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Thread: Servo stepdown question

  1. #1
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    Default Servo stepdown question

    I am wondering how much difference a stepdown from 6v to 5.3/5.1 would make in a servo for speed.
    I have a 6v capable servo but it's to fast and thinking a cheap solution would be run less volts to slow it down some.

    What do you think worth while or won't see much difference?
    OSE GIFTING ELF
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  2. #2
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    The difference in speed will be almost imperceptible. Some radios have a feature built in to slow down a channel (servo). Another alternative is one of these:

    http://www.hobby-lobby.com/servo_slo...18550_prd1.htm
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  3. #3
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    Quote Originally Posted by monojeff View Post
    I am wondering how much difference a stepdown from 6v to 5.3/5.1 would make in a servo for speed.
    I have a 6v capable servo but it's to fast and thinking a cheap solution would be run less volts to slow it down some.

    What do you think worth while or won't see much difference?
    I use these UBEC's http://www.hobbyking.com/hobbyking/s...2_6s_LiPO.html in a couple models and you can select 5v or 6v. On the 5v setting, the steering servo is half as fast (still quite fast) as the 6v setting (I always use the 6v setting for fastest response). I've never tested to see if there was the same amount of torque at the lower setting. Maybe that is where the Servo Slow module would come into play. It probably supplies the full amperage while PWM'ing the speed down. Some sewing machine foot controls do the same thing - supply full amps while limiting the speed.
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  4. #4
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    Servos are powered by electric motors and follow the same principals as the ones powering your boat, at 5v rather than 6v it isn't half as fast it is 5/6ths as fast a speed reduction of under 20%, and yes it will produce less torque at 5v than it will at 6v.
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  5. #5
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    Look for a feature called "dual rate" on your tx-- that would slow down the servo response.

    Chief

  6. #6
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    Well I was wrong. This afternoon I went to verify that slower servo response (a jet drive boat) and found it was the steering con rods binding in the boots. Applied some marine grease, and things changed significantly(!) And now there's hardly any difference between 5 and 6 volts - just like Sailr said earlier. I assumed it was the difference in voltages that was causing the big response time difference. My apologies to Sailr and Monojeff. I hate it when I'm wrong.
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  7. #7
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    Quote Originally Posted by sundog View Post
    Well I was wrong. This afternoon I went to verify that slower servo response (a jet drive boat) and found it was the steering con rods binding in the boots. Applied some marine grease, and things changed significantly(!) And now there's hardly any difference between 5 and 6 volts - just like Sailr said earlier. I assumed it was the difference in voltages that was causing the big response time difference. My apologies to Sailr and Monojeff. I hate it when I'm wrong.
    No worries. 5v is slower just not a noticable difference. I am wondering what if I connected 2 of the step down would this bring it down even further?
    The servo has more then enough torque so that is no problem....

    Another option I have is the servo I am using can be reprogrammed if I buy a controller for it might do that but trying to find a CHEAP option at the moment.
    Quote Originally Posted by BHChieftain View Post
    Look for a feature called "dual rate" on your tx-- that would slow down the servo response.

    Chief
    As far as I know the dual rate had to do with travel not speed.
    OSE GIFTING ELF
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  8. #8
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    Servos have a minimum input voltage in order to work, it depends on the servo. Most will not function below half the max rated voltage. But I am curious, why do you say that the servo is "too fast"? What would be slow enough? If this is a steering servo, the obvious solution is what thousands of R/Cers have always done - slow down their hand movement. If it is a 3rd channel servo then a programmable servo or the device Jim linked above are probably all that will work. But again, what is slow enough?
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    Well I'm not sure on the speed.
    It is probably fine just figured something else to mess with to help tune the boat.
    The speed is probably fine and yes a slow steady hand on the wheel can do the same thing I'm still getting the hang of it so was figuring possibly some added help wouldn't be a bad thing to help slow down my movements. I probably don't need to do it was just wondering if I wanted to some ways to accomplish it.
    I'll prob try to get a programmer for it.
    OSE GIFTING ELF
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  10. #10
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    Dual rate is a throw limiter, not a speed limiter. Speed is dictated by the voltage the servo is running at. I use 6V on everything to get the speed and extra torque the servo will provide. Some servos are specifically designed for 4.8 or 6V but not both and usually say so in the spec section. I also use dual rate on everything I own to reduce my bad habbits.
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