d9d368b6   
   From: phil_a@tpg.com.au   
      
   "Patrick Turner"   
      
   Even the simplest thing you may want to do with 500Vdc needs careful   
   analysis and thought or else you'll end up with smoke and regrets. If   
   there is a choke involved in the 500Vdc rail, it makes matters worse   
   to design around it, and a suitable diode, say IN5408 may need to be   
   placed across the choke to prevent back EMF causing voltage across the   
   relay to go very high when contacts oen and DC flow is interupted.   
      
      
   ** Putting a diode across filter choke defeats the choke's operation.   
      
      
      
   .....  Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)