24v to stable 1.5v drop?

Discussion in 'The Projects Forum' started by paco811, May 15, 2015.

  1. paco811

    Thread Starter New Member

    May 15, 2015
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    0
    Hi, I am very new to this site, but I am currently completing first year mechatronics and have become stuck with creating the right voltage for a particular motor. We are building a crane and I have designed trolley system around this really small hi-torque motor that runs at max eff= 1.5v @0.16A and the power supply is set to 24v and we can not use any batteries. I have designed the circuit below (sorry about the crappy schematics) to use on the 3 motors, with just inserting the appropriate value zener diodes for voltage (12v & 4.5v) and resistors to limit current. But as I am finding out now is that 1.5V zener are pretty much impossible to get, well at least within the next week and a half anyway.
    I know a simple resistor voltage divider circuit wont work because the motors fluctuating impedance, I have found 1.5V voltage regulators but I don't know if this can be used in the same way as the zener. I also thought of this way (second pic) but I dont know about voltage regulators at all.
    Any suggestions or help would be great! If your from Australia/Brisbane any suggestion of parts I could pick up from places like jaycar would be amazing considering the tight time schedule.
    cheers
    EDIT: 1.5V voltage regulators also seem like they are hard to come by.

    Screen Shot 2015-05-15 at 5.53.50 pm.png Screen Shot 2015-05-15 at 6.07.56 pm.png
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Last edited: May 15, 2015
  3. MrChips

    Moderator

    Oct 2, 2009
    12,447
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    My offering:

    [​IMG]

    Edit: You would need a power transistor with a heat sink.
     
    Last edited: May 15, 2015
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,801
    1,105
    A switched-mode DC converter is the most efficient way to drop the voltage. Any linear voltage-dropper/regulator is going to dissipate quite a lot of heat (at least 3.6W for each motor load). Here's one option for a linear regulator:
    1V5-supply.gif
     
  5. paco811

    Thread Starter New Member

    May 15, 2015
    2
    0
    Thanks heaps for all the help everyone! I have decided to swap the motor, after investigating this suggetions further, it was starting to over complicate the design. Its not very pretty but it works.
     
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