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???
07/28/05 14:41
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 		 #98368 - Nevertheless...
Responding to: ???'s previous message
Erik said:
shunt resistor, jusr for fun, I calculated one.
lat's say we allow 1% of voltage drop across the shunt = 100mV at full rate 300A

so the shunt is 100m/300 = 333 microohms at 30 Watts.

fun resistor, I doubt Digi Key has one :)

Nevertheless, your brief calculation also shows how important good common mode rejection is with this application, as only rather small voltage drops across the shunt are allowed due to heat dissipation!

Kai

List of 59 messages in thread
TopicAuthorDate
Op amp input, high voltage measurement            01/01/70 00:00      
   You need...            01/01/70 00:00      
   ISO106, and: BE CAREFUL!!            01/01/70 00:00      
      Very dangerous indeed!!!!!!            01/01/70 00:00      
         Oh dear...            01/01/70 00:00      
            thanks guys, & Mahmood, my condolences            01/01/70 00:00      
               a question for Kai....            01/01/70 00:00      
                  Answer            01/01/70 00:00      
                     Precision            01/01/70 00:00      
                        I'd say that the DC "current transformer            01/01/70 00:00      
                           Not            01/01/70 00:00      
         Condolences            01/01/70 00:00      
         Condolences            01/01/70 00:00      
         busbars            01/01/70 00:00      
            Thank you all            01/01/70 00:00      
   Isolation transformer            01/01/70 00:00      
      DC            01/01/70 00:00      
         maybe this is what a "DC current transfo            01/01/70 00:00      
   High Voltage Op Amps            01/01/70 00:00      
   Problem Change, change in supply values            01/01/70 00:00      
      INA117 is a good choice then            01/01/70 00:00      
         shunt resistor            01/01/70 00:00      
            Thick piece of wire            01/01/70 00:00      
               fine if you can calibrate.            01/01/70 00:00      
                  Yes            01/01/70 00:00      
               Piece of Wire.            01/01/70 00:00      
            Nevertheless...            01/01/70 00:00      
               Try these            01/01/70 00:00      
            Shunt Resistors            01/01/70 00:00      
   change in problem - different supply val            01/01/70 00:00      
   The application..........sorry its late            01/01/70 00:00      
      Not really            01/01/70 00:00      
      More questions...            01/01/70 00:00      
         Answers.......I hope this is clearer            01/01/70 00:00      
            I smell smoke            01/01/70 00:00      
               Toasty warm            01/01/70 00:00      
            Volt range            01/01/70 00:00      
               welder voltage            01/01/70 00:00      
                  Extremely informative!            01/01/70 00:00      
                     So...            01/01/70 00:00      
                        ahm confoosed            01/01/70 00:00      
                           millivolts            01/01/70 00:00      
      Simon says            01/01/70 00:00      
         So the aim is to test for shorted turns?            01/01/70 00:00      
            I doubt this will work with DC motors            01/01/70 00:00      
   Ring Counter theory and schematic            01/01/70 00:00      
      Spot on Charles            01/01/70 00:00      
   millivolts and growler test            01/01/70 00:00      
   Test readings            01/01/70 00:00      
      Shorted turn            01/01/70 00:00      
      Could you draw a scheme?            01/01/70 00:00      
         Windings            01/01/70 00:00      
            I'm a bloody amateur...            01/01/70 00:00      
      Where you are measuring            01/01/70 00:00      
         Big fault ?            01/01/70 00:00      
            shorted turn            01/01/70 00:00      
               Update            01/01/70 00:00      
   Latest update            01/01/70 00:00      
      Much much more details needed!            01/01/70 00:00      

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