Smart Timer
TOMZN TOS7-B Bluetooth Smart Timer Switch 40A 63A 85-265V EasyCon App Remote Control
DIN-Rail
40A / 63A
EasyCon App
OEM Rogowski Sensing & Control Products
Precision Current Acquisition & DIN-Rail Switchgear Systems
Engineered for high-harmonic environments, non-intrusive electrical retrofits, and high-amperage monitoring across Tokyo commercial substations and global clean energy platforms.
Multi-Function
TORT7 Series Delay-ON Delay-OFF 10in1 Asymmetric Cycler Time Relay Multi-Function Switch
0.1S-10D
Pulse Gen
Cycler Relay
Wall/Rail
TOMZN Bluetooth Smart Timer Switch 85-265VAC 10A 30A EasyCon Countdown 28 Groups
85-265V AC
10A / 30A
28 Groups
Programmable
TOMZN New Type DIN Rail Single Phase Weekly 7 Days Programmable Digital Switch 16A
7-Day Weekly
12V-230V
16A Load
1NO + 1NC
TOMZN 1NO 1NC DIN Rail Single Phase Weekly 7 Days Digital TIME SWITCH Relay AC 220V 230V
1NO 1NC
220V/230V
Precision Cal
Heavy Load
TOS6-40 Bluetooth Time Control Switch 35mm DIN Rail Wall-Mounted Timing AC85-265V 40A
35mm Rail
AC85-265V
40A Direct
Solar OEM
IP65 Pre-Wired Solar PV Combiner Box with Integrated DC MCB, Fuse & SPD Protection
IP65 Solar
Pre-Wired
DC Isolation
High DC Volt
2P DC MCB 1000V Solar Photovoltaic Miniature Circuit Breaker 3A to 63A C Curve
1000V DC
C Curve
Arc Chute
24+
Years Manufacturing
5,700m²
Factory Floorspace
92Staff
TÜV Assessed Technicians
0.2%
Class Accuracy Linearity
100+
Global Export Markets
Technical Whitepaper: Electromechanical Principles of Rogowski Coil Current Sensors
In modern power electronics, the transition from traditional iron-core current transformers (CTs) to flexible Rogowski coil sensors represents a fundamental technological paradigm shift. Traditional ferromagnetic cores suffer from iron losses, hysteresis, narrow dynamic ranges, and severe magnetic saturation under high inrush currents or DC offset components. For mission-critical infrastructure in metropolitan hubs such as Tokyo, where switchgear cabinets operate at extreme density and electrical noise from variable frequency drives (VFDs) is prevalent, magnetic saturation causes distorted secondary waveforms, leading to dangerous tripping errors or degraded energy metering fidelity.
Our Tokyo-engineered Rogowski coil current sensors operate on the electromagnetic principle derived from Ampère's Circuital Law and Faraday’s Law of Induction. The coil consists of a helical winding of wire wrapped uniformly around a non-magnetic (air-core) toroidal former. The induced open-circuit electromotive force (EMF) $e(t)$ generated across the coil terminals is strictly proportional to the rate of change of the primary conductor's current:
Mathematical Governing Formulation:
$e(t) = -\mu_0 \cdot N \cdot A \cdot \frac{di(t)}{dt} = -M \cdot \frac{di(t)}{dt}$
Where $\mu_0$ is the permeability of free space, $N$ represents the turns density per unit length, $A$ is the cross-sectional area of each turn loop, and $M$ denotes the mutual inductance between the measured conductor and the sensing winding.
$e(t) = -\mu_0 \cdot N \cdot A \cdot \frac{di(t)}{dt} = -M \cdot \frac{di(t)}{dt}$
Where $\mu_0$ is the permeability of free space, $N$ represents the turns density per unit length, $A$ is the cross-sectional area of each turn loop, and $M$ denotes the mutual inductance between the measured conductor and the sensing winding.
Because the mutual inductance coefficient $M$ is inherently non-ferrous and constant across unlimited current amplitudes, our custom OEM Rogowski coils exhibit infinite theoretical dynamic range with zero core saturation. Whether sensing a nominal 50 A baseline current or an abrupt 100 kA lightning or short-circuit fault transient, linearity remains absolute (typically ≤ ±0.2% deviation across the rated span).
