Current Transformers

Sirio is a leading manufacturer of electromagnetic components for applications in industrial electronics. Their range of power transformers has been used in high frequency insulated power converters over the last ten years. Manufactured by a special dedicated automatic machine, Sirio's power transformers are widely used in demanding, high power applications with very high reliability expectations. 

Today, Sirio is one of the world's leading manufacturers of power transformers, specialising in the development and production of current transformers, with more than a quarter of a million power transformers in the field.

Download Sirio's High Frequency Power Transformers and Inductors Brochure

 

Main Frequency Current Transformers

Main frequency current transformers are used to measure alternate currents at 50-60 Hz, up to 600 Arms.

Examples:

 

They are based on toroidal Silicon Iron core; they typically have a high number of secondary turns, so that the secondary current is relatively low. By connecting a burden resistance to the secondary side, you can read a proportional voltage signal, isolated from the mains. As the secondary current is low, the low power burden resistance can be connected to the PCB.

Current transformers are used to measure and detect alternate currents by keeping the galvanic isolation between the primary cable (the network) and the control stage. They typically have a high number of secondary turns, so that the secondary current is relatively low. By connecting a burden resistance to the secondary side, a proportional voltage signal, isolated from the mains can be read. As the secondary current is low, the low power burden resistance can be connected to the PCB.

 

Part Number	Ip (Arms)	Is (Arms)	n	Rc (Ω)	Uout (Vrms)	Outputs	D (mm)	Drawing
TA 150120	400	0.400	n1-4=1000	20	8.0	Faston 1-4	26	150A
TA 150130	200	0.400	n1-2=500	20	8.0	Faston 1-2	26	150C
	400	0.400	n1-3=1000	20	8.0	Faston 1-3	26	150C
	600	0.400	n1-4=1500	20	8.0	Faston 1-4	26	150C
TA 150140	400	0.200	n1-4=2000	20	4.0	Faston 1-4	26	150A
TA 150150	200	0.200	n1-2=1000	20	4.0	Faston 1-2	26	150C
	300	0.200	n1-3=1500	20	4.0	Faston 1-3	26	150C
	400	0.200	n1-4=2000	20	4.0	Faston 1-4	26	150C
TA 150160	600	0.600	n1-4=1000	10	6.0	Faston 1-4	26	150A
TA 150170	600	0.200	n1-4=3000	20	4.0	Faston 1-4	26	150A
TA 151008	200	0.300	n1-4=1000	10	2.0	Faston 1-4	18	151A
TA 151100	100	0.200	n1-4=500	20	4.0	Faston 1-4	18	151A
TA 151110	25	0.200	n1-2=125	20	4.0	Faston 1-2	18	151C
	50	0.200	n1-3=250	20	4.0	Faston 1-3	18	151C
	100	0.200	n1-4=500	20	4.0	Faston 1-4	18	151C
TA 151133	100	0.100	n1-4=1000	20	2.0	Faston 1-4	18	151A
TA 152023	25	0.050	500	40	2.0	Pins 1-2	13	152B
TA 152025	25	0.050	500	40	2.0	Faston 1-2	13	152A
TA 152027	50	0.050	1000	80	4.0	Pins 1-2	13	152B
TA 152050	50	0.050	1000	80	4.0	Fastron 1-2	13	152A
TA 153001	70	0.140	500	25	3.5	Fastron 1-2	9	153A
TA 153002	70	0.070	1000	50	3.5	Fastron 1-2	9	153A
TA 153003	70	0.035	2000	100	3.5	Fastron 1-2	9	153A
TA 153004	100	0.040	2500	100	4.0	Fastron 1-2	9	153A
TA 153006	70	0.140	500	25	3.5	Pins 1-2	9	153B
TA 153007	70	0.070	1000	50	3.5	Pins 1-2	9	153B
TA 153008	70	0.035	2000	100	3.5	Pins 1-2	9	153B
TA 153009	100	0.040	2500	100	4.0	Pins 1-2	9	153B

 

Current Transformers for Measurement Applications

Current transformers for measurement purposes are used to measure alternate currents at 50-60 Hz, up to 50 Arms. They are typically used in energy metering applications, where high accuracy and small dimensions are required at the same time.

