Page 1 of 3 123 LastLast
Results 1 to 10 of 23

Thread: Adjustable DC 1800

  1. #1
    Join Date
    Apr 2008
    Location
    Ann Arbor, Michigan
    Posts
    7,037

    Adjustable DC 1800

    181010-2438 EDT

    If you needed a continuously variable DC voltage supply to run experiments in the early 1800s what would you use to perform this function?

    .

  2. #2
    Join Date
    Apr 2015
    Location
    phoenix az
    Posts
    139
    im not sure but i am sure you had to make it. and i bet it resembled a speed control for a lionel train! how much d.c. voltage are we talking? im sure they used a home made variac with windings..

  3. #3
    Join Date
    Sep 2008
    Location
    UK
    Posts
    12,021
    Quote Originally Posted by gar View Post
    181010-2438 EDT

    If you needed a continuously variable DC voltage supply to run experiments in the early 1800s what would you use to perform this function?

    .
    A DC generator with a variable speed prime mover possibly?
    Si hoc legere scis nimium eruditionis habes.

  4. #4
    Join Date
    Sep 2008
    Location
    UK
    Posts
    12,021
    Quote Originally Posted by rambojoe View Post
    im not sure but i am sure you had to make it. and i bet it resembled a speed control for a lionel train! how much d.c. voltage are we talking? im sure they used a home made variac with windings..
    A variac wouldn't do you much good on DC.
    Si hoc legere scis nimium eruditionis habes.

  5. #5
    Join Date
    Apr 2008
    Location
    Ann Arbor, Michigan
    Posts
    7,037
    181011-0759 EDT

    A little study of electrical history shows that the above mentioned items did not exist.

    Some references:
    https://en.wikipedia.org/wiki/Electricity
    https://en.wikipedia.org/wiki/Timeli...ic_engineering

    .

  6. #6
    Join Date
    Feb 2016
    Location
    Illinois
    Posts
    1,039

    Adjustable DC 1800

    Depends on the voltage range you need. I have built such an animal using an LM317 chip. I believe it’s limited to about 36V max.

    Edit: I thought you wanted a modern alternative to run some old stuff....I see now you want to know what they used then.....never mind.

  7. #7
    Join Date
    Jun 2004
    Location
    Cherry Valley NY, Seattle, WA
    Posts
    4,740
    How about a variable resistor? That may have "steps " depending in the design, not sure if that meets your criteria. It wouldn't be hard to make a truly variable one using conductive fluid.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  8. #8
    Join Date
    Sep 2008
    Location
    UK
    Posts
    12,021
    Quote Originally Posted by gar View Post
    181011-0759 EDT

    A little study of electrical history shows that the above mentioned items did not exist.

    Some references:
    https://en.wikipedia.org/wiki/Electricity
    https://en.wikipedia.org/wiki/Timeli...ic_engineering

    .
    DC machines were around since the 1830s.
    Si hoc legere scis nimium eruditionis habes.

  9. #9
    Join Date
    Apr 2008
    Location
    Ann Arbor, Michigan
    Posts
    7,037
    181011-1006 EDT

    In the early 1800s little was known about resistance. There were no alloys for making high resistance resistors. There were no variable wirewound resistors with a sliding contact. The concept of a potentiometer may not have existed.

    It is hard to make a constant voltage source with resistance. This really only became feasible with the advent of the vacuum tube.

    Instruments for measuring current were very crude. The earliest was a wire and a compass.
    https://en.wikipedia.org/wiki/Galvanometer
    The concept of current was in its development stage.

    Much common knowledge today was a mystery in 1800.

    Generators https://ethw.org/Generators

    .
    Last edited by gar; 10-11-18 at 10:40 AM.

  10. #10
    Join Date
    Jun 2007
    Location
    Fredericksburg, VA 21 Hours from Winged Horses with traffic
    Posts
    196
    Circa 1800 would be Leyden Jars.....

    Growing up in Richmond and fascinated with electricity, I knew we had the world's first electric street car system in the world.

    1888 (January 9) – Company opened its first electric line with six cars. This first electric streetcar system served as a demonstration model for municipalities and countries from all over the world.

    Started by the predecessor to Dominion Energy: VEPCO (Virginia Electric and Power Co., Virginia Railway and Power Company, Richmond City Railway Company. Et all.

    Power (electricity) was made by hydro electric, tapping the James River.

    So, I'm with Besoeker, variable energy input (wind, hydro, steam, belt) to a DC generator capable of the loads.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •