 A050 B001 D001 J001 J021 K001 R026

I am attempting to use it at my house on a 120/240 volt single phase system. I have rewired the control transformers and switched the board to single phase, the linear actuator is rated at 208/240 volt so I should be fine there. The problem is, is that I believe that I need to rewire the sensing circuit and I cant seem to find a diagram to do this anywhere, I have searched and searched with no such luck. I have the unit temporarily wired so that I can test it and when I supply utility power I get no switching action and I only get lights to light up on the generator transfer board of the power sentry. The outside lights on the box are also lit. If anybody could help me with this issue or possibly provide a service manual that would be greatly appreciated.

Thanks,
Justin
 

Gunny

Subscriber
Last Subscription Date
gratis
Sounds to me that you have it covered if you have reconfigured that transformers on both the line and load sides. You have changed the linear motor to the correct voltage, switched to single phase sensing. About all I can think if it to calibrate the voltage sense circuit cards and it should work.

Assume you configured the jumpers as per the single page transformer wiring diagram.

That is probably the best and most reliable switch Onan ever made.

Not where I have access to my manuals or I'd copy and send you the directions to calibrate the sensors.
 

Max Thompson

Sponsor
Last Subscription Date
09/03/2019
For the price of an e-mail address, I will send you manual #962-0503 for the OT transfer switch.
 

jurick

Registered
Yeah I am having a lot of trouble just finding a diagram or instructions on how to recalibrate them. I am hoping after I find something and recalibrate them everything will work right.

Didn't see your message until after I posted the last one. My email address is justin.ricks@verizon.net

Thanks,
Justin
 

jurick

Registered
I looked over the service manual and it appears to be an older manual. It says prior to spec E at the top of the manual I don't really know the exact spec number on mine but the pictures and the data in the manual do not match the switch I have.

Thanks,
Justin
 

EricWood

Subscriber
Last Subscription Date
10/15/2019
Just sent the OT III service manual and a couple page references to the OP.

eric
 

jurick

Registered
Thank you that was the exact manual I needed. After I rewired the sensing transformers everything worked correctly. Now I just need to mount it and get everything hooked up.
 

Billy J Shafer

Subscriber
Age
69
Last Subscription Date
09/03/2019
Be sure that transfer rod. Works freely. It should move with ease. If it hangs up it can burn out. That is one of Onan's better switches.
 
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