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mazman

GE Profile Arctica PSC25PST Refrigerator Always Running

6 posts in this topic

I have a week old GE Profile Arctica PSC25PST Refrigerator which is always running. It only pauses when I open the door.

The temperatures in the fridge & freezer are OK and the fridge is in a 74 degree or so environment.

I understand that new refrigerators will generally have longer run times than older one's but does this seem right?

Thanks.

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Need appliance parts? Call 877-803-7957 now!

Call for warranty, the food side should not be 74 degrees, should be 35-38....cancell that, just re-read your post....yes some of the new friges do run 24 hours a day if they are the variable speed compressors....

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I believe it does have a variable speed compressor.

It's hard for me to understand how running all the time is more efficient than cycling and off, but so be it.

Thanks.

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I do not understand this theory either, however it does cost more for a compressor to start than run....others in here will be able to explain this operation in detail...we will be watching for their replies so we can both learn....;)

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With some searching into the matter at hand, I find no support for the theory that this model has variable speed drive. At least no technical sheet I could locate will give any info regarding this.

Anyway, variable speed compressors could be driven by a stepper motor or "brushed" motor... An induction motor with inverter control is not out of question, but the stepper motor doesn't require an inverter as sophisticated as the induction motor would.

My inquiries into some Internet sources, and my conversation with the Spirit of Seppo Ilmarinen, the Forger of the Sampo (and various other, more or less successful artifacts), give support to the stepper motor drive. The other way to operate the compressor at a supersynchronous speed (above 3600RPM) would require an inverter drive anyway, and a motor designed for a lower than normal freq/voltage ratio. So the induction motor would have to be redesigned for the system.

The benefit of variable speed versus on/off generally regards almost any solution. 

In this case, the fridge temp can be kept more stable. The system can employ a PID control with low hysteresis, rather than an on-off thermostat. One problem that it cleverly fixes is, that when the fridge is almost empty, the air temperature inside the fridge can fluctuate quite rapidly, and on a generic thermostat, the compressor would cycle on and off with short intervals. This consumes more energy than necessary and burdens the control circuit (burns out relay contacts etc). A lonely milk bottle can go bad unexpectedly although the average temperature is OK for storing milk. With variable speed, the compressor will just run at a lower speed when there is less stuff in the fridge, and a relatively even temperature can be maintained at all times.

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Check out this page, it has info about the newer variable speed compressor.

http://www.kwantlentrades.com/appliancerepair/technology.htm

This is what it says, and there are two .exe download files that have animated pictures of the technolgy.

The "new" Inverter Technology Variable Capacity Compressor

Arriving on the Appliance scene recently are the high end "Sub Zero"-type refrigerators Sub Zero, Kitchenaid, Jenn-Air "Alaska", to name a few, are using a new technologically advanced compressor manufactured by Embraco. This is not the old split-phase Tecumseh, Matsushita etc. that was the workhorse in refrigeration for over half a century. The new Variable Capacity Compressor runs continually at varying speeds dependent upon the cooling required. Speeds vary from 1400 R.P.M. up to maximum speed of 4500 R.P.M. These compressors are driven by " inverter technology" using 170 VDC and a square waveform (anywhere from 53Hz to 153 Hz). This automatic control is the PCB inverter board. The new compressor has 3 windings (gone are the old run & start windings) which are alternately "switched off & on" by solid state transistors contained within the inverter board. Apart from the noise reduction of a compressor running at a lower speed, efficiency, and the obvious advantages of being able to call upon full speed by the indication of a temperature requirement, these new breed of compressors will eventually replace all existing ones being used at present.

The compressor drive (inverter board operation) and the variable capacity compressor animations are downloadable. Courtesy of Maytag, showing the operation of their new Jenn Air "Alaska" refrigerator.

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