Measurement CT - Sirio Inductive Components

Current transformers for measurement applications

The most common application is in energy meters for residential and industrial applications, or in wallbox installations. For this type of component, the choice of magnetic material is crucial, allowing high accuracy and low phase shift in the input/output signals in extremely compact dimensions. These characteristics are particularly important when designing measuring devices for RMS, peak, or waveform measurements, such as the analysis of harmonic content of an alternating current.

By connecting a resistor to the transformer’s secondary winding, a voltage signal isolated from the mains and proportional to the primary current can be obtained. However, various amplification techniques and signal conditioning exist, depending on the application circuit or required analysis.

The same transformer can be supplied in a through-hole version and in a version with an inserted primary turn, to facilitate mounting on a printed circuit board. The typical operating temperature ranges from –25 to +85°C. Some standard models are listed below.

Through-hole version

Code	I_p [Arms]	n	R_c [Ω]	f_n [Hz]	R_s [Ω]	E [%]	Φ [°]	D [mm]	Drawing	U_p [Vrms]
TA 150800	15	(1) : 1000	7	50-60	21	0,2%	1°	5,0	1508FA	4200
TA 150815	50	(1) : 1000	4	50-60	14	0,1%	1°	6,0	1508FC	4200
TA 150810	50	(1) : 1000	50	50-60	36	1,0%	2°	6,0	1508FB	4200

Model 1508FA

Model 1508FB

Model 1508FC

Version with an inserted primary turn

Code	I_p [Arms]	n	R_c [Ω]	f_n [Hz]	R_s [Ω]	E [%]	Φ [°]	D [mm]	Drawing	U_p [Vrms]
TA 150830	15	(1) : 1000	7	50-60	21	0,2%	1°	0,8	1508SA	4200
TA 150811	50	(1) : 1000	50	50-60	36	1,0%	2°	2,0	1508SB	5000

The high-accuracy current transformer characterization refers to the following quantities:

n ratio between primary current and secondary current (it typically corresponds to the number of turns of the secondary winding)
R_S secondary winding resistance
I_p rms primary current rating
f_n nominal operating frequency (or optimal frequency range)
R_c nominal load resistance
U_OUT output voltage at nominal current (connecting the nominal load resistance)
Φ typical input/output phase shift
E maximum measurement error at nominal current and load
D diameter of the through-hole or primary turn (in the version with molded-in turn)
U_is maximum primary/secondary operating voltage
U_p primary/secondary insulation voltage

Would you like to receive the datasheet of these components? Haven’t you found the features you need, but you would like to get a transformer of such a size? Please, send an e-mail to our Technical Department.