From: noone@nospam.com   
      
   Στις 25/1/2020 7:24 μ.μ., ο Grant Taylor έγραψε:   
   > Is anyone willing to explain Negative 48 Volts DC?   
   >   
   > I'm trying to learn about it because we're using it for a few things at   
   > work and I'd like to better understand what we're working with than   
   > simply going through the motions that someone else dictates.   
   >   
   > I've learned that -48 VDC uses what is called "Positive Ground" and that   
   > what I'm used to is called "Negative Ground".   
   >   
   > I'm trying to correlate and understand the typical red and black wires   
   > with them being ground / return / common / hot / etc.   
   >   
   > I suspect that there is more to it than simply reversing the + and -   
   > lead from a battery or meter.  But I can't wrap my head around it.   
   >   
   > Can ~> will someone offer any comments that might help me understand   
   > better?   
   >   
   >   
   >   
   I know two examples:on a common microwave oven, so as to avoid the   
   microwave gun being at high voltage potential, it is earthed and the   
   magnetron filaments are being at negative high voltage potential. Also   
   the diode is being earthed. If the oven is not properly earthed there is   
   the danger of electrocution. Also a modern IGBT inverter welding power   
   supply, when welding all electrodes but aluminium, the electrode is on   
   the plus pole and the ground is negative. When welding aluminium the   
   electrode is negative and the ground is positive.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)