3 in 1 current transformer for easy installation compact in size ,save space good accessories for panel meters and kWh meter
INTRODUCTION Current Transformer was used to change the high primary current to low secondary current. Connected with the Panel Meter or Relay, they can help to measure the current or protect the equipments which were connected to the high voltage line.
SELECTION OF THE CURRENT TRANSFORMER To select the Current Transformer correctly, the following points should be clarified: The application(for measuring or protection) The features of the working environment (indoor or outdoor, operating temperature, air humidity etc...) Operation voltage and frequency Range of the primary current (maximum and minimum of the current to be measured) Dimension of the cable or bus bar Data of the overload Short circuit current Specification of the measuring device associated with the Current Transformer (accuracy, rated current, consumption etc...) The diameter and length of the cable which was used to connect the Current Transformer and associated measuring device
POWER LOSSES OF THE CURRENT TRANSFORMER In the practical application, the power generated by the primary curr ent shoul d be equal or bigger than the power requirement of th e associated measuring device plus the consumption of the connecting line. Losses in the line, PL: This is the power lost, through heat, generated by the passage of current through the resistance RL in the cables, in the transformer's secondary circuit. Factors to be taken into account: Secondary current: PL = RL /2 Cable diameter: RL is inversely proportional to the square of the diameter Cable length: RL is proportional to the length of cabling (there and back) Power: The nominal apparent power (V A) with a specified power factor, which was supplied by the Current Transformer, to the secondary current with the assigned current when it is connected to its nominal load, Sc (V A)=Zc (/sn)2 According to Standards, for apparent power greater than or equal to 5 V A, the power factor is 0.8 inductive. For apparent power less then 5 V A the power factor is considered to be one (unity).
TABLE OF LOSSES IN THE SECONDARY LINE V A 5 4 3 2 1 5 10 15 20 25 30 35 40 45 50 (m) Length of secondary line Note:With.../1A transformers losses are reduced 25 times 2 s=1.5mm 2 s=2.5mm 2 s=4mm 2 s=6mm 2 s=10mm .../5A ACCURACY OF A TRANSFORMER The percentage of error, produced in a transformer, is established by IEC60044-1. In measurement transformers: 25 % and 100 % of nominal power. In protection transformers: 100 % of nominal power.
SCT-242 description:
A new range of high quality plastic case current transformer which dereloping from SCT series, suit for primary currents from 60A to 630A; perfect match installation with MCCB.
3 in 1 current transformer
