Help me Out pls!!

Discussion in 'The Projects Forum' started by arunshan92, Sep 29, 2013.

  1. arunshan92

    Thread Starter New Member

    Sep 29, 2013
    3
    0
    I've been searching for this for like 2hrs straight now.......:mad:

    We are planning to make a small trike say the added weight of two people and frame is abt 200Kg.... Will a 500w dc motor suffice????????? Or how mch torque will it need to move??????? Pls help me out.....:(:(:(:(
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,003
    3,232
    Depends upon how fast you want the trike to move.
     
  3. arunshan92

    Thread Starter New Member

    Sep 29, 2013
    3
    0
    Well about 40km/hr
     
  4. Shagas

    Active Member

    May 13, 2013
    802
    74
    Ofcourse you can get the trike to move! but with only 500 watts you will need quite abit of
    gear reduction. Nevertheless I doubt you will make anything more than 10-20km/h and that's on a straight road
     
    arunshan92 likes this.
  5. arunshan92

    Thread Starter New Member

    Sep 29, 2013
    3
    0
    Thanks a lot!!!!!! I'll be using 1kw motor......
    How does varying the voltage take effect on it???????
    say will a 48v lead acid battery work?????
     
  6. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,797
    1,103
    Apart from '1kW' we know nothing about your motor so can't answer those questions.
     
  7. wayneh

    Expert

    Sep 9, 2010
    12,107
    3,038
    On level ground the principal sources of drag are wind resistance, tire rolling resistance, then everything else (bearings, power transfer, etc.), in that order. Air drag goes up roughly with the square of speed, and that will determine your top end speed.

    Acceleration or speed up a hill is limited by simple physics, and you can get a decent estimate by just ignoring wind resistance.

    It takes a fair amount of power to raise 200kgs up an incline; about 54 watt-hours for an elevation increase of 100m.
     
  8. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    2 people is already close to 200kg. The trike frame with batteries, motor, steering, 3 wheels etc will be pretty heavy too. Budget for maybe 350kg total.

    500W is totally inadequate for that size vehicle. Even a 1kW motor will give pretty poor performance, and you can forget 40mph. You may get a "fast jogging" speed 10-12mph.
     
  9. Experimentonomen

    Member

    Feb 16, 2011
    331
    46
    Most likely your gonna need a motor larger than 10kW, probably closer to the power of a small car engine ie 50-100kW.
     
  10. kubeek

    AAC Fanatic!

    Sep 20, 2005
    4,670
    804
    That seems a little excessive. A car with 50kW engine usually weighs around 1200kg and gets 0-100km/h in about 15 seconds. I think that 10kW motor will still be overkill for a two-person trike.
     
  11. MrChips

    Moderator

    Oct 2, 2009
    12,440
    3,361
    By law, my e-trike is limited to a 500W motor and a speed of 32km/h = 20mph.

    You notice the lack of power on acceleration and going up an incline. Otherwise it runs well on level road.
     
  12. Shagas

    Active Member

    May 13, 2013
    802
    74
    For two people you probably want at least 1-2 Kw for anything decent , otherwise you will have have alot of gear reduction which will lead to low speeds.

    As mentioned above , you need to know what voltage the motor operates at and I would suggest operating it with PWM .

    The less KV* the motor has the better in your case because the less gear reduction hardware you will need.

    *KV is a rating of a motor which tells you how many rotations the motor gives per volt supplied .
    For example if you have a motor which has 250KV that means that With 10 volts it will run at 2500rpm
     
  13. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    5,435
    1,305
    I believe the law limits the rear wheel (drive wheel) power of a vehicle. So you are allowed no more than 500W drive power at the rear wheels.

    That allows you to use a motor much larger than 500W (regardless of what most people think) provided you limit the electrical power into the motor to an amount that ensures no more than 500W appears at the drive wheels.

    So if your motor efficiency is 75%, and your gearing/chain/bearings etc runs about 85%, you can legally input about 500/0.75/0.85 = 784W into a 1kW or 2kW motor at ANY speed (even from a standstill), which can make for a very nicely accelerating electric vehicle. :)
     
Loading...