Automobile starter motor to lift weight?

Discussion in 'The Projects Forum' started by raviprakash.hegde, Dec 30, 2014.

  1. raviprakash.hegde

    Thread Starter New Member

    Nov 14, 2011
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    Hello Friends,

    I need to move 10 kg of payload from ground to 15 meters vertical height in 25 seconds(approx) on a metal pole.
    Setup is similar to this - https://grabcad.com/library/rope-climbing-and-descending-robot-1 (Pole instead of rope)

    Which type of motor is ideal for this application? and what would be the motor specification?
    Should be powered by 12V DC battery.

    Would an automobile starter motor (ebay - 2 wheeler starter) do the work?

    Thanks!
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    A starter motor should certainly provide the torque required.
    It does not show if it is a P.M. motor or a traditional series motor.
    Series motors have very high initial torque for instant on starting.
    You have to take care they are under load at all times, otherwise they can spin at a very high rate (runaway).
    But either should do it if of the starter motor variety.
    Max.
     
  3. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    I don't know how powerful the motor should be but I think it will need to be geared and should probably have a speed controller to control the ascent.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I don't think gearing would be necessary to increase torque, 10Kg is not that much for a starter, I would expect the one shown to be sufficient?
    Max.
     
  5. blocco a spirale

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    Jun 18, 2008
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    It may work without gearing but I assume that the motor will transmit its drive via a rubber wheel of some type and envisage the rubber disintegrating while the payload remains stationary, as soon as power is applied. The payload only needs to average 0.6m/s.
     
  6. crutschow

    Expert

    Mar 14, 2008
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    Note that a starter motor is a low duty-cycle device so it must have some time to cool between uses.
     
  7. raviprakash.hegde

    Thread Starter New Member

    Nov 14, 2011
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    Starter motors doesn't have gears?
    According to my calculations, for speed of 0.5 m/s, 60rpm speed at output shaft is needed.
    So, if starter motors rotate at 10k rpm, do I need respective gear ratio? (166:1)
     
  8. blocco a spirale

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    Jun 18, 2008
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    The speed of ascent depends on the final rpm of the motor and the diameter of the drive wheel. How big is the drive wheel?
     
  9. raviprakash.hegde

    Thread Starter New Member

    Nov 14, 2011
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    Yes. This should be possible. Because after climbing 15m pole it will have 10sec before climbing down.
    Also, it will have 30-60 sec time before climbing up again.
    Should this time gap be sufficient?
     
  10. raviprakash.hegde

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    Nov 14, 2011
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    Drive wheel diameter is 100mm
     
  11. blocco a spirale

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    Jun 18, 2008
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    Ok, so you need 2 revolutions per second or 120 rpm to achieve 0.6m/s.

    You may get this kind of performance from a large windscreen wiper motor.
     
    Last edited: Dec 30, 2014
  12. MaxHeadRoom

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    Jul 18, 2013
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    If my reckoning is right, that is less than 1.5Nm is required?
    Max.
     
  13. ronv

    AAC Fanatic!

    Nov 12, 2008
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    I'm not very good at this but I get around 150 RPM and 80 inch pounds. But your motor has no specs so it's hard to say.
     
  14. raviprakash.hegde

    Thread Starter New Member

    Nov 14, 2011
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    If my calculations are correct, I got 50Nm considering 100cm diameter drive wheel.
     
  15. raviprakash.hegde

    Thread Starter New Member

    Nov 14, 2011
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    But I feel this is too much to lift 10kg payload. I would be wrong.
     
  16. MaxHeadRoom

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    Jul 18, 2013
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    No It looks like ronv is correct I used the wrong sign, just under 10Nm.
    Alot may depend on whether the motor is a series (wound) field where there is considerable torque available, with a P.M. field it is fixed.
    Max.
     
  17. Bernard

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    Aug 7, 2008
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    Rough figures: 118 RPM, 44 in-lb; extrapolating from other gearhead motors gives me 1/10 hp, drawing about 16A @ 12 V or about 200W. Did onot find a match unless 2 motors used which might be easier than belts or gears.
     
  18. raviprakash.hegde

    Thread Starter New Member

    Nov 14, 2011
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    Thanks Bernard.
    Can you please show me the calculations. I want to learn.

    Yes I will be using 2 motors placed at 180 deg to each other, similar to the design in the link provided.
    https://grabcad.com/library/rope-climbing-and-descending-robot-1

    Can I use the automobile(2 wheeler) starter motor? (ebay - 2 wheeler starter)
    Unfortunately, I do not know the technical specification of this motor.

    Also, I do not know whether starter motors will have gears. I think they'll provide very high rpm (8k-10k rpm). But what I need is 120 rpm as you told.
     
    Last edited: Dec 31, 2014
  19. blocco a spirale

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    Starter motors are not usually geared down, and the one you reference appears not to be geared either.
     
  20. captainssbn

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    Sep 24, 2012
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    I would use gearing to help the motor match the ratios to get 25 sec .
     
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