Discussion Overview
The discussion centers around the current-carrying capacity of a wire with a diameter of 3 mm, particularly in the context of its use in transformers. Participants explore various factors that influence this capacity, including wire gauge, fusing current, and thermal considerations.
Discussion Character
- Technical explanation, Conceptual clarification, Debate/contested
Main Points Raised
- One participant inquires about the current capacity of a 3 mm diameter wire, noting concerns about insulation melting.
- Another participant references the American Wire Gauge (AWG) system, suggesting that a 3.264 mm diameter corresponds to gauge 8, which can carry 472 Amperes for 10 seconds before fusing.
- A different participant agrees with the previous claim but cites a different source, indicating that a 3 mm diameter is approximately equivalent to #9 AWG, which has a fusing current of 396 Amperes for copper.
- One participant seeks clarification on the concept of fusing current and asks about the continuous current capacity of the wire when used as a primary wire in a transformer, as well as its potential kVA rating.
- Another participant discusses the complexities of wire usage in transformer windings, emphasizing the importance of mechanical design, insulation, and core heat, and suggests a holistic approach to estimating temperature rise and wire sizing.
Areas of Agreement / Disagreement
Participants express varying opinions on the current capacity of the wire, with some agreeing on the fusing currents from different sources, while others raise additional considerations regarding continuous duty and thermal management in transformers. The discussion remains unresolved regarding the exact current capacity for continuous use.
Contextual Notes
Participants note that the fusing current is not the same as the continuous current capacity, and emphasize the need to consider thermal resistance and potential hot spots in transformer applications. There are also references to different sources of data that may have varying results.