MOSFET or Rheostat or Potentiometer pros and cons?

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Discussion Overview

The discussion centers around the selection of components for controlling the strength of electromagnets in a project involving levitation using a Halbach Array. Participants explore the pros and cons of using potentiometers, rheostats, MOSFETs, and other energy controllers, considering factors such as power loss, complexity, and battery versus outlet power sources.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants note that rheostats and potentiometers serve similar functions for DC current, emphasizing that either could be suitable if power loss is not a concern.
  • Others suggest that for minimizing power loss, active current controllers should be considered, despite their added complexity and cost.
  • A participant expresses a preference for battery power over outlet power, indicating a desire to avoid transformers and seeking ways to create a variable speed motor and electromagnet controller without purchasing new components.
  • One participant raises a question about the specifications of the electromagnet, such as size and field strength, indicating that these factors may influence the choice of control method.

Areas of Agreement / Disagreement

Participants generally agree on the basic functionality of rheostats and potentiometers but express differing views on the implications of power loss and the suitability of active controllers. The discussion remains unresolved regarding the best approach for the specific application of electromagnets.

Contextual Notes

There are limitations regarding the assumptions about power loss and the specific requirements for the electromagnets, which have not been fully detailed. The discussion also does not clarify the mathematical or technical specifics of the proposed solutions.

Who May Find This Useful

Individuals interested in electrical engineering, particularly those working on projects involving electromagnets, variable speed motors, and energy control systems.

Yitzy
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Preface: I'm a chemical engineering undergraduate student but as small-time and noob electrical engineering hobbyist. I really only have minimal experience in circuitry and the like.

I want to build a series of electromagnets with a variable their strength in order to levitate an opposing circular Halbach Array up to and from a certain height. This array will be separated from the electromagnets so I don't have to worry about it "sticking" to the electromagnets when off. There will also be a guide pole through the center of the array so that it stays balanced.

What would be the different factors I should consider when using a either a potentiometer or a MOSFET or PWM or some other kind of voltage variant?
Are there other kinds of energy controllers, that I could potentially use?
How do they differ from each other?

Thank you so much in advance.
 
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Rheostats and potentiometers are just physically different versions of exactly the same thing and for DC current they have the same effects. If you don't care about power loss/waste in those passive current limiting elements then either one would be fine. If you would like to avoid that loss/waste at the expense of some complexity (and cost), look into active current controllers
 
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phinds said:
Rheostats and potentiometers are just physically different versions of exactly the same thing and for DC current they have the same effects. If you don't care about power loss/waste in those passive current limiting elements then either one would be fine. If you would like to avoid that loss/waste at the expense of some complexity (and cost), look into active current controllers

Thank you for the response!

That would be perfect, but I need the device to either run on battery power or through an outlet (Battery being the preference as I don't want to deal with the craziness that is a transformer...Yet) . I also want to be able to create my own variable speed motor (and electromagnet) controller, without having to buy new active current controller.

Any tips?
 
If you don't care about reduced battery life due to the waste in a pot you have no problem. Is this something that you plan to run for extended periods?
 
Powerful electromagnets tend to need large currents. Got any more info on the electromagnet? Size? Field strength?
 

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