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Optimize DC motor to run on 2V?

  1. Nov 14, 2011 #1
    What would you do?

    Would you increase or lessen the turns of the coils?

    Would thinner or thicker wire be better?

    Would you increase the size of each of the iron cores of each pole of the armature?

    How do bearings assist the motor?

    Would simultaneously using both a perma magnet and an electromag interfere with each other?

    Would you _______________ ....?

    Plz help :S
     
    Last edited: Nov 14, 2011
  2. jcsd
  3. Nov 14, 2011 #2
  4. Nov 16, 2011 #3
    Use a drive.
     
  5. Nov 16, 2011 #4
    What's that? o_O is it something I can get without spending over $50? o_O
     
  6. Nov 16, 2011 #5
    One Day
    Basically - in this case is would be modifying the voltage to match the motor - instead of modifying the motor to match the voltage.

    So you have a 2V source of power - correct?

    How big is the motor? What is it's rated voltage and current?
     
  7. Nov 18, 2011 #6
    Yes for full marks, the motor must be able to run smoothly on 2V.

    I have not built the motor yet (the reason I'm asking all these questions is so that I don't have to rebuild it and use up more of my parent's money). However, the projected size of the armature as of now, is about 9-11cm in diameter and 7-9cm in length.

    Would a lighter and smaller armature with less coils be better than a larger and heavier one with more coils? Would the flux generated by the larger armature make up for its weight?
     
  8. Nov 18, 2011 #7
    Ohhhh - I thought you were asking how to optimize an existing motor. If you are building one from scratch - not quite my realm.

    The dimensions you give seem very large - weight is your enemy.

    For low voltage you will need thicker wire and fewer windings. Without knowing all of the requirements it is difficult to give much advice - optimize can mean a lt of different things. I also did not realize it is an assignment.
     
  9. Nov 18, 2011 #8
    Yeah it is very large...the main reason for that is because the bolts I got from bunnings were too large xD

    So the answer is less coils but lighter weight is better?

    Oooooft. the wires I got were 0.25mm and 0.4mm diameter magnet wires.

    Btw, this is my current design:

    LZseW.jpg

    For full res: http://i.imgur.com/huDRz.jpg
     
    Last edited: Nov 19, 2011
  10. Nov 18, 2011 #9

    cmb

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    Makes little sense to run a motor on such low volts. The resistive losses would be excessive. What's it for? Why are you creating such a specification?
     
  11. Nov 18, 2011 #10
    It's for my assignment for physics. On the criteria it says:

    Performance
    Starting the motor

    -Electric motor is self-starting on 2-12V and can run continuously on 2-12V - 5 marks
    -Electric motor is self-starting on 6-12V and can run on 6-12V - 4 marks
    -Electric motor is self-starting and can run on 12V - 3 marks
    -Electric motor needs assistance to start and can run on 12V - 2 marks
    -Electric motor needs assistance to start and shows limited movement - 1 mark
    -Electric motor does not start - 0 marks

    I'm trying to get 100%, or should I just sacrifice the 1 or 2 marks?


    EDIT: Oh btw, for the electromagnetic panels, do I connect one or both ends of the wire to the power supply?
     
  12. Nov 18, 2011 #11
    Ah heck, I'll just work with whatever I've got xD wish me luck! :D
     
  13. Nov 18, 2011 #12
    xD my armature is massive LOL
     
  14. Nov 19, 2011 #13

    cmb

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    So the assignment is to actually build a motor? OK, so now you need to specify what qualifies as 'run continuously'. I presume this doesn't mean an inertial load, it just has to get its own armature rotating?.. In which case [if my guess is right], think small.... Think real small. You are over-thinking the assignment.

    (What is the relevance of the 3-phase type motor design you've posted up?)
     
  15. Nov 19, 2011 #14
    By 'run continuously' it means runs for two minutes, without load. Well I've already started my first model, sooo if I have time, I'll try to make a much smaller one :D

    Yeah, I'm probably waayyyy overthinking this XD

    My only wish is that this runs on at least 5 volts, so at least its only one mark off :D

    EDIT: Oh yeah, design and originality are also two more of the criterias, hence why I am doing this xD Some people in my class are seriously just making a motor with just the coil (no armature) =_=........
     
    Last edited: Nov 19, 2011
  16. Nov 19, 2011 #15

    cmb

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    How is this design of yours, above, supposed to work?
     
  17. Nov 19, 2011 #16
    theres noreason to do that.. better do aomething like engine of internal ocmbution that will work on small omount of electric energy and magneticy!
     
  18. Nov 19, 2011 #17
    WELL.. umm...ummm..The shaped galvabond sheets encompassing the armature are supposed to act like radial electromagnets. The steel hangers lined on the sheet and wrapped with the copper wire are supposed to act like an iron core (since the galvabond is being a bastard =_=). Therefore, the actual sheet is only supposed to act as a frame, so the whole thing doesn't fall apart. The coils of one plate, will be connected to the positive terminal, whilst the other, the negative terminal. This should create opposing fields (I'm so rusty at this stuff D:). When a current is run through the wire, it should become a magnet xD (*fingers crossed*) EDIT: LETS ALSO HOPE IT DOESNT MELT!! DX

    As for the armature itself...its pretty much normal (although excessively huge xD), except that its got three splits (120º each) on the commutator to match the three poles of the armature. I'm using carbon brushes designed for 12V, but lets hope itll work on at least 6V. :S

    The whole thing is connected to a transformer/power supply which can provide voltages of 2-12V. The perma mags are for back up xD.

    Let's hope it works! :D

    Oh btw heres how its going so far:

    AA Battery for size reference.

    3FPUS.jpg

    I also added clipped hangers in between the bolts because I've got OCD :D well and because they're good cores, but I hope they didn't add too much weight. They're really light, but the armature is not xD
     
    Last edited: Nov 19, 2011
  19. Nov 19, 2011 #18
    lolwut. O.O
     
  20. Nov 19, 2011 #19

    cmb

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    Once one pole of the armature 'locks' with the opposite pole from the fields of the stator, why would it rotate any further? I presume we're talking a DC current here?
     
  21. Nov 19, 2011 #20
    Umm this guy can explain it heaps better than me xD

    Go to 4:39
     
    Last edited by a moderator: Sep 25, 2014
  22. Nov 19, 2011 #21

    cmb

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    Sure, his diagram looks just fine. But you appear to have coils around two cores that would only produce magnetic fields right at the ends of those two arcs. You need the 'N' field for most of one side, and S field most of the other. Your coils (if I understand your diagram) would produce mag fields only across the gap at the very top and bottom of the drawing.
     
  23. Nov 19, 2011 #22
    Okay I'm officially confused xD What do you mean by 'two arcs?' [EDIT: Oh do you mean the electromagnets?] :S The coils weren't completed in the picture, and the commutator is supposed to be on the empty right hand side of the dowel, if that solves anything xD I can always centre/shrink my electromagnets on the two cores, the diagram was just a quick one i did in 2 minutes lol.

    Could you please explain again, with diagrams :D? I'm not following... D:

    Oh btw, if I connect both ends of the coils of one of the electromagnets to the same terminal, and the coils of the other electromagnet to the other terminal, would that short circuit?
     
    Last edited: Nov 19, 2011
  24. Nov 21, 2011 #23
    ITS ALIIVVVVEEEE!!!! :DDDDD

    ...although I've only tested it with perma mags xD I have yet to complete my electromagnet 8D
     
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