From: amdx@knology.net   
      
   On 10/11/2021 6:10 PM, Phil Allison wrote:   
   > bobenge...@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   
   >   
     I had a 28V 2hp motor on a go cart and ran it on 48V. Ran it for a few   
   years, and never saw any commutator problem.   
      
     But we did have an especially long, hard run and it came back with the   
   windings smoking. It would draw over 250 amps untill you got up to speed.   
      
   I will admit it was a motor designed for a military application, so   
   probably had some good specs.   
      
   Mikek   
      
      
   --   
   This email has been checked for viruses by Avast antivirus software.   
   https://www.avast.com/antivirus   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)