Cleaning/disassembling the K1 AC Circuit Interrupter

Browning1 said:

i have been using the WD-40 contact cleaner.

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DeOxIt is my go to cleaner/deoxidizer. I think that there is a difference between clean (free of gunk), and electrically clean (free of oxides and other insulating materials). You want the latter. DeOxIt isn't cheap, but a little goes a long, long way, so the cost/use ends up being not much.

If the solenoid cylinders/rods in the center of the block on K1 move freely, then you should be good to go on K1. The other switches may need work; DeOxIt, cycle the switch, rest, repeat, more DeOxIt, repeat. The behavior that you describe sounds like more of a switch / contact issue, rather than a relay issue to me, but that is definitely armchair quarterbacking.

All the best,

2Pbfeet

Guyfang said:

I think the possibility of K1 being the problem is very small. In fact, I have never seen those symptoms when a K1 type relay had any kind of failure. Test the K1. Then put it back together. Ray, I think this sound more like he needs to clean S6 & S8 with some contact cleaner.

When it drops off line, what fault indicator light comes on?

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Definitely would normally suspect dirty switches, but for some reason he isn't getting a fault light. Normally it should throw the short circuit or overcurrent light. Could be a combination of issues... dirty switches causing a false overload AND another issue with the short circuit / overload relay box or the fault control panel itself.

thanks. I will look into getting the Deoxit cleaner. Yes the rods on K1 move freely.

Do not forget, you can test K1 on the work bench. Two wires from the Slave rcpt. to the X & Y contacts. If the plunger goes down, and you should test at least 20-30 times, then put it back together. Then install it. Put the gen set on load and let it run. See if the fault happens again. If so, then put the set back on lone and place S7 in the up position. Will it now run 1-2 hours? Will it run and a fault light come on? When it stops, will the engine slowly load RPM and take a little bit to stop? Or simply cut off in less than a few seconds?

thanks. I will look into getting the Deoxit cleaner. Yes the rods on K1 move freely.

Have you used 24 VDC to make them move? Or just pushed them down and let them spring up?

If it stops slowly, then its a fuel problem. And that doesn't mean at the tank. it can mean the set starves for fuel because of maybe trash? Or junk in the system. That will not set off the fault indicator. What we need is more accurate info.

Guyfang said:

thanks. I will look into getting the Deoxit cleaner. Yes the rods on K1 move freely.

Have you used 24 VDC to make them move? Or just pushed them down and let them spring up?

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I've been just pushing them down and letting them spring up. I will test everything this weekend as long as the weather holds out. Thanks for all of ya'lls help.

@Browning1

If you aren't getting any fault lights when the contactor opens on its own under a light load, then I'd suspect an issue in the latching circuit that is supposed to keep the contactor closed.
The diagram below shows the electrical path of the latching circuit. K20-9 gets 24 volts when the set is running. The path is how 24 volts gets to K1-X. K1-Y is grounded by the balance of the red path holding K1 closed.
The Yellow boxes with red text are the component terminal numbers. The blue boxes with white text are the base wire numbers. 100 is chassis ground.

If it were me, I'd do the following to find out what's causing K1 to open when it shouldn't. I'd jumper out sections of the latching path and run your set under your load and see if the problem goes away.
*** Doing some of the following steps will cause the contactor to immediately close when the set is started. ***
For example I'd put a jumper from K1-Y to chassis ground. If the problem goes away the issue is somewhere after K1-Y on its way to ground.
Assuming the problem goes away I'd remove the jumper from K1-Y and connect it to S5-5. If the problem goes away the issue is somewhere after S5-5 on its way to ground.


Repeating the process..
Assuming the problem goes away I'd remove the jumper from S5-5 and connect it to S5-2.
Run test
Assuming the problem goes away I'd remove the jumper from S5-2 and connect it to S5-3.
Run test
Assuming the problem goes away I'd remove the jumper from S5-3 and connect it to K8-7.
Run Test
Assuming the problem goes away I'd remove the jumper from K8-7 and connect it to K8-8.
Run Test
Assuming the problem goes away I'd remove the jumper from K8-8 and connect it to K8-11.
Run Test
Assuming the problem goes away I'd remove the jumper from K8-11 and connect it to K8-12.
Run Test
Assuming the problem goes away I'd remove the jumper from K8-12 and connect it to K1-11.
Run Test
Assuming the problem goes away I'd remove the jumper from K1-11 and connect it to K1-12.

At some point in the test steps above the problem will come back. When it does it'll indicate where the ground path in the latching circuit is faulty.

Thanks guys!!! I will let ya'll know what I find out

Ran gen set Sunday and everything worked fine. Started with a 20amp load for 20 mins with no issues. Then increased to a 40amp load for 30 mins. Decided to increase load to 61.5 amps and genset ran flawless for 1hr. I was happy that my cleaning of contacts and switches work but was ready to go deeper into it if needed. Now just need to do a 4-6 hour run test. Thanks again guys!!!!!!

How about a little more detail, on what you did.

For the cleaning I cleaned the contacts of the K1 and sprayed contact cleaner on the S6 and S8 switches. I have 2 ea. 5kw heaters from amazon and 1 ea. 40amp heat strip that I used for my load. When I did my 20amp test I just unhook one heat strip from the 40amp heat strip. Once the test ran to 20 mins with no issues, I turned my two 5kw heaters on high and let them run also. When checking the amps being pulled the 5kws heaters were at 10.3 and 10.9 amps and the heat strip was at 21.6. The volts at L1 and L3 where 120. Then ran the 2 5kws and 20amp heat strip for 30 mins with no issues and all the gauges worked great also. For my final test I turned the other heat strip on and it pulled 40.3 amps along with the two 5KW heaters for a hour with no issues what so ever. I even turned the 40amp heat strip off and cut it back on just so see how gen set handle it and it lugged just for a second or two when load was applied like it should. Then when shutting down I cut the heat strip off first and let genset run a few mins before I cut the two 5kw heaters off. After I cut the 5kw heaters off I let gen set run with no load for a couple of mins and then shut it down. All in all I am very happy how the gen set ran. Thanks again guys for the help.