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The Hioki CT6904 is an ultra-high performance AC/DC current sensor rated for 500 A AC/DC primary current with a 4 MHz (±3 dB typical) measurement frequency range. The sensor uses a Zero Flux (Fluxgate Detection) measurement method, combining a fluxgate element for DC to low frequency current detection with newly developed opposed split coil winding technology for high frequency current detection. This architecture delivers a wide measurement range from DC to 4 MHz from a single sensor body that accepts conductors up to φ32 mm in diameter.
The CT6904 is designed for current measurement applications where both wide bandwidth and high accuracy are required at the same time. Applications described on the datasheet include high-precision efficiency testing of SiC and GaN inverters, where the sensor measures both the fundamental wave current and the switching frequency current and its harmonics during PWM output, and reactor and transformer loss analysis in power converter development, where switching current that has been obscured by noise on conventional sensors can be measured accurately. The sensor is built to support the demands of the power electronics, natural energy, and automotive industries.
| Category | Specification | Value |
|---|---|---|
| Basic Specifications | Rated primary current | 500 A AC/DC |
| Diameter of measurable conductors | φ 32 mm (1.26 in) or less | |
| Maximum input current | Within derating shown in figure. Up to ±1000 A peak allowable if within 20 ms (design value). When measuring current in the vicinity of derating, use a cooling time that is 10x or more greater than current input time. | |
| Output voltage | 4 mV/A | |
| Maximum rated voltage to ground | 1000 V CAT III; Expected transient overvoltage: 8000 V | |
| Linearity | ±10 ppm Typical (23°C / 73°F) | |
| Offset voltage | ±10 ppm Typical (23°C / 73°F, no input) | |
| Accuracy Guarantee Conditions | Guaranteed accuracy period | 1 year |
| Guaranteed accuracy period after adjustment by Hioki | 1 year | |
| Temperature and humidity for guaranteed accuracy | 23°C ±5°C (73°F ±9°F), 80% RH or less | |
| Warm-up time | 30 min. or more | |
| Input waveform / Connection | Sine wave; measuring instrument with input resistance of 0.9 MΩ to 1.1 MΩ; terminal-to-ground voltage 0 V; no external magnetic field; conductor center position | |
| Accuracy (Amplitude / Phase) | DC | ±0.025% rdg. ±0.007% f.s. |
| DC < f < 16 Hz | ±0.2% rdg. ±0.02% f.s. / ±0.1° | |
| 16 Hz ≤ f < 45 Hz | ±0.1% rdg. ±0.02% f.s. / ±0.1° | |
| 45 Hz ≤ f ≤ 65 Hz | ±0.02% rdg. ±0.007% f.s. / ±0.08° | |
| 65 Hz < f ≤ 850 Hz | ±0.05% rdg. ±0.007% f.s. / ±0.12° | |
| 850 Hz < f ≤ 1 kHz | ±0.1% rdg. ±0.01% f.s. / ±0.4° | |
| 1 kHz < f ≤ 5 kHz | ±0.4% rdg. ±0.02% f.s. / ±0.4° | |
| 5 kHz < f ≤ 10 kHz | ±0.4% rdg. ±0.02% f.s. / ±(0.08×f)° | |
| 10 kHz < f ≤ 50 kHz | ±1% rdg. ±0.02% f.s. / ±(0.08×f)° | |
| 50 kHz < f ≤ 100 kHz | ±1% rdg. ±0.05% f.s. / ±(0.08×f)° | |
| 100 kHz < f ≤ 300 kHz | ±2% rdg. ±0.05% f.s. / ±(0.08×f)° | |
| 300 kHz < f ≤ 1 MHz | ±5% rdg. ±0.05% f.s. / ±(0.08×f)° | |
| Frequency range | 4 MHz (±3 dB Typical) | |
| Effects of Temperature | Range | -10°C to 18°C (14°F to 64°F) or 28°C to 50°C (82°F to 122°F) |
| Amplitude sensitivity | ±0.005% rdg./°C | |
| Offset voltage | ±0.005% f.s./°C | |
| Phase | ±0.01°/°C | |
| Noise Rejection | Common-mode voltage rejection ratio (CMRR) | 140 dB or greater (50 Hz/60 Hz); 120 dB or greater (100 kHz) |
| Effect of conductor position | ±0.01% rdg. or less (100 A input, 50 Hz/60 Hz), using wire with 10 mm (0.39 in) outer diameter | |
| General Specifications | Operating environment | Indoors, Pollution Degree 2, altitude up to 2000 m (6562.20 ft) |
| Operating temperature and humidity | -10°C to 50°C (14°F to 122°F), 80% RH or less (no condensation) | |
| Storage temperature and humidity | -20°C to 60°C (-4°F to 140°F), 80% RH or less (no condensation) | |
| Dielectric withstand voltage | 7.4 kV AC (sensed current of 1 mA), 50 Hz/60 Hz: 1 min (distance between feed-through window and cable output terminal) | |
| Power supply | Supplied from PW6001, PW3390, and CT9555 | |
| Max. power consumption | 7 VA (500 A/55 Hz measurement, with a power supply of ±12 V) | |
| Interface | Dedicated interface (ME15W) | |
| Dimensions | Approx. 139 mm (5.47 in) W × 120 mm (4.72 in) H × 52 mm (2.05 in) D (excluding protrusions and cables) | |
| Output cable length | Approx. 3 m (9.84 ft) including relay box (10 m / 32.81 ft made-to-order option available) | |
| Bracket hole diameter | φ 5.2 mm (0.20 in) (M5 screws, recommended tightening torque: 1.5 N·m to 2.0 N·m) | |
| Physical | Mass | Approx. 1.0 kg (35.3 oz); 10 m output cable variant approx. 1.3 kg (45.9 oz) |
| Product warranty period | 3 years | |
| Connectable Products | Power Analyzer PW6001 | Combined accuracy per datasheet table |
| Power Analyzer PW3390 | Add PW3390 accuracy and CT6904 accuracy (consider sensor rating when calculating f.s. error) | |
| Sensor Unit CT9555 | Combined accuracy: sensor accuracy × 1.5 (when output coaxial cable is no longer than 1.6 m / 5.25 ft) |
Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.
Model No
Hioki
Condition
New
Manufacturer
Hioki
Frequency
4 MHz
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