XPost: sci.electronics.design, sci.electronics.misc   
   From: invalid@invalid.net   
      
   I need to provide jog function on a machine (run the motor for a few seconds   
   under load) without use of VFD**. It was done on this small printing press   
   with a 3 HP, 3-phase motor but the customer has no multiphase power so I¹m   
   changing to a 220 ³single phase² 5 HP motor.   
      
   Is there any inherent issue with starting an asynchronous motor under load? A   
   3ph motor does this with ease, but can the same be said of an async motor?   
   Should I be looking at a particular design of async motor?   
      
   Also, reversing an asynch motor‹is this a straightforward thing to do? I'm   
   thinking about bringing the directional wiring inside the motor's terminal   
   box out to separate contactors. I'm also thinking about cross-connecting aux   
   contacts in the contactors to eliminate possibility of actuating both   
   simultaneously and some kind of timer relay to provide delay between forward   
   and reverse actuation.   
      
   Any observations or experience you¹d like to share would be greatly   
   appreciated.   
      
   Thanks!   
      
      
   ** The customer has said ³absolutely no VFD². Apparently his business   
   neighbor has had nothing but troubles with VFDs (blowing the supply fuses;   
   smoking at least one VFD) and he is terrified of them. It¹s an emotional   
   issue, not a logical one so no amount of discussion can change his mind.   
   We¹ve tried.    
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)