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September 22, 2020, 04:49:17 PM

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World Racing Series beta14 available! :)


time for a real moto controller(diy)

Started by tseklias, June 12, 2014, 08:23:06 PM

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h106frp

Techie note for driving home made servos... :)
Just one thing i have found from my own servo trials, if you want to use switchmode power supplies to drive your servos (i.e. PC power supply) you will need something like this;
http://www.protoplant.com/power

Power Supply Multiplier with Back EMF Clamp - without it, every time you reverse direction on the servo the supply will trip on over voltage due to back emf from the motor and cause either the drive circuit or supply to drop out or become unresponsive while it resets from over voltage protection mode.
The electronic regenerative brake side (big resistor/mosfet/comparator)  of the circuit will make the servo motor much more responsive during direction change as this sheds the kinetic energy stored in the rotor as heat.

Seems a poorly documented issue and took a while to track down, i have built my own inspired by this design and another to try out using mainly bits harvested in the past from old PC power supplies so it cost next to nothing and is quite simple construction, it works great and allows the use of cheap switch mode supplies rather than massive linear supplies or batteries.

Hopefully one more learning step to high power/relatively low cost servo system :)