Kinda agree with Jim. I am an electrical engineer and write all the safety procedures on how to test my equipment and troubleshoot it, plus I know how to work on all of it as well and how to use the test equipment to get the right answers. It's not necessarily for the faint of heart if you aren't trained or understand how to work it and can cause loads of problems.
That said, the easiest way to isolate the problem is to open the electrical panel at your house when it is acting up and measure the 2 phases coming in to ground and to each other. If you have an imbalance or aren't getting the right voltage then any of those measurements tell you what your problem is and potentially where.
It sounds like you have either a problem with a phase drooping or the ground\neutral failing. Whether this is at the electrical utility transformer\lines or at your main power box or in a sub-panel somewhere in the house is not something I can determine over the internet. Any electrician worth their license can make measurements with a multimeter and determine it in pretty short time.
I had a squirrel chew through my earth ground from the transformer several years ago and ended up with a 40V imbalance between phases that would do very similar weirdness you describe. When I called the power company to tell them they were completely uninterested until I told them exactly what the measurements were and then they perked up and had a crew there in less than 2 hours to have it fixed - a missing neutral can kill someone and they were not going to take on that liability by blowing me off.
|