From: tombiasi@optonline.net   
      
   On 10/5/2013 4:50 PM, Salmon Egg wrote:   
   > In article <87a9inog8h.fld@apaflo.com>,   
   >   floyd@apaflo.com (Floyd L. Davidson) wrote:   
   >   
   >> Salmon Egg  wrote:   
   >>> In article ,   
   >>> "Kissi Asiedu"  wrote:   
   >>>   
   >>>> Hello,   
   >>>> I was wondering if an American Made Referigrator rated 120V 60Hz could   
   work   
   >>>> efficiently with the use of a step down transformer in Africa where the   
   >>>> electricity is rated at 240V 50Hz.   
   >>>> Thanks,   
   >>>   
   >>> As usual, the answer is: It depends.   
   >>>   
   >>> If you can, contact the manufacturer to get more information.   
   >>>   
   >>> You can try monitoring the current to see if it becomes excessive.   
   >>>   
   >>> If the refrigerator does not have to work hard, You might want to get an   
   >>> transformer or autotransformer to change to 100V. That would mean that   
   >>> as the transformer rotates at the lower speed, current for the same   
   >>> output torque will be close to what it would be for 60Hz. Bit do not   
   >>> expect the refrigerator to work at full capacity.   
   >>   
   >> Good way to burn your house down...   
   >>   
   >> The change from 60Hz to 50Hz is an issue with heat.   
   >> Running a synchronous electric motor at low voltage is   
   >> also an issue with heat.   
   >>   
   >> The transformer does not rotate, and the lower voltage   
   >> would not change the speed of either the transformer   
   >> current or the motor rotation.   
   >   
   > I do not think you know much about modern refrigerators. They usually   
   > use induction motors lubricated by the refrigerant. There are no slip   
   > rings or other electrical connections with rubbing parts.   
   >   
   > If the refrigerator manufacturer is not cutting corners too much, there   
   > should be enough iron and copper to prevent such catastrophe. Even if   
   > the motor cannot run at 50Hz and 120V. it should be able to run no load   
   > at 50Hz/100V at about the same CURRENT as at the 60Hz/120V. The only   
   > problem comes when you add the load of the compressor. If you get   
   > satisfactory performance without exceeding the the rated current for   
   > 60Hz/120V, you should be ok. That is, for 50Hz operation, do not exceed   
   > a VA input more than 5/6 of the VA allowed at 60Hz operation. Just take   
   > the resultant loss in performance.   
   >   
   There is merit in what you say, however, the efficiency loss will   
   manifest as heat since the reactance is not optimal and the starting   
   capacitor will not be doing it's job properly. And manufacturers do cut   
   corners considerably to compete in the US market.   
   I still would not do it.   
      
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