To reconstruct the primary current waveform $i(t)$, the differential voltage output must pass through an electronic integrator. Our factory integrates low-noise operational amplifiers paired with high-stability metal film resistor networks and drift-compensated capacitor banks. This active or passive integration stage provides a true proportional voltage output (e.g., 0-333 mV AC, 0-5 V RMS, or 4-20 mA DC through secondary processing), allowing seamless interfacing with digital power meters, IoT microcontrollers, and RTUs without altering breaker cabinet architecture.
| Performance Vector | Custom OEM Rogowski Sensor | Split-Core Iron CT | Hall-Effect Transducer |
|---|---|---|---|
| Magnetic Saturation | Zero (Pure Air-Core Architecture) | High Risk at Surge / DC Inrush | Moderate (Core Dependent) |
| Dynamic Measuring Range | 1 A to 100,000 A Continuous | Fixed Narrow Ratio (e.g., 500:5) | 10 A to 2,000 A |
| Frequency Bandwidth | 0.1 Hz to 1 MHz (Ultra-Broadband) | 45 Hz to 400 Hz Typical | DC to 50 kHz |
| Phase Shift Error | < 0.2° (With Digital Calibration) | 1.0° to 3.5° Dependent on Load | 0.5° to 1.5° |
| Weight & Form Factor | Ultra-light flexible loop (50-150g) | Heavy iron core (1.5kg - 10kg) | Rigid module (300g - 800g) |
| Installation Mechanism | Non-intrusive clip-around; zero downtime | Requires busbar disassembly or split gap | Cable feed-through or terminal break |
| Dielectric Isolation | Up to 10 kV AC RMS / 1 min | 2.5 kV to 3.0 kV Typical | 3.0 kV to 5.0 kV |
High-Density Infrastructure
Localized Application Scenarios in Tokyo & Japan
Precision-engineered to meet stringent Ministry of Economy, Trade and Industry (METI) electrical standards and Tokyo's ultra-dense urban infrastructure requirements.
Tokyo High-Rise Substation Retrofits
In Tokyo's premier commercial high-rises across Marunouchi, Roppongi, and Shinjuku, electrical risers and distribution shafts are engineered with minimal spatial tolerances. Power shutdowns for installing bulky iron-core CTs result in millions of yen in commercial disruptions.
- Flexible Rogowski coil loops feed through tight busbar gaps down to 8 mm clearance.
- Enables non-intrusive sub-metering upgrades without main breaker disconnections.
- Complies with Japanese fire prevention regulations and non-flammable cable jacketing.
Hyperscale Data Centers in Greater Tokyo
Data center clusters in Inzai (Chiba Prefecture) and western Tokyo require real-time Power Usage Effectiveness (PUE) tracking down to individual server rack taps, demanding precise phase angle fidelity for accurate active power (kW) and harmonic distortion calculations.
- Harmonic analysis capability up to the 50th harmonic order without signal clipping.
- Ultra-low phase displacement (≤ 0.15°) ensures true power factor calculation in IT loads.
- Compact DIN-rail transmitter modules interface directly with Modbus/BACnet gateways.
Railway Traction Power & Shinkansen Substations
Japan’s high-speed rail network demands current sensors capable of enduring rapid current gradient spikes ($di/dt$) exceeding several thousand amperes per microsecond during overhead catenary pantograph transitions and regenerative braking feedback.
- Air-core Rogowski structure eliminates risks of secondary high-voltage open-circuit hazards.
- Reinforced silicone encapsulation stands up to continuous mechanical vibration and shock.
- Fast response time (< 100 nanoseconds) suitable for high-speed protective relay tripping.
Market Intelligence & Evolution
Japanese Grid Modernization Trends (2025–2035)
How the shift toward distributed renewables, EV mega-chargers, and digitized distribution systems is driving Rogowski coil sensor adoption across the Kanto region.
Microgrid Inverter Harmonic Resonance
As Tokyo increases rooftop solar PV and commercial battery storage penetration under the Tokyo Metropolitan Government solar mandate, bidirectional power flows introduce complex multi-frequency harmonics that saturate traditional metering CTs. Rogowski technology provides linear wideband capture essential for modern anti-islanding relays.
CHAdeMO 3.0 & ChaoJi High-Power Charging
The rollout of ultra-fast EV charging hubs (150 kW to 350 kW) across the Tokyo Expressway corridors requires compact current transducers capable of handling massive ripple and switching noise generated by Silicon Carbide (SiC) and Gallium Nitride (GaN) power conversion stages.
Smart Substation Digital Twins
Tokyo Electric Power Company (TEPCO) grid zones are transitioning toward comprehensive predictive asset management. Digital twins require real-time current telemetry from thousands of distribution transformers where Rogowski sensors deliver direct digital mV data streams to local edge gateways.
Verified Supply Chain Superiority
Engineering Strengths: Tokyo Design Combined with Liushi Scale
By marrying Tokyo's rigorous precision design standards with our 5,700 m² TÜV Rheinland-verified smart manufacturing facility in Liushi, we deliver unmatched technical consistency and cost efficiencies.
