When on shore power and charging, the L2 MPII shows a negative value on AC out L2. When disco, from shore ac out 2 positive values. When on shore not charging reads positive values.
Has done this since unboxing. Ive scoped I’ve DVOM’d everything more than once. Would like to figure it out while I have some beard left.
Im not finding any results when I try to search the topic. Any insight will be greatly appreciated.
Thank you.
Is the autotransormer neutral connected to the shore power neutral?
If so, the AT is in parallel with the grid and will send current back.
No sir, N goes straight to the distribution panel with L1 and L2 from the AT.
Shore is a separate line to a seperate panel that connects to the multis only.
Ground relay is enabled on the multis and signal wired to the AT. The AT switches off its ground relay when charging with shore power. The ground relay indicator light on the AT illuminates when shore power is disconnected.
Thank you kindly for responding.
Is there any chance the neutral current from the AT is being sent back over the ground lines to the shore power, not due to ground-relay in the AT, but due to a Neutral-Ground bond in the boat/RV/vehicle panel?
This would be called “objectionable current”. One way to test for it is to put an AC clamp meter on the ground conductor going to shore power.
I will do just that and let you know. Thank you for the lead.
Ok. All Systems Nominal.
Unfortunately I do not have a definitive awnser as to what circuit was causing the negative value. I was unable to detect any current on the shore neutral. I installed a Canadian Cadet 240 split phase heater that I had been working on for a long time now. (Great heater btw) And I changed out the battery that runs the back up genny. When doing so i did clean all connections and disconnected the AC out puts for better access to my battery task. Reconnected everything. And it was sometime later that I heard the “song”. Its what I call it when the system whirrs, a faint, lovely yet eerie sound. Like a ghost humming a slow ballad. The power room only sounds like this when everything’s perfect. Or atleast as close to it as we can get.
I sincerely apologize for the laps in time. That life thing im sure you know all to well about…
My hunch is something must have bridged the connection at the generator. Its the only thing that shares any part of the shore circuit. Unless it was the disconnected wires going to the heater? I am unable to see how that could have been the cause. im going to blame technique on my part for not detecting the “objectionable current” with my scope or my meter.
If not for your advice I wouldnt be hearing the song right now. I Thank You Kindly. For your time, your knowledge and willingness to share it. Please know, that I am grateful for it.