China CTKT Series Current Transformer - Reliable Suppliers and Factory Solutions for Power Management
A current transformer (CT) is a vital component in electrical systems for effectively managing, monitoring, and safeguarding power supply. These devices are designed to measure large quantities of alternating current (AC) with precision and reliability. In various applications, including power generation, transmission, and industrial distribution, high-current circuits are often equipped with safety relays and sensitive measurement instruments. Sourced from reputable China suppliers and manufacturers, our current transformers ensure top-notch quality and performance, making them an essential addition to any electrical setup. Trust in our factory to provide you with the best current transformers for your needs
A CT operates on electromagnetic induction and consists of two windings: a secondary winding with many turns linked to safety or measurement devices, and a main winding with a few turns connected in series to a high-current circuit. The primary winding receives a large amount of current, but the secondary winding, which is usually set to 5A or 1A for the bulk of industrial applications, receives very little. This proportionality, also known as the transformation ratio, enables accurate current monitoring while protecting workers and equipment from unsafe voltages.
CTs need sufficient insulation to sustain a high voltage between windings, linearity to minimize measurement mistakes, and high precision for energy metering.
⚠ Important: Never leave the secondary winding open circuit when using a CT. An open circuit can produce extraordinarily high voltages that could damage electrical equipment and pose serious safety risks.
Current transformers are essential to the reliability, effectiveness, and safety of modern electrical systems because they enable more precise current monitoring and problem identification.
Technical Parameters
Type
Current Range
Signal Output
Lead Length
(mm) Outline Size
c
A
B
C
D
TIO
0–75A
0–50mA / 0.333V
1m
10
30
34
40.5
14
T16
0–150A
0–5A / 0.333V
1m
16
38
38.5
51
19
T24
0–250A
0–5A / 0.333V
1m
24
51.5
49
73
22
T36
0–600A
0–5A / 0.333V
1m
36
70
53
89
24.5
T45
0–800A
0–5A / 0.333V
1m
45
79
59
98
22
T50
0–1000A
0–5A / 0.333V
1m
50
94
70
120
29
G Accuracy Grade: 1.0
Overload Current: ≥ 1.2% In
Frequently Asked Questions
Q
What is a Current Transformer (CT) and how does it work?
A Current Transformer (CT) is an instrument transformer that operates on the principle of electromagnetic induction. It steps down high primary currents to a lower, proportional secondary current (typically 5A or 1A) that is safe for use with measuring instruments and protection relays. The ratio between primary and secondary current is called the transformation ratio.
Q
Why should the secondary winding of a CT never be left open circuit?
When the secondary winding is left open circuit while the primary is energized, all the primary magnetomotive force drives the core into deep saturation. This generates an extremely high and dangerous voltage across the secondary terminals, which can damage insulation, destroy connected equipment, and pose a serious risk of electric shock to personnel. Always ensure a burden (load) is connected before energizing.
Q
What current ranges are available for these CT models?
The product line covers a wide range of applications. Available current ranges include: 0–75A (TIO), 0–150A (T16), 0–250A (T24), 0–600A (T36), 0–800A (T45), and 0–1000A (T50). All models come with a 1-meter lead length and output either 0–5A or 0–50mA at 0.333V depending on the model.
Q
What accuracy grade do these current transformers comply with?
These current transformers are manufactured to Accuracy Grade 1.0, which meets the requirements for general industrial energy metering and power monitoring applications. This grade ensures that measurement errors remain within ±1% across the rated operating range, making them suitable for billing meters and control systems.
Q
What is the overload current specification for these CTs?
These current transformers are designed to handle an overload current of ≥ 1.2% of the rated current (In). This means the CT can withstand short-term overcurrent conditions without compromising accuracy or causing permanent damage to the core or windings, providing added durability in demanding industrial environments.
Q
How do I select the right CT model for my application?
To select the correct CT model, consider three key factors: (1) Primary current range — choose a model whose rated current matches or slightly exceeds your maximum expected load current; (2) Physical size — ensure the aperture (dimension "c") is large enough to fit around your conductor; (3) Signal output — confirm whether your measuring device requires a current output (0–5A) or a voltage output (0.333V). Refer to the Technical Parameters table for full dimensional and electrical specifications.
