Jean-Noel was fixing a broken Lurem woodworking machine equipped with a three-phase Dahlander motor. The trio of operation modes originally included: stop, half speed and full speed.
As HackADay’s Eric Evenchick notes, the motor uses a special mechanical switch to select the operating mode. However, the mechanical components inside the switch were broken, preventing the motor from being activated.
How to solve the problem without sourcing a new switch? Well, Jean-Noel decided to build his own Atmel-based, Arduino Pro Mini (ATmega328 MCU) powered Dahlander switch consisting of three relays tasked with selecting the wiring configuration for each speed mode.
Jean-Noel also added a button to toggle settings, along with two lamps to indicate what mode the motor is currently operating in.
“The Arduino runs a finite-state machine (FSM), ensuring that the device transitions through the modes in the correct order,” Evenchick explained.
“This is quite important, since the motor could be damaged if certain restrictions aren’t followed.”
Meanwhile, the state machine graph was generated using Fizzim, with the final product housed in a DIN rail case, allowing it to be securely mounted along with the rest of the wiring.
Interested in learning more about the Arduino-based Dahlander switch? You can check out the project’s official HackADay page here.
Atmel | Bits & Pieces 