​

Suggestions for simple problem resolution:  (Applies to most brands / types of DC compressor systems)

​

Compressor fails to start or cuts out prematurely:

By far the most common problem DC refrigerators experience is the 12VDC power supply, and not  the actual system, compressor or Motor Driver Module itself! (MDM or Black box!)

 

To explain:   All of these DC compressors have a Motor Driver Module, (MDM) which inverts the supplied DC power into 3 phase AC power to drive the 3 phase AC compressor motor. These MDM's are sensitive to and internally protected against the various power supply issues'. These internal  safeguards of the MDM include protection against high / low supply voltage, over heating, excess current draw, and compressor or fan overload,  

For example:

If the voltage drops away too much at a start attempt or when running, the MDM's low voltage cut out prevents the module driving the motor, starting or running.  (Resumes 'On mode' when voltage again rises to approximately 12.5v) 

This shut down because of a poor power supply, is usually due to either a defective, or faulty battery, battery to MDM wiring, or faulty devices along that circuit like bad *spade terminal connection, switch or overload.  (*Specially - & + on the MDM)  

 

If unit won't start or continue to run, below is the easiest and industry recognised way to identify if voltage drop is the problem or if the MDM is faulty..   Note: Simply connect multi-meter probes to terminals 8- and 8+ on Ozefridge system.