User manual

E-Clip 1 / E-Clip 2 Current Clamps
5
Clamp current transformer must always have a low impedance load on its secondary side. This
loading is realized with an A-meter (for current sensors with current output). Current clamp with
voltage output already contains the load resistor and its output voltage is proportional to
measured current.
The N1:N2 ratio (primary to secondary winding turns ratio) defines the step-down current ratio
and sensitivity of current clamps. For N2 = 1000 the sensitivity is defined as
1 mA / 1 A, i.e.: 1 mA of output current is generated from 1 A primary current for
N1 = 1. The general formula for sensitivity are given below:
2
1
N
N
II
mS
= for current output, and
Lm
R
N
N
IU
2
1
= for voltage output.
N1 is always integer and means number of passes of conductor carrying measured current
through conductor opening of current clamp.
4.2. Typical applications
Some typical applications of current measurement for standard sensitive current clamps
(E-Clip 2) in combination with appropriate measuring instrument:
- Harmonic analysis,
- Measuring electrical power,
- Measuring current and energy consumption,
- Functional testing of appliances, machines,
- Measuring equipment inrush current, etc.
Additional applications related to low current measurements can be covered with high sensitive
type current clamps (E-Clip 1):
- Measurement of PE leakage current,
- Measurement of differential current and/or current difference,
- Contactless measurement of earth resistance,
- Determining problems in lighting and grounding systems.