Instruction Manual

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 = I1ncl / I2ncl where: I1ncl and I2ncl are the clamp nominal primary and secondary currents.

Examples: 1) I1ncl =1000A and I2ncl =1A; CT=1000 2) I1ncl =1000A and I2ncl =5A; CT=200 3) I1ncl =200A

and I2ncl =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) I1ncl =300A, V2ncl = 2V; CT=150

2) I1ncl =3000A, V2ncl = 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 = (Ip / Is ) • (I1ncl / I2ncl) • 0.005

where: Ip = external Current Transformer primary nominal current Is = external Current Transformer

secondary nominal current Examples:

1. When measuring current without external transformer (Ip / Is=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