Cheap Inverter Checker

[paul_h]

I use diode test mode on my multimeter. The inverter has postive and negative in, and three phases out.
With the unit powered off and multimeter in diode test mode, put one lead on one of the inputs (solder point on the pcb, or flying lead into IPM chip) and put the other lead on each of the outputs. (again solder point on PCB, or flying lead to compressor plug).
Basically in one direction you'll get between 0.3-0.6v, the other direction you'll get open circuit.
Then you reverse your postive and negative multimeter leads. This proves all the diodes are OK, and thats how inverters make the three phases, diodes.
attached is some pictures to show what I mean. Shown is testing of the diodes starting with multimeter red on input terminal "P", checking the inverter output to the compressor with the multimeter black.
Then you reverse test, ie test with black on "P" terminal/plug, and multimeter red lead on all the outputs.

Not shown is: Then you put your red multimeter probe on the "n" input terminal, then run your multimeter black over each of the outputs, then reverse again. ie multimeter black on the 'n' terminal, and test each of the output pins with your red multimeter lead.
What you're looking for is any shorts, anything that reads 0v is stuffed.