The CT PT turns ratio tester is a portable and intelligent power testing equipment that integrates multiple testing functions. It is mainly used for comprehensive testing of key parameters of current transformers (CT) and voltage transformers (PT) in the laboratory or on-site. Its working principle is to integrate traditional functional modules such as volt ampere characteristic testing, transformation ratio testing, polarity (or angle difference ratio) testing, etc. into one instrument, control and switch the measurement circuit and excitation source through an internal microprocessor, and automatically calculate, display, and store the results.
The following is the working principle of its core functions:
1.Volt-Ampere (Excitation) Characteristic Test:
Applies a variable current to the secondary winding.
Measures the voltage developed across the secondary winding. (Plots V-I curve).
2.Ratio (Turns Ratio) Test (Common Voltage Method):
Applies a known small AC voltage to the secondary winding (primary shorted).
Measures the induced voltage on the primary winding.
Calculates ratio as Primary Voltage / Secondary Voltage.
3.Polarity Test (DC Pulse Method):
Applies an instantaneous DC pulse to the primary winding.
Detects the instantaneous voltage direction on the secondary winding.
Determines polarity (Subtractive/Additive) based on the direction.
Key Takeaways:
Integrated Device: Combines necessary power sources (current, voltage, pulse) and measurement circuits into one unit.
Automatic Switching: Internal circuitry connects the correct sources and measurement points based on the selected test.
Smart Operation: A microprocessor controls the test sequence, data acquisition, calculations, and result display.
Core Value: Automates and integrates multiple traditional, complex tests into a single portable instrument, significantly improving efficiency and ease of use. Simply connect the wires, select the test, and the instrument handles the rest.