Is my solenoid's resistance too low?

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Discussion Overview

The discussion revolves around the calculated resistance of a solenoid being constructed, with participants exploring the implications of this resistance in relation to the solenoid's performance and power supply requirements. The scope includes technical calculations, conceptual understanding of resistance in inductors, and considerations for current handling.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant calculates the resistance of their solenoid to be 0.175 ohms based on the dimensions and material properties provided.
  • Another participant notes that there will be inductive reactance present initially, which may affect the overall behavior of the solenoid.
  • A different viewpoint suggests that the significance of resistance is context-dependent, questioning the relevance of how low the resistance is without considering the current that will be used.
  • The original poster indicates a requirement of 10A to achieve the desired magnetic field strength.
  • One participant mentions that ideally, an inductor would have zero resistance and highlights the need for a specific type of power supply that can provide low voltage and high current for the solenoid.

Areas of Agreement / Disagreement

Participants express differing views on the implications of low resistance in the solenoid, with some focusing on the technical calculations and others emphasizing practical considerations regarding current and power supply. The discussion remains unresolved regarding the significance of the calculated resistance in relation to the solenoid's performance.

Contextual Notes

The discussion does not clarify the assumptions behind the resistance calculation or the specific conditions under which the solenoid will operate, leaving some aspects open to interpretation.

thomsonm
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I've just calculated the resistance of a solenoid I'm making, but it seems far too low.

240 turns of 1.6mm wire, 30 turns per row, 8 rows deep.

total length of wire (L) = 21.96m
area of wire (A) = pi * (0.0008)^2 m^2
resistivity of copper (rho) = 1.6*10^-8 ohms m^-1

R = (rho * L) / A
R = 0.175

Is the resistance of my solenoid really only 0.175ohms?
 
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There will initially be some inductive reactance as well...
 
How 'low' the resistance of something is really doesn't mean anything. Someone once asked me how low of a resistance you could get 'before it shorts out'. A meaningless question. If the wire size you have chosen will handle the current you end up putting through there without burning up then you are fine. So what kind of current do you expect to put through the solenoid?
 
I'm need 10A to get the right magnetic field.
 
Ideally, an inductor would have zero resistance.
To supply a solenoid satisfactorily you tend to need an unusual sort of power supply - low voltage and loads of current available.
 

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