SİGMA ELEKTRİK Do Not Risk Your Safety LOW VOLTAGE CURRENT TRANSFORMERS ISO 9001 : 2008 www.sigmaelektrik.com

Sigma Elektrik is one of the leading com- pany focused on designing, manufactur- ing and marketing of Low Voltage switch- gear components such as MCCB, MCB, RCCB, AC Contactors, Instrument Trans- formers, Motor Protection Switches, Sigma Elektrik is a leading supplier of so- lutions and services for electrotechnical installation in residential and commercial buildings as well as for industrial applica- tions. Quality assurance and customer satisfaction are among SIGMA's top pri- orities. The quality of products and ser- vices are constantly aimed at achieving customers' satisfaction and corresponding...

SHORT CIRCUIT TESTING LABORATORY LAB□ RATDRY Sigma Elektrik owns the most comprehensive low voltage short circuit testing laboratory in which all the type test of low voltage switchgear and LV distribution board can be made. This laboratory which accelerates the company in product development studies, still provides services for many customers at home and abroad and contributes to the national economy. This guarantees the highest quality standards of our products. Since 2003 October it has been used by TSE (Turkish Standards Institution) as a Subcontractor laboratory and accredited by TURKAK....

Open Secondary Voltage Of CTs. Construction And Fixing Details Assembly Of DIN Rail Mounted Ordering Information

Sigma current transformers are maintenance-free Low voltage current transformers for indoor They comply with EN 60044-1, VDE 0414, DIN 42600, BS 3938 and GOST 7746-2001. The LV current transformers are used for 2 main purposes. Instrument current transformer is intended to supply to indicative devices, integrated meter and similar apparatus. They are characterized by their accuracy and for saturating at moderate overcurrent. This effect protects the measuring instruments from possible overcurrent. Protective current transformer is intended to supply to protective relays whereby accuracy of CT...

Open Secondary Voltage Of CTs CTs generally are secondary short-circuited when no burden is connected. In doing so a continuous operation is possible. Open secondary terminals have the same effect as an secondary circuit which is burdened with an infinitely high resistance. The waveform of the secondary current is heavily distorted then. Mo- reover, high peak voltages occur which are hazardous for the personnel and dangerous for the CT (internal puncture or external flashover). Rated primary current: The value of current which is to be transformed to a lower value. Sigma CTs have primary current...

Further to the general CT specifications, we now need to know : Vkp - Voltage knee point lo - Maximum magnetising current at Vkp Rs - Maximum resistance of the secondary winding Knee point voltage: That point on the magnetizing curve where an increase of 10% in the flux density (voltage) causes an increase of 50% in the magneti- zing force (current). Highest voltage for operating equipment (Urn): Urn is the rms value of the highest voltage occurring between the conductors in a network. Technical Specifications

Compact and modern design Nickel plated brass secondary terminals Supply real routin test report together with each CT Self-extinguishing glass-reinforced PA6 Housing Double connection for secondary terminals DIN rail mounting for mini types Ratio value as engraved in the body 5 kV dielectric strength for wound primary types Selection Criteria Information on associated relay or instrument - Nominal current 3. Loss contribute from power loss in power line - Distance between transformer & instruments - Diameter of cable use for connection - Operating temperature Burden is the impedance of the secondary...

Burden Presented By Copper Leads Return leads Burden Presented By Instruments Pw = Burden presented by copper leads in VA

Table - limits of current error and phase displacement for measuring current transformer (Classes 0.1 To 1) Table - limits of current error and phase displacement for measuring current transformer For special application Table - limits of current error for measuring current transformers (classes 3 and 5) Table - limits of error for protection current transformer Important of accuracy & phase angle Current error is an error that arises when the current value of the actual transformation ratio is not equal to rated transformation ratio. Kn = rated transformation ratio Ip = actual primary current...

Class X Current Transformer Class X current transformer is use in conjunction with high impedance circulating current differential protection relay, eg restricted earth fault relay. As illustrated in IEC60044-1, the class X current transformer is needed. The following illustrates the method to size a class X current transformer. Step 1: Calculating knee point voltage Vkp Vkp = Required CT knee point voltage Ift = max transformer through fault in ampere Ret = CT secondary winding resistance in ohms Rw = Loop impedance of pilot wire between CT and the K = CT transformation ratio Step 2: calculate...

Assembly Of DIN Rail Mounted CTs It is possible to fix din rail mounted CTs both vertically and horizantally.

S25BN SERIES WOUND PRIMARY TYPE CURRENT TRANSFORMERS A range of compact low cost moulded case current transformers suitable for primary currents from 20A to 150A with built in sealable terminal covers. Suitable for measuring applications in AC power systems For metering and relaying applications in low voltage switchboords, Wiring Diagram Technical Data Note: Other specifications on request Range Table

S20 SERIES WINDOW TYPE CURRENT TRANSFORMERS Wiring Diagram A range of compact low cost moulded case current transformers suitable for primary currents from 30A to 250A with built in sealable terminal covers. Suitable for measuring applications in AC power For metering and relaying applications in low voltage switchboords, switchgear Technical Data Range Table

S30 SERIES WINDOW TYPE CURRENT TRANSFORMERS Wiring Diagram A range of compact low cost moulded case current transformers suitable for primary currents from 60A to 600A with built in sealable terminal covers. Suitable for measuring applications in AC power For metering and relaying applications in low volta- ge switch boords, switchgear Technical Data Note: Other specifications on request Range Table