SATEC EDL175 - Manual (Page 9)

9
2.5 CT Setup
Set up the CT according to the PM175 Installation and Operation Manual, Table 4-1 or the
PASUser’s Manual, Section 6.1.1.
2.5.1 Normal Measurement
Set the CT = 1.
2.5.2 Direct Measurement (via clamps) All clamps require the CT according to the following
formula: CT = I 1ncl / I 2ncl where: I 1ncl and I 2ncl are the clamp nominal primary and secondary currents.
Examples: 1) I 1ncl =1000A and I 2ncl =1A; CT=1000 2) I 1ncl =1000A and I 2ncl =5A; CT=200 3) I 1ncl =200A
and I 2ncl =1A; CT=200 FLEX sensors and clamps with nominal output voltage of 3V require the CT to
be set to the nominal primary current. FLEX sensors and clamps with nominal output voltage of 2V
require the CT to be set to 150% of the nominal primary current.
Examples: 1) I 1ncl =300A, V 2ncl = 2V; CT=150
2) I 1ncl =3000A, V 2ncl = 3V; CT=1500
2.5.3 Measurement via External CTs Secondary Current, Clamps and Special Cables
The CT value should be set according to the following formula: CT = (I
p
/ I
s
) • (I 1ncl / I 2ncl ) • 0.005
where: I
p
= external Current Transformer primary nominal current I
s
= external Current Transformer
secondary nominal current Examples:
1. When measuring current without external transformer (I
p
/ I
s
=1) via clamp 1000/1,
then
CT=5, If will be set CT=5000 the instrument display in mA;
2. When measuring secondary of current transformer 3000/5 via clamp 1000/1,
then