01
Automated Helical Pitch Winding
Micro-controlled CNC winding machinery guarantees zero variation in coil spacing ($N$) and cross-sectional loop area ($A$), eliminating conductor positioning errors.
02
Thermal & Drift Stabilization
Every coil undergoes thermal pre-conditioning (-40°C to +125°C) to relieve winding internal mechanical stress, locking in a temperature coefficient ≤ 25 ppm/°C.
03
Dual-Shield Electrostatic Isolation
Equipped with 360-degree continuous copper-mesh electrostatic shielding to eliminate capacitive coupling from adjacent high-voltage busbars ($dV/dt$ immunity > 50 kV/μs).
04
Dielectric High-Pot Impulse Verification
Each unit is subjected to 5.4 kV AC insulation breakdown testing and 10 kV (1.2/50 μs) lightning surge impulse testing in accordance with IEC 61869-10 standards.
05
Precision Integrator Calibration
Active integrators are laser-trimmed to balance low-frequency gain offsets and phase angle delays, ensuring Class 0.2 and Class 0.5 revenue-grade compliance.
06
Traceable Export Audit & Barcoding
Serial-numbered test reports capturing linearity, mutual inductance value ($M$), and phase displacement are embedded with QR codes for Japanese customs and OEM tracking.
Procurement Intelligence
Frequently Asked Questions by Japanese & Global Engineers
Direct technical answers addressing standards compliance, integrator calibration, minimum quantities, and export logistics from our Tokyo operations team.
Do your custom Rogowski coils comply with Japanese Industrial Standards (JIS) and METI safety guidelines?
Yes. Our custom Rogowski sensors are engineered in full alignment with JIS C 8366 and IEC 61869-10 standards governing electronic current transformers. For insulation reliability, our outer jackets use flame-retardant, halogen-free UL94-V0 thermoplastic polyurethane (TPU) and high-grade industrial silicone capable of withstanding 5,000 V dielectric stress, ensuring hassle-free approval by Japanese electrical inspectors and certified third-party testing bodies.
How does your factory solve the conductor positioning error inherent to flexible Rogowski loops?
Conductor positioning sensitivity in inferior Rogowski coils stems from winding non-uniformity and imperfect closure at the coil junction clasp. Our factory overcomes this via automated high-density CNC pitch winding that maintains an absolute constant turns density ($N$) around the entire circumference. Furthermore, we deploy a patented magnetic return wire nested coaxially through the coil's core and a precision interlock connector clasp that guarantees near-zero flux leakage across the join, reducing conductor position error to less than ±0.5% anywhere inside the loop.
Can you configure custom output voltages, sensitivities, and integrator form factors?
Absolutely. We specialize in comprehensive OEM/ODM hardware customization. Our engineering team can configure coil loop lengths from 100 mm to 2,000 mm with coil diameters ranging from 15 mm to 600 mm. For the integration electronics, we offer both passive coils (calibrated mV/kA outputs directly interfacing with Rogowski-ready ICs) and active DIN-rail/PCB-mounted integrators providing standard 0-333 mV AC, 0-5 V RMS, 4-20 mA DC loop power, or high-speed RS485 Modbus RTU telemetry.
What is the Minimum Order Quantity (MOQ) and sample lead time for custom OEM prototypes?
To facilitate R&D prototyping and pilot batch validation for Japanese panel builders and power meter OEMs, our trial prototype MOQ starts at only 5 pieces for catalog Rogowski sensor models and customized coil lengths. Standard engineering evaluation samples are produced and dispatched within 5 to 7 business days. High-volume OEM production orders (up to 50,000 units/month) typically ship within 15 to 25 business days.
How do Rogowski coils perform in the presence of strong external magnetic fields from nearby busbars?
External field rejection is governed by the symmetry of the loop winding and the positioning of the return conductor. By feeding the return path back through the exact geometric center of the helical coil, our design cancels external stray magnetic fields induced by adjacent high-current phases (three-phase busbar crosstalk rejection is better than -45 dB). This ensures that three coils installed in parallel on a dense 400 V or 6.6 kV switchgear board operate without inter-phase mutual interference.
What export certifications and factory verification documents are provided with shipments?
All exported units carry CE compliance marking, RoHS 2.0 hazardous substance compliance declarations, and ISO 9001:2015 quality control traceability. Furthermore, our manufacturing facility has undergone thorough on-site verification by TÜV Rheinland, with formal supplier assessment reports available upon request. Routine test certificates, insulation test logs, and phase displacement curves are packaged with every export crate.