[Boatanchors] AC Meter Shunt Help]

[RBethman]

John Forster wrote:
>> > Personally, I would NOT use a CT!  They can DEFINITELY be dangerous!
>> >
>> > Take a look at VTVMs and DVMs.  They ALL use a hard wire SHUNT to
>> > achieve their high amp readings.  [snip]
> 
> And the meter is at line potential. Not the greatest idea IMO. In a three phase
> system each meter is a different phase HV. Don't touch two of them at the same
> time.

I agree totally.  In the metering of quite a few OLD Boatanchors, the 
metering IS at line potential.  Take the BC-610 series as an example. 
The PA Current meter IS at the final plate potential.  The meter IS 
insulated and IS sealed - WITH warnings about LETHAL VOLTAGES present.

  However I do NOT believe that one of our list members is dealing with 
a 3 phase system, nor with a system where a CT is being used OR that

 > The 5 Amp meter in question will almost certainly be a moving iron 
type of
> instrument,it WILL have a 5 Amp coil!.

> 
> A properly insulated and terminated CT is a good thing. You just have to
> understand what you are doing.
> -John
> 
That's where I agree entirely!  UNDERSTAND WHAT YOU ARE DOING!

This STILL begs the questions as to WHAT the circuit is that this meter 
is in, AND what "main transformer" that Ed referred to:

> So, the transformer Bought or made would run in parallel with the main transformer? If I make one do you suggest how many turns per primary/secondary would be sufficient and core type?
> Again, sorry for responding too quickly 

This is WHY I have suggested a SHUNT in lieu of a CT.

SO:

Ed, what PRECISELY is the circuit that this is in.  WHAT is this meter 
reading, (Besides AC Amps) - what IS the specific application?

Bob - N0DGN