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    CT Ratio to Current Calculator: Calculate Primary Current Easily

    Created by Md jony islam

    secondary current to primary current

    Compute the principal current with the CT ratio and current on the secondary. This CT ratio to current calculator makes conversions using a current transformer easy and fast. A current transformer (CT) steps down high primary currents to a manageable secondary current based on its ratio. The primary current Ip = Is × R, where 𝐼𝑝 is the primary current, 𝐼s is the secondary current, and 𝑅 is the CT ratio (primary turns : secondary turns). This calculator simplifies this calculation for practical use.

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    CT Ratio to Current Calculator

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    What do you need to know to calculate CT Ratio to Current?

    The CT Ratio to Current Calculator allows you to get the primary current passing through a current transformer (CT) using the known CT ratio and the secondary current. Current transformers reduce high currents to a lower current to measure or to indicate protection. Multiplication of the secondary current with the CT ratio provides the primary current.

    🙋 Try our Hall Voltage Calculator . If you want to learn more about conversions using Electrical Engineering Project Calculators.

    Secondary current to primary current

    This tool is handy for the electrical engineers, electricians, and technicians in rapid and accurate calculations related to CT and safe and efficient monitoring and measurement of current. Just insert the value of the CT ratio and secondary current to have the value of the primary current.

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    Frequently Asked Questions - CT Ratio to current Conversion FAQs:

    What is the CT ratio of current calculation?

    Electric current measurement requires CT (Current Transformer) ratio evaluation to find the relationship between actual circuit current and transformer output current. The CT (Current Transformer) ratio takes its calculation formula from the following relation of primary to secondary currents. CT ratio = Primary Current / Secondary Current. A CT ratio equals 20:1 when the primary circuit current amounts to 100A and the secondary circuit output reaches 5A. The CT ratio enables electrical personnel to measure high currents in systems by evaluating secondary currents despite operating at a distance from primary currents.

    What is the CT ratio of 100A?

    A CT ratio designation of 100A implies that this refers to the primary current, which equals 100A, with secondary current operating at certain pre-defined values such as 5A or 1A. The ratio of a 100A CT with a 5A secondary amounts to 100:5 or 20:1. Secondary circuit measurement receives 5A output while the primary circuit passes 100A through the device.

    What does CT ratio -/5 mean?

    The symbol “CT ratio -/5” represents a Current Transformer with an unspecified primary current marked by a space before the slash, which has a fixed output of 5 amperes at the secondary end. The symbol “CT ratio -/5” reveals that the target primary current measurement remains undefined at this time, and the transformer will produce a secondary output of 5A no matter what primary current levels are present. The CT has a ratio of 200:5, which produces 5A of secondary current when 200A flows through the primary.

    What is the CT ratio used for?

    Measurements through electrical measuring equipment use the CT ratio to decrease high currents to levels fit for observing by meters and protection relays. The CT uses its primary function to transform primary current into secondary current that measures accurately yet remains harmless for user safety. Monitoring system protection and control needs accurate observations of large electrical currents since the CT ratio is an essential element in this domain.

    How do you calculate the CT ratio?

    The CT ratio results from the primary current divided by the secondary current value. The formula is: CT ratio = Primary Current / Secondary Current. When the primary circuit contains 200A while the secondary circuit holds 5A, then the CT ratio will adopt a 40:1 combination. The conversion rate between primary and secondary circuits amounts to 40A at the primary side, generating 1A at the secondary side. Any CT safely measures high currents in the secondary circuit because of its calculated ratio.

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    About the Author

    Md Jony Islam

    Md Jony Islam: Multidisciplinary Engineer & Financial Expert:

    Md. Jony Islam is a highly skilled professional with expertise in electronics, electrical, mechanical, and civil engineering, as well as finance. Specializing in transformer service and maintenance for 33/11kV substations, he ensures reliable and efficient electrical systems. His mechanical engineering skills drive innovative designs, while his financial acumen supports effective project budgeting. With a strong foundation in civil engineering, he contributes to robust infrastructure development. Md. Jony Islam's multidisciplinary approach ensures efficiency, quality, and reliability across all projects.