Once I Saw It, I Knew The Cause

No One Understood Why I Immediately Knew The Answer

         Date: Sometime in June/July 1979

         Location: Somewhere in the Pacific Ocean on board the USS Sargo, SSN 583

         True story. Names have been changed to protect the ‘innocent’.

         First, a little background about the USS Sargo, and the conditions in Electrical-Division (E-Division) when I reported aboard.

         I had served 4 years on the USS Theodore Roosevelt, SSBN 600 Gold, and had transferred to the USS Sargo in October 1978 to serve as the E-Division Leading Petty Office. E-Division did not have a good rapport with the Submarine Base Shops and I don’t remember why. That was one of the first things I set about to correct. A second factor that was even more of a concern, was that the division I was to lead had failed a recent 3M inspection. They were the only division on the boat to fail that inspection. Another priority to address. (We passed the 3M inspection a month or two later with flying colors). A third concern was that each member of the division had a piece of equipment that they took care of. That meant that when it was time to perform a Preventicve Maintenance procedure (PM) on it, it would be assigned to that man. If he needed help, someone would help him, but he was responsible to see it was completed.

         Three major concerns that needed to be addressed immediately.

         First, I met with the shop Leading Petty Officers (LPO’s), we discussed our past performance. I explained that my division would no longer be irresponsible about jobs sent to the shop. I asked them to give me a chance, and let me know if anything occurred that was not in keeping with standard procedures. I’d had a lot of experience in dealing with the same kind of shops on Tenders while stationed on the Roosevelt, and knew how things should be coordinated and completed. Needless to say, we had things turned around before leaving on WestPac in January.

         The fastest (and easiest) thing to correct was the 3M inspection results. Let’s just say that the Preventive Maintenance (PM) schedules were not written as they should have been. That was an easy correction to make. In doing so, I assigned PMs to anyone I thought could do the job. This meant that a man would be performing a PM on a piece of equipment he hadn’t worked on before. After posting the new schedule, someone wrote “WTF” next to their name, because this was new to him. Knowing it was most likely the person I’d assigned to that PM, I asked him about it. He said “Yep, I don’t work on that machine.”

         My reply was something like, “It’s a piece of E-Division equipment we perform PMs on, so now you do.” I then had the division gather together in the Stern room for a brief meeting. I explained what I had done, and why. Of course there were comments about not knowing how to do the PM, and I essentially said, :”Ask the man who's been doing the PM all this time if you need to. The issue is, suppose that Roy is on leave for a month, and a PM is due on his equipment. What do we do?” Note: The Commanding Officer walked through the Stern Room during our meeting. He later complimented me on what was being said in that meeting.

         The reply was “Wait for him to return.”

         I replied, “Well, Roy was injured in a major accident and won’t return for a few months. Now what?”

         There were a few moments of uneasy silence, they had gotten my point. In correcting the 3M Inspection failure, I had also corrected the issue with one person being the only one who performed PMs on a particular piece of equipment.

         We left on WestPac in January, and stopped in Guam, Yokosuka, Japan, Hong Kong, and Subic Bay, Philippines. The stop in Subic Bay was extended some because of mechanical issues. We finally left for our extended deployment in April. We were supposed to return to Pearl Harbor in June, but because of circumstances beyond our control, we were extended to mid-August. During our extended stay in the Philippines, a senior chief (E-8) electrician reported aboard as LPO, and I was now his ‘Leading First’ (I was an E-6, there was nothing I could do, or wanted to do). It was fine with me.

         Now, on the real subject of this story.

         In operating a Nuclear Reactor, you record log readings hourly, as I assume happens on most power plants. One of the things we noticed, is that the Starboard (right side) AC bus had a steadily lowering ground. The electrical system on every boat I was on is ungrounded. 440 VAC, 3 phase on the AC bus, 270 VDC on the Battery/ SSMG DC bus. All of it is ungrounded though.

         Normal grounds ran about 1.5 Meg Ohms (million ohms), but the ground on the Starboard bus was steadily lowering, and was now less than 1 Meg. Standard ground isolation procedure was to open a large breaker remotely from a panel called the Electric Plant Control Panel (EPCP). This divided the bus, with the ‘Non-Vital’ bus isolated from the ‘Vital’ bus. But when we did this, the ground disappeared! Of course the powers that be (senior officers like the Engineers, XO and CO) felt the ground had to be on the breaker itself. I explained that there was no way it could be, but we were told to ‘rack it out’ anyway. We did that, and found there was no ground on it, just as I had said.

         The ground continued to lower, it was now almost out of spec. One day (or night) the messenger woke me and said I was wanted in Maneuvering. When I for there, my LPO said, “Petty Officer Dorrell, you’re aware of our starboard bus ground, but look at this. The EO (the person on watch operating the EPCP) split the starboard bus as usual. My LPO said, “The past hour, when he isolated the bus, he accidentally took readings on the Port Bus.”

         At this point the EO took the ground reading on the Port bus, and it was exactly what the Starboard bus had been before opening that breaker. Under our LPO’s direction, he then took reading on the Starboard bus to show that its gronc reading was now at normal levels. My LPO said, “What’s going on?”

         I looked at him and said, “The ground is on the Port Motor Generator (SSMG), in fact, it’s on the DC end. I’m going back to my bunk, I have the next watch.” Of course I didn’t get back to sleep, I had to prove my ‘theory’, except it wasn’t a theory. I knew where the ground was. I asked the Engineering Officer of The Watch (EOOW) if we could shut that starboard breaker, and open the Port SSMG AC Breaker. I told him, “You’ll see the ground is on the output of the MG, not on the Non-Vital bus.”

         He asked how I was sure it was on the MG, and not something on the Vital bus. I explained that the ground detector was connected to the MG output, not the Vital bus. That being the case, with the MG AC breaker open, any ground on the bus would be on the MG itself. He finally agreed to have that done, and sure enough, the ground was on the MG output.

         The next step was to pull out the prints and show my LPO why the ground shifted as it did. He still didn’t understand why it could be on the Starboard bus when it was really on the Port SSMG. More prints. I showed him how the load sharing circuit was wired, and that when in a Normal Full Power Lineup, the load sharing circuit was powered from one Vital Bus to prevent any AC power ripples. When one of the AC breakers was opened, the load sharing circuit on each side was powered from its respective SSMG. That explained why the ground could shift as it did. No one else in E-Division knew this, and of course I was asked how I knew it. I explained that while on the Theodore Roosevelt, I had attended many week long schools during our off-crew periods. During one of them, I had learned how the load sharing circuit worked and that stuck with me.

         As it turned out, we couldn't correct the ground on the SSMG, we could keep it in spec, but we couldn’t get it up to its original reading. It wasn’t until the boat entered the shipyard (after I was transferred off of it) that it was corrected. They had to disassemble the Motor Generator and take the rotor to the shop to correct it. The root-cause was an excessive build up of carbon dust from the DC end brushes. This was most likely due to the age of the boat, and the Preventive Maintenance not being properly performed for many years.

         That was my ‘moment’ in the spotlight so-to-speak. There were others of course, but this one was a little unique because no one else knew this one small fact.

Jim Dorrell
7/9/22