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   alt.engineering.electrical      Electrical engineering discussion forum      2,547 messages   

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   Message 1,224 of 2,547   
   josephkk to DaveC   
   Re: Replacing a 3ph motor with single ph   
   17 Jul 14 19:07:44   
   
   XPost: sci.electronics.design, sci.electronics.misc   
   From: joseph_barrett@sbcglobal.net   
      
   On Tue, 15 Jul 2014 21:48:50 -0700, DaveC  wrote:   
      
   >> However, in this case of a jog function- If a single phase capacitor    
   >> start single phase motor has the same starting torque as the 3 phase    
   >> motor (and with the right capacitor- this may well be done) a single    
   >> phase motor may well fit the needs-electrically-but likely not    
   >> mechanically with respect to mounting.   
   >   
   >I (OP) am concerned about jogging. The single-phase motor will be using its    
   >start winding, and the associated high current will heat the winding. Jogging    
   >means usually repeated, sometimes back-and-forward direction changes, short    
   >motor actuations.    
   >   
   >With all this jogging the centrifugal start switch will be abused over time    
   >which probably means early failure.    
      
   Two easy answers:   
   a.  use a cap run motor   
   b.  use a current sensing start switch   
      
   Also this will almost always be within the start time of the jogger motor.   
      
   ?-)   
       
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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