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motor advise

rjcjacobs's picture
Submitted by rjcjacobs on Thu, 01/20/2011 - 20:26
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Hi, I am building my own dolly based on the IGUS 10-40 rail and the MX 2 kit (planning on buying it in the near future).
But I have a few questions.

1. I will use a 12V 81 RPM gearmotor (servocity) for real time filming (cameraspeed = 100 cm in 10 s) with a small timing pulley(0,75") and belt (9mm).
My question is: how does the MX 2 kit manage to slow down the motor? Is it via steps (will it generate vibration and and not run smooth?)or otherwise.

2. I will also use a 8 RPM gearmotor for timelapse. Is this a good choise or need I go slower? (I will use a very small pulley, 0,75")

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Ron, You can use any DC motor

Submitted by shutterdrone on Fri, 01/21/2011 - 01:36.

Ron,

You can use any DC motor is that 1A or less of draw at full-load.

Basically, yes, at speeds below the available PWM range (which depends on the motor), it uses "steps" (brief periods of on-time) to achieve very low speeds, so at the very lowest speeds it will vibrate and not run smooth for real-time applications. However, if you keep it within the functional PWM range of your motor, it will only use PWM control which is smoother.

I'd recommend going slower for timelapse use, but that's just me - we use the 8.75RPM in the Stage Zero, and it's highly functional, but 8.75RPM was chosen for the wider range of speed - best performance will be out of <= 1 RPM motor.

!c

Thanks !c I don't think I

Submitted by rjcjacobs on Fri, 01/21/2011 - 15:09.
rjcjacobs's picture

Thanks !c

I don't think I will be much under the top speed of the motor. That's why I use 2 motors. The 1 RPM motor results in a speed of 16 minutes for the total length of the rail (1m) using 0,8" pulleys.