I. Structure of the Temperature Rise High Current Generator
The structure design of the temperature rise high current generator focuses on three core goals: “stable output of high current, precise monitoring of temperature rise, and ensuring the safety of the test”. Depending on the output capacity and usage scenarios, it is divided into integrated and split types. The core components are the same, including the following four parts: each module works collaboratively to ensure the stability and accuracy of the test process.
(1) Core Power Unit
The core power unit is the main component for generating high current in the equipment. It consists of a current booster transformer, a voltage regulator, and a power compensation module. The current booster transformer serves as the core for energy conversion, using low-loss silicon steel sheet cores and large cross-sectional copper wires for winding. The primary winding has a large number of turns, high voltage, and small current, while the secondary winding has very few turns (usually 1-5 turns), low voltage (generally ≤10V), and extremely high current. Through electromagnetic induction, it realizes the reverse conversion of voltage and current, being the key carrier for high current output. The voltage regulator is divided into self-coupled voltage regulator and thyristor voltage regulator, used for smoothly adjusting the input voltage to the primary winding of the current booster transformer, thereby achieving stepless adjustable output of high current and avoiding current shock to the tested equipment. The thyristor voltage regulator is more suitable for high-precision and automated control scenarios. The power compensation module is used to compensate for line losses during the test, ensuring the stability of the output current, especially suitable for long-term continuous test scenarios.
(2) Temperature Control Monitoring Unit
The temperature control monitoring unit is the exclusive core module for temperature rise tests. Its main function is to real-time collect and record the temperature data of key parts of the tested equipment, providing precise basis for temperature rise determination. This unit is composed of a multi-channel temperature inspection instrument, temperature sensors (mainly thermocouples and platinum resistors), and a data recording module. The temperature inspection instrument usually supports 8-24 channels and can simultaneously monitor multiple heat-generating key points of the tested equipment, such as contacts, busbars, and cable connectors. The temperature measurement range is 0-200°C, with an accuracy of ±0.1°C. Some high-end equipment can be equipped with an infrared thermal imager for non-contact observation of the entire temperature distribution, enabling intuitive capture of hotspots. The data recording module can store temperature and current data in real time, automatically draw temperature rise curves, and facilitate data traceability and analysis after the test.
(3) Control and Protection Unit
The control unit is responsible for the overall operation control of the equipment, divided into manual control and intelligent control modes. The manual control mode adjusts current and sets test time through the knobs and buttons on the operation console, suitable for simple test scenarios. The intelligent control mode integrates PLC and industrial control computer, supporting preset test parameters, automatic current boosting, constant temperature maintenance, and automatic shutdown, enabling unmanned test scenarios, and also having data export and report generation functions, suitable for high-standard test requirements. The protection unit is the key to ensuring test safety, featuring overcurrent, overvoltage, overtemperature, zero-start interlock, and phase failure protection functions. When the output current, temperature exceed the set threshold, or the equipment encounters abnormal working conditions, it can quickly cut off the power supply to prevent equipment damage and safety accidents. Some equipment also has fault recording function, providing a basis for abnormal analysis.
(4) Auxiliary Structure Unit
The auxiliary structure unit varies according to the type of equipment: the integrated type integrates all units into one cabinet, small in size and light in weight, equipped with wheels, facilitating on-site mobile testing, suitable for small capacity (≤5000A) test scenarios; the split type separates the control operation console from the current booster transformer, with the current booster transformer designed separately, having better heat dissipation performance, suitable for large capacity (≥10000A), long-term continuous test scenarios, facilitating heat dissipation and on-site layout. In addition, the equipment is equipped with dedicated output terminals, connection lines (large cross-sectional copper bars or special cables), grounding devices, etc., to ensure the stability of current transmission and the safety of the test. The grounding resistance should be ≤ 4Ω to avoid ground potential surges.
II. Working principle of the temperature rise large current generator
The core working principle of the temperature rise large current generator is based on the laws of electromagnetic induction and energy conservation. Essentially, it simulates the actual operating conditions of the tested equipment through a closed-loop process of “voltage regulation – current increase – temperature monitoring”. The specific working process is divided into three stages, and the core logic is to achieve stable output of low voltage and large current and precise collection of temperature rise data.
(1) Voltage regulation stage
After the equipment is connected to the AC 220V/380V industrial power supply, the voltage is regulated by the voltage regulator. According to the test requirements, the voltage regulator smoothly regulates the input voltage to an appropriate range and transmits it to the primary winding of the current-increasing transformer. The core purpose of this stage is to indirectly control the secondary current size by adjusting the primary voltage. Using stepless voltage regulation technology, it can avoid sudden changes in current causing impacts on the tested equipment and the generator itself, ensuring the smoothness and stability of current regulation. Some equipment uses IGBT inverter technology or thyristor voltage regulation to further improve the voltage regulation accuracy and response speed.
(2) Current-increasing stage
The current-increasing transformer realizes current amplification based on the law of electromagnetic induction (I₁N₁ = I₂N₂, where I₁ is the primary current, N₁ is the primary turns, I₂ is the secondary current, and N₂ is the secondary turns). Since the primary turns of the current-increasing transformer are much more than the secondary turns, the secondary current I₂ can be calculated as I₂ = I₁ × (N₁/N₂) through the design of the turn ratio. This stage converts the small primary current into a large secondary current. For example, when the primary turns are 1000 and the secondary turns are 1, and the input primary current is 10A, the secondary can output a large current of 10000A, meeting the test requirements of different tested equipment. At the same time, the power compensation module compensates for line losses in real time to ensure the stability of the output current ≤ 0.2%, with a waveform of standard sine wave and total harmonic distortion THD ≤ 1%, avoiding the influence of electrical loss on the test results.
(3) Temperature rise monitoring and stabilization stage
The tested equipment is connected to the secondary output terminal of the current-increasing transformer, and a temperature sensor is attached to the key heat-generating points of the tested equipment (such as contacts, busbar joints, windings, etc.). The temperature inspection instrument collects the temperature data of each measurement point in real time and transmits it to the control unit. During the test, the control unit continuously monitors the output current and temperature data, maintaining a constant current until the temperature of the tested equipment reaches a stable state (industry standard: each hour’s temperature rise ≤ 1K is considered temperature stability). During this process, if the temperature or current exceeds the set threshold, the protection unit will immediately activate, cut off the power supply, ensuring the safety of the test; intelligent control-type equipment can simultaneously record the curves of temperature and current changes over time, automatically determine whether the test is qualified, and generate a standardized test report, adapting to relevant detection requirements.
It should be particularly noted that the core feature of the temperature rise large current generator is the “long-term continuous working mode”, which can work continuously for 4-8 hours or even 24 hours, with strong heat dissipation capacity and precise temperature control system, ensuring the stability of the test over a long period.
Post time: May-06-2026