Current transformers for measurement applications are available in two different versions; with passing-through hole and with the primary turn inside, this was developed to get an easier assembly process on the PCB.

Part Number	Ip (Arms)	n	Rc (Ω)	Rs (Ω)	E%		D (mm)	Up (kVrms)	Drawing
TA 150800	15 max	(1):1000	7	21	0.2	1	5	4200	1508FA
TA 150815	50	(1):1000	4	14	0.1	1	6	4200	1508FC
TA 150810	50	(1):1000	50	36	1.0	2	6	4200	1508FB
TA 150830	15 max	1:1000	7	21	0.2	1	0.8	4200	1508SA
TA 150811	50	1:1000	50	36	1.0	2	2.0	5000	1508SB

 

Current Transformers for High Frequency Applications

Current transformers for high frequency applications are used to detect high frequency currents, in order to protect an electronic switch against overcurrents in switching converters. They are typically connected at the primary side of medium-high power high frequency transformers, but they are also suitable for currents measurement, in applications which do not require high accuracy, but prompt response of the measurement equipment instead. 

They are developed to detect alternate currents in the frequency range of some kHz. By connecting a burden resistance to the secondary side, you can read a proportional voltage signal, isolated from the mains. Depending on the application, other types of signal processing are available to use either by using digital or analogue techniques.

Part Number	Ip (Arms)	n	Ls (mH)	fmax (kHz)	Vt (μVs)	Drawing	D (mm)	Uis (Vrms)	Up (Vrms)
TA 150511	20	(1):50	1.9	1000	180	1508FA	5	1000	4500
TA 150512	20	(1):100	7.5	400	400	1508FA	5	1000	4500
TA 150513	20	(1):200	30	100	850	1508FA	5	1000	4500
TA 150521	20	(1):50	4.5	500	160	1508FA	5	1000	4500
TA 150522	20	(1):100	19	200	360	1508FA	5	1000	4500
TA 150523	20	(1):200	76	50	750	1508FA	5	1000	4500
TA 150524	20	(1):500	475	10	1800	1508FA	5	1000	4500
TA 150320	25	(1):200	100	80	500	150320	6	750	3500
TA 150563	25	(1):1000	5000	10	2500	1508FB	6	750	4000
TA 150621	20	1:100	10	100	550	15062X	1.2	440	4000
TA 150622	20	1:200	40	50	1100	15062X	1.2	440	4000
TA 150625	20	1:1000	1000	10	6000	15062X	1.2	440	4000
TA 150641	50	1:100	10	100	850	15064X	2.3	480	4680
TA 150642	50	1:200	40	50	1900	15064X	2.3	480	4680
TA 150645	50	1:1000	1000	10	9000	1506X	2.3	480	4680
TA 152009	100	(1):100	31	60	2250	152A	13	1000	4000
TA 152059	100	(1):200	124	25	4500	152B	13	1000	4000
TA 153201	70	(1):50	11.5	500	650	153A	9	1000	4500
TA 153202	70	(1):100	45	200	1300	153A	9	1000	4500
TA 153203	70	(1):200	180	50	2700	153A	9	1000	4500
TA 153206	70	(1):50	11.5	500	650	153B	9	1000	4500
TA 153207	70	(1):100	45	200	1300	153B	9	1000	4500
TA 153208	70	(1):200	180	50	2700	153B	9	1000	4500
TA 150671	70	1:100	31	100	1400	15067X	3.5	600	5000
TA 150672	70	1:200	124	50	2800	15067X	3.5	600	5000

 

EE Core Based Drive Transformers

Pulse transformers are used in high frequency power converters, when an electrical pulse has to be transferred from the control stage to the power stage, by keeping the galvanic isolation between the circuits, according to the required safety standards. The electrical signal is applied to the primary winding and transferred to the secondary side, to fire electronic switches. The 109, 117 and 118 families are based on different sizes of EE cores.

The part numbers listed below are some examples, Sirio can also develop special drive transformers with any turns ratio, dedicated and bespoke to your application.

