From: pallison49@gmail.com   
      
    boobenge...@gmail.com wrote:   
    ===========================   
   >>>   
   > >> I have a 24v DC motor that I'm using with a PWM controller supplied by a   
   > >> 24v SMPS. I want to be able to briefly switch the motor to 48v with a   
   > >> relay.   
   >   
   > > ** Bad idea.   
   > > Doubling the DC input to a brush motor will quickly destroy it - it may   
   last only a few minutes of such abuse.   
   > > Over voltage creates severe acing across the segments of the commutator.   
   > >   
   > > A good rule is to have no more than 2.5V for each pole of a DC motor.   
   > >   
   > >   
   > Phil thanks - I didn't know that. Nevertheless I'm going to proceed   
   > with my arrangement:   
      
   **  So you did not want our advice  -  did you ?   
      
   > - it's for my own use & not a customer's, nor a product   
   > - the "briefly" is 5-10 seconds and a duty cycle of maybe 5-10%   
   > - I have a few of these motors and if one is destroyed I'll use another   
   > and have learned a lesson   
      
   ** Did you count how may poles on that motor?   
      It matters just a tiny bit  ......   
      
      
   .....  Phil   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)