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MCB long time thermal calibration bench
MCB long time thermal calibration bench for overload testing per IEC 60898‑1. Multi‑station (4‑16), high‑stability current (0‑500A, THD<3%), timing accuracy ±0.1%, data logging. Ideal for MCB production QC, type testing, and R&D. Customizable for 6A‑125A.
Professional MCB Long‑Time Thermal Calibration Bench
Long-time thermal calibration for MCB in the Bus Mould case.
The Long Time Thermal Calibration Bench conforming with IEC 60898-1 provides a professional testing tool to performed to verify the thermal (long-delay) tripping characteristics of Minature Circuit Breakers (MCB) and assess their ability to trip correctly within a specified time range when tested with overload currents that are below the instantaneous levels (1.13×, 1.45× In).
The Long Time Thermal Calibration Bench provides the capability to simulate long time duration overload current conditions at precise control of test current, time and temperature influences, all resulting in stable and repeatable results. Therefore, it is ideal for use as part of a routine type testing process, within a production line sampling basis, or for laboratory verification purposes.
With the modular layout of the system, multiple MCB’s can be tested at the same time (multi-station). Each station has its own constant current supply (up to 500A per station, true RMS), a precision timer (precision +/- 0.1%) and independent pass / fail indication. There are built-in safety features (overload, overtemperature, short circuit) and data recording to ensure reliability. There are optional temperature monitoring and MES Data Export. Most common applications for use are MCB manufacturing QC, certification laboratories and R&D validation.
Standard delivery: 30-45 days | Multi‑station parallel test | Data logging & safety protection
What is an MCB Long‑Time Thermal Calibration Bench?
An MCB long term thermal calibration bench is the specialized test rig to verify the overload trip characteristics of miniature circuit breakers by applying a stable, overload current at a set value (normally 1.13 x In for no trip check and 1.45 x In for trip test), for a defined duration (seconds to hours) and measuring the exact trip time. Unlike instantaneous magnetic testers, the thermal calibration test bench utilises the bimetal thermal trip element, which has a trip phenomenon which is dependent upon the magnitude of the current, the ambient temperature and the duration of the test. The bench is equipped with a constant current source with a low waveform distortion (
Test 4‑16 MCBs simultaneously for high throughput.
Up to 500A per station, accuracy ±1%, THD <3%.
Timing range 1s – 9h 59min, accuracy ±0.1%.
Automatic recording, overload/over‑temp protection.
Test Process & System Features
Technical Specifications
| Power supply | AC 220V ±10%, 50Hz |
|---|---|
| Air supply pressure | 0.2 – 0.8 MPa (for pneumatic clamps, optional)– |
| Rated power per station | 1 kVA (standard)– |
| Maximum output current per station | Up to 500A (configurable, true RMS)– |
| Current display range | 0.01 – 500A (true RMS value)– |
| Time display range | 1 second – 9 hours 59 minutes 59 seconds– |
| Timing accuracy | ±0.1% of reading– |
| Overall measurement accuracy | ±1.0% (current)– |
| Waveform distortion (THD) | < 3%– |
| Insulation resistance | > 10 MΩ– |
Core Technical Advantages
Multi‑station parallel testing
The modular design allows 4‑16 independent test stations, each with its own current source and timer. This drastically reduces per‑unit test time and increases throughput – essential for high‑volume MCB production lines.
Exceptional current stability & low distortion
The constant current source delivers stable output over long test durations (drift <2% over 8 hours) with total harmonic distortion below 3%. This ensures accurate bimetal heating and repeatable trip times per IEC standards.
Comprehensive safety & data management
Built‑in overload, over‑temperature, and short‑circuit protection automatically cut power in fault conditions. The data recording system logs trip time, test current, and pass/fail status for each station, enabling SPC analysis and quality traceability.
User‑friendly control & flexible test profiles
The HMI touch screen allows programming of test current, trip time windows, and pre‑test dwell times. Operators can run standard 100% / 135% In sequences or custom profiles for R&D. One‑key start for routine QC tests.
Customer Success Story – MCB Manufacturer
Due to inconsistent thermal trip calibration, a top manufacturer of MCBs had high levels of rework. The old calibration bench had a very unstable current (drifting over 5%) and contained only one testing position. When Benlong delivered an 8-station long-term thermal calibration bench with closed loop current control and data logging to them, this was their result after doing so for three months.
The bench paid for itself in 9 months and passed IEC audit with full traceability records.
Applications and Integration
Custom Engineering & Delivery
Request a Custom MCB Long‑Time Calibration Bench Quote
Our engineers will build a testing bench based on your MCB specifications (current ratings and test volume) using the best combination of testing locations per product, current range, and data logging – also including an ROI analysis.
WhatsApp: +86 150 5837 0007 | Email: xsb@benlongkj.cn | English & Chinese support
Why Choose Benlong for MCB Calibration Benches?
- 15+ years designing thermal calibration equipment for MCB manufacturers
- Proven high‑stability current sources (drift <2% over 8 hours, THD <3%)
- Multi‑station parallel testing (4‑16 stations)
- ±0.1% timing accuracy, ±1% current accuracy
- Full data logging & safety protection
Standard Bench Includes
Constant voltage source, 0 to 500 Amps per station; Multi-station Test Stand; HMI Touch Screen Control; Digital Timers with accuracy +/- 0.1%; Data Collection Software; Overload and (or) Over Temperature Protection; Calibration Certificate Included; 1 Year Warranty.
Frequently Asked Questions
Generally at 100 percent, or 135 percent for trip time and no-trip verification per data bus protocol, of the rated current for the current transformer under test. Bench also accommodates custom test currents for R&D and custom test procedures as required.
The standard arrangement is: 4, 8, 12, or 16 independent stations, each with a current source and timer, allowing for parallel testing capabilities.
Yes, it is possible to add an optional ambient temperature sensor to the system. Additionally, you have two options for testing: you could either have your temperature-dependent memory testing automatically update based on temperature measured from the optional ambient temperature sensor, or you could place your system inside of a climate chamber.
The industry standard bench will accommodate MCB (miniature circuit breakers) for up an electrical current of 125 amps. For MCCB (molded case circuit breakers/greater capacity/bigger frame) breaker’s, we have developed an individual MCCB long‐time thermal calibration bench with the ability to support up to 1600 amps.
The test will run for 1 hour (no trip) at 100% In, and at 135% In, the trip times are usually between 45 – 55 sec. These sequences can be run automatically by the bench.
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