How do I explain it? Potential difference in the system discussed is independent

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Discussion Overview

The discussion revolves around the independence of potential difference in a system involving two voltage sources: an AC mains voltage and an inverter voltage sourced through a battery. Participants explore the implications of their phasor relationships and how they may or may not affect each other, particularly in relation to shared grounding and circuit interactions.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant asserts that the two systems (AC mains and inverter) are independent because they only share a common ground and do not form a complete circuit with each other.
  • Another participant agrees with this viewpoint, suggesting that without a common return path, there should be no interaction between the two systems.
  • Conversely, a colleague argues that the differences in voltage and phasor relationships could adversely affect the loads connected to both systems, suggesting that fluctuations in the AC mains could influence the inverter voltage due to the shared neutral.
  • Some participants reference experiences with wiring practices, noting that improper connections can lead to issues such as ground loops and interference, which could complicate the independence of the systems.
  • There is mention of the differences in electrical standards between regions (e.g., US vs. European systems) and how these might impact the discussion.
  • Several participants emphasize that frequency and voltage differences should not inherently cause issues if the systems are wired correctly.
  • One participant shares a personal experience with grounding issues in a laboratory setting, indicating that grounding practices can significantly affect system performance.

Areas of Agreement / Disagreement

Participants exhibit a mix of agreement and disagreement. While some support the idea that the systems are independent, others challenge this perspective, suggesting potential interactions due to shared components. The discussion remains unresolved, with multiple competing views presented.

Contextual Notes

Participants note that the discussion is influenced by different electrical standards and practices, which may affect the interpretation of system interactions. There are also references to specific wiring practices that could lead to complications, but these are not universally agreed upon.

  • #31


b.shahvir said:
Dear Vishal,

In lieu of the original attached schematic, both the systems are independent and both share only a common Earth conductor for protection. This is how most of the electrical systems are inter-connected with each other for protection.

Abnormilities in either circuit will never affect each other as both are independent closed circuits feeding independent loads. Hence, in my opinion, your colleague is wrong!

Regards,
Shahvir
I know, but I will try to make him understand that, may be the way ssana has put it.
That may do the trick.
 
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  • #32


yungman said:
Do you know even if the wire you use is 10 gauge or 8 gauge. DC wise is very low resistance. Because of the inductance, any moderate frequency, it is quite high impedance. There are electronics that communicate through the AC wall plug. YOu plug the transmitter in one wall plug of the house and recievers in different plugs throughout the house, you can set up a communication link throughout your house using the AC wires! That is noise you are talking about! Big time. Once you go into AC( not 60Hz AC), all bets are off.
But Yungman, the ckt I posted in the DC part is a pure DC ckt, with battery source. So is it still a problem?
 
  • #33


vish_al210 said:
But Yungman, the ckt I posted in the DC part is a pure DC ckt, with battery source. So is it still a problem?

In a small way, yes. As I said, there are voltage drop on [DB] due to ckt B, ckt A is going get different voltage from the battery supply. Yes if it is all DC, it is not that important.

BUT did you really read my long post on how ckt A or ckt B can inject noise even though it take DC power?
 
  • #34


yungman said:
In a small way, yes. ...BUT did you really read my long post on how ckt A or ckt B can inject noise even though it take DC power?
Hi, sorry Yungman, was entangled with my wrk the last few days.
And well yes I did go through the :) long post, actually was not that long.
I thought the toroid is to protect the ckt from noises (EMI, ESD, Switching noises) from the power distribution side and also to protect the other devices on the main lines from the switching noises. But in the example that you have cited the ckts (laptops or any other appliance) share the same power source (both phase and neutral). That is a problematic situation.
I don't know why that would apply on the ckts that we have been discussing here. If I am missing something do let me know...
 

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