Freezer/fridge
By Opera House, Section Controls Posted on Wed Jun 18th, 2008 at 07:13:42 PM MST
Working semi automatic

The GE 5CF fridge is up and working.   This was made from a UL sample liquid level control I designed years ago. Held on to side of fridge with plastic magnets.  Temp sensor is 5 diodes in series. Cant seem to get the other photos uploaded into this document.  Bought a defective 2,000W inverter and removed some of the unneeded FETs and run it without the 3 fans. According to the display, the initial start current is about 80A @ 12V.  Plans changed and I have to run really long lines to the controller.  That causes low voltage shutdown at startup.  I start inverter manually with panel switch and then turn on temp controller and turn off inverter switch.  That gives me automatic turn off at 32 degrees. Not too much of a bother to turn it on once an hour.  About all I can do with these primitive conditions.

Freezer/fridge | 1 comment (1 topical, 0 editorial)

Re: Freezer/fridge (3.00 / 0) (#1) by Opera House on Wed Jun 18th, 2008 at 03:04:59 PM MST (User Info)

The inverter is a 2,000/4,000W unit. Notice the two missing FETs and the wire soldered to the switch. I learned as a child building model airplanes that there are always extra parts that aren't needed.  The temperature probe is six silicon diodes in series.  The globbing is hot melt glue.  This assembly is inserted in some heat shrink tubing and when reheated makes a great watertight seal. This gives about 10mV per C and makes the voltage ref less critical.  The controller was depending on thermal delays and really needs a 30 minute delay before starting the next cycle.

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