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Question PGSAW 50:1 Motor current draw and PSU

Discussion in 'DIY Motion Simulator Building Q&A / FAQ' started by Ian Pace, Feb 15, 2021.

  1. Ian Pace

    Ian Pace Member

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    Hi All,


    I tried searching the forum but i can’t seem to find a direct answer to my query. I currently have x3 50:1 Pgsaw motors in hand and also have MeanWell 12v 17Amp PSUs. (LRS-200-12). These PSUs are rated at 204w and PG saw motors are 180W. Is it safe to assume that they are sufficient enough for them? (obviously x1 per motor)

    Can’t seem to find the exact spec sheets for the Pgsaw motors. According to my calculations, the motor should not need more than 15a at full power.... but not sure re stall current.


    I have access to Servers PSUs as well, if the meanwell are not enough, however just to keep things clean and tidy i would rather use the MeanWell PSUs as they are smaller and also brand new.
  2. Ads Master

    Ads Master

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  3. Zed

    Zed VR Simming w/Reverb Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, JRK
    I run those pgsaw motors on my sim but used 600W supplies (50A rating) fused at 30A. I have real-time ammeters set up on my rig and have seen spikes into the 20-30A range but never popped a fuse. They are standard auto fuses, though, so will stand very short spikes above rating but I doubt that happens much if at all. Most of the time currents are less than 10A, driving there are lots of spikes in the 10-20A range, but I do see occasional spikes up above 20A and nearing 30A. For flying the currents are rarely that high. I’d guess almost always below 15A.

    I believe that rating on the pgsaw motors is continuous (but won’t swear to it). Stall currents can go way above that depending on your wiring, controllers, etc. (all the added resistances in your circuit). In a motion sim application with frequent reversals under load (e.g. driving), you will see lots of stall and near-stall currents.

    Those power supplies will likely deliver a little more current than rated but ripple and voltage may go out of spec. That probably doesn’t matter. Mine specify outputs in the range of 105-125% rated power before they trip on overload so you may have some headroom but maybe not that much depending on your application. If your supplies have overload protection, they will tell you if you push them too hard.
    • Informative Informative x 2
  4. Gadget999

    Gadget999 Well-Known Member

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    My Motion Simulator:
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    use a car battery as a buffer - you will only need to provide enough power to charge the battery
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  5. yellofella

    yellofella Member

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    Hi @Ian Pace. I also have 3x pgsaw 50:1 motors on my 2 dof seatmover with oversteer. I use 3x 480w power supplies to drive the motors hard as i dont just want movement while im racing i want the movement to be sharp and snappy when needed.
    Each power supply (480w) drives a single motor through a half bridge motormonster (32a c0ntinuious 60a max) using 10 awg cables. Now the limiting factor is the power supply at 48a(480w) as this is all they can deliver even if the motormonster could deliver the 60a peak.
    The amount of torque that you will need will depend on many factors like the design of your rig, what the frame is made of, and your body weight. The more torque you require to move your rig will use more current and run the motors at a higher temp.
    My rig is well balanced so the motors use very little current (holding torque) when not moving but the offset is my brake pedal has a 120kg loadcell in it and when braking hard i push hard against the motors pushing the seat forward. This is the reason i use a lot of current to each motor. However the motors never get hot and are warm to the touch after an hour of racing.
    To sum up id say that only testing will tell you how much current you will need for your particular rig design. I would use a single 17a supply per motor if that is what you have as most motor drivers that you will use will have a higher output than 17a.
    What motor drivers are you looking at using buddy?
    • Informative Informative x 2
  6. Ian Pace

    Ian Pace Member

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    Hi Guys,
    Sorry didn't realise i had replies....
    Based on the above mentioned loads, its not worth bothering with the MeanWell supplies when i have access to an unlimited supply of server PSUs :) (i'm an IT Admin)

    I just wanted to use the MeanWell as they look 'cleaner'

    Thanks for all your help, you all answered my question and concerns perfectly!
    • Like Like x 1