• Bringup

    lion mclionhead • 2 days ago • 0 comments

    To remotely control a blower, the lion kingdom would be hooking an el cheapo dimmer.

    to an el cheapo servo.  The same dimmer 20 years ago, for 1/2 the price, was hooked up to a fan & proven to do a good job at speed control.  They just chop the sine wave so they don't get hot.  The useful range with an inductive load is a tiny fraction, but this tiny range can be resolved with software.

    Chinese alternatives were nosebleed expensive & lacked any display.

    It was immediately found to have a nearly 360 rotation to go from off to full power.  The useful range for the blower was the top 50%.  Instead of a complicated mechanism to make the servo go 360, a relay for turning it off was a simpler option.  It was also found to cut off slightly below 100%, so a 2nd relay would be required for a bypass mode.  It would need 2 relays to have off, dimmer & bypass states.

    This was the 2nd project to use a PLA servo attachment.  Just heat the PLA & press it on.

    The enclosure was reused from the failed inverter project.  This servo mechanism was very precise.  It had to be installed with the dimmer & servo at maximum.  The servo had a 3 second timeout to avoid running the motor constantly.

    Maximum PWM was .5ms.  Minimum was 2.5ms.

    Stock wattage on low was 67.  Decided to make 60W on medium or 1.5ms the new minimum for cold winter nights while not stalling the motor.  The servo's full 180 deg was .5ms to 2.5ms so it would only be going 90 deg.  

    The trick with this, like a lot of coroplast enclosures, was weighing it down.  The smartest design would probably have it narrower, with all the plugs in back & display in front.