Sometimes the manual doesn't have all the answers

[Summerpaws]

If the contacts close putting the two resistors in parallel the resistance should be 3.75 ohms.

Got it. I was going to remove the wires and test individually,

 

[Summerpaws]

Good Day: If your checks of all the external things does not provide the answer, you may have to carefully drill the rivets of the K8 to open it. Then you can see if things inside are in order, or overheated in a spot. POP rivet it closed if nothing found, or find short screws.

Seeing as I have a high voltage on terminal 3, to me, it is a definite cause and effect. Correct me if I am wrong, but to suspect K8, the voltages have to be correct...correct?

 

[Summerpaws]

KloppK, question. Can I do a real time voltage reading on either side of R12 and R13 under a 5K load? (or 4K). If the resistors and the contacts are good, I should get the same reading on both, correct? If the contacts were bad, wouldn't I get a different reading on R13?

 

[kloppk]

Correct. If the AC voltages to the K8 terminal pairs is less than 5.6 volts AC and you get an overload fault then I'd say K8 is bad. Since you are seeing voltage in excess of that then the issue is with the switch contacts, wiring or R12 or R13.
Yes, you would normally see the same AC voltage across R12 and R13 when running loaded in 120/240 mode.

 

[Ray70]

I'd have another go at cleaning S8. Get the cleaner inside the switch contacts and work the switch aggressively, then spray it again!
It sounds like the last cleaning made an improvement to where you can now apply a 5K load, but can't sustain it indefinitely?

 

[Summerpaws]

Correct. If the AC voltages to the K8 terminal pairs is less than 5.6 volts AC and you get an overload fault then I'd say K8 is bad. Since you are seeing voltage in excess of that then the issue is with the switch contacts, wiring or R12 or R13.
Yes, you would normally see the same AC voltage across R12 and R13 when running loaded in 120/240 mode.

Ok. For that matter, I can take a voltage reading on either side of the contacts on K8. I've left the covers off the gen until I solve this mystery so I will see if I can spare a few minutes to test that. Thank you so much for the help!

 

[Summerpaws]

I'd have another go at cleaning S8. Get the cleaner inside the switch contacts and work the switch aggressively, then spray it again!
It sounds like the last cleaning made an improvement to where you can now apply a 5K load, but can't sustain it indefinitely?

Sorry Ray. Just saw this. No, no real change. It's able to handle a 5K load for about 15 seconds. Long enough for me to take a reading. I am headed out now to take readings on either side of K8 and both burden resistors. I'll do it at a 4K load so I don't have to rush. First I have to find the alligator clips for my Fluke. Clipping one to terminal 4 of the overload will make my life easier.

 

[Summerpaws]

More testing today. All tests done at 4K load. I switched my test lead from terminal 4 to terminal 3 on K8.

R12...6.8
R13...7.0
Terminal 14...6.8
Terminal 13...6.8

To me, that eliminates S8. As I understand this circuit, the voltage is an inductive current from the output of the generator. The burden resistors add a load to that circuit.

Because R12 and 13 are soldered, I can't isolate them to test. Looking closely it appears that they have been soldered in a non factory way. I don't belive in coincidences so I'm thinking someone's been down this road before.

My question is, what is my next step? Could is still be K8? It seems to be doing it's job because it opens the output contactor when it sees a high voltage. I'm confident is it not S8.

@kloppk, @Ray70

 

[kloppk]

Since you have the same voltages across R12 and R13 I'd suspect one of those burden resistors failed and is open circuit.

 

[Summerpaws]

Since you have the same voltages across R12 and R13 I'd suspect one of those burden resistors failed and is open circuit.

Makes sense. I have to remind myself that I am dealing with low voltage inductive current. Before I see if anyone has a couple of burden resistors, I really should unsolder the both of them and test them. I will do that in the next couple of days and report back.

 

[grywitt]

I've found you can isolate the resistors by pulling the wires off k8 and unplugging J6. The component to component wire list they made sure helped when I was wanting to measure them. R10 goes to K8-1, R11 goes to K8-2, R12 goes to K8-3 and R13 goes through J6 so if you unplug that then the wire is isolated. It was the bottom wire on the K8 terminals when I checked them.

 

[Guyfang]

Thats what I was just looking up. Glad you saved me the time. Great minds think alike.

 

[Summerpaws]

I've found you can isolate the resistors by pulling the wires off k8 and unplugging J6. The component to component wire list they made sure helped when I was wanting to measure them. R10 goes to K8-1, R11 goes to K8-2, R12 goes to K8-3 and R13 goes through J6 so if you unplug that then the wire is isolated. It was the bottom wire on the K8 terminals when I checked them.

It's funny I woke to see this! I was thinking about it last night and it occurred to me that all I need to do is remove the wires from K8, terminal 3 and I can test the resistors. I looked at the wiring schematic and didn't see J6. I'll be out there today and will check. I have the TM's so I'll check the wire list. Thank you!