How to read & understand a Current Transformer (CT) Nameplate?
This post presents the difficult nameplate as a hidden code, which makes the explanation more interesting and memorable.
Let’s understand the secret language on a Current Transformer (CT) nameplate.
Every number and character on a CT is a significant component of information that determines its functionality and safety. This wonderful handbook is the ideal “decoder ring.”
Several specifications are absolutely necessary for any protection (or) metering scheme:
CT Ratio
CT Ratio (for example, 1000/5 A): Starting with the basics. This means it reduces a primary current of 1000 A to a safe realizable 5 A on the secondary side.
Accuracy Class
Accuracy Class (for example, 0.5 against 5P10): This is important. The CT has two personalities: highly accurate for metering (0.5) under normal loads and reliable for protection (5P10) during large fault currents.
Knee Point Voltage (Vk)
Knee Point Voltage (Vk): For protective CTs, this is the voltage at if the core reaches saturation. If your fault condition surpasses this threshold, the CT’s output becomes unreliable.
Choosing the wrong CT specifications can result in inaccurate billing (or) worse, full failure of your protection program during a fault.
You can also follow us on AutomationForum.co, Facebook and Linkedin to receive daily Instrumentation updates.
You can also follow us on ForumElectrical.com , Facebook and Linkedin to receive daily Electrical updates.