13 replies to this topic

[Magenta#90]

Input voltage to Inverter is 120 AC, voltage output to inverter from J15 on the motherboard is 4-6 volts VDC, resistance at compressor  pins 2-3 is around 6 ohms,  no voltage at compressors pins from inverter.. any clue

 

[Samurai Appliance Repair Man]

Inverter output voltage is pulse width modulated so measuring it is meaningless.  The way to diagnose these units for compressor inop is as follows:

 

- Test compressor windings.  Should be about 10 ohm ± 1 ohm  for each winding-- none of that start, run, common stuff, all windings are equal.  If that's good, we move upstream...

 

- Check for valid 120vac supply input to inverter.  If present, replace the inverter, slam dunk and done ==> http://www.repaircli...ber=PFSF5NJWAWW

 

Edited by Samurai Appliance Repair Man, 28 December 2012 - 04:13 PM.
Corrected winding resistance specification.

[DurhamAppliance]

Inverter output voltage is pulse width modulated so measuring it is meaningless.  The way to diagnose these units for compressor inop is as follows:
 
- Test compressor windings.  Should be about 1 ohm for each winding-- none of that start, run, common stuff, all windings are equal.  If that's good, we move upstream...
 
-

That tip alone is worth the price of admission.

[Samurai Appliance Repair Man]

Actually, I was off on the compressor winding resistance but only by a factor of 10-- each winding should read about 10 ohms ± 1.  

 

Edited my previous post.  

Edited by Samurai Appliance Repair Man, 28 December 2012 - 04:13 PM.

[RegUS_PatOff]

http://appliantology...rators-31-9154/

[Magenta#90]

What  if the reading in the winding with a digital meter is around 6 ohms, still go ahead with the inverter installation, put an ammeter in line  and measure the amperage  within 8 second  of start and unplug the refrigerator to see if the compressor  has problems, would this works...

[Samurai Appliance Repair Man]

Double check your meter calibration-- most meters, especially cheap ones, are horribly inaccurate at lower resistance measurements.  If the reading is still 6 ohms, then that's UNSAT, recruit, and deviates outside the manufacturer's specifications.  Don't try to second guess their specs, that's not our job.  Our job as technicians is to ensure that we are accurately and precisely determining whether or not the component conforms to specifications.  If it does not, then it is, by definition, "out of spec" and must by rooted out like an intestinal parasite.  

[Magenta#90]

I have a BK and a Fieldmaster digital meter, I'll check first before installing the inverter,  if the reading is still 6 ohms, more likely the compressor has a major problem and i wont even try to  plug in, what you think..

[Samurai Appliance Repair Man]

If the compressor windings are out of spec, then the compressor is the problem. In which case, what would you gain by installing the inverter?

[Magenta#90]

you're right should be between 9-11 ohms, that the reason why the inverter went out, installing a new compressor and inverter is going to be too expensive , is just 5 years old.

[RegUS_PatOff]

are all (3) windings on the Compressor reading the same ?

[Magenta#90]

yes they're, we are going back to double check, we also found the label on the compressor  on the top  kind scorched   liked burned

[Cactus Bob]

HOT ? Hot enough to melt the tag ?

 

these compressors never get hot !

 

even of there frozen (LRA) , hot there not !

 

if it where my job , i think i would step back a moment and think about the parts your buying , can you sell it in the next year to someone else , or will you live with it forever if the job goes wrong  ?

[RegUS_PatOff]

... also found the label on the compressor  on the top  kind scorched   liked burned

pictures ?