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3 phase vfd to sim tools inerfacing

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by bob golding, Mar 16, 2021.

  1. bob golding

    bob golding Member Gold Contributor

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    hi still reading and getting ideas. Spoke to a mobility scooter wheelchair repairer today about eBay motor gearboxes. I was going to get 6 of them as they turn up, but I have found a potential problem with that regarding the gearboxes. He said the same model can have different speed gearboxes, so you need to check they are all from the same run. This brings me back to my first idea, which is to use 3-phase motors and variable frequency drives. Not sure how to interface them with sim tools, though. they have a lot of advantages over dc motors. They are simple no brushes to wear out, cheap and plentiful and VFD controllers are easy to find and cheap. Wondering why people don't use them? Still considering linear actuators but need to do a lot more reading first.

    bob golding
  2. Gadget999

    Gadget999 Well-Known Member

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    i did see a 3 phase motor and vfd conversion a while back - the performance was very slow and it was quite noisy

    the builder may have chosen poor parts

    also - 3 phase is not always available
  3. RacingMat

    RacingMat Well-Known Member Gold Contributor

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  4. bob golding

    bob golding Member Gold Contributor

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    The beauty of using VFDs is you only need a single phase supply. the VFD converts it to 3 phase so you can use 3 phase squirrel cage motors. No brushes or caps to worry about. Just a rotor and stator. they are cheap are plentiful. being 440 volt the current draw is low as well.
  5. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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    Wow! Amazing! How come no-one tried using these before?
  6. Gadget999

    Gadget999 Well-Known Member

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    440 v is 3 phase ?? (240v on each phase)

    single phase is 220v / 110v

    i have not heard of 440v AC single phase
  7. bob golding

    bob golding Member Gold Contributor

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    you can get vfds that do the up voltage conversion but that is not neccasry
  8. bob golding

    bob golding Member Gold Contributor

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    you don't need the full voltage as long as you reduce the frequency by 50 % you lose some speed but, the important part is the toque remains the same. as we are going for high torque rather than high speed, you just make allowances when designing to account for the slower speed. I am not totally sold on this idea yet, still researching the options, but there are a lot of 3 phase 415 volt motors around. industry standard item
  9. Thanos

    Thanos Building the Future one AC Servo at a time... or 6

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  10. bob golding

    bob golding Member Gold Contributor

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    not sure what sort of load to expect yet so it's all a bit theoretical at the moment. still bouncing ideas around . Have noticed some large steppers on ebay. 60 volts per phase at 6 amps. that seems in the ball park. £165 including the controller. not sure about stepper ratings compared with normal ac motor ratings but 360 watts per phse sounds pretty good to me unless i have misunderstood the rating.
  11. Gadget999

    Gadget999 Well-Known Member

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    stepper motors can not be controlled using pid control - they move one step at a time from a to b

    the cant speed up and then slow down when they get near the target

    however - they are cheap and reasonably powerful for the price and may be worth a try

    it may me possible to fit a shaft encoder and use pid on them if you can control the steps another way ;)
  12. bob golding

    bob golding Member Gold Contributor

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    still reading, I suspect this will take me a while. definitely leaning towards the dof reality design but with 3-phase motors. This is based mainly on my limited resources. I like the idea of home made linear actuators but i have nothing that i could make those with. No local machine shops that could the parts at a reasonable price either. The local blacksmith can do the odd bit of welding for me but precision drilling or turning no. so I have decided to get a cheap Chinese motor gearbox with the controller and power supply and do some experimenting. not sure how much torque they can produce but being Chinese i suspect it will less that what is stated. Not sure how much I need either. Will i need less if i go for 3 dof with a centre column?
  13. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
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    A dofreality type design, with a uni joint pivot, give 2dof but with the possibly of adding traction loss as an additional axis, which is great for racing games.

    A 2dof gives you roll and pitch, but it can also simulate sway, surge and heave.
  14. bob golding

    bob golding Member Gold Contributor

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    ok think i will try 2 dof with a spring loaded centre rod first to test the motors. i have thought of buying a cheap linear actuator and modifying to. antone been inside the cheap ones. may a good source of the precision parts to make a faster one? i have found some new geared 3 phase motor gearboxes at a reasonable price. 0.5 kw which I'm sure is too much but better than too little, and a burnt-out motor. 185 pounds each.
  15. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    My Motion Simulator:
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    Cheap linear actuators are generally not suitable for motion simulation, they are often too slow and components are not durable enough. If you want actuators either buy quality ones or DIY.
    • Agree Agree x 1