The waveform on this webpage is an example of the decaying oscillatory type of ringing that GoldDigger described. The ringing is initiated at the fast rising and falling edges of an applied square wave.
Do you have anything with a DC motor, like a garage door opener?The clamp I got does measure DC as well. It is a TA019 from the same company as my scope. Yesterday I did in fact see some DC components on my scope, but it must be intermittent because it was not present while I measured today. I was specifically looking for it since you mentioned it the other day. I'll keep monitoring it to see if it shows up again and I will ask the engineer about it as well. What could cause that? Seems really strange. Also, should the current frequency be 60hz just like the voltage frequency? I was seeing some fluctuation. It spiked a few times, the highest being 72hz for a split moment then returned to bouncing up and down between 59hz-61hz. It may not matter but figure I should ask anyways.
GDO's only operate for maybe 10-15 seconds at a time.Do you have anything with a DC motor, like a garage door opener?
“ shoot low boys their riding shetland ponies”
No surge protective equipment here. I am posting some new findingsDo you have any surge protectors on your circuits? You might try unplugging them to see if that has any effect on the current waveform.
Also, if you have a whole house surge protector that's wired in (not the kind that looks like a circuit breaker) then try putting your current probe on each wire of the protector to see if any significant waveform is present.
I had a thought that maybe a defective surge protector could be drawing current near the peaks of the voltage waveform and thereby cause the sharp peaks in the current waveform on phase B. Although if that was happening I'd expect the surge protector to get hot and eventually burn out.
Thanks for doing the math. Does this give you any ideas on what could cause this? Also, the engineer I am working with thinks we might having a failing buried cable. We are discussing megging from the transformer to the meter.The absolute values of the two currents are close but the power factors are different. For instance, I1 20.1 A cosfi=0.8 but I2=20.3 A cosfi=0.957.
The real part of I1=16.08 A and the reactive -12.06 [absolute=20.1]
The real part of I2=-19.426 A and the reactive +5.89 [absolute=20.3]
The real part of Io=-3.346 A and the reactive -6.17 [absolute=7.018]
Okay I tested most of what you asked for in post #196. I will try to keep everything as organized as possible so it will be easy to follow.200917-2128 EDT
This thread is far too long without getting anywhere. There are many posts that make no sense relative to the problem.
The problem and experiments are not described clearly.
I have only intermittently read some of the posts.
Apparently we have a single phase system with a center tapped secondary from the power company. Really a two phase source when viewed relative to the center tap. We can expect the power transformer center tap is grounded (earthed) via a ground rod at the transformer. Then three wires come from the transformer to the main panel. At the main panel the neutral wire is again grounded (earthed).
We need to know if the Pico common (shell of the BNC connector) has a DC path to the EGC of the AC power cord to the computer. If it does, then this has to be opened.
I suggest that the AC neutral at the main panel be used as the scope common reference.
We need to know what is being used for current transducers. Coordinates on plots need proper labeling.
The wiring to the water pump needs to be completely opened.
With the main panel disconnect open we need to see the voltage waveforms of each hot to neutral, the EGC to neutral, and a screw driver somewhere in the yard to neutral. Also separately the currents in each hot, and neutral coming into the meter, and the grounding wire to the meter ground rod.
This is the starting point.
You guys are way more educated than I am, so ... if I make you laugh, don't insult me too hard.Hi, I have run into a strange issue and can't seem to find any good information on this so I am hoping someone here can help me understand how this can happen. We have been having some mild electrical issues in our home ranging from flickering lights to computer hardware damage. We have had 2 electricians out to check the electrical wiring in our panel and everything seems to check out. We then had our electrical provider out to check the wiring in our meter base and the guy they sent said all the wiring looks good, but he also measured the current on both of our hot legs and on our neutral and discovered that our neutral current is not equal to the difference of the two hot legs. I spoke to our electrician again and he told us to get both hot legs to 20 amps and check the neutral current again. I got phase A to 20.1 amps and phase B to 20.3 amps and our neutral current was still showing 7 amps. Clearly something isn't how it should be. So my question is how is this possible?