China YZ Series Current Transformer - Reliable Suppliers and Factory for Power System Monitoring
Product Overview
A CT is powered by electromagnetic induction and consists of two windings: a secondary winding (many turns coupled to safety or measurement devices) and a main winding (few turns connected in series with the high-current circuit). While the secondary winding, which is typically specified at 5A or 1A for most industrial applications, receives a relatively low current, the primary winding receives a large current. This proportionality, also known as the transformation ratio, ensures precise current measurement while protecting personnel and equipment from potentially harmful voltages.
High Accuracy
Essential for reliable energy metering in industrial applications.
Strong Linearity
Minimizes measurement error across the full operating range.
Insulation Strength
Maintains high voltage isolation between primary and secondary windings.
Important: The secondary winding should never be open-circuited while utilizing a CT. An open circuit may produce extremely high voltages, which can damage electrical devices.
Current transformers are essential for guaranteeing the reliability, effectiveness, and safety of contemporary electrical systems — enabling precise current monitoring and improved fault protection.
Technical Parameters
| Type | Main Loop Current | (mm) Outline Size | ||||||
|---|---|---|---|---|---|---|---|---|
| a | b | d | c | e | f | g | ||
| YZ-45 | — | 45 | 102 | 87 | 37 | 36 | 77.5 | 18 |
| YZ-65 | < 250A | 65 | 126 | 109 | 37 | 36 | 100.5 | 18 |
| YZ-80 | — | 80 | 146 | 129 | 37 | 36 | 121 | 18 |
| YZ-100 | < 630A | 100 | 158 | 144 | 37 | 36 | 133 | 18 |
| Rated Primary Current: IA | Rated Secondary Current: 0.5mA | |||||||
* All outline dimensions are in millimeters (mm). Specifications subject to change without notice.
Frequently Asked Questions
Q What is a Current Transformer (CT) and how does it work?
A Current Transformer (CT) operates on the principle of electromagnetic induction. It consists of a primary winding connected in series with the high-current circuit and a secondary winding coupled to measurement or safety devices. The large current in the primary winding induces a proportionally smaller current in the secondary winding, enabling safe and accurate current measurement.
Q What are the standard secondary current ratings for industrial CTs?
For most industrial applications, the secondary winding of a current transformer is typically specified at either 5A or 1A. These standardized output levels allow for compatibility with a wide range of measuring instruments, protection relays, and energy metering devices.
Q Why should the secondary winding of a CT never be left open-circuited?
If the secondary winding of a CT is left open-circuited while the primary is energized, the transformer attempts to drive the full primary current through an open circuit. This can generate dangerously high voltages across the secondary terminals, potentially causing insulation breakdown, equipment damage, and serious safety hazards to personnel.
Q What are the key performance requirements for current transformers?
Current transformers must meet three critical performance requirements: (1) High Accuracy — to ensure reliable energy metering; (2) Strong Linearity — to minimize measurement errors across the full current range; and (3) Insulation Strength — to maintain safe high-voltage isolation between the primary and secondary windings.
Q What main loop current ratings are available for the YZ series CTs?
The YZ series current transformers are available for different main loop current ratings. The YZ-65 model supports main loop currents of less than 250A, while the YZ-100 model is designed for currents up to less than 630A. Different models offer varying outline sizes to accommodate different installation requirements.
Q How do current transformers contribute to electrical system safety?
Current transformers play a vital role in electrical system safety by stepping down high primary currents to safe, measurable levels for instrumentation and protection relays. They provide galvanic isolation between high-voltage circuits and measurement equipment, protect personnel from dangerous voltages, and enable accurate fault detection and protection, ensuring the overall reliability and safety of modern electrical systems.