Re: Output Characteristics of SIMPSON 200:5 Current Transformer

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net> 

The usual x:5 current transformer is a current output device, designed for a
rated current in the sense winding of 5Amps, corresponding to X amps through
the hole.  Under no circumstances should you run one of these open circuit
(the core saturates, and that makes big voltage spikes on the secondary).
If you're feeding into a A/D, put a small burden resistor across the
secondary (say, 0.1 ohms) and measure the voltage across the resistor. Even
at 5A, that 0.1 ohm resistor will dissipate 2.5 Watts, so make sure it's big
enough.  You could also put a 0.01 ohm resistor, which will have lower
voltage (50 mV at 5A), but will also disspate less power.

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, February 07, 2004 3:29 PM
Subject: Output Characteristics of SIMPSON 200:5 Current Transformer


 > Original poster: dhmccauley-at-spacecatlighting-dot-com
 >
 > Does anyone have an idea of what the output characteristics are of the
 > common SIMPSON 200:5 Current Transformers are??
 >
 > I'd like to use one to monitor input current and interface to the A/D port
 > of a PIC microcontroller.
 > However, without knowing the output characteristics of these things, I
can't
 > really design a proper interface (level converter / RMS converter etc...)
 > for it.  I tried getting specs from the manufacturer but to no avail.
 >
 > Thanks
 > Dan
 >
 >