 

Part Number	n	Vt (μVs)	Ip (mArms)	Lp (mH)	Ls (μH)	Ck (pF)	Uis   (Vrms)	Up (Vrms)	Drawing
TI 109204	1:1:1	120	300	0.85	2.0	14	700	4200	109B
TI 109210	1:1:1	250	300	2.50	5.0	25	330	3100	109A
TI 109215	1:1.2:1.2	150	250	1.30	3.0	20	500	4000	109B
TI 109217	1:1	200	350	1.75	5.0	25	440	3750	109C
TI 117110	1:1	300	200	3.50	5.0	35	500	4000	117C
TI 117120	1:1:1	300	200	3.50	2.2	35	500	4000	117D
TI 117147	2:1	250	400	5.80	10.0	25	500	4000	117C
TI 117160	3:1	150	500	5.80	13.0	30	500	4000	117C
TI 117610	1:1	150	600	0.35	0.9	25	700	4000	117C
TI 117615	1:1:1	150	600	0.35	0.6	40	700	4000	117D
TI 118310	1:1	500	400	2.3	4.0	50	500	4000	118E
TI 118320	1:1:1	500	400	2.3	2.5	50	500	4000	118F
TI 118330	2:1:1	500	300	9.0	6.0	50	500	4000	118F
TI 118340	1:1	1000	300	9.0	14.0	50	500	4000	118E

 

Low Coupling Capacity Gate Drive Transformers   

Sirio's low coupling capacity gate drive transformers is a crucial component in today's industry, the low coupling capacity between the windings is particularly important to avoid any unwanted firings of electronic switches. 

They are predominantly used in the multiple shot firing techniques. Standard versions are designed with one or two secondary windings and the automatic winding process enhances their quality and price ratio.

 

Part Number	n	Vt (μVs)	Imax (mA)	tr(μs)	Rc (Ω)	Ck (pF)	Uis (Vrms)	Up (Vrms)	Drawing
TI 108010	1:1	250	250	1.5	40	7	500	3100	108A
TI 108020	1:1:1	250	250	1.5	40	7	500	3100	108C
TI 108030	2:1	350	250	3.5	40	8	500	3100	108A
TI 108040	2:1:1	350	250	3.5	40	8	500	3100	108B
TI 108050	3:1	300	250	2.5	40	8	500	3100	108A
TI 108060	3:1:1	300	250	2.5	40	8	500	3100	108C
TI 110153	1:1:1	600	100	1.2	100	8	500	4000	110D
TI 110154	3:1:1	600	100	1.2	100	7	500	4000	110D
TI 110155	1:1	500	100	1.0	100	7	500	4000	110E
TI 110233	1:1:1	300	250	1.2	40	7	500	4000	110D
TI 110234	3:1:1	300	250	1.0	40	7	500	4000	110D
TI 110239	1:1	350	250	2.0	40	5	500	10000	110F

 

Ring Core Based Gate Drive Transformers  

The electrical signal is applied to the primary winding and transferred to the secondary side, to fire electronic switches. The 111, 112, 113 and 114 families are based on different sizes of ring cores. The characteristics of these components are very different because several magnetic core materials and sizes can be used and different winding distributions can be chosen. 

 

Laminated materials are a preferred option for most engineers because they have much higher values of saturation flux density compared to ferrites which allows reduced dimensions, especially for medium-low switching frequency values (some tens kHz), and a much stable behaviour with temperature, making them the ideal solution for critical environment conditions. Ferrites are the most cost effective option for engineers and toroidal components, similarly to the laminated materials, offer impressive technical features.

Part Number	n	Vt (μVs)	Imax (mA)	tr (μs)	Rc (Ω)	Ck (pF)	Uis  (Vrms)	Up (Vrms)	Drawing
TI 111010	1:1	200	400	1	27	160	380	2000	111A
TI 111020	1:1:1	200	400	1	27	160	380	2000	111B
TI 112130	1:1	500	2000	1	15	70	500	4000	112A
TI 112140	1:1:1	500	2000	1	15	70	500	4000	112B
TI 113150	1:1	1000	2000	1	10	100	500	5000	113A
TI 113160	1:1:1	1000	2000	1	10	100	500	5000	113B
TI 114070	1:1	2000	2000	1	8	230	380	3100	114A
TI 114080	1:1:1	2000	2000	1	8	230	380	3100	114B

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