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Post Info TOPIC: ENGEL MRFT-5400-G4 comp failure


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ENGEL MRFT-5400-G4 comp failure


Cutting open the compressor to find out why it failed.COMP.1.JPGCOMP cut open.1.JPGCOMP cut open.4.JPGCOMP head.1.JPGCOMP PISTON.4.JPGCOMP PISTON.6.JPGCOMP COIL & MAGNET.1.JPG



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D.L.Bishop


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The failure is a cracked insulator on the bottom of the coil. The power is fed through the bottom spring. The coil is grounded through the top spring. The insulator with the crack is the cause of the short.COMP PISTON crack in Insulation.2.JPGCOMP PISTON insulator short.1.JPG



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D.L.Bishop


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How old??



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well done got find . like quanger said how old .

dibs

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gdyble

DONT DIE WONDERING ONE LIFE ONE CHANCE JUST DO IT 



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Not sure, but the code on the compressor (96-9-10) may indicate 1996. Picture of the spec plate on the fridge. It was given to me to find out why it didn't work.MODEL PLATE.JPG



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D.L.Bishop


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Hi debe;

           Are you shure you are mesuring correctly !!  Don't get me wrong, and i'm not trying to shoot you down but i would think that with that small amount of windings and the size of the wire, it would appear as a near dead short ( 0.5 Ohms ) . Try and find both ends of you coil, and join together and measure from the join to the body. These compressors use a voltage of about 22 volts AC and I have used as a test a old 12 Volt battery charger transformer to run just the compressor, just to se if i had a compressor lock up or a inverter /power supply problem, i used to work in the electronics industry and these fridges would come in for repair, i could only repair the electronic side if things i would leave the refridgeration side alone.

I have dealt with engle brand before and while a very good brand, the fridge side of things is only avalable as a complete unit, compressor, dryer, evaperator, and condenser all sealed and ready to just drop in to the cabinet. 

When i measure inductors i would normaly use a impeadance and inductance meters, only then would i have try accurate idear of the coil at hand. This way even a shorted turn on the coil at hand is easly read.

The standard multimeter uses a DC voltage through the coil and may be alright for a resistive load but not a inductive load, all that would happen is the multimeter would show continuity.

Useing a impedance meter uses a AC voltage at a frequency ( 1khz ~ 10khz and depends on the inductor size at hand ) and this measures more closely to real life.I've oftern used a impedance meter when working on 100 Volt PA speaker set up ( schools etc ).

 



-- Edited by valiant81 on Thursday 15th of January 2015 08:50:50 AM

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Heres a pic of the resistance of the windings. Also AC current draw on the compressor & it was pulling the 22v ac down to 8V ac. There is also another post on this site were I started on the electronics side of this fridge.COIL RESISTANCE.1.JPGComp current.JPG



-- Edited by DeBe on Thursday 15th of January 2015 02:17:23 PM

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D.L.Bishop


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Hi debe;

           I would think that the coil is ok, the coil could have shorted turns, but running at it's normal voltage ( 22 Volts AC ) one would think voltage break down would not be a problem, IF the coil was to prove to be faulty, one would think there would be some form of stress, color of the winding would change ( heat stress ) ?? or shorted turns ( high voltage break down and insulation falure ). One thing that crosses my mind would be the frequency of the output  AC voltage under load from the compressor, maybe this has been the real cause of the problem all along. Some of the electrolitic capacitors in the inverter could cause all type of problems with the output wave form /and frequency.

A big problem with smps in televisions, were the frequency of the inverters internal oscillator in the power supply causes the filter capacitors on the secondary voltage rails to fail ( dry out, esr of the cap goes high  and the capacitor swells and ) end results is the power supply fails to put out the correct voltage and current.

In all of the years i've worked in electronics and have repaired quiet a number if engle fridges over the years, i've only had one compresser fail and that was from a faulty valve. All of the others were electronic of one form or the other.   



-- Edited by valiant81 on Thursday 15th of January 2015 05:55:11 PM

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Theres nothing wrong with the coil the short is at the crack in the insulator. These are the wave form & voltage from the transformer with the compressor disconnected. Im very aware of SMPS as ihave been repairing them for years in TVs VCRs etc, also do refrigeration repairs.No load Voltage.JPGENGEL 22V ac on 240v ac.JPGENGEL. MRFT-5400-G4.jpg



-- Edited by DeBe on Thursday 15th of January 2015 06:13:48 PM

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